[racerboy]

I picked up a set a clean set of 15x7 Rally II wheels for my '70 TA. I was looking to get a set of radials for it and keep the JW wheels, and Polyglas tires for shows.

Even with the factory wheels, it looks like the TA could use a bit wider tire, especially in the back. What's the widest I could run (on a 15x7 wheel) and would you recommend staggered widths (a bit narrower up front)?

I was originally just going to order a set of the ubiquitous BRG Radial T/A tires, but I was reading though a number of posts that complained about the RWL yellowing on the modern versions. So then I thought about getting a set of the Firestone Wide-Ovals. I'm assuming these will be more expensive than the BFGs, but I'm willing to pay the extra cost to avoid the yellowing. Any thoughts?

[Formulabruce]

Really should NOT run wider than a 60 series tire on a 7 inch wide rim as the sidewall can roll MORE than it should. Factory 26 inch tall tire gives limited options. The BFG , Cobra, and the repro Firestone All don't balance well when you high speed balance them. A 15x8 rally might be what you want on the rear. Keep in mind these cars were built to sit slightly lower in the rear for a few reasons.

[racerboy]

Thanks Bruce. If I stay with the stock F60 size (not sure what that translates to in modern sizes) is there really no difference between the BFG and Firestones?

Is the G60 wider than the F60? I think I saw those on the Coker site.


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[72projectbird]

I run 245/60-15s on the front and 275/60-15s on the rear.

Definitely not a stock look, but they fit fine.

[71GP76TA]

I'd run a 235 or 245/60R15 on all 4 corners. Running a larger back tire on the same size wheel as the front doesn't look right in my opinion. They end up looking like balloons... throws off the balance of the car... If you are going to run a fatter tire in the rear.... buy a wider wheel for the rear..

[SD455DJ]

Racerboy, You can run 255/60R15's without any problems on all 4 corners of your TA. They mount very nicely on 15x7 wheels and are 27"+ tall, so about 1.5" to 2" taller than F60-15 Polyglas's. Here is my '71 Formula with 15x7 Honey's w/255/60R15 Radial TA's and 15x7 steelies with 255/60R15 Mickey Thompson's (which are 1/2" taller?).

Dennis

[78w72]

255/60 are the closest in height to the stock 225/70 tires & fit on a 15x7 wheel nicely... no ballooning or rolling of sidewalls.

check out the M/T st radials, they are a solid white letter & dont have the browning issue of BFG's from what ove seen. they are also a more modern tread than bfg with higher speed ratings... & cheaper too.

[napster]

Racerboy,

Here are some pixs of my '70 & '73. I'm running 245's on the front of the '70 and 255's on the back. Using the original JW's. The '73 I'm running 255's all around.

I was running a 255 on the front of the '70, but had a slight rubbing problem. going to the 245 solved the problem. The '73 uses 15x7 rims with no rubbing issues.

Hope this helps.

[Norwood]

245 fit nicely and look correct. I have run 255s on the back in the past

[Formulabruce]

Originally Posted by 78w72

255/60 are the closest in height to the stock 225/70 tires & fit on a 15x7 wheel nicely... no ballooning or rolling of sidewalls.

check out the M/T st radials, they are a solid white letter & dont have the browning issue of BFG's from what ove seen. they are also a more modern tread than bfg with higher speed ratings... & cheaper too.

225/70 is a 26" tire.
Think you will find that the 255/60 are over 1 inch taller.

[Norwood]

Originally Posted by 78w72

255/60 are the closest in height to the stock 225/70 tires & fit on a 15x7 wheel nicely... no ballooning or rolling of sidewalls.

Just to clarify stock size on a 1970 Trans am is F/60-15

[weranc55]

Originally Posted by Norwood

245 fit nicely and look correct. I have run 255s on the back in the past

Yup that’s what I would run. 245/60/15 bf’s.

[racerboy]

Appreciate all the feedback and photos!


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[72projectbird]

Originally Posted by 72projectbird

I run 245/60-15s on the front and 275/60-15s on the rear.

Definitely not a stock look, but they fit fine.

Here's some pics:

[78w72]

Originally Posted by Formulabruce

225/70 is a 26" tire.
Think you will find that the 255/60 are over 1 inch taller.

26"? where do you see that? a 225/70 is 27.4" tall & was the stock size on later 2nd gens & fill the wheel wells better than a f60 at 26" tall IMO. 225/60 is 27.1.

https://tiresize.com/tiresizes/225-70R15.htm

[SD455DJ]

Originally Posted by 78w72

255/60 are the closest in height to the stock 225/70 tires & fit on a 15x7 wheel nicely... no ballooning or rolling of sidewalls.

check out the M/T st radials, they are a solid white letter & dont have the browning issue of BFG's from what ove seen. they are also a more modern tread than bfg with higher speed ratings... & cheaper too.

I'm running the MT Sportsman S/T's...so far I like them better than the BFG TA's, and they were cheaper and have nice smaller solid white letters that have stayed white over the past 2 years since I bought them.

My only complaint is the perimeter sidewall scallops/ribbing (for lack of a better term) looks too heavily textured to me. I prefer the total smooth sidewall look like on the original Wide Ovals and Polyglas tires, even the original Goodyear Eagle ST's...but, still they are very good tires.

Dennis

Dennis

[keith k]

Originally Posted by SD455DJ

My only complaint is the perimeter sidewall scallops/ribbing (for lack of a better term) looks too heavily textured to me.
Dennis

Agreed. They almost look like off road tires from the side...

[Formulabruce]

Originally Posted by 78w72

26"? where do you see that? a 225/70 is 27.4" tall & was the stock size on later 2nd gens & fill the wheel wells better than a f60 at 26" tall IMO. 225/60 is 27.1.

https://tiresize.com/tiresizes/225-70R15.htm

I run the late second gen tires on one of my cars. The 225 are 26 inches, on the car with 31 lbs of air though. Not a calculator

[Formulabruce]

Originally Posted by SD455DJ

I'm running the MT Sportsman S/T's...so far I like them better than the BFG TA's, and they were cheaper and have nice smaller solid white letters that have stayed white over the past 2 years since I bought them.

My only complaint is the perimeter sidewall scallops/ribbing (for lack of a better term) looks too heavily textured to me. I prefer the total smooth sidewall look like on the original Wide Ovals and Polyglas tires, even the original Goodyear Eagle ST's...but, still they are very good tires.

Dennis

Dennis

Sipes!! They have lots of sipes, and are on the sidewall. Haven't seen those on street cars before

[78w72]

Originally Posted by Formulabruce

I run the late second gen tires on one of my cars. The 225 are 26 inches, on the car with 31 lbs of air though. Not a calculator

ok, never really heard of anyone sizing tires by measuring when on the car, the weight of the car obviously changes the height of any tires stated dimensions. a f60 would be 24.5" based on that.