I have a set of Hollow Spoke Turbo Twists 8x18 and 10x18. What is the widest race tire I can put on them front & back without rubbing?
I have 225's in the front and 285's in the rears on my street set up.
My car is lowered with H&R springs.
Thanks,
Luis

 

245's in the front and 285's in the rear. some 993 will need rolled fenders for a 285 in the rear. also note that some 285's run wide...

cheers,
boris

 

Boris,
Have you personally used 245's in the front? Will they be way different than 225's?

 

This for narrowbodies or widebodies as well?

 

yes i've personally used and continue to use 245's in the front. i run 245x40x18 hoosiers in the front and the 285's rear for autox'ing.

if you are asking do they make a difference - YES HUGE in two ways.

1. if you are indeed running 285's in the rear you will get a far more balanced car with 245's in the front.

2. the turn in and handling is considerably better in autox.

and yes this is on a narrow body.

cheers,
boris

 

I had no problems with the Hoosiers on my NB but did have rubbing on the fronts With Toyo RA-1s. Just enough to round the outside edges. I have Moton Club Sports with 800/1000 F/R springs. The top of the front tire sits level with the bottom of the wheel arch at rest.

 

Alan,

i've never run toyo tires, but i have succesfully run the following 245's in the front: MPSC, Hoosier, Pirelli Corsa & Khumo V700's. Never a rubbing problem at all. The only rubbing problem i had was with the 285's in the rear with the MPSC's.

Cheers,
Boris

 

Luis, the sizes of tires for NB 933 depend greatly on three factors when selecting a tire width. The wheel width to support the tire width, the side wall size (height of tire or overall diameter), and the wheel offset. If you get the proper offset you can run a 285 fairly tall rear tire without any rubbing on the outer fender lip or the inner. When the improper wheel width to support a tire width is used you get some strange tire wear and you also get some bulging that can cause rubbing. Most folks that are trying to run a 245/285 set up on a 993 NB will have a non-stock suspension, they will have some camber at least in the range ot 1.5 to 2.5 degrees, and are using a DOT race tire.

Hoosiers are very low profile in side wall and create the least amount of rubbing potential given you have the correct offset on the wheels. Hoosiers are normally a 245/35/18 and a 275/35/18. Some folks use the 285/30/18 but this has some diameter issues. You also might consider your rake of the car. The angle from front to back which is best at about 1 degree. This also plays into the diameter of tires as if done incorrectly the car will not handle as it should becaue the car sits wrong due to different tire diameters front and back..

So maybe I did not tell the truth about three things, there are many things when it comes to tire sizes, camber, tow in, toe out, suspension, wheel offset, tire diameter, rake.........

Get a correct offset and you will have the most choices in tires. I recommend using an 8.5" front wheel though and a 10" rear wheel minimum. 10.5" is better yet but again depends upon how aggressive you want to be with offset to the outside fender lip. You can go to 11" but this is not needed for a NB 993.

I use an 8.5" and 10.5" wheels with aggressive camber (for slicks) and have the fenders rolled aggressively. BTW, no one would ever know my fenders are rolled unless you run your fingers under the fender to check. I run a 245/645/18 and 285/645/18 Pirelli slicks that is fairly tall in terms of diameter (25.5") Both are the same diameter front to back to setting the rake appropriately allows the car to handle very well.

Hope this help!

 

Running 285 MPSC's in the rear (235's in the front) transformed my car from a foul-mouthed, brittle, trailer-trash one-night stand to a compliant, do-anything-in-bed, faithful wife with a PhD in particle physics. Okay, a bit of an exaggeration, but the wider tires *finally* gave me the willing steed I had been looking for to explore the limits with. Never going back to 265's and so wishing I had a Hoosier budget to knock two seconds off of my time. Aaaah, I have enough terror in my cup (check out Mark Dalen's/Sunday Driver's "Terror While Driving" thread) that I know I can do it in the next, oh, ten years or so.

I'm going to try 235/295's next year and see what happens.

 

I had a set of 225/275 R1's (old). Will I be ok running 245s and 275? From what you guys are telling me, rubbing with the 245's wont be an issue but, will I be OK with 275s instead of the 285's I currently run on the street? (Will it be a noticeable difference?)
Thanks for the responses guys!

 

the 275's would be taller (i assume you are going to do 275x35x18). If i'm doing the math properly it will raise your rear end by 0.8". I'm not sure that serves as a benefit, but the flip side is i've heard that 275's last longer and it will give you a higher speed in each gear.

cheers,
boris