alfetta

2 newbie questions here. First, recommented tire pressure for 7 and 8" stock Fuchs with street tires. Second, is the 350mm Momo wheel I now have on the car too small? Should I use the standard 380mm wheel? Thanks in advance.

De Jeeper

Yes, no or maybe tell us what car u r driving... and tire size?

Joe250

The only reason to go with a larger diameter steering wheel is for more leverage. Even if the car has no power steering, steering is relatively light above just a few miles per hour, so I don't think this is an issue while autocrossing. On the other hand, a smaller diameter steering wheel makes it easier to make quick corrections. Unless I'm missing something, I recommend staying with the smaller wheel.

edfishjr

No one can tell you the proper pressures. You didn't even tell us what tires you have and you want to ask for pressure advice? Plus, the number of people who have seriously autocrossed a 3.2 Carrera with any of the last two generations of autocross tires is really very small. Maybe zero? Every tire brand and model is different and I don't mean just slightly. It doesn't matter anyway. You have to test. Lots of procedures are used, but here's what I do. Warning: you can't be worried about beating anyone right away.

Step 1: Probably do a couple or three runs with placard pressures. Then go way lower, front and back, lower than you think can be best. Then move both front and back higher in big steps until you are way higher than you think is possible to be best. Get a feel for the differences. Then fill in the blanks and find the sweet spot where the grip vs. response feels best and you can't tell the difference. It will probably be +/-2 or 3 psi.

Step 2: Test a big range at one end from the results from step 1, keeping the other end the same. Then vice-versus.

WRITE EVERYTHING DOWN. WHAT YOU DID, HOW IT FELT.

This will take a lot more than one event. If you can get to a test & tune you might be able to do step 1 in a single day.

When you finish you'll know what's right for you, your car, your tires and whatever surface you tested on. Other surfaces will be close, but not exactly the same. This is what srzbzns racers do.

A friend of mine finally just did this with his '68 XKE after autocrossing it all last year in a ****load of events. There have been maybe 2 guys in the US in the last 25 years that could have given him intelligent advice, but they are both dead. He was totally shocked at the pressures he found to be best.

It's not worth doing this if you don't have a set of tires you believe in, that you're gonna run for a while. If you have crap tires, and that means all except for maybe three brands/models, then I suggest you just run placard pressures (they probably won't be too terrible) and if you begin to feel like the car is doing something you don't like then play with pressure front or rear to fix it.

Welcome to street tire autocross.

BTW, I'll be co-driving that Jag at the SCCA Tour event in Moultrie the 23rd and 24th of this month in DSP. On street tires!

alfetta

Sorry about the late reply. Work stuff. Running 205/55-16 and 225/50-16. I am using my 1985 Euro car. Going to try it once and see if I like it. Odinarily I have been using the 29/36 psi. Thanks for the reply.

alfetta

I'm going with the smaller wheel. I think my reservation was at slow speeds it does take a lot of effort. But I'm not parking the car, which takes some arm strength, but driving it. Thanks

ehuggins

If you roll your front fenders, you can run 225’s in the front on 7” Fuchs. I ran 225’s front and rear on 7” Fuchs. 87 Carerra

alfetta

Interesting to have 7" at both ends. Thanks for the tip on the fronts.