Maximum tire size in SC/Carrera configuration

Jack Olsen · 04-02-2002, 02:10 PM

I know their are smaller limits with stock one-piece Fuchs, but I'm looking to get custom 3-piece HRE wheels made, with carefully set up offsets/rim sizes. I've been told that I can fit 8.5x10x17 3-piece Fuchs with 235's in front and 275's in the back -- all under my stock front fenders and SC rears.

Has anyone else succeeded at this? I appreciate any and all advice.

Glasgow 911SC · Glasgow 911SC's Garage

Bill Verburg runs large tires but I cant remember the exact sizes. Poss 265 / 235

pbs911 · pbs911's Garage

I run 215 and 255 on 8 and 9.5 on custom offset Fikse wheels. 225 and 265 would easily fit without mods to the fenders, but I didn't want to go that far.
The widest I have seen are on Randy Wells' RS replica. If I recall correctly, some other mods aside from wheel offset were made.

I like your thinking of keeping Black Beauty's current body configeration. I know great painters once painted over masterpieces for lack of canvus, but . . .

Bill Verburg · Bill Verburg's Garage

I am using 235/45 & 275/40 on 8&9.5x17 Kinesis, this is about the limit for street use. I am also leaning toward 235/40 & 265/40 for my next set. The 275/40, while great on the track because of the great lateral grip, is less than satisfactory for 98% of my driving(street). The increased traction is wasted but the taller tire is felt at every stoplight. It's not slow mind you, just slower.

If you really want to be track biased 8&10 x17 Fikses are common at local tracks, but not used on the street at all.

skinnerd · skinnerd's Garage

I've got the same set up as Randy Well's for autocrossing on my narrow body RS replica. Fikse's 10x17 rear and 8.5x17 front. For tires, you can go to 275x40x17 rear and 245x45x17 front. These are serious steamrollers, and are not all that practical for daily driving. The car really hunts going down the road (neg. toe doesn't help), and you really feel all the potholes, expansions strips, etc. The wheels were specially built (offset), and I still needed to do a lot of custom fitting (filing off the heads of rear camber adjusting bolts, rolling fender lips, etc) to get them in. The mods to get 'em to fit are not all that tough to complete. Beer and buddies help alot! They are massive and the only way to go to keep up with the fast crowd in autocrossing. One day I'll post some pictures of the set-up for those that are interested. -Doug

Jack Olsen · 03:51 PM

Thanks. That's helpful. The appeal of not going to a widebody configuration is partly performance -- I don't want to give up the handling characteristics that made the RS a legend in the first place. (Turbos are great, but they're not known for being nimble). And it's partly financial -- I don't want to have to tear the car apart and repaint it. And I also don't want to have to buy two sets of 3-piece wheels.

With the body left alone, I can run the wide wheels/tires on the track, and then continue to use my 7x8x16's on the street.

It seems like a sensible way to do things.

orbmedia · 04-02-2002, 03:58 PM

The combination that skinnerd describes is the biggest I've seen too. Most of the winning F club race cars emply this setup on Carreras. To add to his clearancing list I've heard oil lines may need to be moved too. Apparently Fikse knows the exact offset you need for this setup, a few mm one way or the other would probably not work out.

Randy W · Randy W's Garage

Hi Jack - Doug and I have the same setup for our RS look 911s for autocross/track:
Front - 8.5x17" Fikse three piece wheel with 245/40-17 Hoosier
Rear- 10x17" Fikse three piece wheel with 275/40-17 Hoosier
Jim Fikse, Greg Fordahl and Jeff Gamroth know the offsets needed.

This is the max non-slick combo you can fit on an SC/RS flared 911 with narrow front fenders. You will probably have to max out your negative camber, shave spring plate bolts, roll fender lips and possibly move oil lines and hoses to make them fit. Here's a pic of my 911 with this set-up at Nationals in Topeka last year.

orbmedia · 04-02-2002, 04:08 PM

Here's a gaggle of F club race cars with this setup too:

Eric Coffey · 04-02-2002, 05:17 PM

Good idea Jack, I too would stick with the SC/Carrera flares. Randy was gracious enough to give me a ride in the white car at a recent Auto-x, and I can assure you that the big rubber definitely works under non-turbo flares!

(with Randy taking top time of the day no less). Also, the other downside of the wider flares is the substantially increased frontal area & drag coefficient.

hilandscott · hilandscott's Garage

Is there any consensus as to the best tire size for a 16" or 17" wheel? I ask given the desire to increase the contact patch yet not decreasing torque off the line (as Bill hinted) or having an easily damaged rim from too little sidewall.

At the moment I have the stock 16X5 and 16X7 setup.

Thanks

Bill Verburg · Bill Verburg's Garage

I don't think you will ever reach a consensus as to the best setup because it will always depend on the type of use the, the engine power, gearing, and the owners personal bias. The bigger tires/rims are worth every penny and every bit of trouble on the track, but they offer little real benefit for normal street use.

Here are some pics showing the mods to the trailing arm nuts and oil lines which the 9.5 7 275/40 combo required.

RarlyL8 · RarlyL8's Garage

Common Jack...................think WIDE. You know you secretly like 'em hippy.

When this car was stock I ran a set of Gembala 9&11x17s. Had 225s on front and 255s on the back. Made for a REALLY cool look. The rims fill out the well and the tires don't interfer. This was for the street though. Can't help you with track stuff.