Arominus

I was messing around over at the tire rack and noticed that there is actually a 245 tire available for a 16" rim that isn't a track tire. Toyo just starting making the Proxes T1R in that size so all of the stock Turbo S guys can get a street tire! its 280 treadwear and has no reviews as of yet since its so new. Its selling for $118 a tire.

Get it while you can if your trying to keep 16" inch wheels on your car. From what i remember, its been hard to get a decent street tire in this size for a few years now.

arthropraxis

I just sold my phone dials because there were no good options for 245/45 tires. Guess I should have held out.

cas951

The Proxes T1R have been around for sometime. I'm tempted of buying a pair just to have it.

Anyhow, I did a search by tire size and a Bridgetone Potenza RE-11 245-45R16 94W Extreme Performance appeared. This one doesn't appear if I do a search by vehicle model 944 turbo S.

I'm. It sure what the difference is other than the R speed rating.

Any ideas? I know newer Porsche's tires will have "N" on them. I don't recall older ones having these designations.

Paulyy

The T1r in a 245 isn't anything new. I've used those for a few years. They're an Ok tyre. Quip wise in the dry is pretty good. in the wet it's not that great and sidewall strength isn't that great either. Has quite a bit of movement.

JacRyann

Won't be that much sidewall movement with a 16x10" wheel.

Paulyy

I don't recall 944s coming out with 10" wide wheels. the turbo S had 9" rears with factory 245 45 r16 tyres.

JacRyann

Not a factory wheel, just that 16x10" would be better for the 245/45-16 tyre to minimize sidewall flex.

lee101315

How do you figure? 245 is already pretty stretched out on a 9" rim....

JacRyann

On 9" rim, there's still enough sidewall outside if the rim-edge to flop laterally. With 10" rim, pretty much all of the sidewall is inside the edge.

So during the turn-in, you don't have to compress sidewall laterally inside the rim edge, then load it in tension. You can't push with a rope, only pull it in tension. Same thing with sidewalls, they only act in tension when they are inside (laterally) the rim-edge.

Looking at a car cornering head-on, we've seen all those photos of front tyres that looks like they're going to be pulled off the rim. By pre-stretching tyre sidewall in tension, you eliminate the 2-3" of lateral motion needed before a tyre starts pulling on the wheel.

CO951

Of all the tires I've tried the Proxes T1R wore quicker than anything else when used for quite a bit of track time. Overall, there were better options for less $ 10 yrs ago, but times have changed. There were a few years I couldn't find any street 245/45R16s, so they must have stopped and then started making them again. I might be able to pull my old rims out of retirement.

Cloud9...68

Not to hijack this thread, but you make an interesting point. So many people try to stuff the widest tires they can on a given rim, but Grassroots Motorsports did an interesting test about a year ago comparing the performance of the same tire on different size rims, and their conclusion supports what you're saying. Their test was on a souped-up Honda CRX, and they got by far the best results with a 225 tire on a 9" rim, so not far off from your recommendation of a 245 on a 10" rim. Might be a little tough to get a 10" rim on the front of a 944, though.

divil

It sounds like the problem would be even worse on the front then?

245mm = 9.6" (9" wheel)
225mm = 8.8" (7" wheel)

JacRyann

Yeah, stuffing a 225mm tyre on 7" wide rims causes A LOT of sidewall flopping.

Interference is not a problem in front with 2.5" coilovers. I fitted 255mm tyres onto 10.5" wide rims without any problems.

964-C2

This is the stock front wheel spec on my 1988 turbo.. So why did Porsche go with such a narrow rim?

JacRyann

They used whatever they had in stock. Production cars are full of compromises based on costs, availability, legalities, etc. The '88 has 205mm on 7" rim. TurboS used 225mm on 7" front and 245mm on 9" rear.

Now the odd thing is that the 16x9" ClubSport rear wheel is a 928 part. There's also a 16x8" ClubSport in 928 as well. I suspect Porsche uses the CS 16x7" because it fit better with 65mm offset. The 928 16x8" wheel with 60mm offset probably caused too much rubbing on the outside. The original 205mm tyre was already rubbing as it is.