SloMo228

So, I've managed to obtain two sets of Cup II wheels for my '87 944S. I had planned on using the 17x9s for summer tires and the 17x7s for winter tires. I may still do that, but as I was moving them around the garage, I noticed how much heavier the wider wheels/tires are, and got to thinking that maybe I'd be better off performance-wise by using the narrower wheels for summer tires and keeping my phone dials on winter duty.

I would likely mount 225-series tires on all 4 of the 17x7s, or 245-series tires on the 17x9s. I know the 245s would likely provide more grip, all else being equal, but they are also about 7-10 pounds heavier per wheel.

Is the extra grip from the wider tires worth the extra weight? My S is stock engine-wise except for an S2 intake manifold swap. It's definitely making less than 180whp.

My car is street driven. After I finish catching up on the deferred maintenance, I plan to run it in some AX and DE events, but I have no plans to turn it into a trackday car, mainly just a nice-handling street car.

morghen

You can use 225 tires on the 9" wheels, here is how they look...but i think you need spacers to use the 9" wheels to clear the springs.
In my opinion for street driving you dont need the extra grip of the 245 tires.
I am driving with Conti Sport 5(had 3s before) 225s on all 4 corners on 9" wheels and i never felt i need more grip.

SloMo228

That's a nice looking 944!

The 245 series tires do weigh a couple pounds more than the 225s, but most of the weight difference is in the wheels, from what I can tell. I'm seeing weights of about 20lb each for 17x7 Cup IIs and about 28 pounds each for the 17x9s. So I'd probably stick with the 245s if I'm going to use the heavier wheels anyway.

Another consideration is that I'm going to be running an 015 manual steering rack - is the steering effort going to be too high for a DD with 245 series summer tires?

Arominus

I run 17x7/17x9's in a stagger and it works out well on the street, i run 225/255 re-11s. I have more power than you do though so i need the tire in the back. I ran 225's all around on 16" rims with my S and i liked it but it does get a little light in the *** when your really getting after it.

If your going to Auto-x or DE the car, more tire is always better as this means you can carry more speed through the corners.

morghen

Thanks, but its a 924 And it has manual steering, i never had anything wider than 225 on the fronts...but 225 on manual steering is quite ok even for city driving/parking.

This 924 has a rather large K27 hybrid turbo runing at about 1 to 1.1bar of boost on a 8,5:1 CR engine.
If the tires are not warm and/or the road is not clean it gets wheelspin regardless of the tire size. I had 3rd gear wheelspin in the wet with 245 older tires on the rears. But in a warm day with warm tires its on rails...but then again i never drove this setup on a track to see if its smoking its tires coming out of a corner or not.

JustinL

My vote is on wide. Our cars (n/a) aren't winning any drag races no matter what wheel is on. Wider looks so much better too. But then again, I'm biased as I run 18X10 on all 4 corners.

SloMo228

Whoops, you're right! Still nice looking!

SloMo228

Thanks for the inputs, all. I do have tires on all the wheels currently (even though they're old and hard) so I think I'll do some back-to-back testing to see if I can even tell the difference between them. I'm leaning more toward the 17x9s unless the difference in acceleration and suspension performance is dramatic.