TXT High speed shimmy and front end parts

[dougs_huntingcart]

Originally Posted by kab69440

Worn kingpin bushings (they're plastic) would be at the top of my " to check" list.

agreed +1
also wheels may be out of round and causing a bounce feel

[dougs_huntingcart]

Originally Posted by yurtle

Question:

Since toe-in is supposed to be measured at the outer edge of the tire, should the toe-in change based on the tire's radius, or is it just an angle? To clarify, if I run 18" tires, and I used your method, I'm assuming my measurements would be taken at 9" from the center of the axle. If I were to be running 24" tires (just for argument's sake) would I still use 9" so the angle is the same, or would I use 12" so the difference between the front of tire and back of tire is consistent, since a bigger tire probably has more "rubber on the road"?

for the alignment, I've found that using the center of the tire has worked very well with my tires that all have the rubber protruding from the center of the tire. Otherwise I've also used chalk and measured to the center and made a line with the chalk. If you measure from the outside or the center it doesn't matter as long as you measure from the same opposite place on the front and back.....measure twice, cut once.

[yurtle]

I guess what I meant was, if we use the jig proposed by Sportcoupe, where should the 1/8" (or whatever) be measured from?

[cbryan88]

Originally Posted by yurtle

I guess what I meant was, if we use the jig proposed by Sportcoupe, where should the 1/8" (or whatever) be measured from?

It's intended to represent actual toe of your setup, so it should be measured at equivalent distance of wheel radius away from hub center. So in your example, 12". That will give you an accurate and consistent measurement. On the race cars, we have a jig that sits against rim bead edges and measurement is taken at tire contact (tread for some) point. It is also effected by wheels with a high offset, which is part of why we do it with wheels on hubs.

It is an angle that is constant, so each additional inch away from hub center would add just over ten thousandths more toe-in as measured at that point, if we were 1/8"(.125) at 12"

On carts, we just need the stability, not performance per say, so my guess is that it may be hard to tell diffc between 1/8" and 1/16...at 3/16+ though, you will certainly start to slow cart and increase tire wear.

Hope this helps...

[yurtle]

Thanks. Took six quarters of calculus, but never took trig. Victim of public schools, before Georgia Tech.

[cbryan88]

LOL...I never doubted your smarts...but as an NC State man, I now see a friendly rivalry emerging, lol...at the end of the day, I don't think we need Trig or Calc to work on these carts, just patience mostly :-)...and of course all the helpful insight we get from our friends on this forum...

[azTony]

I need to do my toe tonight, with the new PQ, Reverse Contactors and the move to 48V the least bit out is enhanced. I think my tires are out of round.

[yurtle]

It's been said in many other posts, but I'll repeat it for those who may have missed. If the buggy sits quietly for several days, or weeks, the tires seem to develop flat spots, and are bumpier when you first hop in. May be more noticeable on some tires than others. I noticed it the other day, after talking about it, and it seemed to go away as soon as the tires warmed up.

[azTony]

I see that as well. Living in Arizona and the temps are high and even higher in the garage where my buggy lives it is not as bad I suppose as other states in a colder climate.

Using mine everyday... except for the last week when the controller was at Alltrax... it should not be that bad but I can lean out and see the change in the diameter. I need to work with the tire pressure and see what works best. Not sure what the max pressure is that they can take but I will dig around and see what I can find.