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Tires toe out as front end is raised #2874596
01/15/21 04:07 AM
01/15/21 04:07 AM
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Houston, Texas
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FastOrange Offline OP
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Slowly working through alignment issues, although I haven't had much spare time to work on the car. 1970 Challenger with mostly stock front end. Adjustable PST upper control arms and Strange D/A shocks. Aligned front end at resting ride height. Set caster at 3.2* Positive and zero toe. As the front end is raised, the tires toe out 11/16" at 3" rebound. Attempted to raise the outer ball joints by backing the caster back to 2.2* positive. Tires still toe out when raised. I looked at the Hotchkis website, where they sell some upper control "A" arms with a lowering bracket attached to the front of the upper control arm. Appears to me, that bracket will raise the outer ball joint by lowering the front of the upper A arm? Anyone have experience with these? Any other suggestions? Do they sell just the lowering brackets without the A arms? https://www.hotchkis.net/product/do...kis-1110u-a/?mk=&yr=&md=&sm=
Ideas? Thanks Paul

Re: Tires toe out as front end is raised [Re: FastOrange] #2874764
01/15/21 03:03 PM
01/15/21 03:03 PM
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Houston, Texas
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FastOrange Offline OP
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Ordered the adjustable steering rod kit from hotchkis. I suppose A person could use the stock sleeves and just order rod ends, studs, and spacers somewhere. Should allow me to ditch the tie rods and replace with rod ends, which should allow for more adjustability in raising the tie rods (rod ends) since the rod ends are smaller than a tie rod. Hopefully correct the bump steer. Will let you know how it works out. In the mean time, I will add more positive caster angle back into the front.

Re: Tires toe out as front end is raised [Re: FastOrange] #2874927
01/15/21 10:18 PM
01/15/21 10:18 PM
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MYRTLE BEACH SOUTH CAROLINA
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ek3 Offline
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how do the a arm angels look ? if not that, spindles may be in correct for the app.

Re: Tires toe out as front end is raised [Re: ek3] #2875097
01/16/21 01:54 PM
01/16/21 01:54 PM
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UPPER MICHIGAN, MARQUETTE COUN...
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NITROUSN Offline
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I do not know what you are trying to build or accomplish here. On an A-frame suspension with a fixed to frame steering gear along with center link and idler arm fixed no matter what you do up or down the toe is going to change.

Re: Tires toe out as front end is raised [Re: FastOrange] #2875518
01/17/21 01:34 PM
01/17/21 01:34 PM
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Pikes Peak Country
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TC@HP2 Offline
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What is the toe doing during jounce?

You can have one or several combinations of problems with this; Outer tie rod end to high or low, inner tie rod end to high or low, tie rods too short or tie rods too long, or partials of several of these.

If you have access to the Mopar Oval Track Modifications book, its got a full explanation of toe plots and suggested corrections.

Modifying inner up/down position is going to require a combination of shims and slotting/welding to move the entire center link up/down.

Also check both sides, they may not necessarily perform identically.

Re: Tires toe out as front end is raised [Re: TC@HP2] #2875579
01/17/21 03:16 PM
01/17/21 03:16 PM
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Seattle, WA
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375inStroke Offline
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Are you checking this by raising the car with the tires touching the ground? This could cause erroneous readings. My racecar was toeing out 1/4" per inch of jounce. The way to fix this is to shim the steering box to raise or lower the pitman arm to adjust the driver's side, and to slot the idler arm bolt hole or holes to raise or lower it. You put a washer under the bolt or nut, and weld it in place when you're done adjusting to lock it in place.

Re: Tires toe out as front end is raised [Re: 375inStroke] #2875594
01/17/21 03:41 PM
01/17/21 03:41 PM
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Here is a quote from another thread about the process being used.

Originally Posted by FastOrange
Here is where I am at. 70 Challenger stock front end with Spc adjustable upper control arms. Drum brake car with Wilwood front brake conversion kit that retains the stock drum brake steering knuckle etc. FLAMING River Fast ratio manual box, but stock length pitman arm. Car used to be a power steering car. Idler and pitman arms are the stock length and are the same..
Car is set at stock ride height. Took the shocks off to assist with alignment.
Centered the steering wheel travel in the middle. Its 3.3/4 turns lock to lock
Set the Caster at +3.4* both sides
CAMBER Close to 0. About .1 to .2 degrees positive
Set the toe at ZERO at static height
As I Jack up (rebound) the car in 1" increments
The wheels toe out. The higher the car, the toe out increases.
At 3" raised toe out is 11/16".
I did measure the outer tie rods to the ground. There is a 1/8" difference between drivers side and pass side..
Options?????? Not sure what my options are to correct the bump steering? Book mentions bending the steering knuckles up and even. I thought I might start out with less caster, just to see how that measures out..
Thanks.


Re: Tires toe out as front end is raised [Re: TC@HP2] #2875990
01/18/21 11:28 AM
01/18/21 11:28 AM
Joined: Mar 2005
Posts: 1,545
Seattle, WA
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375inStroke Offline
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There are more expensive tools you can buy, but you can make fixtures like this, and get a dial indicator for $20 from Harbor Freight. You get a flat plane of your favorite material, particle board, formica counter top, aluminum plate, and bolt it up like a wheel, with one inch marks on it. The dial indicator is on one end of another board, and a screw opposite it to track the board that's simulating the wheel. Place them about 26" apart, since that's the general size of the original tires that toe settings are based on. The hinge on the bottom is because the wheel moves in and out as it moves up and down, so the hinged board will follow the "wheel." Unload the torsion bar as much as possible, place a jack under the lower control arm, and raise it in one inch increments that you marked on the "wheel." The dial indicator will read directly how much toe change you're getting per inch of travel. To adjust bump steer, you need to raise or lower the pitman arm by shimming the steering box for the driver's side. For the passenger side, you elongate the idler arm mount bolt holes so you can raise or lower it. You then use a washer the size of the mounting bolt, and tack weld it in place to lock in your adjustment.

bumpsteergauge_3.jpgbumpsteergauge_2.jpgbumpsteergauge_1.jpg
Re: Tires toe out as front end is raised [Re: 375inStroke] #2876078
01/18/21 02:15 PM
01/18/21 02:15 PM
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Posts: 686
Houston, Texas
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FastOrange Offline OP
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Houston, Texas
Tires are on turntables and I'm using Quick Trick alignment tools for measurements.
With the tires on turntables, I dont feel like there are any issues with my current measuring setup. I believe I'm getting accurate information and repeatability. According to my plot, the outer tie rods need to be raised. My current thinking has been, replace the tie rods with rod ends for more adjustability. Then spacers can be used as needed. Havent tried it yet though. I have not measured it in Jounce, since its more of a strip car. The torsion bars are installed and the ride height is set.. Thanks for the tips. If the rod ends dont give me the adjustability I need, then I will start over again. Thanks for all the great ideas!

Last edited by FastOrange; 01/18/21 02:17 PM.






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