Hi fellow Autoxers, i just got myself a set of RA-1s on spare stock Rims. They are used about half way most of the wear coming on the sides of the tires. The previous owner had about 35 psi in them all around. They are stock sizes. Also, my car is stock as well.

I was running 35-33 on my SO2s front/back.

What do you guys recommend i run, i liked that ratio on my SO2s but have no idea in this case. My first goal is to reduce grip in the front and/or increase grip in the back to compensate for the added grip in the front.. Also, i have never had two sets of rims so i am wondering is it the same to set the pressures off the car as on the car?

Thank you for your help.

 

The target pressure for the RA-1 on the road course is 40-41 so you start pretty low (29-34) there, but autox does not give you a chance to get them quite as hot, so you may have to start higher. I am not an experienced autox

 

Thanks Chris.

Just to keep matters simple though, i never adjust pressures at the track, i always set the pressures at home, i don't think i am a good enough driver yet that tire pressure tuning at the autoX will matter. I try to keep things constant so i can learn...

So guys, i forgot to mention this but lets talk cold pressures please.

Thank you.

 

Sev, I've never owned RA1's so anything I say will be something of a guess. With that in mind I would probably start out at 36/37 front and about 3lb's lower in the rear. If this feels good to you when you run leave it alone, if the car has too much oversteer I would then drop the rear by two pounds to see if it will tighten up. I know you don't want to adjust at the track but it's easy to start high and take air out. This over simplifies everything but if you take this and what Chris said up above you'll have something a starting point.

 

Thanks guys, i slapped them on today so i can make sure all is well and drove it on some deserted streets all i have to say is. Wheeeeeeeeeeeeew, boy do they grip.

I put 38 / 36 cold Front / Back to start and it seemed to be good. I am going to need more time behind the wheel, luckily i have an autoX school Saturday and an event on Sunday.

 

I ran RA-1s for quite a few years and still run them for practice and track days.

I HIGHLY recommend you bump up the pressures. They are a great tire if you run them at higher pressures.

On my 2500-2600, pound car, I run them 48-50psi rear and 46-48psi front.

A very good driver in a Firebird ran them from 50-55psi.

They are a very good tire that is 98% as grippy as the best Hoosier autocrosser....unless you are on a cold or slippery surface. They last forever too. They also have a built in excuse factor as to why you went slower.

 

Don't forget that 'cold' ambient temperatures may easily vary 50 degrees, so don

 

The tire sidewall claims a maximum pressure of 44 psi, the way i see it, i wouldn't dare pass 40psi cold since when it gets hot, it might pass 44 psi on a hot day...

I am going to try 39-37 and see.

Too bad no weekly autoXers have responded yet.

Thanks gusys for the help so far.

 

Sev, and anybody else who doesn't know Randy Chase. While he doesn't race an S2000 he is one of the SCCA's top national drivers. He is the current C Stock Pro Solo National Champion.

Randy, happy to have you on the board!

 

[QUOTE]Originally posted by randychase
[B]I ran RA-1s for quite a few years and still run them for practice and track days.

I HIGHLY recommend you bump up the pressures. They are a great tire if you run them at higher pressures.

On my 2500-2600, pound car, I run them 48-50psi rear and 46-48psi front.