Dark930

I am having a 1988 930 race car rebuilt and trying to decide between bias and radial tires. It currently has Goodyear 23.5x11.5R16 fronts and 25.0x13R16 rears. Car hasn't been driven or raced in 10 years so the tires are too old to drive on. Apparently last raced at the Molson Indy in Vancouver in the early 2000's. I am inclined to switch to radial which requires more negative camber than current set up. I have read that depending on the car, the radials are likely faster but bias gives a little more warning when it starts to break loose. The rep at Hoosier said it is mostly older guys still on bias tires because that is what they are comfortable with. I am used to Hoosier 315/30R18's on my 2007 Audi RS4 which I race in autocross but speeds never go above 60 mph.

Any thoughts or experience welcome.

Igooz

Let me share with you what I know...sorry if not totally relevant.

I vintage raced a '67 Mustang for quite a while and went back and forth and ended up loving bias ply. I appreciated the softer side walls and the more roll I got when on the edge. My car liked to over steer and I needed the early feedback. Radials did not give me as much of a chance on the edge. (my car weighed in at 2890 with your truly and I made around 425hp at the crank out of a small block Ford)

The power comes on different on a 930 and you may want the stiff radials unless if you are trying to solve a roll problem. With those side wall sizes you will get an additional 3 degrees or so...

(With modern pcars I have only run radials and DD's only. )

Dark930

Thanks for your input. Any thoughts on handling characteristics of going to a lower profile radial on an 18" rim?

Igooz

^It is safe to say that if you can go to low profile then you can likely go with Radials.

UberXY

Oversteer in an old Mustang....how familiar I am with that! (See avatar)

Igooz

^I love it!! So what do you think? I am thinking that if the OP can run 18" wheels in his class then go for it with Radials.

Dark930

If I stick with the 16" rims for now do you think bias would be better then?

The Baron

Hey Igooz,

I think your opinion is very biased.....

Igooz

I expected nothing less from a Radi(c)al!

Porsche 930

U 2 R 2 FUNNY!

MUSSBERGER

Widest in a 16 inch Hoosier R compound is a 275. Tire choices for 16" wheels is not good.

Give Bill Rudtner a call. He raced one very well for years in PCA and may have some advice and perhaps even wheels for sale.

http://www.rudtnersracing.com/index2.php

Dark930

I spoke to the Hoosier rep and they have 23.5x11.0 R16 and 25.5x12.5 R16 Road Racing radial slicks which I think I will go with until I can find some 18" rims in 11 and 12" widths. I will look up Bill Rudtner too if I can get the link to work.