Picked this up at Mopar Nationals Saturday. I spent some time checking out the tubular k frame kits offered by a few companies. I've heard good things about a relatively unheard off company out of Iowa called Gerst Tubular Suspensions. Ended up with a Gerst Tubular Suspension.

So far, everyone I talked to personally that has one and is running one, can find nothing negative to say. There are even some circle track and road race cars running this thing, talked to one of the owners/drivers over the weeked, nothing but rave reviews about it.

Thoughts so far, will update on install.

This thing is built stout, I'd mount it on a tank. And he's proud of it. Said that if you can find a stronger unit, let him know, he'll make it even stronger.

Full IFS coil overs, Shocks are dual adjusting.

Ball joints are rebuildable and maintainable QA1 units. Very nice

TIG welded and man do the welds look amazing.

I compared all 3 that I saw at the nats, RMS, HDK and GTS. All had similarities, all had differences. To me, its about building a better mouse trap. That's pretty much what the after market is about. Improving on what is already out there. Here's why I chose the kit over the others:

A: It didn't use the factory shock towers like the HDK. I know HDK rienforces the towers in their kit, which I'm sure does work just fine. But it's not something I wanted ultimately

B: It uses stronger and thicker steel than the others, granted it weighs a tad more than the others, but it appears stronger. It's also got more gussests than the others I saw as well. RMS is at 3/16th steel, GTS is 1/4, not sure on the HDK to be honest.

C: No drilling the frame. Only cutting required is to remove the bump stops.

D: Construction. The welds look AMAZING. again, everything is designed to improve factory caster/camber specs, lowers and uppers are designed to eliminate the caster/camber issues with the factory. Plus fully adjustable. Lower control arms are double shear, 2 cross bars, bucket style lower control arms, all of which are unique to this kit.

E: Bang for the buck. Price is way less than the RMS and even the HDK, even if you go high end on the brake kits. There are a couple cheaper kits out there, but I saw their quality and it sucks. Ultimately, this is to me, the best bang for the buck.

If you're in the market for a tubular suspension kit, look up Gerst. You wont be disappointed. Plus, its almost half of an RMS and cheaper than a Hemidenny as well.

3300 plus shipping for a basic kit with stock style brakes and a manual rack. you can upgrade from there to power steering, wilwood, sway bar etc.

I opted for no brakes since I have a set of mustang 2 brakes in the shop from my dad's project. A kit like mine is 3050 plus shipping. Course bare, non powdercoated may be even cheaper than that.

Comparison: All data off respective company's websites and or flyers. Prices may have changed or whatever but this is the most recent i could find.

RMS ALterkation = with brakes: 5600 plus shipping without brakes: 4995.00 plus shipping

HDK= bare kit, no powder coatingno brakes, no spindels, no rack, no coil overs: 2800, add 100 for the rack, plus 600 in brakes plus 600 in coilovers, plus the spindels (price not listed on their website for spindels, so i didnt include that): 4100 plus shipping

GTS: Basic kit, everything but the brake kit. = 3050, basic kit with stock style brakes, 3300 plus shipping. The GTS kit comes with QA1 rebuildable and adjustable tension ball joints, viking dual adjustable coil overs and springs. Manual rack(upgradable to power), mustang 2 spindels, upper, lower control arms.

800 cheaper than the HDK and complete. and 2300 cheaper than RMS.

Looking from the picture does this kit move the wheels forward the controls look way in front of other designs

hmmm, I probably would have went this route if I knew about it over a year ago. For the price of a RMS kit, it was the same as buying all top of the line stuff that bolted in for the front and back of the car so I went that route instead. Does this kit use mustang spindles like rms?

What keeps the upper coil over mounting areas from tending to bow inwards under load ? If it was used hard on a track you'd think those area would tend to move. At least maybe with a high rate spring.

And odd to not gusset the upper control arm tubes where they meet the ball joints isn't it ?

All that money just to clear a rear sump pan.

Nope factory location. Pic is from the rear looking towards the front.

Yes

I didn't do it to clear a sump. Matter of fact, if I recall right, GTS recommends a center c body style pan for big blocks.

I did it to improve handling and lighten the front end and yet be strong. I added up thecost of simply replacing with all new factory components, it was gonna be almost 2600 bucks....for 400 more, that's just for oem spec, not upgrades, I got modern handling.

Simply using thicker materials is not an engineering design breakthrough. Making the LCA pivot points double shear is solving a problem that has not been shown or proven to exist in our application, and seems to be a "straw man" issue that many can protest about single shear vs double argument to showcase their engineering prowess. The tilting in on the upper coilover mounts under load, I addressed and measured and shared in a thread here over a year ago. Knowing the mounted angle would also help determine how much force is present with the OP's pictured solution. I also find it strange with all the double shear effort, and with an added large shear internal LCA gusset (looks heavy), there is no visible effort to beef up the UCA, which seems to be the standard typical aftermarket design. It would seem both arms are needed to resist braking loads which are induced radially centered on the spindle. Can't tell from pictures where that is located exactly between the Upper and Lower Control arms. The main upside, competition drives competitive juices, and RMS has a possible worthy competitor in their rear view mirror.

Cool to have more Mopars doing autocross, and circle track racing.

Could you post some pics of those cars and invite them to join and contribute to this forum?

Interesting to use it in a Dirt Track car. Wonder what class it would fall into?

It certainly looks like a worthy alternative to consider if you were wanting to get an Alter-k. Great for a drag race car or something with a tough engine swap

What can you get for sway bars? How do they mount? What are the end links like? What size tires can you fit on an A-body with this?

With that being said, I'm really quite unsure on the modern handling part - maybe you get modern steering feel with a rack, but otherwise this is basically a 1970's Pinto/Mustang II front end. I wouldn't really consider that to be much of an improvement over the OE setup. Ultimately this reduces triangulation over the stock front end in the case of the UCA. The cradle itself (this is no longer a K shape) doesn't appear to really have much/any triangulation going on either. Ultimately that increases stiffness the best.

I would love to see someone make a more modern design like a C5/C6 type setup work. There's so much really great stuff out there that could be copied.

I'd really like to see something this tested head to head with a car that has a sorted/aftermarket parts added stock design suspension.

The stock style design works amazing with some real torsion bars (I have 1.06), taking compliance out of the bushings, adding caster, borgeson steering box, and some 18" rims with some real tires, and the Fox Shocks...I now have 275s on the front.

Every time I've seen these coil over conversions go up against stock based cars at the Autocross they tend to fall far short of the competition. Even with ringer cars and drivers.

As was previously stated, You're not modernizing anything, you're just putting 1970's hotrod technology onto the front of your car. Big upgrade if you have a springaxle upfront, not so much with the stock-based Torsion bar setup that has done so well over the last 40-50 years.

Where what is the Bump and curve data on this stuff? What events have been won running it? Have we seen it punished in the wild against competitors?

...and with .25 wall thickness everywhere, how much does that set up weigh?

I believe in the FABO thread he said it was more than an RMS and HemiDenny K-frame, but less than stock.

http://www.forabodiesonly.com/mopar/showthread.php?t=323486

I'll try to get an exact weight on it. I know its much lighter than the factory, maybe just a few pounds heavier than the RMS and hemidenny.

For those saying its simply a 1970s pinto front end, I have to disagree there for a few reasons.

Yeah, it uses mustang 2 spindles and brakes, but that's it. Back then, they didnt have coil overs with adjustable rebound, adjustable compression, adjustable track width, adjustable ride height and a adjustable spring rate. They also were much heavier and werent tubular.

Is this kit for everyone, no. I have nothing against torsion bars and they do fine, see the Green Brick and Jim Lusk for example.

Now, you're right, a lot of people have swapped coil over kits in expecting a massive change. and they get their butts kicked. Why. well for a few reasons. 1: I've seen several of these kits, whether RMS, Hemidenny, Magnum force etc under cars here locally during our SCCA events. I'd say a vast majority of them have swapped over their fronts to coil overs only with out doing anything in the rear. Some have just swapped shocks and to SS leafs or caltracks etc. But the balance of the car is all wrong because they didn't take the time or money to make sure the rear works with the new front and vise versa. Not saying that is the case 100 percent of the time, just some things I've noticed at different events.
2: They dont understand how to actually tune it.


I'm not saying that torsion bars are junk, but i ran 1.03s in my charger when I had it, and while the handling was pretty good all things a considering, I just didnt have the adjustability this kit will give me. Will I need all that adjustability, maybe, maybe not. But I have it. My rear suspension will have adjustibility designed and built in as well.

He's got a couple options on sway bars. I opted not to run one at this time. I can add it later if I need it. Opinions on whether you need a sway bar on IFS fronts vary from person to person.

I've not measured for rims/ tires yet, so I'll report back. Others with this kit claim to run 7s to 9s on their rims widths on the front. But I've not tried myself yet.

Thanks for posting- I'm sure I'm not the only one who hasn't seen this offering yet. Price point looks good. Looking forward to hearing how it does in competition.

The 'A body shootout' hasn't been spoken of in a while. When do you expect to have this car running? Would love to have you (or someone else) with this front suspension attend.

Last 2 years at Carlisle the RMS shop cars got clobbered by the Hotchkis Challenger.

I'd love to. as to when the car is finished, honestly, I have no idea. I'd love to have it done by the Nats next year but that probably wont happen with a new baby on the way. The engine is still at the shop, plus I've changed my plans on my 4speed idea. decided more gears was a better way to go so I'm saving for a 6 speed road race trans from American power train. Basically the same as the Viper 6speed with closer ratios and a final drive of .68 instead of .58

Not surprised really. I don't care for the streetlynx from RMS either.

" just didnt have the adjustability this kit will give me."

What "adjustability" does this solution give betterthen the others or for that matter an OEM TB set-up? Its not ride height, TB swap out faster then coils, and if UCA adjustability is a concern beyond OEM, there are numerous aftermarket options.

I think many forgot or weren't in the hobby when the RMS was first revealed, it was not originally a "handing" IMO upgrade, and wasn't marketed as such. It was header clearance, oil pan clearance, lighter weight, engine mount relocation solution. It did all those at the time better then anything, and nothing else was on the market. Later it morphed into a handing solution I think by those not up to speed on how well a well tuned OEM TB set-up will deliver. However" sizzle" sells, and it became the holy grail IFS, beyond its original designed goals. Thicker materials does not change any of the above.

Regrading weight, K frame to OEM k frame, my measured weight is the same. Any weight savings is found elsewhere.

There's more than just thicker material here. do I think thicker is all that better, i think its better but that alone doesnt make this kit what it is. However, there are some features this has that RMS doesnt or any others. I've mentioned a few of those above.

I've autocrossed/pt since I was 16 locally, never gone national or regional, so usually only a few times a year . Ive ran T-bars before, theyve done okay. But I have to disagree with you about T bars being easier to adjust/swap out. T bars, you have to remove the clips, loosen the adjuster and knock them back wards. To simply swap coil overs, it's 2 bolts, or if you're just swapping out springs, its one bolt and a spanner nut or two. i described, briefly, the other parts that are adjustable in a previous post above.

You are right, the cradles do weight roughly the same. The real weight savings comes from no torsion bars, steering linkage, brakes and especially from the power steering box. Removing that box alone saves 40+ lbs.


and you are right, there's others out there. Ultimately, thats a good thing. As competition drives advancements and can eventually lead to lower prices for us Mopar guys. And what I like, someone else wont like. What works for me, may not work for you. Nature of the beast.

To be fair, how experienced were both the drivers.

Eric Wracker drove the RMS Shop car last year and he drove his personal car this year.
Last year the Hotchkis Challenger was driven by Co-owner of HPE who had never autocrossed before in his life or driven the car on a track. This year it was head engineer of HPW, Aaron.

Cheap and effective hardly ever go hand and hand. If I was going to ditch my factory stuff, it would have to be for something that used a "good" spindle like a Coleman or one from Ron Sutton. That is where the "advantage" starts.

https://www.youtube.com/watch?v=O3q1nNOcj-Q

I would guess this is the RMS car.

Left a lot of cones standing.

I know what you're saying that it's "improved", however, the basic design is still that of the Mustang II/Pinto. Specifically the lower arm mounting points. That front end was designed to be compact for such a small car. We don't have to worry about small here

Up until recently we didn't have much for torsion bars either but we basically have all the same stuff for torsion bars except adjustable track width (which really I'm unsure why this matters to us other than for fitting shelf wheels).

Naturally you'd be looking for how well the geometry works, caster/camber gains and whatnot during cornering, and how big of tires can be fitted. I hate to be so skeptical but data helps. 9" rim width and a 275-35-18 easily fits on the stock front suspension on a 67-76 A-body for reference.

Mmmmm nah..
https://www.youtube.com/watch?v=Wl7TnYQxf6g

looks undersprung, over powered and over driven.

That was a piss poor example to say the least. Car didn't do ANYTHING good IMO. But hey, Bill showed up, put on his gloves and went for it! I never thought his stuff looked like it had enough front sway bar at all, and that video kinda explains that. Plus I think he runs some pretty hard tires IIRC, or did he have RT615K's?

Well, I know for a fact that Dart has something like a 472 or 528 ci Hemi up front.

All Aluminum though.

I was pushing more towards the power part of the argument over the weight. Either way, you guys both make decent points. The car does look a tad sloppy, but fun to be in to say the least.

I don't have any hard numbers yet for you as I've not got it fully installed yet.

However, in regards to track width. While you wont play with it much for autoX, for road racing, which is the goal of this car, it is an extra tuning tool provided you understand how to use it to tune your car. Now this kit obviously isn't something you'd adjust at the track or on a daily basis, that I'll admit. But its a nice little bonus to have it. Will I use it a lot, probably not. I'll use wheel spacers mostly still. But it wasn't the main selling point.

Now back to your geometry questions. I know this kit was designed by 2 mechanical engineers who also happen to be racing enthusiasts. The lowers not only are double sheer but have some positive caster built in as well. They also told me they set out to reduce or eliminate the negative caster these cars have factory. I'll get you some hard data when i can.

Whats so special about the Ron Sutton spindels?

For autoX i want ackerman. Going to a pinto front steer setup the steering arms would have to be angled to the outside of the car and basically into the side of the wheel. I think that is why all the pinto knuckles have strait sticks for steering arms. A couple have bolt on steering arms, but even i think there would be a package problem to have ackerman.

edit: it seemed like a bad idea 2 years ago, today IDK. from this pic the oem MII spindles had the tierod outside the ball joint more than i recalled. if that really was close to 100% ackerman at 96" a longer wheelbase car would end up with more ackerman. cant say without a part in hand so i guess i take back bad things about pintos, for now.

I'm not worried about these spindles, they are forged units, not standard cast OEM spindles.

Forged vs cast means nothing. It's all in the material used.
I can forge one out of 1018 and it'll fail before the cast 4140 piece feels the load.

very true. These are IMCA approved forged ones. Besides, I can always upgrade to a set of Ron Suttons down the road.

While I agree Bill’s green dart looks bad the black duster looks decent in the first video looks decent, it too looks like it could use more sway bar as it has lots of body roll. I would like to see a RMS( or similar) vs stock test but I would guess if you had 2 cars with the same tires, brakes, weight, horsepower and driver you would not really see a lot of difference between them.

Autocross is for road course wannabes. Let's take your new fangled gerst set up and go pound some 130 mph laps and see how well your car "rotates" thru the turns and how much heat your brakes can take. Then again you are only playing autocross so it does not matter. This product has no real data, just opinions. I have results. I built 2 nice driving street cars with cruise control that utilized torsion bars that ran hot laps just fine. Both cars rotated thru the turns nicely...Why would I buy something untested, unproven that reduced the rigidity that a welded k member gives a car?

The biggest problem with these cars is no one want to do the most important modification to these cars which is weld the k frame, box in the steering box mount and add the welded plates to the lcas. It's less expensive than this untested hardware. If you think I want to trust my well being to this product going 140 mph I got news for you.

First, I never said I was going to auto cross it only. Matter of fact,if you had paid attention, you'll see that my build has always been geared toward Pro-touring/road racing.

Second, I'll gladly take that challenge, once my car is finished, if you want to throw down still, we will.

3rd, congrats, youve built 2 cars. That's awesome, want a cookie? You're not the only one.

4th, I don't see where you're getting that the rigidity of the k frame is reduced or inadequate. But it's your choice whether to buy or not to buy. I'm not a salesman, I don't get a thing or care whether you buy it or not. I'm simply sharing a new national product.

5th, I've have personally seen cars that run this set up here in the midwest. It's hardly untested and its been out for a few years, but until recently, he'd only been building them by word of mouth and then for only a few people. I've spoken to those people that have ran it on road racing, no complaints or failures from the 3 I've talked too, yeah 3 is a small sample size I realize that.

6th, with regards to brakes, there's numerous kits out there that fit this, from basic OEM spec to full on Wilwood and Baer race kits. I've even found a 15in, 6 piston race kit for it.

7th, what data do you want? Lap times, camber,caster, ackerman, strength? I can get those specs from the manufacturer if you want. Lap times would be subjective and really wouldn't be a good comparison unless it was the exact same car/driver,track/course, temps etc before and after a swap. I don't have those numbers for my car yet.



My factory K frame was welded and I have the reinforced and braced LCAs from Firm feel along with their fast ratio steering box. And 1.03 T bars. All of which have now been sold.

As for trust, that I can't help or tell anyone on. That's a question for each of us individually. Do I trust this over metal that was stamped over 40 years ago, drove on the street for 23 years and then parked in a field until 2 years ago, absolutely I do. Can you now a days get new/reproduction products to replace or even upgrade the OEM spec stuff?, absolutely you can. But also keep in mind, the factory didnt design those parts or these cars even to go 130 mph on a road course, so by doing so, even reinforced, you're stressing the factory parts too.

There's risks in racing, any true driver understands this. The only thing you can do is build the strongest, safest car you can.

A lot here to comment on

1. Understand Tom is has a long track record here, and on the track, try to overlook his "tone" and succinctness, he is the D Trump of Moparts in presentation.
2. Everyone pretty much believes what they what, uses only data/info that supports their position, and disregards/dismisses what doesn't.
3. With the millions of 40+ year old K members, there is a dearth of failed ones to base any real suspicion on their integrity.
4. When somebody mentions LCA reinforcement without reservation, I usually pigeon hole them right away.
5. Tom has been a long time avid proponent of K member reinforcement benefits. No one has substantially countered his position.
6. There are no aftermarket K's IMO that even match the structural integrity of a decent condition OEM K member, forget even the benefit of adding welds or reinforcement gussets.
7. I think your IFS system will likely be fine, and if you stay with the leaf rear, you will be happy. Convincing others this is better or a real improvement, will be a tough task.

Fair enough. Plus I like people who speak their mind. I'm one of those as well Like I've said, this is more of a hey, there's another option out there as opposed to me trying to convince anyone of anything. That is not my intention.

It drives me nuts that very few of these kits gusset their upper control arms.

Only one I can think of that does is Hotchkis. The question is, is a gusset a requirement?

many circle track tubular upper arms are not gusseted. Although some have legs that come in more from the side than others.

IMO The main forces the arm sees that a gusset would assist, would be braking, unless hitting a curb as high as the spindle is a concern. I personally don't like the look of the sweeping curved UCA. However I can't make the case they are inadequate. It would seem with all the, again IMO, unwarranted LCA stiffening plates in the field, the same solution would be in fashion for the UCA, but it just hasn't caught on, I guess. There doesn't seem to be many shared examples of failure. I also suppose the UCA are curved and gusset free, due to cost, and room for Coil overs. The first, easy improvement would be straight tubes, ala Firm feel design and a few others.

Have you measured the forces in the upper control arm? In most situations it's essentially along for the ride. The LCA controls the majority of the fore/aft movement, takes the cornering loads, and handles the spring.
The upper arm keeps the wheel from falling over.

so what you're saying is, a gusset isn't needed...which confirms what I've been researching

Remember, "majority" can be anything >50% and the "minority" is anything just <50%, dismissing minority just off of hand is a leap, IMO. If the spindle was for some strange reason at the same height of the lower ball joint taper, Saying the UCA was just along for the ride, might have some merit, But if just hyperbole to make a point, then make your own decision. If say the spindle was equal distance vertically from the UCA and LCA, braking forces in opposite directions would be equally shared by both arms, same for cornering forces.

If you're going to bring up the critical thinking thing again, do some for yourself.

Do the math. Tell us what so many people already know.

There's a reason that Chrysler had the UCA mounted to lightly reinforced sheetmetal.

....cause the factory design is soooo good at resisting deflection under loads. Why do we add subframe connectors and cage the crap out of these cars again?

Never seen an upper control arm failure. I would look at the TA cars or old Petty Enterprise pics for reference here. We can argue and speculate until we've pissed down our legs and prove nothing. Firm Feel gussets theirs too.

Dunno what you are thinking of, but I cannot recall one Mopar front suspension I have seen that meets your claim.

Closest I've seen is the UCA inner mounts are welded to the frame rails. I do not know that I would call that lightly reinforced sheetmetal. Granted it's not as stout as the LCA inner pivot mount, but that one is in single shear. If you look at a stock UCA it is massively gusseted in comparison to aftermarket ones.

I can think of many other brand vehicles that have real problems with UCA mounts bending inward (Mustang comes to mind) but they are coil sprung with the top of the coil in the shock tower.

"Do the math. Tell us what so many people already know."

That you stepped it down a bit and went from "majority" to "many"?

Back to the discussion, "Supers" point on the mopar LCA being single shear is rarely mentioned in these type of threads, and a very valid point to keep in mind when weighing design strengths.

You challenged me. Bring your game. Do it. Lets see what you've got.


Take a look:



Most of that reinforced upper structure is designed to withstand pounding from the shock absorber. They can be fairly significant loads. Assuming the shock is in good condition it will be subject to some sort of force at all times.

The upper arm floats in the middle of that shock reinforcement. The center brace is spot welded to the reinforcement. This makes it possible to use two shorter bolts instead of a crazy long and flimsy single bolt.
Had the arms been subject significant loads you would see much more reinforcement. In fact, the inner support would likely be tied to the rail instead of being supported by 4 spot welds.

It works in partnership with the lower arm to resist braking forces and keeps the wheel from falling over.

The upper arm is not subject to significant loads.

Feets Wins, he has an awesome red hammer

The nipple condoms are cool too

I stole that pic off the interwebs.

A lot of assumptions there. Your entire basis seems to hinge on the definition of "significant". How about we go back to the your "majority" definition", where this issue was first raised. Ponder this while you gather your thoughts, if, and I will admit I don't know the exact answer at this time, if for arguments sake, the spindle is equally distance ( we can talk dropped spindles later on) between the UCA joint and LCA, what percentage of say the braking loads does the UCA resist? We can talk cornering loads after the above is settled.

We don't need to continue this discussion. You have admitted that you don't know and are hinging your argument on semantics.

If you want to determine the exact numbers for a given tire on a given surface with a specific load and an exact rate of acceleration using a pad and rotor combo for which you have perfect friction numbers at the caliper pressure used then you can figure it out for your own self.
Don't forget the modulus of the bushings and other bits involved. Go ahead and get the shock damping rates for the amount of travel and temperature.


Face it, you're clueless and continuing into your critical questioning hoping that your opponent will give up and make you look like the smartest man in the world. After all these years, unfavorable police interactions, cheating spouse, many web forum discussions like this one, and who knows how many other situations you still haven't learned when to shut up.

Knock it off already.

Sensitive, are we?

For those left and, still following, if not bored to tears, my previous hypothetical question regarding brake torque the UCA would resist, would be 50%, certainly not, sorry having to resort to "semantics", "floating". And we still haven't looked at any of the other forces the "floating" UCA has to contend with.

No. Just tired of your crap like so many others. Perhaps they don't say anything to you but I've had messages from more than one person talking about your unrelenting crap on other boards. You want to poke, prod, and argue with others but don't have the answers yourself.



NUMBERS, YOU BLEEDING IDIOT! SHOW THE NUMBERS.

Put up a serious challenge for once in your life. Give us the proof that you use to call others on their knowledge.

50% of 2 is 1. 50% of a dollar is a pair of quarters.

50% of what value?

The entire universe is waiting with baited breath. Puhleeeeze give us the answers Great One.

On the A-body it is welded to the frame rail in several places, the metal is in multiple layers and is thicker than one might think.

Here is a "cutaway" from the inside where you can see some of the extra reinforcement. The only thing spot welded in place is the inner fender, and it has quite a few spot weld locations.

Looks like they use the heavy shock mount and put tabs on the outside to hold the arms.

The arms see torsional forces but they are not all that heavy. If they were, you'd see much heavier reinforcement.

It's pretty rare to see damaged UCA mounts. When you it is usually from someone spinning the alignment bolts and flattening the lips.

Off your medication?

You obviously can't back up your argument.

Your inability to understand a basic concept is not a good reason to argue against it. Instead of asking questions of others you should begin asking questions of yourself.

Perhaps you're too old and set in your ways to grasp this modern method of communication. Whatever it is, figure it out. All you are doing is making others irritable.

This is kinda like Obama dodging the question about proving he has a birth certificate.

Typical "feets" argument, go OT and personal.

I asked you to back up your words and you have failed to do so.

You made this personal by attacking so many of my posts in the past.

Now, can you back up your argument or are you going to concede to your questioning being out of line?

Kessel is right. So far, you have dodged this like a politcian asked for a birth certificate.

Let me offer a little visual assistance.
Here is a pic of the UCA mount on my 92 D250 diesel. This truck has the heaviest front axle package they offered that year.
Do you see heavy bracing or triangulation on the UCA mount?

Hint: NO.

It is a piece of stamped steel flapping off the side of the frame. Look at the distance from the rivet to the UCA mount. It is a fairly weak structure that could easily be flattened by a six year old weilding a claw hammer. I could likely bend it out of shape with my large channel locks.
Once again, the plate doubles as a shock absorber mount and that duty places a much higher load on it than the UCA.

I dare say the LCA and radius arm handle the bulk of the braking forces and the UCA is along for the ride.

I agree. And you're not the only one to say that either.

Kinda funny that the radius arm has those big fat bushings mounting it to a big beefy chunk of steel instead of that comparatively flimsy USA bracket.

I don't know that the thickness of the stamped steel K member at the strut rod bushing makes it more functionally substantial than the two double shear UCA mounts. I suspect it's a case of it was easier/cheaper to do that then thin the gauge out in that area to something that just enough but not overkill. I also note that your "flimsy" UCA mounts pictured above aren't as flimsy as you pretend. They are reinforced around the mount with the turned up edges, with a nicely radiused filet and it's more substantial than "sheetmetal". BTW, there is another rivet behind the UCA pivot that is not easily visible in the picture.

If you dissect most aftermarket MII based suspension their LCA mounting is no better than the Mopar factory UCA mount, worse in some as they are in single shear for the real cheapo kits.

Personally, I don't know which of you is right, or care, but neither of you can claim victory without running the numbers.

I'm not gonna run the numbers either.

The issue has just devolved into character assassination from my perspective. To revisit, the objection I first raised was about a claim about the loading of the UCA was not carrying a "majority" of the loads. That by itself doesn't mean much. I explained that, for those paying attention. Next the claim was the "UCA is going along for the ride", with nothing to back it up, number or logic wise. I again questioned that, and gave an example (with numbers) of when both members carry, for instance braking torque, the same forces. Next we heard a counter claim that the UCA could not be carrying much load, because the OEM would not have made the frame mounts so sheet metal "flimsy", which is just an opinion. Then we heard the UCA itself was just "stamped Lightweight sheetmetal", (which I think is a pretty decent design actually) which is odd because some think the aftermarket UCA's are lighter and therefore desirable (although the best reason for the upgrade is better caster). All the while, hurdling multiple OT insults, asking for numbers, and making unwarranted claims. The original contention was regarding, what "percentage" of forces in question (braking was the first mentioned) did each arm have to resist. That number in braking is mainly determined by height of the spindle between the two ball joints. I am not sure who is right. I don't care much either, But the loudest biggest wannabe bully doesn't get to win by default.

I'd like to see some gussets in parts. Also, it seems that for a part that is "along for the ride" there seems to be some serious loads against these parts as seen here:

Scroll to the bottom of the page....
http://ls1tech.com/forums/conversions-hybrids/1324170-l-q-9-ls1-71-chevelle-convertible-24.html

FWIW, those are made by SPC, the same ones BAC sells, and that isn't the first one I've seen fail like that or at the plate that holds the UBJ for that matter.

That Chevelle has an ugly setup.
Why did they have the upper ball joint going into a sleeved (aluminum?) spindle? That doesn't strike me as a good idea, especially when the sleeve can pull out.

A quick look at the photos tells me the failure was the sleeve coming out of the spindle. The really thin aluminum spindle twisted and released the sleeve. When that came apart the control arm shaft was obviously pushed beyond it's capacity.

You gould get Molloy's opinion on the failure (what he does for a living) but my eye lays blame on a significantly under engineered spindle.



As for jcc's observation, he challenged yet another suggestion but can't do anything more than ask questions. If he's so brilliant that he can shoot down a theory why isn't he brilliant enough to come up with answers?

He can't.

I stand by my assertation that the UCA does not see forces anywhere near those imposed upon the LCA. Fore/Aft motion is transferred into the mounts in a compression/tension relationship. One side is squished while the other is pulled. The mounts sharing the load means they do not need to be all that large.

The UCA isn't exactly flapping in the breeze. It obviously takes a load but it isn't as large as many may think.

Looks like I was on target with the Chevelle failure.

I went back to read the rest of the thread.
The UCA failed at a stress riser from poor machining. They drilled out the center of the threaded rod. Looking at the failed parts shows it came apart at the bottom of the hole and there is a horrible amount of chatter in there. That poor quality attempt at weight reduction was instrumental in the failure of the part.

That spindle was crap to begin with. The sleeve pushed in from the top and had nothing to prevent it from being pulled out. A weak loop of aluminum around it was unable to contain the stress of the upper ball joint. Stupid design bound to fail. Whoever did that will be lucky if nobody dies using that garbage.

Make the loop of aluminum thicker, pull the sleeve in from below, and it'll likey last a good long time.

I noticed his replacement was much beefier and had no sleeve inserted. No doubt his failure was not a solitary incident.

Poor design combined with poor execution led to failure.



It's interesting to look at the GM UCAs. They mount on that common pin. Not only is it in single shear it also has to hold the arms well outboard of the fasteners. That gives the UCA extra leverage to break away and run free. Webbing between the tubes helps reduce deflection and keeps the pin loading more consistent.
It's a much heavier setup than the Mopar stuff by necessity. Poor load paths mean heavier contruction requirements.

You crack me up. , you've almost gone full circle.

Disappointing to see the SPC? failure. However looks to me, the threaded portion that failed, was as mentioned a typical stress riser location at the transition, but the perfect storm was the jam nut was exactly at that point, and its added stress of being I suspect torqued to its maximum value, combined to promote failure. The hollow drilling should be an option only for full bore race cars. A post weld heat treat wouldn't be a bad idea either.

Look again. The jamb nut was well past the point of failure.

If you examine other parts involved you would see that the culprit is no doubt the poorly designed spindle. The UCA failed when the car came crashing down on it. If you can't figure that out by looking at the pics then you're even less capable than I thought.

Perhaps you need to go back to asking questions about shock absorber placement. That one was funny.

Yes, you are correct, jam nut was on other side and its torque played little if any role in the threaded portion failed. My deepest apologies to everyone. I will do my best to not let it happen again.

( FWIW, I realized this on my own shortly after posting, but was unable to return until now to correct)

That guy just bought new parts and moved on. I would've freaked out on Speedtech over that deal. So who drilled the hole in the arm? SPC?

I agree. It was amazing to not see the guy fly off the handle and bring in an army of attorneys.

It looks like the threaded rod was drilled out to remove weight and be more race-like. In the grand scheme of things, it wasn't a good idea for a street car. However, it was not the initial point of failure. That thing was caught up in the suspension parts collision and found a place to break.

I've seen similar failures without the spindle coming apart. The spindle failure could be a result and not the cause.

I don't know, look at how egg shaped the hole in the spindle is?

Not sure why this needs a lot of our lengthily attention in the first place after seeing the drilled thread. I don't understand why or what the design is exactly that would allow the Upper ball joint to pull thru a spindle. Nothing we typically use would allow that. I don't see how or why the UCA thread would fail AFTER a ball joint/spindle separation, at that point the UCA is, just along for the ride. I do understand somewhat why the the balljoint would be highly loaded after the thread failure, causing a poor ball joint design to fail.

I'm rethinking this, the broken thread could have been distorted greatly while the balljoint was seperating leading to the hollow thread failure. nit sure how e can be decisive here with proof

Click on the photos with the broken threaded rod.
When the new page opens, click on the photo again.
Move the super sized image around until you get a good view of the broken parts.


It's pretty clear that the threaded rod failed after the ball joint.

Go ask Molloy to examine the photos. He does structural failure analysis for a living.

Thought I'd pass on that GTS does now in fact have a website up and working:

www.gerstsuspensions.com

Did anyone else cringe at the 5 foot stack of spacers for the steering endlink at the spindle?

Nope

Good drag car stuff but hat is as far as I would go. Plus why have a front swaybar when you cant turn your front tires without hitting it.

Huh?

I don't see a very wide tire fitting on this.
http://nebula.wsimg.com/9397017bb1dcefbf...p;alloworigin=1
Please prove everyone wrong and out run a torsion bar car.

Well. Just so you know, the gentleman running that very kit pictured is in fact running 18x 8 rims with a 245 tire up front.


And I'll worry bout out running a t bar car when I get mine done haha

Pizza cutters lol!

You're not gonna get much wider on A body....not even a stock one.

OK.

Nice way to answer..

275's clear fine on most A bodies up front.
https://www.facebook.com/305030966187707...e=3&theater

A little, I am sure we all agree it's nobody's first choice, but there have been few reports I am aware of this solution causing any problems. However those with 11/16" TR upgrades are probably having a coronary seeing that bump steer stack.

Thanks for the link, the coil over kit using the stock spindles looks interesting, I could see lots of interest in that set up for guys who are looking to free up some room in the engine bay.

Nice, I was under the impression that 255 was as wide as one could go.

245s=roughly 9.7 inches

275= 10.8ish so roughly an inch give or take.


We're gonna find out for sure shortly, I've ordered a tire/rim measuring tool designed to bolt onto the hub and we'll see just how far we can go I suppose.





No problem, Yeah I seen that as well. Didn't know he was making that too. Price looks good too considering Viking dual adjustable coil overs retal for 600 and change.

I would guess that you could fit the same size tires as you could with the stock front end, over 275 you may as well star looking into flaring out the fenders.
If I was doing a budget big block car I would be considering the coil over kit, it would make header/starter install and removal a lot easier.

If you are looking for 26" tall the 255 40 18 is on the money. 275 35s are 25.6. Even though it seems almost the same, on my car it looked too low profile so I stuck with 255 40s which fit better on my 9" rims anyway

FWIW, I ran the cost comparison between the Gerst IFS basic kit with P/S and going with a T-bar set-up including QA1 K-frame and all new upgraded components. Both set-ups with 11" disc brakes.

Although not a true equal comparison- due to coilovers, rack/pinion VS T-bars w/ Borgeson P/S, you can add $900 for the Gerst set-up.

It's been mentioned before, do you NEED the adjustability? Probally not for a 80% street car like mine. So, I think personally, I will put the $900 into other parts and retain my T-bars, etc. Food for thought though, & the Gerst stuff looks very appealing.

Exactly. I have seen suspension loads aquired with wheel force transducers and strain and accel data on the frame at various points. Feets hit the nail on the head.

Another misconception about front suspension many here are guilty of: spring load being greater than shock loads. Those that have seen shock curves and understand them know the loads from a shock are far greater than loads from the spring. All of our cars could benefit from a shock tower brace whether torsion var or coil over. The main cause for concern in going to coil over is jounce bumper loads. Once you engage the jounce bumper the loads can get very high, as in 10+g's. If the factory jounce bumper arrangement is left intact a coil over conversion won't result in dramatically higher inner fender loads, assuming using the stock mounts.

They had a booth this weekend at the Indy swap meet and my cousin asked tons of questions. The owner had great answers for everything he asked and my cousin is definitely interested in that set up. The owner has been doing these for a while and decided a year or so ago to start a business with others praise of his product. Definitely appreciate any aftermarket options you can get with these mopars.
His big problem is he is putting a 4 cylinder diesel in a 72 swinger, so he liked he extra space, just obviously was worried about steering fitment on the driver side. Interesting project for sure and the company caused me to come here and search it leading to this thread. All that weight added to he front end with a diesel and another member pointing out how it's just 4 bolts holding it in place makes you think. Torsion bars onviously are there for a reason on our cars but as long as you watch those four bolts you should be alright. Always gonna be a weak link, but his system seems proven.