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shiftydr · 05-11-2009, 10:30 PM

I have a 1967 GTO Hardtop and a set of 4 15x7 Rally 2's. What size tire can I put on the rear without fitment problems. These are stock rims off of a later 70's T/A. I was going to put 215/70-15's on the front and was considering 255/60-15's for the rear. Is this the max rear size for these rims with stock offset? Any advice/experience will be appreciated. Also, anyone tried the new Mickey Thompson street tires yet? Thanks, Shiftydr.

carcrazy · 05-11-2009, 10:42 PM

I believe I have 225/60's on the front and 235/60's on the rear. Given the exisiting clearance, don't think I could go more than 245 on the rear. Not certain of the backspacing but probably stock.

BLUE67gto · 05-11-2009, 11:16 PM

I've had a set of 275/60/15 in the rear of my 67.

jotrout · 05-12-2009, 12:48 AM

I have 275/60/15 on the rear of my 66 now. You will love the look!

Joe

george kujanski · 05-12-2009, 01:09 AM

Jo and blue: what wheel width and backspace are you guys using on the rears? I'm planning on wheels and tires in the near future.

George

BLUE67gto · 05-12-2009, 01:43 PM

Mine was on a set of 2nd gen. Camaro rally wheels. I'm unsure of the exact size and backspace. They may have been widened from stock, But I think they would be close or the same as a 15x7 rally II . I should also mention that my car is lowered 1.5 inches and has had the inner wheel well rolled. My buddy still has them. so I will ask what size the rim is. I was just seeing how they fit.

BLUE67gto · 05-12-2009, 01:43 PM

Quote:

Originally Posted by jotrout

I have 275/60/15 on the rear of my 66 now. You will love the look!

Joe

I gotta say it fills it out nicely.

Rugratman · 05-12-2009, 07:47 PM

On mine with 4.5 inch backspacing. The widest that would fit are 245x60x15.
275/60 were way too wide.

235/60 on the fronts

GT182 · 05-12-2009, 09:35 PM

When I got my 66 it had 275/60s on the rear, on the 15x8.5 Cragars. Not sure of the back spacing tho. Needless to say they rubbed the wheel openings. I could barely get a finger between the two. That was the main reason she has airshocks and airbags, to keep the rear up so they wouldn't rub.

When I can afford new BFGs, I going with 245 or 255/60s on the rear and 225/70/14s up front. Also thinking for rolling the rear wheel opening lips too. Might even cut them close to the wheel opening mouldings. Which should give close to 2"s of clearance on each side.

Rugratman · 05-13-2009, 07:50 AM

5 inch backspacing is do-able. That will open up some options.

george kujanski · 05-13-2009, 09:01 AM

I have some old Keystone Klassics on the rear with 225/70-14 and the outer sidewall rubs the edge of the wheel lip.

Checking the specs of the Keystones, they are not available in a variety of backspacings; and these are probably 3" or so, causing the problems.

So it sounds like if I go to a backspace of 4' or so on a 7' wheel, I'll be ok with 235's without issues.

I really like the look of the Klassics, but not a lot of choices there. I'll probably go with Cragar SS; that's the traditional muscle car look for me.

George

GT182 · 05-13-2009, 04:51 PM

George, I'm running 235/60/15s on the 8.5 Cragar SSs now. They do look a little small tho. I'm leaning towards 245s or even 255s for new tires, as soon as I get the chance. I'm hoping the bigger tires on the rear might help a little with better gas mileage. Those 3.55 gears are a killer on gas. I know, an overdrive or 5 speed would be better but that's not an option for now.

vamman1 · 05-15-2009, 12:12 PM

255 60 15 BFG on 4.5 Backspace Cragar SS.

touched outer fender until I installed air shocks.
I like the raised rear so I've ordered El Camino springs as the air shocks were working too hard.

6 Grrrs · 05-16-2009, 10:34 AM

I have 255/60-15 on a stock 15x7 GM steel wheel. I believe the backspacing is either 4.25 or 4.375 on the ralley IIs, which is the same as the std steel wheels. There is a 225/60-15 on the front on the same 15x7.

shiftydr · 05-17-2009, 01:00 PM

Thanks to everyone for your replies. I was pretty sure that I could fit a 255/60-15, on a stock 15x7 rally, under my 1967 GTO. Tod Hoffman's last reply, with a picture of his beautiful 1966, has sealed the deal for me. Thanks again, Shiftydr.

b-man · 05-17-2009, 03:34 PM

Keep one very important thing in mind.

The '66 cars had a narrower rear end, by one inch overall (1/2" per side).

Late in 1966 the rear end changed in width. All 1967 cars have the wider rear end, MOST 1966 cars should have the narrower rear dimensions shared with the '64 & '65 cars.

I have a '66 3.36 posi rear end here in my collection that is one of the narrower rear ends, the date code verifies that it's a '66 rear.

Don't go by the recommendations of a '66 owner for rear tire fitment on your '67 unless they can tell you which rear end their car has.

Of course by this time the rear end may have been replaced at least once, GTO owners were known for hammering on their cars.

When you're trying to shoehorn the biggest rear tire possible onto your car that 1/2" makes a huge difference.

6 Grrrs · 05-18-2009, 05:14 PM

Bart,

What is the total length of the '66 rear that you have? I'd be interested in knowing if I have the narrow or wide rearend.

Also, where is the date code on the rearend?

The rearend in my car appears to be original with the proper 2 letter code for a 3.55 ratio in 1966. I don't know it off the top of my head. This car had 3.90s in it when my dad bought it in 1982. It now has 3.36's in it. Again, I have no way of knowing if it is indeed the original rearend, but when I 1st got it, I checked the code & it was accurate for the 3.55. The original trans is in the car & has the car's sequence # (VIN) on it. The original motor was long gone as there was a Poncho 350 in it with a 4bbl.

Thanks,

b-man · 05-18-2009, 07:54 PM

Tod,

The date code can be seen just above the casting #, looking from the rear it's at about the 4 o'clock position on the back of the lower stiffening rib.

My narrow '66 rear measures just about exactly 60" from drum to drum where the wheels mount up.

Bart

6 Grrrs · 05-18-2009, 08:57 PM

Quote:

Originally Posted by b-man

Tod,

The date code can be seen just above the casting #, looking from the rear it's at about the 4 o'clock position on the back of the lower stiffening rib.

My narrow '66 rear measures just about exactly 60" from drum to drum where the wheels mount up.

Bart

Thanks. I will measure mine up when I get a chance, and look for a date code.

shiftydr · 05-18-2009, 10:12 PM

Dang B-Man, I totally forgot that the rear end width was changed sometime in 1966! I do know for sure that my 1967 has a 1968 "N" coded rear axle that has 3.55 limited slip. I don't know if this is the original ratio for this rear as East coast oxidation has erased any stamping on the axle tubes. I am curious as to what length axle is in Tod's 66 as this could negate my wish to use 255/60-15s on my Rally 2s. Thanks again for keeping a close eye on us lead paint eaters. Shiftydr.

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