86 Turbo Tire Size Questions

[wildcatbc]

Guys,

I need to put new tires on my 86 Turbo. I am new to the 944 world and would really appreciate hearing a few opinions to the below questions:

1) Is it better to stay with the factory sizes of 205 front and 225 rear or does putting the same size all the way around make more sense? If so, would it be 225's?

2) How wide of a tire can you put on it with the factory 16" wheels?

2) I am planning on using an all-season performance tire as I will most likely drive it pretty much year round. Any suggestions on tire brand and model?

Thanks in advance!

[AaronM]

The rear wheels are physically wider than the fronts. However, it is possible to fit 225-series tires on the front wheels.

I currently have 245/45 R16 on the rear and 225/50 R16 on the front of my '86 Turbo with the stock phone dial wheels. I have really liked this setup. However, it is ridiculously difficult anymore to find 245/45 R16 tires today. IIRC the only street option is the summer-only Fuzion ZRi ("Fuzion" is a Bridgestone brand though). Other than that, you're stuck with track tires (albeit DOT-approved track tires).

If you go with the stock sizes or even with 225/50 R16 all-around you'll definitely have many more options, especially for all-season tires.

[chally72]

Just installed 255/55/R16's rear and 225/50's on the front. That's the max I would go with tire size. The 255's give you many more choices, because as Aaron said, there's nothing for 245/45's.

[AaronM]

255/55 R16 is really going to throw the speedometer off. You'll be going 65 when the speedometer reads 60.

[Paulyy]

Originally Posted by AaronM

255/55 R16 is really going to throw the speedometer off. You'll be going 65 when the speedometer reads 60.

That's okay since our speedos run a little fast!

[derekc23]

I'm also in need of at least two new tires for my 86.

Currently, it has a set of old 205's up front (BFG Comp T/A's) and new 225's in the rear (Dunlop SP Winter Sport M3's).

Since these cars tramline (mine does anyway), how would 225's in the front and 255's in the rear affect its tendency to wander?

Otherwise, I'll probably just stick with 205's up front if I can't find a set of 255 Dunlop's for the rear.

[KEV951]

I will say this once, if you want handling out of your car, run the same size all around, buy a pair of 8" phones or fuchs or whatever, put them up front and run 245/45/16 all around. this balances the car and gives you WAY MORE FEEDBACK when you push the car to its limits, in otherwords, staggering is looks only. If your running 17 or 18 " wheels , same rule applies, your alignment guy and corner balancer will thank you

You can get toyo r888's and bf goodrich r compounds all day long in this size

[AaronM]

Originally Posted by derekc23

Since these cars tramline (mine does anyway), how would 225's in the front and 255's in the rear affect its tendency to wander?

Tramlining is much more a function of tread design and suspension geometry than of tire size. Any steering system that offers a lot of feedback and is combined with aggressive tires is going to tramline; there's not much to be done about it other than try less aggressive camber and toe settings or using less-aggressive tires.

Originally Posted by KEV951

I will say this once, if you want handling out of your car, run the same size all around, buy a pair of 8" phones or fuchs or whatever, put them up front and run 245/45/16 all around. this balances the car and gives you WAY MORE FEEDBACK when you push the car to its limits, in otherwords, staggering is looks only.

With 245/45 R16 tires in the rear and 225/50 R16 in front I'm already on the edge of excessive power oversteer. Anything I do right now to give the front proportionally more grip will only upset the balance of the car, not improve it.

[billy mild]

I got stock tire sizes. It seemed hard to find tires for our 16 inch wheels. But I got some Goodyear Eagle GT's. They are High Performance All season tires. They handle very well and are pretty sticky. Supposedly they are some of the best all season tires. Also I looked at some Continentals from Tirerack that were supposed to be really good in all weather as well.

[KEV951]

aaron , depending on your susp. setup, you will get more grip with 245's all around, atlease i did on my 951 , did the same on a racing 01 gti car running 255 all around and the same on an s14 autocross car also running 245's all around

[AaronM]

Originally Posted by KEV951

aaron , depending on your susp. setup, you will get more grip with 245's all around, atlease i did on my 951 , did the same on a racing 01 gti car running 255 all around and the same on an s14 autocross car also running 245's all around

More total grip, absolutely. However, since the car already has a tendency to oversteer and since going to 245s all around would only add grip at the front and not at the rear, I would only make the oversteer stronger by using wider front tires, which would make the balance worse despite having more total grip.

I have the car set up mostly for street though, so I can see it changing if I were to fudge the suspension setup exclusively for track use.

[RedDragon]

Aaron have you tried;
1.lower your rear tire pressure
2. Stiffer front sway bar
3. Dropping the rear ride height 10-15mm? US cars are set up to have a high bum for crash regs

Any of these will reduce your oversteer

[AaronM]

Originally Posted by RedDragon

Aaron have you tried;
1.lower your rear tire pressure
2. Stiffer front sway bar
3. Dropping the rear ride height 10-15mm? US cars are set up to have a high bum for crash regs

Any of these will reduce your oversteer

1) I run 40 PSI front and 38 PSI rear. I could increase rear pressure to 40 PSI to reduce oversteer (by increasing pressure you reduce the tire's tendency to rollover on the sidewall and by doing so you increase cornering grip, up to a point, of course, but in corners you get better grip by going up to 40-44 PSI or thereabouts). If I run 40 PSI all around, the oversteer is less and if I run 38 front and 40 rear, I'm nudging understeer.

2) Car's stiff enough as-is. It's a street car. :P

3) The car scrapes the sill extensions on speedbumps enough as it is. Dropping the rear 10-15mm would make it absolutely worthless as a street vehicle because I'd never be able to drive it in a parking lot again.

If this were a trailer queen that I drove only on the track, I could see points 2 and 3 (point 1 you have backwards), but for a car that has to pull commuting and grocery duty in addition to the occasional back-road fling they just don't make a lot of sense.

[RedDragon]

Stiffer front sway bar will not make it stiffer around town, just when you turn in as the weight transfer loads it up.

You could also try a sticky tire on the back and a harder tire on the front.

[derekc23]

I'm looking at putting 205/45R16's on the front 7's on my '86 951 since 205/55R16's aren't made in the tire that's on the rear - Dunlop SP Winter Sport M3's - has anyone tried that profile up front?

Will it leave too much of a gap with the fender?

The other option is to run 225/50R16's on all four. I just need them on there until I can find a set of 18's (or maybe 19's) that I like.