Stupid tire question

[ronaldtrotter]

I have four (4) 7jx16 fuchs and was wondering about putting 225/50's front and back. What would I be looking at handling wise and what would be the problems. I would use these as track wheels/tires for an 82SC.

[Jad]

The tires will fit fine on the rims, but a 911 with equal tires front and back will be a mess. WAY TOO much oversteer. I would not recommend that at all.

[Dan Chambers]

Ron: Probably depends on the offset of the Fuchs, and whether or not you can fit them under the wells. Being a 944 guy with a 912 in the stable (wife's car) my knowledge is limited on 911/912 tire configurations.

My guess (and it's only that, a guess) is that you might experience quite a bit of tail-out cornering (oversteer) with equal sized tires all-around. On an SC with the good power an SC has, and the weight of the engine behind the axle, the back end seems to like to "step-out" when you corner hard and either lift, or give a lot of throttle. (See Jad's post)

Many SC's and other 911's have wider rear tires as compared to fronts to help reduce the oversteer characteristics. There have been a couple of early 911's using 205 front and 225 rear set-ups for a more balanced cornering 911. Often they run wheels that are 6" front and 7" rear, or 7" front and 8" rear, I think. I can only tell you what I've seen at the A-X's in the past.

If Paul Young sees this thread, I'm sure he can recommend the best set-up. He drives an SC, and is absolutely a terror on the track (#1 in BRI at Big Willow recently). Maybe try to PM him from this forum for additional info.

And, of course, you can always go to a FAQ page on any number of forums/sites, or contact a local shop like Black Forest, Dieter's, Mind Over Motorsports or Mirage International, and bend their ear about this query. The local shops are really helpful.

One last thing, check the Rules Page run classification chart for proper and allowable tire size in your run group (I-Class, I believe). That will also give you some clue as to proper tire size.

Good Luck!

[Gary Burch]

Jad wrote:

but a 911 with equal tires front and back will be a mess

Jad, most of us 911 guys in F class run the same size tires(205/50/15) front and rear. Maybe that's our problem

[Steve Grosekemper]

The question is not can you, but should you?

The answer is NO.

They will fit sitting in your garage but the soft stock suspension will cause tire to fender contact in turns, and cut the front tires.

The 225's on a 7 is a but "wiggly" for the rear. This set-up with bigger torsion bars, proper shocks and 8" rear wheels would be great.

As for equal tire size on early cars... They don't have as much tail weight or torque so it is not an issue. 205's all the way around an SC would last about a block before it ended up backward into someones front yard.

[ronaldtrotter]

Thanks for all the info. Dan, I believe I can run up to 245's rear without going over my points. But, I can't find an affordable 8 at this time, which I need to run 245's. I am running 205/225 front rear now, but got a good deal on these wheels which came off a 80SC (and good Fuch's are not going down in price) So I don't see a problem there.

I think Don Middleton is running 8x15 wheels all around and the same size tires front and back. He seems to move the car around the course very well. I guess that was why I asked. Plus if you could it would be a great $ savings. I"ll keep asking right now the wheels have Bridgestones on them in 205/225 and they are very good, so I run those on the street and the Kumho MX's I have on the track for now.