Moparts
Torsion bar size: How big is TOO big?
Posted By: Kern Dog
Torsion bar size: How big is TOO big? - 01/01/15 12:10 AM
I realize that feel is a subjective thing, but at what point do these 1.12 and larger T bars start to make the cars feel too tightly sprung?
I thought that I was doing well with the 1.0 bars in my car. I have a 70 Charger with an aluminum headed 440/493. Aluminum radiator, intake, TTI headers do shed weight as compared to factory stock. The battery is in the trunk. It rides nice, not too firm. I don't notice excessive brake dive. I have a custom 1.25 front sway bar with urethane bushings. The rear is MP XHD leafs with a 7/8" sway bar using rubber end links to reduce the slight oversteer the car had with the tighter urethane bushings. I've ran without the rear bar to reduce oversteer but I didn't like the extra body roll.
I understand that to reduce understeer, the rear needs more roll stiffness via bigger sway bar or stiffer leaf springs. Conversely, to reduce oversteer the front needs more spring rate or a bigger sway bar. The 1.25 is about as big as I can fit in there without touching the K member, so that leaves me with larger Torsion Bars.
The 1.12 and 1.15 ones from Bergman come at a decent price. My car went from .88 to 1.0 when I went from the 318 to the first 440 I had. It wasn't a direct comparison in terms of ride quality since I added weight to the car. As the car sits now, I'd expect the jump from 1.0 to 1.12 or 1.15 to be quite noticeable.
Mopar Mitch often chimes in to say ..." Make the switch to the big bars. You will not regret it". Thatis probably true in the case of an autocross car but what about a car like mine? I may autocross someday but I also drive on mediocre California roads. I had stiff springs in a 76 Camaro that would sometimes skip and skitter over rough roads, often understeering as the front bounced over the cobble like asphalt. I don't want to spend $300 to have a rough riding car that handles worse.
Opinions?
Posted By: cudazappa
Re: Torsion bar size: How big is TOO big? - 01/01/15 02:04 AM
Hotchkis has bars in 1.10" range. They've found that's the best compromise in ride and handling. They use their 1.25" hollow sway bar.
I run 1.18" with an aluminum headed small block and 1.125 solid sway bar. Next change in my front end is to go to better shocks and the hotchkis front sway. Currently my car oversteers a bit. The Bilstein Shocks feel to be beyond the limit of the torsion bars. The ride is stiff. Not skip across the road stiff, though.
Another thing to consider is fatigue of the chassis with stiff bars. The unibody can become the spring and that will stress all the hundreds of spot welds.
I used to run the 1" bars and found them much better than stock, but still soft. My jump to 1.18" was a vast improvement and right now, I don't want to go to 1.22".
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/01/15 02:34 AM
IMO, you can't over spring a t-bar suspended mopar. However, you can certainly under shock it.
So previously, you stepped from .88 to 1, or a 22% increase. You also went from a 318 to a 440, or another 22% increase. Almost a net zero situation. Taking 50# off the engine for the aluminum bits, you still increased weight 15-17%, so as a percentage, you only realistically stepped up the wheel rate 5%, but you added a rear sway bar and ended up with a slight oversteer. Moving from 1 to 1.12 will step it up another 11% for about a 16% increase in total from where you originally started, so you may put yourself in a slight understeer position relative to where you are at now with the rear sway bar. So you may be able to swap back to the urethane bushings for the rear bar to level things out.
Given the way you like to dial things in, I'd almost wonder if a conversion to a splined tubular sway bar wouldn't be the better choice. Open up the K frame some(its not as strong as you might think) to allow up to 2.5" and pick up the pieces for a splined kit. Odds are you could put on together one for around $200. Swapping out the splined bar for more precise rates could be done for as little as $100, maybe less if you shop for used ones. Plus the options for end links may prevent any potential tire interference issues.
Posted By: PHJ426
Re: Torsion bar size: How big is TOO big? - 01/01/15 03:45 AM
After ducking under the suspension and really putting an eye ball on the torsion bar size in my Suburban.....I gotta measure thise.
After seeing that I kinda see what TC means. That and my Suburban came stock with 46mm Bilstein shocks and yes it handles well.
So Im thinking 1.24" for the Challenger
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/01/15 04:19 AM
I have welded frame connectors, torque boxes and a welded k member in the car, so chassis flex should be less than it was when new. Currently the LCA bumpstops are about 5/8" to 3/4" from the frame. They do bottom when I drive on bumpy roads. A stiffer T bar would surely reduce that.
I have KYB Gas-a-Just shocks on the car. Many people bad mouth them but I have no complaints. I've said that I'll switch to Bilsteins but the only time I think about it is when I'm on this forum!
Posted By: feets
Re: Torsion bar size: How big is TOO big? - 01/01/15 04:23 AM
The Gas-A-Just shocks are the pieces that are hard to start moving but a bit soft afterwards.
A better shock would make a notable difference.
Posted By: AndyF
Re: Torsion bar size: How big is TOO big? - 01/01/15 04:26 AM
The realationship to watch is between spring rate and car weight (sprung weight). As the spring rate increases the natural frequency of the suspension goes up. If that frequency gets too high then the car becomes unpleasant to drive. The high frequency "jiggles" give me a headache but they cause other problems for other folks.
If the spring rate/car weight ratio is too low then the car feels like a boat.
You typically don't want to get the natural frequency of the suspension much over 1 Hz for a street car. You can go a little higher if you're willing to buy really good shock absorbers.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/01/15 09:12 AM
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The realationship to watch is between spring rate and car weight (sprung weight). As the spring rate increases the natural frequency of the suspension goes up. If that frequency gets too high then the car becomes unpleasant to drive. The high frequency "jiggles" give me a headache but they cause other problems for other folks.
If the spring rate/car weight ratio is too low then the car feels like a boat.
You typically don't want to get the natural frequency of the suspension much over 1 Hz for a street car. You can go a little higher if you're willing to buy really good shock absorbers.
I know that I have read about this before but I'm not sure how to deal with it. The mention of "suspension motion frequency" confuses me! 
Posted By: MuuMuu101
Re: Torsion bar size: How big is TOO big? - 01/01/15 09:17 AM
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The realationship to watch is between spring rate and car weight (sprung weight). As the spring rate increases the natural frequency of the suspension goes up. If that frequency gets too high then the car becomes unpleasant to drive. The high frequency "jiggles" give me a headache but they cause other problems for other folks.
If the spring rate/car weight ratio is too low then the car feels like a boat.
You typically don't want to get the natural frequency of the suspension much over 1 Hz for a street car. You can go a little higher if you're willing to buy really good shock absorbers.
I know that I have read about this before but I'm not sure how to deal with it. The mention of "suspension motion frequency" confuses me!
If you click "Attachment" I've inputted a small document that allows you to calculate wheel rate according to frequency. As far as frequency goes, I'm trying to think of a really good example...
Posted By: AndyF
Re: Torsion bar size: How big is TOO big? - 01/01/15 06:07 PM
Search for "Torsion Bar Tango". It is an old article that I wrote a long time ago. It needs to be updated with pictures and illustrations but if you can wade thru it you'll get a handle on how to calculate the natural frequency for a Mopar front suspension.
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/01/15 08:01 PM
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I know that I have read about this before but I'm not sure how to deal with it. The mention of "suspension motion frequency" confuses me!
That is something you can get into as you get more in depth with information and wish to better understand all the interactions of the systems. Its not a prerequisite to setting up your car now.
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As far as frequency goes, I'm trying to think of a really good example...
A porpoising drag car is a good example of when frequencies are harmonized instead of complimentary.
I've also heard of guys setting up their cars with brand new, wiz bang, 300 different setting double adjustable shocks that do not understand the frequency situation and set all four shocks to identical settings. The net result a car that porpoises anytime it hits a highway expansion joint and produces a ride that is scary at anything over 50 mph.
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Search for "Torsion Bar Tango". It is an old article that I wrote a long time ago. It needs to be updated with pictures and illustrations but if you can wade thru it you'll get a handle on how to calculate the natural frequency for a Mopar front suspension.
This is an excellent starting point for a performance street set up. It can be found on Andy's AR Engineering site.
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After ducking under the suspension and really putting an eye ball on the torsion bar size in my Suburban.....I gotta measure thise.
After seeing that I kinda see what TC means. That and my Suburban came stock with 46mm Bilstein shocks and yes it handles well.
So Im thinking 1.24" for the Challenger
Yes, but don't forget the Suburban bars are also longer and supporting more weight, which supports the numbers in Andy's frequency article.
The origin of my comment is the fact that a 1.22 t-bar for a pre '72 B body is just shy of 400# of wheel rate. In Brand C cars, this equates to an 800# coil spring. Most street performance cars of this make are running spring rates that are starting at 600# and running upwards to 800#. Some competition cars are stepping up beyond that into the 1000# range. So the best we can ever hope to achieve with our mopars is very high end street performance.
One possible saving grace of all this is the current trend towards softer springs and bigger bars that would play into these lower available t-bar rates out there. However, these arrangements require infinitly more shock control than what is currently being offered in bolt on shocks for our mopars and would most likely require some specialized valving in a custom set up. They also need additional suspension travel, which would lead to rising ride heights , which doesn't always look great.
I think the reality in performance mopar handling is that we are ending up with moderate spring rates with moderate anti-sway rates and some pretty good shock options. This is where the Hotchkis development has landed with the best overall street/performance package. The old XV was there with their Level 1 packages before they folded. Copying either of these will lead to ver good results. Personal preference and application can also allow for adjustments up or down on the available rates out there.
Posted By: PHJ426
Re: Torsion bar size: How big is TOO big? - 01/01/15 09:50 PM
Unfortunately it appears the aftermarket companies that sell torsion bars and swaybars stay away from answering these questions about suspension frequency and weight transfer etc etc I suppose they figure it gives away some of their engineering.
Check this place out I have posted this here a while back and for some reason the general population doesn't understand that their is science and engineering behind these facts...but then again most on this site (not likely visitors to this section of Moparts) feel the engineering put into Chrysler products to be superior when in fact these are production cars sold to the masses that were figured to be traded in within 5 years back in the day to do duty as second hand or work cars.
fast forward to today most here are trying to improve the handling of their old Mopar to more compliant and enjoyable status vs the old "dial a rotary phone steering and boat ride quality"
Here is what I have found on Suspension frequency and weight transfer
http://www.racing-car-technology.com.au/index.htmhttp://www.racing-car-technology.com.au/Street%20and%20Track%20index.htmhttp://www.racing-car-technology.com.au/wgttransex.htmhttp://www.racing-car-technology.com.au/What%20you%20will%20know.htm
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 01/01/15 10:14 PM
Another "issue" I see with going big in T-bar diameter is it kills weight transfer and forward bite. The bigger the front bars, the less "effective" front suspension travel you will have. This is where we are at a disadvantage over coilovers IMO. Any BIG bar guys know what im talking about for example, jack the front of the car off the ground and look at how much suspension travel you have downward from where the adjusters actually touch their pads, this is travel lost in real world driving.
Posted By: jcc
Re: Torsion bar size: How big is TOO big? - 01/02/15 12:24 AM
"Another "issue" I see with going big in T-bar diameter is it kills weight transfer and forward bite."
Huh? You lost me.
In my world, in a balanced set-up, any weight transfer is less then ideal, why would that be an issue?
Posted By: PHJ426
Re: Torsion bar size: How big is TOO big? - 01/02/15 12:51 AM
TC so I agree with a nose heave E body with an RB engine a 1.22" bar would put your wheel rate in line with some performance oriented cars. Tuning the shocks for this duty is required along with selecting the proper sway bar rate.
What kind of spring rate would you couple with this for the rear leaf spring package/shock as well as sway bar rate for a car that is driven to a local road course event .... a true road and track car. This would be in a RB powered E body that has not been lightened up much so around 3800# wet without driver.
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 01/02/15 01:16 AM
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"Another "issue" I see with going big in T-bar diameter is it kills weight transfer and forward bite."
Huh? You lost me.
In my world, in a balanced set-up, any weight transfer is less then ideal, why would that be an issue?
Im not surprised I lost you LOL! Forward bite is mostly tuned in the rear geometry so that statement doesn't make sense. The bigger the bar the less stored energy is there to assist front end rise under HARD excelleration and put some weight on the rear tires. Big torsion bars require very little preload at the adjusters to achieve ride height. I know on a track car front end rise or dive is, in a perfect world, little to non existent but guess what, it is there trust me. I haven't measured my car with it off the ground how much extension travel I have from ride height to the adjuster being loose but it isn't near as much as it was with .890 bars. In some cases with the bars being big the only travel you have is UP or compression that has ANY spring rate involved. Does any of THIS make sense?
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/02/15 03:44 AM
It seems like you are touting some implied benefit of a front to rear weight transfer. This is important in drag racing but I see little benefit in a street and road course car. If the front lifts and the rear squats on straight line acceleration, that is fine. If the same conditions occur when powering through turns, your steering geometry just changed and you either understeer MORE or oversteer and spin.
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:13 AM
Ok so I must be the only one that notices what a Nascar is actually doing at Martinsville? Im only relaying what I KNOW about my own car and the changes going from a .890 to a 1.06 in MY A body is my example. Some of you guys act clueless about what your suspensions are doing when you're beating the livin sh!t out of them. How big is to big you asked? From what EVERYBODY has said 100 times on B and E bodies, you cant go to big for good handling on those cars because the hexes are not big enough.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:28 AM
Nascar?
Who am I ? Ricky Bobby? I just wanna go fast! I see Nascar as something totally foreign. The stuff they use is so far removed from our stuff I see very little that we can learn from as it applies to a torsion bar and steering box car.
I have the 1.03s in my 360 67 Dart. That car rides fine. I guess with the B body torsion bars being 4 inches longer, it can be said that the wheel rate of a B body 1.12 isn't much different?
The Firm Feel site lists an A body 1.0 as a 195 WR, and the 1.06 as having a 252 WR.
The B body 1.12 shows a 275 WR so yes, that is a bit more. Not too much though I'd guess.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:36 AM
I forgot that the A body LCAs are 1/2" longer than the B body LCAs. That sorta negates some of the difference between 37" and 41" t-bars.
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:40 AM
If you're considering between the 1.12 and 1.15 that Peter is selling, I would go 1.15's at the drop of a hat on your Charger. If I had my dream car, 70 Cuda, the 1.12's might be a better match. But a B-body? 1.15's and it will go FAST!
Posted By: MuuMuu101
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:45 AM
Also take into consideration, an A and B body torsion bar of the same diameter have different spring rates due to the length. The shorter the bar for the same diameter, the higher the spring rate.
Posted By: Supercuda
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:53 AM
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I forgot that the A body LCAs are 1/2" longer than the B body LCAs. That sorta negates some of the difference between 37" and 41" t-bars.
Wheel rate is wheel rate. If the wheel rate is given then LCA length has already been taken into account.
Posted By: PHJ426
Re: Torsion bar size: How big is TOO big? - 01/02/15 05:38 AM
Need C body Hexes in them E bodiesssssssss
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/02/15 05:42 AM
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What kind of spring rate would you couple with this for the rear leaf spring package/shock as well as sway bar rate for a car that is driven to a local road course event .... a true road and track car. This would be in a RB powered E body that has not been lightened up much so around 3800# wet without driver.
In this situation, it depends on what, if any, rear anti-sway bar is used. With no rear bar, 175#, with a body hung .75" bar 155#, with a 1" axle hug bar, 135#. This should at least get you in the ball park where you can then use tire size, pressure, or rear bar adjustments to dial things in closer.
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/02/15 05:46 AM
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I forgot that the A body LCAs are 1/2" longer than the B body LCAs. That sorta negates some of the difference between 37" and 41" t-bars.
Wheel rate is wheel rate. If the wheel rate is given then LCA length has already been taken into account.
Unless you put A body arms under your B/E body. That you got some ciferin' to do.
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/02/15 07:00 AM
RE: weight transfer - vehicles always transfer weight in dynamic motion. Putting heavier or lighter springs in does not change that. What heavier springs do allow is to lower the ride height without suffering the same bottoming of the suspension during this weight transfer. This lowering allows us to alter some of the geometry that helps reduces dynamic weight transfer through the roll centers. It also keeps suspension travel in a narrower range to minimize dynamic suspension changes that less than ideal component geometry can introduce.
Posted By: TC@HP2
Re: Torsion bar size: How big is TOO big? - 01/02/15 07:03 AM
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Need C body Hexes in them E bodiesssssssss
Yeah, then you could step up to 1 3/8" bars and definetly overspring your E body.
Interestingly enough, the earlier B bodies, despite their size, are much lighter than E bodies. I'm always amazed how heavy E bodies really are.
Posted By: brads70
Re: Torsion bar size: How big is TOO big? - 01/02/15 04:03 PM
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Given the way you like to dial things in, I'd almost wonder if a conversion to a splined tubular sway bar wouldn't be the better choice. Open up the K frame some(its not as strong as you might think) to allow up to 2.5" and pick up the pieces for a splined kit. Odds are you could put on together one for around $200. Swapping out the splined bar for more precise rates could be done for as little as $100, maybe less if you shop for used ones. Plus the options for end links may prevent any potential tire interference issues.
In my next iteration chassis wise I'll be using Schroeder hollow splined sway bars and arms. They are a little more pricey than $200 for a "kit" but....
I have a set of arms and a few different diameters to try and lots more are available.
I currently have A-body LCA's(3/16" longer than E/B-Body's) and 1.120" FF torsion bars. I don't see C-Body sized torsion bars being beneficial to cars that run on the street most of the time. A strictly race car ok, but not a street car. Unless you have a cage and spend a lot of time and effort bracing the entire chassis the whole car becomes a torsion bar when you go too big. How big is too big? I don't know?
I'm think really big torsion bars are a bandaid solution to the poor geometry built into our cars. All your really doing is limiting the suspension travel and making a go cart out of it? Like others have said you will end up breaking spot welds etc... Sure the car will handle better than stock but only because your not letting the suspension travel and that will make for a horrible street car ride I would imagine? If that's what your after why not just make the suspension bump stops taller?
I'm no "expert" but I'd rather work on the geometry , shocks, and sway bars instead of trying to " limit/eliminate" suspension travel.
IMO bigger/biggest is not always better, leave that stuff in Hotrod magazine where it belongs or to the snake oil salesman trying to sell you the latest parts ?
What size you choose has to do with the application. If your building a high banked superspeedway car sure you will need C-Body sized torsion bars. If your occasionally autocrossing and mainly street driving then I'd say Firm Feel has us all covered . Variables such as engine weight etc. will determine what's best .Every car/combo will be different. I get the feeling some people think I'll just bolt in "this" size torsion bar and my car will handle on rails. I've found it's not just one part, it's the combo of parts and again every car combo/weight will be slightly different. I chose a T-Bar that will allow 2-3" of travel.My theory/idea is to control/improve what happens in 2-3" of suspension compression , the rest is secondary. It's always a compromise, there is no free lunch as they say.
Posted By: PHJ426
Re: Torsion bar size: How big is TOO big? - 01/02/15 11:01 PM
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Need C body Hexes in them E bodiesssssssss
Yeah, then you could step up to 1 3/8" bars and definetly overspring your E body.
Interestingly enough, the earlier B bodies, despite their size, are much lighter than E bodies. I'm always amazed how heavy E bodies really are.
All them crash beams in the doors and other federally mandated do dads add up the weight fast over the 8 years from 1962 to 1970.....
Posted By: Dan@Hotchkis
Re: Torsion bar size: How big is TOO big? - 01/02/15 11:40 PM
Its a good thing there is a company out there that sells a balanced package for these cars !
But on a side note, I lowered my front and rear spring rates on the Road Runner, from a 1.18 front to the 1.10 while the shock program was in development. really like the dynamic feel of the car when we went to the lower rate and better shocks. I'm not a super fan of a car used for daily driving that feels like a rollerskate with a big block. Gets a little hairy to drive in adverse conditions too.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 01/03/15 01:02 AM
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Its a good thing there is a company out there that sells a balanced package for these cars !
But on a side note, I lowered my front and rear spring rates on the Road Runner, from a 1.18 front to the 1.10 while the shock program was in development. really like the dynamic feel of the car when we went to the lower rate and better shocks. I'm not a super fan of a car used for daily driving that feels like a rollerskate with a big block. Gets a little hairy to drive in adverse conditions too.
I do appreciate the efforts made by the Hotchkis company. They apparantly do take a lot of guesswork out of the equation.
Before the Charger, I spent years in a 70s Camaro. That car ingrained in me a frugal nature of picking up stuff cheap. If something didn't work, I tried something else and still came out dollars ahead.
I bought my Charger in March 2000. Back then we had limited choices, at least I thought we did. I thought the 1.0 bars were a good pick since I didn't have a Moparts Cornering/Handling forum to consult. I'm in the minority of the Mopar crowd, a guy that prefers a good handling classic instead of a straight line drag car.
If I were to start from scratch, the Hotchkis TVS would be a great way to go. I have no real complaints about the car as it sits except that I have to be careful to avoid entering a corner too hot for the risk of oversteer. Drifting is fun when nobody else is around but I surely do not want to slide into someone because the car gets tail happy.
Posted By: astjp2
Re: Torsion bar size: How big is TOO big? - 01/03/15 01:14 AM
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Its a good thing there is a company out there that sells a balanced package for these cars !
But on a side note, I lowered my front and rear spring rates on the Road Runner, from a 1.18 front to the 1.10 while the shock program was in development. really like the dynamic feel of the car when we went to the lower rate and better shocks. I'm not a super fan of a car used for daily driving that feels like a rollerskate with a big block. Gets a little hairy to drive in adverse conditions too.
OK Dan, how does the corner weights of the front affect the handling, I have a world block (read: real heavy!) 4 core brass radiator, etc...would the extra weight prefer a higher torsion bar rate than a small block with aluminum heads, all things being equal? Tim
Posted By: Pale_Roader
Re: Torsion bar size: How big is TOO big? - 01/03/15 12:08 PM
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Need C body Hexes in them E bodiesssssssss
Yeah, then you could step up to 1 3/8" bars and definetly overspring your E body.
Interestingly enough, the earlier B bodies, despite their size, are much lighter than E bodies. I'm always amazed how heavy E bodies really are.
Although right now my favorite site is down so i cant link actual proof, i'll still have to disagree with you. Unless you are talking pre-65 B-bodies, the E platform is still lighter. I am (always) talking on a base to base model comparison. The B's you saw driving down the road in the mid to late 60's generally were lighter than the E's you saw driving around in the early 70's, but this is misleading. The average options checked off/ordered was certainly less in the late 60's, just the same in the 70's everyone was wanting to look the part and play the part (even if in fact they weren't) and more options got checked. Early B's were more likely to have smaller engines, and there was less to those engines, and really, to every part ov the car. Safety mandates were only half the story.
The reality is, that if you took a bone-stock and ZERO-optioned 70 E-body and compared it to the same 65-68 B-body, it WILL be lighter. But no one wants to drive around in a 6cyl 3speed, 7 1/4" Challenger with no power options, 14x5" wheels and no sway bars (trust me, i have exactly this... its no fun). They want Hemi-everything (save the actual Hemi, but lets jam a 700lb 440 and a Dana 60 in there anyways) and every option.
For a starting point, weight-wise a 70 E-body (preferably a Barracuda) is the best starting point for a mid-sized Mopar race car. They get noticeably heavier with every single year, just like the B-bodies did. A 65 is going to be way lighter than a 70 B, everything else being equal.
I am always amazed at how heavy people let their E-bodies get. A 3800lb Challenger is goddamn ridiculous. Worse, is that the heavier they get the more that weight seems to find itself over the front end. My stock 3000lb 70 still has an appalling frt/rr bias, but it just seems to get worse from there for most builders (not all). Hard for it not to... most ov the fun stuff goes up front.
Another question is, do you really want to 'fix' the handling ov a way front-heavy E-body with stronger T-bars? Before jacking that front rate further, i'd do everything in my power to equal out the frt-rr bias, or get it as close as possible. When you get the bias as good as you can, THEN spring the hell out ov it.
Posted By: RylisPro
Re: Torsion bar size: How big is TOO big? - 01/03/15 06:11 PM
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Before jacking that front rate further, i'd do everything in my power to equal out the frt-rr bias, or get it as close as possible. When you get the bias as good as you can, THEN spring the hell out ov it.
This is why I added 200 lbs. of roll cage to the middle of my car and going with aluminum up front. I have 1.12 TB's and subjectively feel it's undersprung when compared to a typical modern track dedicated car.
Posted By: Dan@Hotchkis
Re: Torsion bar size: How big is TOO big? - 01/04/15 03:55 AM
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OK Dan, how does the corner weights of the front affect the handling, I have a world block (read: real heavy!) 4 core brass radiator, etc...would the extra weight prefer a higher torsion bar rate than a small block with aluminum heads, all things being equal? Tim
It can, but it turns into a balancing act. I'd have to do some digging around at the shop to pull up our corner weights of the cars across the spectrum when the Mopar program first launched. If you wanted to get super specific, yes the rate would help by shifting it a bit. I'd probably suggest a 1.18 front t-bar to someone running an all iron front end RB or HEMI for instance. For what it's worth, my engine was/is a B with aluminum everything except block and water pump. Everything on the chassis is steel except for the hood. A lot of the weight gap could be closed by a composite front end (with sufficient chassis bracing) and shifting the battery to the rear. The bumper and battery make a far greater weight bias difference than the sum weight at the engine and significantly affect yaw and roll centers. Weight has to be factored like a pendulum. The further away from the calculated center of the car, the more it affects the chassis dynamically.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 04/16/15 06:34 AM
Seeing the extremely reasonable prices of the BAC torsion bars, I've decided to order a set of the 1.15s and some Bilstien shocks.
Posted By: goldduster318
Re: Torsion bar size: How big is TOO big? - 04/17/15 02:29 AM
FWIW, My 70 Duster has the 1.06 FFI Torsion bars and the non-adjustable Hotchkis/Fox shocks on it now. It basically rides like a 2011 Mustang GT. Very tolerable. It's actually better than it ever was before in my opinion. It was always way too bouncy before.
The shocks make a big difference.
Posted By: jcc
Re: Torsion bar size: How big is TOO big? - 04/17/15 06:56 PM
Given the way you like to dial things in, I'd almost wonder if a conversion to a splined tubular sway bar wouldn't be the better choice. Open up the K frame some(its not as strong as you might think) to allow up to 2.5" and pick up the pieces for a splined kit. Odds are you could put on together one for around $200. Swapping out the splined bar for more precise rates could be done for as little as $100, maybe less if you shop for used ones. Plus the options for end links may prevent any potential tire interference issues.
<img src="/ubbthreads/images/graemlins/iagree.gif" alt="" />
In my next iteration chassis wise I'll be using Schroeder hollow splined sway bars and arms. They are a little more pricey than $200 for a "kit" but....
I have a set of arms and a few different diameters to try and lots more are available.
I currently have A-body LCA's(3/16" longer than E/B-Body's) and 1.120" FF torsion bars. I don't see C-Body sized torsion bars being beneficial to cars that run on the street most of the time. A strictly race car ok, but not a street car. Unless you have a cage and spend a lot of time and effort bracing the entire chassis the whole car becomes a torsion bar when you go too big. How big is too big? I don't know?
I'm think really big torsion bars are a bandaid solution to the poor geometry built into our cars. All your really doing is limiting the suspension travel and making a go cart out of it? Like others have said you will end up breaking spot welds etc... Sure the car will handle better than stock but only because your not letting the suspension travel and that will make for a horrible street car ride I would imagine? If that's what your after why not just make the suspension bump stops taller?
I'm no "expert" but I'd rather work on the geometry , shocks, and sway bars instead of trying to " limit/eliminate" suspension travel.
IMO bigger/biggest is not always better, leave that stuff in Hotrod magazine where it belongs or to the snake oil salesman trying to sell you the latest parts ?
What size you choose has to do with the application. If your building a high banked superspeedway car sure you will need C-Body sized torsion bars. If your occasionally autocrossing and mainly street driving then I'd say Firm Feel has us all covered . Variables such as engine weight etc. will determine what's best .Every car/combo will be different. I get the feeling some people think I'll just bolt in "this" size torsion bar and my car will handle on rails. I've found it's not just one part, it's the combo of parts and again every car combo/weight will be slightly different. I chose a T-Bar that will allow 2-3" of travel.My theory/idea is to control/improve what happens in 2-3" of suspension compression , the rest is secondary. It's always a compromise, there is no free lunch as they say.
Well the only suspension travel needed is enough to not bottom out, any more allows weight transfer and roll, but must keep tires in contact with pavement tires in contact Lowering a car decreases the force that causes the weight transfer mainly by lower COG, but at the price of less suspension travel normally, hence the needed for higher rate TB's to prevent bottoming, and the approach to go kart handing, which IMO, is pretty respectable. Weight transfer laterally is seldom a good thing. Weight transfer under acceleration may have certain benefits, weight transfer under braking serves little purpose on a "square" set-up car.
Somebody explain to me the need for us for the Nascar reference on this topic, if there is one.
Suspension travel is a factor in ride comfort, but that is a differenyt forum.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 04/17/15 08:03 PM
Seeing the extremely reasonable prices of the BAC torsion bars, I've decided to order a set of the 1.15s and some Bilstien shocks.
I'm about to put some 1.14 bars in one of my A body cars and have started looking into shocks, do you think the Bilstien shocks have enough rebound damping for bars that large?
I have considered the Viking double adjustable shocks but have not heard any feed back on these.
Posted By: BergmanAutoCraft
Re: Torsion bar size: How big is TOO big? - 04/17/15 08:28 PM
Seeing the extremely reasonable prices of the BAC torsion bars, I've decided to order a set of the 1.15s and some Bilstien shocks.
I'm about to put some 1.14 bars in one of my A body cars and have started looking into shocks, do you think the Bilstien shocks have enough rebound damping for bars that large?
I have considered the Viking double adjustable shocks but have not heard any feed back on these.
I have had good luck with Bilsteins in general, but on mine I run a specially valved one that feels great with a 300lb bar. I had to make special bushings to adapt it for this application but it was worthwhile.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 04/17/15 08:51 PM
Seeing the extremely reasonable prices of the BAC torsion bars, I've decided to order a set of the 1.15s and some Bilstien shocks.
I'm about to put some 1.14 bars in one of my A body cars and have started looking into shocks, do you think the Bilstien shocks have enough rebound damping for bars that large?
I have considered the Viking double adjustable shocks but have not heard any feed back on these.
I have had good luck with Bilsteins in general, but on mine I run a specially valved one that feels great with a 300lb bar. I had to make special bushings to adapt it for this application but it was worthwhile.
I have Bilstien's on my Chevy truck and they do work great, but I'm not sure that the off the shelf ones would work with 1.14 bars in a A body. Sounds like you modified yours to work, I want to get something that I can adjust externally for the car and just bolt on.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 04/19/15 08:30 AM
The 2015 Challenger R/T the wife and I have has Bilsteins as part of the Super Track Pack. I LOVE how the car feels with them.
Posted By: gold66cuda
Re: Torsion bar size: How big is TOO big? - 04/19/15 08:59 AM
Seeing the extremely reasonable prices of the BAC torsion bars, I've decided to order a set of the 1.15s and some Bilstien shocks.
I'm about to put some 1.14 bars in one of my A body cars and have started looking into shocks, do you think the Bilstien shocks have enough rebound damping for bars that large?
I have considered the Viking double adjustable shocks but have not heard any feed back on these.
I have had good luck with Bilsteins in general, but on mine I run a specially valved one that feels great with a 300lb bar. I had to make special bushings to adapt it for this application but it was worthwhile.
I have Bilstien's on my Chevy truck and they do work great, but I'm not sure that the off the shelf ones would work with 1.14 bars in a A body. Sounds like you modified yours to work, I want to get something that I can adjust externally for the car and just bolt on.
I have the 1.14 bars in an a body and ran the Bilsteins and they were ok, then I installed the Hotchkis/Fox adjustable and they were a lot better, they take the harshness out of the heavily spring in a light car, much smoother. Having said that I would say if you go with the Bilsteins you will not be disappointed they are a decent shock for sure.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 04/19/15 11:27 PM
Yea I think i'm going to go with the Fox shocks, plus if I need to I could always rip apart the Fox shocks and tweak them.
I won't be getting the car out this week...looks like we might get snow in the next few days.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 04/20/15 01:07 AM
In 2005 I added an 1 1/8" front and 7/8" rear anti sway bar set from Addco. Body roll was greatly diminished, but since then the car has always had some oversteer as I pushed it. It would also do something sorta hard to describe: In faster turns whether under throttle, brake or coasting, the rear would feel as if it were ready to step out, come back and then step out again. This is with zero additional steering input. I am wondering if this were a matter of the small torsion bars reacting to irregular road surfaces; the outside wheel/suspension bottoming against the bumpstops then bouncing up off of them.
With bigger 1.15 bars and Bilstein shocks on the way, I hope to report an improvement.
Posted By: ntstlgl1970
Re: Torsion bar size: How big is TOO big? - 04/20/15 03:42 AM
Are you running biased leaf springs still? I had a problem similar to yours with a rear sway bar until I switched to same rate/arch springs on each side.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 04/20/15 05:18 AM
The leafs are the Mopar Performance XHD. They did have an extra 1/2 leaf on the one spring pack but I removed it when I installed the springs.
Posted By: Mopar Mitch
Re: Torsion bar size: How big is TOO big? - 04/20/15 09:01 PM
The Viking dbl-adjust shocks are probably the best bet... fully adjustable... lower cost that the QA1 of same/similar design. In fact, the Vikings are made by the original pre-owners of QA1.. there was a recent split in personnell and the President of QA1 founded Viking. Viking only makes dbl-adj shocks and thereby keeops the cost down. Viking also has some slight different design thsatis patented, per my discuissikn with the curent Pres of Viking at a recent trade show.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 04/21/15 04:35 PM
I think you make a good point, the Vikings are double adjustable which could really help tune the front of the car. The other advantage I see is I could change torsion bar sizes and keep the same shock, I’m going to start with 1.14s on this car but if they are too stiff I’ll drop to 1.06s. What was the price point on them?
Posted By: Mopar Mitch
Re: Torsion bar size: How big is TOO big? - 04/21/15 04:44 PM
I think the Vikings dbl adj are ~$160 US each.
Don't be afraid of the 1.14 tbs for your BCuda... John Sandberg runs them on his original owner 67 BCuda fb and they are great for the stret, and improves handling overall. stiffer leafs, an better shocks are needed to help balance the package.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 04/21/15 05:26 PM
I'm not to worried about the spring rate, the car is a 68 Plymouth Valiant with a all iron 340, other than the intake. I want this car to be a good all round driver not a full blown race car.
The biggest problem I'm having is what to do with wheels and tires, I would really love to stick to 15" steel wheels and some 225/50 and 275/50 tires but I can't find anything that would work in those sizes.
If I do have to move up to lager rims I will most likely go to the 18" FR500s that Bergman sells with 255 tires on all 4 corners.
Posted By: astjp2
Re: Torsion bar size: How big is TOO big? - 04/21/15 08:14 PM
Keep the front and rears the same size for improved handling, that has been recommended by a lot of people on here for most cars including street cars. Tim
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 04/30/15 05:57 AM
I guess I had to personally experience this to know for sure.
I just finished the installation of a pair of 1.15 T bars from Bergman Auto Craft along with a set of Bilstein RCD shocks. The ride is great, NOT at all harsh. Guys like Mopar Mitch and several others wrote that big T bars are fine for the street and I now see their point. I always went by the guidelines I read in the Mopar Chassis books that listed .96 bars for [/b]Improved street handling[b], 1.0 bars for [/b]Street/Autocross/Road course[b] and anything bigger being for dedicated track cars.
Posted By: Mopar Mitch
Re: Torsion bar size: How big is TOO big? - 04/30/15 04:30 PM
You've made good choices.. Enjoy the ride!
Posted By: YO7_A66
Re: Torsion bar size: How big is TOO big? - 04/30/15 06:11 PM
""I just finished the installation of a pair of 1.15 T bars from Bergman Auto Craft along with a set of Bilstein RCD shocks. The ride is great, NOT at all harsh.""
Can you tell us what size tires you are using all around and what car is this on?
Thanks for your feedback!
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 04/30/15 06:38 PM
1.18's will be in the Dart by the end of next week.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 05/01/15 01:52 AM
Can you tell us what size tires you are using all around and what car is this on?
Thanks for your feedback!
The car is a 1970 Charger. 440/493, 727 and an 8 3/4 axle. 4 wheel disc brakes, welded in frame connectors and torque boxes, welded K member with gussets at steering box mounts. Firm Feel Stage 3 steering chuck with Fast Ratio Idler and Pitman.
As far as wheels and tires, I run a staggered size to fit the biggest tires in the car that I could without interference.
Fronts are 18x9 wheels 4.75 BS. 275/40/18 Nitto 555. Rear are 18x10s with 4.75 BS on a 66 B body axle (Narrower than a 68-70 housing by 3/8" per side) Rear tires are 295/45/18 Nitto 555.
The tires are 12 years old and should be replaced. I will go with a 200 TW tire next time since I'd rather wear them out rather than replace them due to age!
Posted By: Brian
Re: Torsion bar size: How big is TOO big? - 05/01/15 03:43 AM
Bad to the bone Charger!
Posted By: YO7_A66
Re: Torsion bar size: How big is TOO big? - 05/01/15 03:52 AM
Not at all harsh with 1.15" torsion bars and 40/45 series tires is mind boggling to me. It makes me wonder what my sb challenger would feel like with the same 1.15" bars and Hotchkis/Fox shocks with 60 series tires!
Thanks for the update!!
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 05/01/15 04:50 AM
Not at all harsh with 1.15" torsion bars and 40/45 series tires is mind boggling to me. It makes me wonder what my sb challenger would feel like with the same 1.15" bars and Hotchkis/Fox shocks with 60 series tires!
Thanks for the update!!
I recently bought a 2015 Challenger R/T with the Super Track Pack. It consists of stiffer springs and sway bars, better brakes pads and a few other tidbits. The Challenger rides about as firm as the Charger but the dampening of the bigger Bilstein struts makes for better jounce control.
I love how the car feels. There are a few neglected roads around here that I have used as a test section after I've made changes. I drove this road immediately after I installed the subframe connectors. The car felt more solid and had fewer rattles. I installed some Hushmat sound deadener and drove that road again. I heard thump as I hit the rough spots rather than a buzz or vibration.
Yesterday I expected to feel a harsher ride. I've driven Mopars with the torsion bars cranked way up and know how springy they can feel. Leave some coins in the ashtray and they will dance like crazy on a bumpy road. I really don't think that is the case here. I'll have to raid the coin jar and report back!
I'd expect these bars to feel better with more sidewall to cushion them. The price is great.
*************************************************************
Thanks Brian !
Posted By: Skeptic
Re: Torsion bar size: How big is TOO big? - 05/01/15 05:19 AM
The tires are 12 years old and should be replaced. I will go with a 200 TW tire next time since I'd rather wear them out rather than replace them due to age!
Replacing those old tires should be your top priority! Seriously, whenever I dismount old rubber like that the beads just disintegrate. The rubber is so brittle and inflexible that they look fine but crack and distort terribly. I'd hate to see you posting about a tire coming undone.
Posted By: Mopar Mitch
Re: Torsion bar size: How big is TOO big? - 05/01/15 05:49 PM
Yo7 -- With your sb Challenger, stepping up to ~1.15 Tbs and the good shocks you've mentioned, will be a very enjoyable ride.. and not harsh at all.
On my 340-6 Challenger with 1.24 Tbs (425 lb/in), Koni shocks and 60 series T/As (was 245 f, now 255 f, and 275 r), the ride is great, yes a little stiff, but not unbearable at all ... always a pleasure... street or especially hwy. I also have 255-50-16s (BFG GForce) for HPDE/HSAX events, and the ride is great to/from the tracks, as well as on the track.
As the sidewalls get shorter, the ride will become a little more noticeable, but still not bad at all. Naturally, avoiding pot holes and speed bumps, etc, should be done regardless of what you're driving.
With all the talk/concern about harsh rides with bigger TBs, a much more noticeable "harsher" ride will come when stiffening up the rear leafs. I have 225 lb/in (5" arch), and its stiff, but still bearable for street/hwy.
Posted By: cudazappa
Re: Torsion bar size: How big is TOO big? - 05/01/15 08:40 PM
Not at all harsh with 1.15" torsion bars and 40/45 series tires is mind boggling to me. It makes me wonder what my sb challenger would feel like with the same 1.15" bars and Hotchkis/Fox shocks with 60 series tires!
Thanks for the update!!
60 Series tires hide a lot of road feel. You won't notice anything but a nice ride. In the "off season" I run 235/60s on my aluminum headed small block challenger with 1.18 bars and the ride is fine. when I go to the 275/40s road feel amps up considerably. But I can corner at multiples of speed compared to the 15s...
Posted By: Wildjones
Re: Torsion bar size: How big is TOO big? - 05/01/15 09:29 PM
Not at all harsh with 1.15" torsion bars and 40/45 series tires is mind boggling to me. It makes me wonder what my sb challenger would feel like with the same 1.15" bars and Hotchkis/Fox shocks with 60 series tires!
Thanks for the update!!
60 Series tires hide a lot of road feel. You won't notice anything but a nice ride. In the "off season" I run 235/60s on my aluminum headed small block challenger with 1.18 bars and the ride is fine. when I go to the 275/40s road feel amps up considerably. But I can corner at multiples of speed compared to the 15s...
Would you say the 275/40s are too rough with the 1.18 torsion bars? What shocks do you run with those bars?
Posted By: cudazappa
Re: Torsion bar size: How big is TOO big? - 05/03/15 08:13 PM
Not at all harsh with 1.15" torsion bars and 40/45 series tires is mind boggling to me. It makes me wonder what my sb challenger would feel like with the same 1.15" bars and Hotchkis/Fox shocks with 60 series tires!
Thanks for the update!!
60 Series tires hide a lot of road feel. You won't notice anything but a nice ride. In the "off season" I run 235/60s on my aluminum headed small block challenger with 1.18 bars and the ride is fine. when I go to the 275/40s road feel amps up considerably. But I can corner at multiples of speed compared to the 15s...
Would you say the 275/40s are too rough with the 1.18 torsion bars? What shocks do you run with those bars?
I currently have the RCD Bilsteins. I am going to an adjustable shock up front very shortly. I would say that 1.18" torsion bars with my lightened E-body and 17" rubber up front is not for everybody. Hopefully the shocks will change my perspective. Depending how that works out I may try my NOS 1.22" bars.
Posted By: cjskotni
Re: Torsion bar size: How big is TOO big? - 05/03/15 11:01 PM
Geez,
I must be a wimp. I went to Bilstiens and 1.06" T-bars on my 1973 Charger and I think it is about as stiff now as I'd want it. It feels GREAT on the road but going over train tracks makes you get whiplash. I think if I had gone much stiffer, I'd be unhappy.
I guess it's just me. However, I'd take the 1.06" bars I have now over the crap .92" that were on there before!
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 05/09/15 11:06 PM
Anybody know what size bars these are P5249155 ? They are mopar performance bars and I was going to try them in my 68 Valiant.
Posted By: 72Swinger
Re: Torsion bar size: How big is TOO big? - 05/10/15 12:02 AM
1.14" A body.
Posted By: autoxcuda
Re: Torsion bar size: How big is TOO big? - 05/10/15 02:32 AM
That's what I run. 1.14 MP bars. Rate is higher than an E/B-body bars.
MP listed them as nearly the same exact rate as 1.16" E/B body bars. 1.14 A-body @ 323 lbs/in vs E/B-body @ 324 lbs/in wheel rates (at the ball joint).
MP 1.22" bars are listed at 396 lbs/in by MP.
Posted By: 67autocross
Re: Torsion bar size: How big is TOO big? - 05/10/15 02:44 AM
How did the bars work for you? They don't have a left or right and the hex ends are not clocked. I am going to order some Viking shocks to try with them.
Posted By: gold66cuda
Re: Torsion bar size: How big is TOO big? - 05/10/15 06:14 AM
I run them too and they work very good with the Hotchkis/Fox adjustable shocks. They don't have a left and right if I remember correctly but you don't want to switch them up after you run them.
Posted By: Kern Dog
Re: Torsion bar size: How big is TOO big? - 05/10/15 06:21 AM
Hey Evan...Good to hear from you!
I loved seeing your car on the track. I was just looking at some video I shot that day. I didn't get much but I did see a quick shot with your car in it.
The GoPro I had didn't record anything! I thought I set it up right but when I connected it to the computer, I saw nothing but what was on it before. Pisser.
My car is sitting now while I swap to a different cam. I was running a big Lunati that made great top end but felt soft under 3000 rpms. I slipped in a MP 528 solid. Valves are lashed but I had to order gaskets before getting it back together. It should be better suited for street and road course with the smaller cam.
Posted By: autoxcuda
Re: Torsion bar size: How big is TOO big? - 05/10/15 06:39 AM
How did the bars work for you? They don't have a left or right and the hex ends are not clocked. I am going to order some Viking shocks to try with them.
Definitely stiffer than my MP .99 T-bars. I think the Bilstein RCD's helped.
I believe? Evan has run them on his 66 Cuda with RCD's and than Fox's with no other real changes. If so, maybe he can comment on the street ride and handling difference between those two shocks with 1.14" T-bars.
Posted By: gold66cuda
Re: Torsion bar size: How big is TOO big? - 05/10/15 07:56 AM
Hey Evan...Good to hear from you!
I loved seeing your car on the track. I was just looking at some video I shot that day. I didn't get much but I did see a quick shot with your car in it.
The GoPro I had didn't record anything! I thought I set it up right but when I connected it to the computer, I saw nothing but what was on it before. Pisser.
My car is sitting now while I swap to a different cam. I was running a big Lunati that made great top end but felt soft under 3000 rpms. I slipped in a MP 528 solid. Valves are lashed but I had to order gaskets before getting it back together. It should be better suited for street and road course with the smaller cam.
I saw some video to, your car passing mine....Sounds like you have been busy on the Charger for next year. I was running 4:30 gears with a 286 Comp roller cam when we were out having fun so the rpm was always above 3000 if I ran in forth gear, just pulling 6500 on the straight and lifting. I tried 6500 in fifth once and was looking around for a roll cage and didn't see one so thought that might not be the best thing to do. I think your cam choice is a good one for what you are trying to do for sure.
Posted By: gold66cuda
Re: Torsion bar size: How big is TOO big? - 05/10/15 08:16 AM
How did the bars work for you? They don't have a left or right and the hex ends are not clocked. I am going to order some Viking shocks to try with them.
Definitely stiffer than my MP .99 T-bars. I think the Bilstein RCD's helped.
I believe? Evan has run them on his 66 Cuda with RCD's and than Fox's with no other real changes. If so, maybe he can comment on the street ride and handling difference between those two shocks with 1.14" T-bars.
Yes as Steve suggested I have run these bars with both the Bilsteins and the Fox shocks. I haven't messed with the adjustment much yet, for the most part I left them on the firmest setting. The difference between the two is a smoother ride, very firm but not jarring, they hold the car up very well, its a more balanced feeling. The Bilsteins are a very good shock, a massive upgrade over the KYBs for sure. I will say on a street car on full firm setting on the front don't try to take of too quick as they really pin the front end down with the big bars, no weight transfer at all but that's not what I am trying to do with my car.