R&P options?

[rdane]

"7:31 was available until 1975. The Carrera 3.0 had a 8:31."

Anything out there with even taller gearing for a 915 besides the 8:31? If so where do I find one? And are they as durable as the 8:31

[Bill Verburg]

There was one that was marginally taller 7:27 but the difference isn't worth the effort and it is NLA anyway.

You'll need to use taller tires which is generallly what you are forced into anyway.

[rdane]

Thanks Bill. I really appreciate the time you put in here to answer questions.

Another one for you when you have the time. I am running 225/45/17s and 255/40/17s.

I was looking to stretch my short gear box a bit with my new 3.4 since I will be able to more easily push the 17s. Is it better to just go back to a taller 5th like your set up for highway cruising? Could you repeat your tranny's gearing?

[Bill Verburg]

When you say short, 7:31? or 8:31 w/ short gears?

As always gearing is dependant on purpose and usage. Mine is geared(from memory which ain't so good these days) for 180 or so and gives a relatively relaxed rpm range at 60-90mph, but that's its main usage and it has unbelieveable torque.

The 964 enginew/ the same gearing was also nice and relaxed at a that speed level, but I felt that it was somewhat over geared(too low numerically) most of the time, not torqy enough to compensate. But ok for the track use because lower 3^rd & 4^th gears were used.

The 964 w/ 245/45x16 and stock C3 trans was about perfect for that engine.

So i'm guessing that you would likely not want to go any taller than a 255/40x17 @ ~25.1" tall if the 915/67 gears are used.

As a sidebar, There is a very interesting Michelin Pilot Sport tire(not Sport Cup) that is supposed to be available shortly, 265/35x17 @ ~24.3" tall which would suit your application very nicely. There is also a matching 235/40x17 @~24.4" tall

Thanks, its nice to hear that somebody appreciates the effort, too many folks don't even bother to reply w/ a thanks.

My gearing, I use a ~25.7" rear tire