Tire Sizes
Thread Starter
Advanced
Joined: Apr 2007
Posts: 52
Likes: 0
From: central Maine, Currently: Jersey
Tire Sizes
Whats a good Tire Size for an 86' 951 ? Wheel offset? are 17s good or bad? was hoping to up a size and get sport cup 3 wheels and a little more tire surface.
Pro
Joined: Apr 2004
Posts: 652
Likes: 13
From: Rochester, NY
Search my friend, this has been discussed before... but I'll briefly run through it.
the best offset you can get is a wheel with the same offset as stock, which i believe is 23mm. But as i discuss later it is dificult to find such a wheel so most of us 86 offset folk use spacers to make up the difference.
Secondly 17's are better than 16's if they are equal in wieght. A 17 offers more sidewall stiffness, which allows quicker turn-in, and more contact. But 16's tend to be lighter which means less rotating mass, and quicker acceleration. The problem you face is that hardly no one makes a 17in wheel with the same offset as an 86 951. Milli Miglia makes Porsche knock offs but they tend to be a lot heavier and more for show than performance.
As for tire size, you want to find something that maintains the same overall diameter as stock, otherwise you will mess up your speedo and such. My rule of thumb is to try and get as much tire as you can fit under the car and on the rim. Most people try to match equal sizes to all corners so that you can rotate and it helps remove the factory inherent understeer.
i think i covered most of it, if not search for the rest..
-Dan
the best offset you can get is a wheel with the same offset as stock, which i believe is 23mm. But as i discuss later it is dificult to find such a wheel so most of us 86 offset folk use spacers to make up the difference.
Secondly 17's are better than 16's if they are equal in wieght. A 17 offers more sidewall stiffness, which allows quicker turn-in, and more contact. But 16's tend to be lighter which means less rotating mass, and quicker acceleration. The problem you face is that hardly no one makes a 17in wheel with the same offset as an 86 951. Milli Miglia makes Porsche knock offs but they tend to be a lot heavier and more for show than performance.
As for tire size, you want to find something that maintains the same overall diameter as stock, otherwise you will mess up your speedo and such. My rule of thumb is to try and get as much tire as you can fit under the car and on the rim. Most people try to match equal sizes to all corners so that you can rotate and it helps remove the factory inherent understeer.
i think i covered most of it, if not search for the rest..
-Dan
Burning Brakes
Joined: Mar 2006
Posts: 999
Likes: 1
From: Seattle, WA
17" Wheels are prolly the best way to go. Tire Size depends on the size and width of the wheel. Your offset is 23.3mm. Some cars have spacers on them.
For the upper sizes, I personally just put on some 18" 3pc Lightweights, with the rear 11" wide with a 285/30 on it. 295 fits but was a bit too big for me. Need to paint my old center caps grey though.
ps... if anyone knows who makes them let me know :P Only thing on the wheel is made in germany and cassat. They were off of a 993.
For the upper sizes, I personally just put on some 18" 3pc Lightweights, with the rear 11" wide with a 285/30 on it. 295 fits but was a bit too big for me. Need to paint my old center caps grey though.
ps... if anyone knows who makes them let me know :P Only thing on the wheel is made in germany and cassat. They were off of a 993.
Race Director
Joined: Jan 2002
Posts: 10,170
Likes: 2
From: North NJ, USA
Dan,
Is your car lowered? A lowered car + 17 inch wheels can lead to catastrophic ball joint/a-arm failure. (Do a search)
Based in your siggy, it looks like you're into either AX or DE / Track driving. If that's the case, then I would suggest the following:
- Stay with 16's, but try to get 8JX16 wheels all around.
- Wrap some 245-45/16 sized tires around the wheels. They will fit the fronts (and rears) no problem.
That setup is cheaper than going with 17's, and will give you much better turn in, and will give the car a more neutral handling attitude. Plus if you ever get into club racing, I believe going with 17's will bump you out of stock classes. Same applies in AX -- 17's will push you up a class or two, depending on our local club's rules.
-Z-man.
Is your car lowered? A lowered car + 17 inch wheels can lead to catastrophic ball joint/a-arm failure. (Do a search)
Based in your siggy, it looks like you're into either AX or DE / Track driving. If that's the case, then I would suggest the following:
- Stay with 16's, but try to get 8JX16 wheels all around.
- Wrap some 245-45/16 sized tires around the wheels. They will fit the fronts (and rears) no problem.
That setup is cheaper than going with 17's, and will give you much better turn in, and will give the car a more neutral handling attitude. Plus if you ever get into club racing, I believe going with 17's will bump you out of stock classes. Same applies in AX -- 17's will push you up a class or two, depending on our local club's rules.
-Z-man.
Pro
Joined: Apr 2004
Posts: 652
Likes: 13
From: Rochester, NY
I go to de's but, i haven't used 17's. I recently got the 17's and before i used my 16in phonies. I'm aware of the ball joint failure problem. But doesn't that only apply to cars that are lowered, mine is basically at stock ride height.
