odd tire size? [Archive] - Team Camaro Tech

: odd tire size?


mccomas
Nov 6th, 06, 05:13 AM
i just finished a disc brake conv up front and need to go with a 15 inch wheel (my 14s do not clear the new caliper). i am going to select a 15x7 rally. i am trying to select a 225/65r15 but only get one match at tirerack.com. what's the deal? i read through several posts from this forum and it seems like this is a normal size. for the last 20 yrs, i have been driving 4x4s and i am a bit out of touch with tire sizes.

first post and i need to get a signature together. i have a sweet 67 that i picked up about 2 months ago. 100% OEM (except my new disc brakes) with only 68,000

South Side Goons & Hitmen
Nov 6th, 06, 06:22 AM
MC,

P 255/65/R15 is a very uncommon size. I was in the tire & auto game from 1989-1998. I sold tires as well. I think that size may have only been used on 1 import. Maybe Toyota and maybe the Supra. I may be wrong on that. But the fact is P225/65/R15 did not come on anything that I can recall easily. P 225/60/R15 is very common and so is P 215/65/R15, but not P 225/65/R15. See below...

I would go with any of the following for 15" Rally Wheels.

1) P215/65R15 (original equipment on Z28's in the 1980's, even the FWD Cutlass Supreme's & Pontiac G/P/ had this size up until the early 1990's)
2) P225/60/R15 (these were OE on Mustang GT & LX's from the 1980's to early 1990's)
3) P235/60/R15. (I replaced my P 215/65/R15's on my 1984 Z with this size). I also run P 235/60/R15 on the 1969 Camaro I purchased a few months ago.

The P235 will give you a wider footprint/contact patch than the size you are looking for above. This will help dry traction, cornering and braking. The 60 series (called the aspect ratio) will give you a shorter tire than a 65 series but that is made up for in width becasue 235 millimeters is wider than 225. The tire will have very close to the same overall diameter.

My 1969 has 15x7 Rally's with P 235/60/R15 all the way around. They do not rub. You can get P 235/60/R15 from Kelly, Goodyear and others. Alot of tire manufacturers still make this size. The P 225/65/R15 is a very uncommon size and very difficult to find. Go with P 235/60/R15 which was also close to the equivalent of the F60x15 Firestone Wide Oval.

P.S. My 1969 now has disc brakes on the front.

Good Luck!!

Everett#2390
Nov 6th, 06, 06:52 AM
Agree with Goon's suggestions, 215/65's more common than 225/65's.

Food for thought, the skinnier the tire, the easier to steer, less tire contact. It all depends on what you intend to do with the car. If you have GM's one-finger power steering, then its a mute point.

Welcome to the club, hope your membership stays current. Turn out the lights when you leave.

DjD
Nov 6th, 06, 07:51 AM
Not sure why you decided on the 225/65-15 size but the closest to that with lots of brand choices is a 215/70-15. The Z/28 was the only Camaro in '69 (copos excluded) with 15" wheels and they came with E70-15's I believe. The modern equivalent is the 205/70-15.

225/65 = 9.0" sect width, 26.5" tall, 785 revs per mile
215/70 = 8.6" sect width, 26.8" tall, 776 revs per mile
205/70 = 8.2" sect width, 26.3" tall, 791 revs per mile

As others have said the 235/60-15 is the most common tire found on the '69 these days. Wider foot print, fits front and back on Z/28 size rallys, and everyone makes the size.

235/60 = 9.5" sect width, 26.1" tall, 797 revs per mile

BonzoHansen
Nov 6th, 06, 11:45 AM
Agree with above. Almost 10 years in tires and I never remember hearing of that size.

mccomas
Nov 6th, 06, 06:21 PM
thanks for the input. looks like i am going to go with a 235/60/15 on a 15x7 rally. will 4.5 backspacing work or do i need to look for 4 inch? this is on a 67 with stock front end and control arms. when i did the disc brakes, i replaced all bushings, ball joints and tie rods - so it is good and tight. if there is chance of rub, please advise and i will go to a 225.

i am running 275/60/15 in the back and they really fill up the rear end...

South Side Goons & Hitmen
Nov 9th, 06, 04:43 PM
On a 15x7 Rally, 4.5" of backspacing should be fine. Anything from 4" to 4.75" should be ok. I kind of winged it when I measured mine. I used a tape measure and said ah, close enough. I believe it was 4.25 backspacing on them. They are Rally's and look like Rally's but they are not O.E. GM factory Rally's.