I've seen quite a few people have been working on finding a combination of stock parts that fix, or at least improve on, the factory bump steer issue. Has anyone found this golden combination of parts? I'm leaning toward an adjustable center link, rather than using rod end outer tire rods but I wanted to see what other options are out there.
Bump Steer Correction w/Stock parts?
- Thread starter ElkySS89
- Start date
Bumpsteer has basically always been explained to me in the following way, let me know if I was lied to: The A-arm swings on an arc. The tie rod assembly swings on an arc. These arcs don't match worth a damn. This causes one to push/pull on the other during the swing. If the A- Arm and steering both pivoted at the same location it would be nearly perfect. If they mount at different locations but at least swing on the same arc it's pretty damn good. Getting the arcs similar is acceptable. If they don't match it sucks. If this is true then the left and right side inners can be whatever length they identify as because they don't need to be the same.
I've looked into bumpsteer correction myself since I want a "stock" car that they could have made and I haven't quite found a perfect combo. Both 2nd and 3rd Gen Camaro center links have been tried, though they mess up the turning radius. The adjustable unit from All-star is so bulky that you can't run jounce bars, and doesn't seem to cure the issue for many in the first place. It couldn't even whisper "factory stock" if it tried- it'll stand out. The "Improved Geometry" link is very similar to the Camaro one, so much so that people thought it WAS one and nothing else. Despite appearances and turn radius similarities the mounts are relocated.
A couple guys have chopped & adjusted the length of the Camaro pieces, sleeving them upon reassembly. Many would never consider this route due to safety concerns, but many adults also wear diapers. DO NOT GO THIS ROUTE. Diapers are itchy.
*Another dude (on here, maybe?) cut the pitman and idler mounts OFF the center link and welded them into new locations. Naturally, they lined right up, nearly completely solving the issue.
I'll be installing taller ball joints in addition to rod ends for outer links. Simply switching to rod ends doesn't appear to gain hardly anything at all, but it allows you to bolt it atop the spindle after drilling if necessary. That doesn't look very stock though... The taller joints are noticable as well, but less so.
The best I've come up with at this time involves moving the idler arm to to the other side of the frame rail and using a Monza inner to make up for the skewed mounting points. The issue is that if you mount the Pitman straight the idler is crooked, cutting your radius way down in one direction. Same goes if you center the idler- it just goes the opposite direction. If you split the difference and mount it with both a little crooked you won't turn tightly in either direction.
It's worth noting that getting the steering mount higher by using taller LBJs and/or lowering springs helps immensely by eliminating much of the issue. If someone has worn out or shorter springs they may not have much bumpsteer.
* Edit: I think I remembered incorrectly and the guy moved the tie rod mounting points. Sorry for any confusion.
I've looked into bumpsteer correction myself since I want a "stock" car that they could have made and I haven't quite found a perfect combo. Both 2nd and 3rd Gen Camaro center links have been tried, though they mess up the turning radius. The adjustable unit from All-star is so bulky that you can't run jounce bars, and doesn't seem to cure the issue for many in the first place. It couldn't even whisper "factory stock" if it tried- it'll stand out. The "Improved Geometry" link is very similar to the Camaro one, so much so that people thought it WAS one and nothing else. Despite appearances and turn radius similarities the mounts are relocated.
A couple guys have chopped & adjusted the length of the Camaro pieces, sleeving them upon reassembly. Many would never consider this route due to safety concerns, but many adults also wear diapers. DO NOT GO THIS ROUTE. Diapers are itchy.
*Another dude (on here, maybe?) cut the pitman and idler mounts OFF the center link and welded them into new locations. Naturally, they lined right up, nearly completely solving the issue.
I'll be installing taller ball joints in addition to rod ends for outer links. Simply switching to rod ends doesn't appear to gain hardly anything at all, but it allows you to bolt it atop the spindle after drilling if necessary. That doesn't look very stock though... The taller joints are noticable as well, but less so.
The best I've come up with at this time involves moving the idler arm to to the other side of the frame rail and using a Monza inner to make up for the skewed mounting points. The issue is that if you mount the Pitman straight the idler is crooked, cutting your radius way down in one direction. Same goes if you center the idler- it just goes the opposite direction. If you split the difference and mount it with both a little crooked you won't turn tightly in either direction.
It's worth noting that getting the steering mount higher by using taller LBJs and/or lowering springs helps immensely by eliminating much of the issue. If someone has worn out or shorter springs they may not have much bumpsteer.
* Edit: I think I remembered incorrectly and the guy moved the tie rod mounting points. Sorry for any confusion.
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23399 - SMALL METRIC, 78-87 - RACING CENTERLINK
23399 - SMALL METRIC, 78-87 - RACING CENTERLINK
howeracing.com
This is the best I've found so far.
I've also been talking with CPP about their C5 spindles for G Bodies. I noticed A/F/X body spindles are all taller and redesigned but the G Body ones don't mention being taller. The guy I talked to claimed the G Body ones didn't need to be changed at all and the geometry was fine from the factory. Not sure what game him that idea. I was hoping he'd tell me the tie rod mount had been moved for better bump steer but I guess not
I found this article explaining the causes of bumpsteer.
https://www.hotrod.com/how-to/ctrp-1001-bump-steer-explained/
https://www.hotrod.com/how-to/ctrp-1001-bump-steer-explained/
Why doesn't somebody here measure how bad a stock set up is?
Bumpsteer is the toe angle change throughout the suspension travel. Almost impossible to check with coil springs installed but a coil over set up can be checked by removing the coil spring assembly. Then cycling the full compression to full extension and note the toe change.
Years ago I lowered an 87 Ram with shorter coils. The guy at the alignment shop gave me a scolding on messing with stock parts. He went from the lowered height to full droop of like 9" and the toe change was so minor he ate sh*t. Plus this truck would never see full droop in it's normal use.
Same with a 93 Mustang,, lowered with coils. Installed an adjustable bumpsteer kit. On stock settings went for an alignment. He let it out the door on stock settings making me feel like I bought the bumpsteer kit for nothing. This car was so stiff, I doubt suspension travel was more than 2" in 95% of spirited driving situations.
Today I'm convinced most of the mods to correct are a waste of time. Unless you are seeing toe change through your suspension travel, carry on.
Bumpsteer is the toe angle change throughout the suspension travel. Almost impossible to check with coil springs installed but a coil over set up can be checked by removing the coil spring assembly. Then cycling the full compression to full extension and note the toe change.
Years ago I lowered an 87 Ram with shorter coils. The guy at the alignment shop gave me a scolding on messing with stock parts. He went from the lowered height to full droop of like 9" and the toe change was so minor he ate sh*t. Plus this truck would never see full droop in it's normal use.
Same with a 93 Mustang,, lowered with coils. Installed an adjustable bumpsteer kit. On stock settings went for an alignment. He let it out the door on stock settings making me feel like I bought the bumpsteer kit for nothing. This car was so stiff, I doubt suspension travel was more than 2" in 95% of spirited driving situations.
Today I'm convinced most of the mods to correct are a waste of time. Unless you are seeing toe change through your suspension travel, carry on.
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Common CPP issue. They don't know what they're talking about @ times.23399 - SMALL METRIC, 78-87 - RACING CENTERLINK
23399 - SMALL METRIC, 78-87 - RACING CENTERLINK
This is the best I've found so far.
I've also been talking with CPP about their C5 spindles for G Bodies. I noticed A/F/X body spindles are all taller and redesigned but the G Body ones don't mention being taller. The guy I talked to claimed the G Body ones didn't need to be changed at all and the geometry was fine from the factory. Not sure what game him that idea. I was hoping he'd tell me the tie rod mount had been moved for better bump steer but I guess not
IMO, with stock a-arms, don’t mess with the center link. Taller lower ball joints and working your caster and camber to eliminate as much as possible to keep the toe in check.
In the past 8-10 months I have been battling bump steer issues for straight line racing. It has been an educational journey that I’m presently still on. I have the left coil over removed presently measuring and testing since Sunday night. But I have a mish mosh of parts - TRZ uppers, stock lowers, TRZ 1.5” drop spindles, lower coilover support in the lower a-arm, stock lower ball joints and 2” upper ball joints, TRZ bump steer kit for tie rods. All I can is what a giant PITA, but I’m getting close - presently I’m down to a tick under 3/16” of toe in from ride height to 5” of suspension travel - I’m probably going to live with this and see how it works out.
The issue is in the two different length a-arms and the fact that the connection points on the spindle change the caster as the arms are moved through their range of motion. After fighting with this for most of last season it’s completely understandable why race car shops build their own front ends with custom mount points for the arms and custom a-arms.
I’ll try to remember to post some pics tonight. And this process will really make you appreciate a Fox body for drag racing.
In the past 8-10 months I have been battling bump steer issues for straight line racing. It has been an educational journey that I’m presently still on. I have the left coil over removed presently measuring and testing since Sunday night. But I have a mish mosh of parts - TRZ uppers, stock lowers, TRZ 1.5” drop spindles, lower coilover support in the lower a-arm, stock lower ball joints and 2” upper ball joints, TRZ bump steer kit for tie rods. All I can is what a giant PITA, but I’m getting close - presently I’m down to a tick under 3/16” of toe in from ride height to 5” of suspension travel - I’m probably going to live with this and see how it works out.
The issue is in the two different length a-arms and the fact that the connection points on the spindle change the caster as the arms are moved through their range of motion. After fighting with this for most of last season it’s completely understandable why race car shops build their own front ends with custom mount points for the arms and custom a-arms.
I’ll try to remember to post some pics tonight. And this process will really make you appreciate a Fox body for drag racing.
These are the types of issues one runs into trying to hotrod a car originally designed for granny duty.
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