Dude, try the vehicle dynamics assistant I have the link to. Inside rear wheel spin is usually closely linked with inside rear wheel lift. Basically, the inside wheel will spin even if it's still on the ground when it's about to lift and there's not enough differential lockup. So you cure it the same way as inside rear wheel lift, with the addition that you can also try increasing diff lockup if the rear wheel is still mostly planted.

I would start off by increasing the front spring rates. That should help keep the inside rear planted, but you will now get some understeer you will have to dael with.

 

Rev, I think we can all agree on what steps one should take to alleviate wheel lift/spin, on a car where everything is functioning as it should, and assuming the freedom to change whatever is needed.

However, there are two reasons I would recommend against increasing the front spring rates:

1) As explained earlier, 124Spider is constrained by the stock rules, so is limited to tuning for this issue with the shocks and front swaybar. Normally I'd say stiffen the front swaybar and adjust the alignment to compensate for the understeer. However:

2) Wheelspin is abnormal behavior for an AP2 with the swaybar he's using. Wheel lift I've never even seen on an AP1. It sounds as though something is amiss. Whatever that is should be remedied before attempting to tune the suspension.

I'm going to get a chance to see what the AP2 is like first hand, on stock shocks, the same tires, and the solid front Gendron swaybar. If I get wheelspin, y'all will hear about it.

Meanwhile: rear shock siezed or binding? Does the wheelspin/lift always happen when turning the same direction? No spring spacers, right?

 

You've never seen wheel lift on an AP1?!?! Do a search on the forum. It's a constant topic of discussion. Once you put R-compounds on the car, it always wants to lift the inside rear under hard braking while turning.

 

For what its worth, I have pictures of my '00 car with a rear tire in the air. And also with a front tire in the air. Same course.

Back to your regularly schedule thread.

Andy H.

 

Pfft... I have a picture of your '00 car with a rear tire in the air and a front tire in the air *in the SAME CORNER* !1!1!



Peter

 

...

 

Its not so much a problem under braking tho it will activate the ABS. The problem is when it happens while trying to power out of a turn. That forces you to modulate your power to keep the wheel on the ground, keeping you from using full throttle.

 

Pfft!!! That's not in the air! It is light, but I don't see daylight under those tires.

Damn McKee's fast!

 

Cool link. Thanks Rev

 

Rev, thanks for this, but it doesn't solve my problem.

I know that I'm getting inside rear wheel lift, since I can see the inside rear wheel off the ground when my son drives, and I can feel the results whan I drive.

I can't mess with the springs, AFAIK, and stay in stock class. Someday, I will get new shocks, but not for a while.

I never have the problem on the track (RA-1s; 255/40-17 rear, 235/45-17 front), and never had the problem on RA-1s in autocross. I'm pretty fast on the track, and mediocre at autocross.

These huge, sticky Kumho V710 tires (275/40-17 rear, 245/45-17 front) are a different story. With those huge, sticky front tires, I'm not too worried about understeer.

And, no, I have no spring spacers in there (I've looked). The lift is not directionally related; happens turning left and right, and not just under braking; it can happen in a high speed slalom. There's no sign of stuck shocks.