Toyota Supra, Ruined by Bump Steer?!?!

Rapheal

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Did anyone experience this?





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XtremeMaC

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This is very interesting as I experienced this just yesterday on the road and was wondering why it had happened...
 

anajri

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they say its uncontrollable but a good alignment takes this away
my car is already doing times with porshce gt3 at my local track and i dont have this issue
 

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Rapheal

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Last year did a couple of laps on the track. I don't recall I counter this issue. Not even on the road. Instead, On the road on a long high-speed turn (comfort mode) full-throttle car isn't stable. Suspension completely stock.
 

antonio88x

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I wonder if the 2021 suspension tweaks try to correct this?
 

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https://motoiq.com/the-ultimate-guide-to-suspension-and-handling-bump-steer-toe-steer/

Bump Steer

Steering precision and stability are both affected by bump steer. Bump steer is steering input independent of what the driver is doing with the steering wheel created by the suspension moving through its stroke in response to bumps and cornering induced body roll. It is caused by the suspension links moving in different arcs than the steering linkage as the suspension follows its stroke.



BumpSteer%20clean-L.jpg

A common cause of bump steer on the popular McPherson strut front suspension car is that the lower control arm and the steering tie rod are out of plane and pivoting on a different axis. The difference in the arcs is the amount of bump steer that results. Usually, the further from the design ride height a car is, the worse the bump steer will be as the difference in angles becomes more extreme.

suspension-L.jpg

If a McPherson strut suspension has the inner tie rod in line with the lower control arm pivot, bump steer is greatly reduced.
IMG_1292-L.jpg
On this race car, a spacer was made to fit in between the steering rack and the inner tie rod to move it outwards which placed it in line with the lower control arm pivot point. This alone got rid of 80% of the bump steer. With the stock steering, this car had a severe issue with bump steer.
 

roadtripper

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I'll be watching this thread. I have also noticed some stability issues at higher speeds on a bumpy road.I boosted tire pressure up to 42 all around and it had no effect.
 

jtsang25

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If this is causing accidents wouldn't this call for a recall and change of parts?
 
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gdi2290

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I watched this today I think this is great and explains some of the bad reviews on handling for the car. Even though this is a huge flaw remember he did mention everything else about the car is amazing and they want to fix it. My supra is totaled but i still plan on getting another one even after this vid and knowing the 400z is coming out next year
 

JakeM

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What do you guys think of this?

Anyone with lots of track time feel he is correct? I have heard very mixed opinions on this, but I have seen enough evidence to think that he may be right.

Has anyone successfully fixed this 'issue' ? If so, how did you go about correcting it.
 

CantEven_Supra

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it sounds like this issue doesn't necessarily affect the handling of the car when talking about corners, or lateral steering changes. To me this sounds like this is an issue only when talking about large weight transfers from front to rear, and the opposite rear to front.

So depending on the track or road you tested the Supra on, it could be the best handling car in its price category....or if you have a track or road that requires a hard braking zone in a straight line and have this issue pop up and lose faith in the car
 

Kaizen

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This is an issue I've noticed with loading the car into high speed corners and letting off throttle. It gives a wiggle in the rear end. Feels unsafe and unstable. BUT I think this is normal for RWD cars especially ones with lots of torque and a short wheel base. I've experienced this in Miatas as well. I watched the vid, and imo I don't think it's a flaw at all. It's just the nature of abruptly coming off throttle on a RWD car, the suspension will become unsettled.
 

Pacchin55

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From his explanation, I think if you take away some of the suspension travel by dropping it and adjusting the toe alignment then you should be able to reduce it.
 

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