Some time ago (seems like months) I made my own gauge
to measure bump steer. With all the other suspension
work I was doing I figured I may as well try to
correct/align everything I could. Yesterday I finally
got to test it out.
Here are a few pics of the setup.
Essentially it measures the amount that the toe
changes as the wheel moves up and down. I took a few
measurements with the tie rod in the stock location on
top of the steering arm. I was sort of surprised to
find that under compression there was toe out, and
under rebound there was toe in. This would mean that
when you corner hard to the right your tires would
(due to the suspension geometry) "turn" to the left!
I then swapped the outer tie rod to the bottom of the
steering arm. Then I got toe in under compression and
toe out under rebound. The exact opposite just by
moving the tie rod to the bottom of the steering arm.
This seemed to make sense as I was changing the angle
of the tie rod in relation to the lower control arm.
I also played with shimming the tie rod some which can
add or subract the total amount of toe in/out
depending on the spacer thickness and position. I am
able to do this since I drilled out the taper on the
steering arm and am using a regular 5/8" bolt and a
rod end threaded onto the factory tie rod adjusting
bolt. I dont have any pics of them on the car, but i
think you'll get the idea.
My goal in doing all this was to eliminate, or reduce,
bump steer. It doesnt seem that it wil be possible to
do that now, probably due to the suspension geometry
that we cant change, but at least there is a way to
use it to my advantage.
There will be more to come on this as I get everything
aligned and do a "final" bump steer adjustment.
Dan
YEP, my 60' times suck
247HP/267ftlbs at 13psi with built motor
Project updates and stuff:
www.clubhousecustoms.com
email: dan@clubhousecustoms.com
nice looking gauge , and tie rod end
Wow, that's some overkill. Way to go the extra mile though. I wish I had time/money to do more stuff like that. Good info too!
Ya, I live for overkill. lol
I literally have $20 bux into it and a few hours of work making the gauge, and about an hour so far doing some measurements.
When my Smart Camber gauge gets here and I get my string toe gauge setup I am going to get everything aligned and then repeat this process. Hopefully I will have even more useful info.
Dan
YEP, my 60' times suck
247HP/267ftlbs at 13psi with built motor
Project updates and stuff:
www.clubhousecustoms.com
email: dan@clubhousecustoms.com
Beautiful. We need more people like you around here. Keep us informed please.
Go Go OG Traction!!
That is an excellent write up. Very cool.
juicedz4 wrote:This would mean that when you corner hard to the right your tires would
(due to the suspension geometry) "turn" to the left!
I can definatley see the outside tires moving out under hard cornering based on your results, but I doubt your inside tires are going to toe in much at all.
What kind of suspension components were you testing this on? How much was the toe changing(range)?
I have a horrible bump steer problem. Keep trying it out i need to fix it! Ohh and does anyone know what i can do to minimize bump steer? Maybe something is bent how would i be able to tell?
Zach wrote:That is an excellent write up. Very cool.
juicedz4 wrote:This would mean that when you corner hard to the right your tires would
(due to the suspension geometry) "turn" to the left!
I can definatley see the outside tires moving out under hard cornering based on your results, but I doubt your inside tires are going to toe in much at all.
What kind of suspension components were you testing this on? How much was the toe changing(range)?
I am running Koni double adjustable race dampers in some modified strut tubes with GC sleeves, Eibach 10" 300lb/in springs, and camber plates.
With the tie rod in the normal position(top), I measured 0.145" of toe out under 2" of compression and only about 0.013" of toe in under 2" rebound. Im using control arm level as my ride height (or 14" hub center to fender lip on my second gen).
With the tie rod on the bottom I got 0.280" of toe IN under 2"of compression and 0.345" of toe OUT under rebound.
This is ALOT of "action". I almost think that the ideal location in right in the middle somewhere, which is pretty well impossible at this point. Im not sure if maybee i could make some offset bushings for my steering rack to change things some.
I think the 3rd gens use a different rack location (right?) which may be easier to adjust the position of.
Doing that will most likely end up being a long term project.
Here is some good reading about bump steer and the possible fixes for it
Longacre bump steer tech
Dan
YEP, my 60' times suck
247HP/267ftlbs at 13psi with built motor
Project updates and stuff:
www.clubhousecustoms.com
email: dan@clubhousecustoms.com
