I've been using a 330mm sparco steering wheel on my car for the last 5 months or so. I have apexi n1 coilovers with 12k front springs and the car is lowered so that the tires are about even with the bottom of the fender in the front. I noticed that the car felt like it had some bump steer driving around town. I didnt think that the susp, was that low, and I still have quite a bit of travel in the front. Well, I had to put the stock wheel back on for inspection ( steering wheel less than 13" in NJ is illegal), and all these "bump steer" symptoms have disappeared. Is this normal for a smaller steering wheel to give this impression? I'm probably going to be purchasing a 350 or 360mm one soon anyway, but I'm curious.

BTW. . . I weighed the stock eg steering wheel with airbag - over 11 lbs. The sparco 383 suede with ltb quick release was less than 5 lbs.

 

technically speaking, "bump steer" has nothing to do at all with the steering wheel. it has to do with the changes that the front end goes through during compression of the suspension when one of the tires hits a bump and the suspension compresses. this in turn causes (can cause) a change in the toe of the front of the car. the alignment changes, and the car seems to be "steering" itself in a different direction when bumps are encountered.

there are ways to alleviate this; moving the steering rack around, suspension height changes, etc. etc.

so, the long and short of it is, no, your steering wheel diameter has nothing to do with bump steer taking place in the front end of your car. in fact, you could be driving around with a large vise grip on your steering column, and if your suspension and steering rack was set up right, you would not experience any bump steer problems!

 

Not diss'ing you, but could you please describe what you think "bump steer" is. I have a feeling it may be incorrect.

Bump steer means when you hit a bump, the wheels steering the car change direction. A classic case is going around a circular on-ramp and hit a bump. While your hands never moved the wheel, the car steers itself left, then back right. That is bump steer.

 

I'll give this another shot at explaining:

take your car to a shop that has accurate toe plates and gauges. now take off your wheels. take off the springs and shocks, but leave your knuckles, upper control arms, lower control arms, tierods, steering rack, etc. attached. put the car on blocks. set the front suspension at its "at rest" ride height. align the car (toe setting). now lift one of the front suspensions thru its range of travel. you should see NO change in the toe settings throughout this movement. most likely, you will see some change. you must fix this by shimming the steering rack or making other changes to the suspension. do this for both sides. recheck the alignment.

when the suspension changes its toe as it is compressing, this is STEERING your car without you moving the wheel. this is making your car go in directions you don't want to go! this is what bump steer is.

i have had this done to my vintage racecar, a Super Seven. it was exhibiting really really bad bump steer beforehand, and no bumpsteer afterwards. we had to shim the steering rack quite a bit.... i have not done this to my Honda, as I feel no bumpsteer when racing it.

good luck.

 

also, fwiw, civics and integra's suffer from toe-out bump steer, while other cars have the much more maligned toe in bump steer. (imagine going into a turn and as the suspension compresses, the outside front turns _more_ to the inside of the turn) while toe out bump steer is still worse then no bump steer at all, it's the lesser of two evils. carol smith actually talks about racing teams designing the front suspension to have a very small amount of toe out bump steer to promote mild corner entry understeer.

nate

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kb58 &raquo;</TD></TR><TR><TD CLASS="quote">Not diss'ing you, but could you please describe what you think "bump steer" is. I have a feeling it may be incorrect.

Bump steer means when you hit a bump, the wheels steering the car change direction. A classic case is going around a circular on-ramp and hit a bump. While your hands never moved the wheel, the car steers itself left, then back right. That is bump steer.</TD></TR></TABLE>

Sorry for the confusing thread title. I know that the steering wheel has absolutely nothing to do with actual bump steer, but with the smaller 12.9" wheel, my car definitely exhibits what you are describing above. I have it aligned with the toe in factory specs, and -1.5 degrees of camber in front, with no camber correction. I just wanted to know if going from the bigger to smaller wheel has made this feeling more noticable, or if I'm just crazy or what.

 

I know where you're headed w/ this... i drove a hybrid hatch at slummit (Time Trial practice) last weekend and the car had a manual rack w/ a 330mm sparco steering wheel.

The suspension was too stiff for the shocks, and the car did bounce around a fair amount in the bumpy track sections. When the car hit said bumpy portions, the car tracked straight and did not shift around on the track, but w/ the manual rack and little wheel and victoracer tires it was very easy for the wheel to want to move out of my hands, and i'd have to recenter it here and there. Not a big deal and very easy to manage once i got used to it.

I figure this is what you're experiencing... and the fact is you're just going to have to deal with it (or find smoother tracks)

RJ

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 743 &raquo;</TD></TR><TR><TD CLASS="quote">I just wanted to know if going from the bigger to smaller wheel has made this feeling more noticable, or if I'm just crazy or what.</TD></TR></TABLE>

Please don't ask a question like this. The temptation to answer, "Yep. Crazy" is too great.

But seriously, folks, it's not impossible that you're feeling not bump steer, but either torque steer, if you only feel this during acceleration, or normal steering feedback. A lighter wheel might provide less damping of the normal feedback, allowing a better sense of what's going on as your wheels encounter changes in road surface.

 

Well after driving the car around today, I realized that what I was feeling was just alot more feedback. The smaller size of the wheel probably added some twitchiness that I got used to. Until I was using a bigger, more "giving" wheel, I didn't realize how much more I feel with this sparco. Nonetheless, 330mm is too small for stock eg cx rack and daily driving, and I could do without the suede, so I'm going to track down something bigger and leather.