im going to be working on a friend of mines 924 who is putting a widebody kit on the car. I found some wheels at a swap meet and bought them for the guy who needed some wide enough wheels. The tires on the rims which is prob. the size we will stick with, is 285/40/15. I cannot find these tires available anywhere! Any ideas. They would need to be streetable tires, not slicks.

can you believe i only paid $200 for these? THey are very nice, 205's on the front. Almost thought about putting them on the teener but...just cant do it.

no one makes 285/40 15 or 16 anymore. and i mean *NO ONE* ...

i have been trying to find that size for months now as i have a set of 8x16 and 9x16 rims i want to put on the teener.

i couldn't find a single manufacturer that still makes them. pirelli used to make them, but they stopped like 15 years ago.
which means if you still manage to find a set of pirellies, they're probably hard as a rock by now ...

anyways, if you find a manufacturer,
PLEASE let me know!

Andy

my .02

285 seems like too much tire for an 8 or 9 inch rim, Andy.
A 245 or 255 seems like plenty according to manufacturers specs.

xsboost, what is the rim width on those wheels you have?

I would measure the tires you have, section width and overall diameter, then compare to some tires you can find at tirerack.

They usually post tires specs from the manufacturer on Tire Rack.

Here's some Hoosier specs:

Hoosier specs

QUOTE (tommy914 @ Dec 22 2004, 09:55 PM)

285 seems like too much tire for an 8 or 9 inch rim, Andy.

factory porsche specs for the 914 GT:

front:
8 x 15 with 245/45 tires

rear:
9 x 15 with 285/40 tires


285 is perfectly fine for a 9" rim ...
Andy

and because the proof is in the pudding, here's are the factory specs, tire/rim combo in question highlighted green:

I don't know that I would base my selection on what was used in 1970. Tires have changed a lot. Bias ply vs radial etc..
I think you would find that looking at the tire manufacturers recommendations on modern tires would be a better guideline for finding something that will work.

Those specs are kinda interesting. there seems to be a huge difference between the v. and h. sizes. What does that mean?

Porsche may have picked that huge section width for other reasons. Since section width is also tied to overall diameter, maybe they were trying to get the tallest tire that they could under GT rules so they could go faster at LeMans.

QUOTE (tommy914 @ Dec 22 2004, 10:28 PM)

I don't know that I would base my selection on what was used in 1970.

i have to disagree.
the only reason why you can't find 285/40 x 15 anymore is *not* because the width/ratio of the tire is unusual, it's just that the manufactures today don't make a good selection of tires for the 15"/16" rims anymore.

you *can* get 285/40 in 17/18/19 because those are the more *common* sizes there days.

there is nothing wrong with 285/40 on 9" wide rims, i can get them in 17 or 18, just not in 16 or 15 anymore.

i have looked at *a lot* of tires lately (trying to find something for my 16 x 9) and while a 245 tires would technically fit on a 9" ALL the manufactures list 9" as MAX width for their 245 tires.
that means that the tire will be streched to the max. on a 9" rim.
something i do NOT like at all.

i currently run 225/50 on 7" and when i compare the sectionwidth/rimwidth of that combination, the best fit for the 8" would be a 245 and for the 9" a 285 ...

225 on 7" = 1.265 ratio
245 on 8" = 1.206 ratio
285 on 9" = 1.247 ratio

Andy

QUOTE (tommy914 @ Dec 22 2004, 10:28 PM)

there seems to be a huge difference between the v. and h. sizes. What does that mean?

v = vorne = front
h = hinten = rear

Andy,

I'm running:

- 225/50/16 on 8s

- 245/45/16 on 9s

Yokohama a032r

It seems like a perfect fit. Nice straight sidewall (less flex keeps the tread flatter on the road).

Eddie

Looking at current Porsche Carrera specs.
235/40 on 8 inch fronts.
265/40 on 10 inch rears.

ok, i give up ...

if anybody has a lead on a set of 285/40 x 16 tires, please let me know.

have cash $$$, need tires ...
Andy