[79TA455]

I have a '76 Trans Am that has 15x7 honeycombs and the current tire combination is 245/60/15 on the rear and 235/65/15 on the front. I was wondering if I could go bigger all the way around? Ideally, I would like to see 255/60/15 all the way around but have a feeling I could run into clearance issues and I'm not sure how bug of a tire the honeycombs can handle. Pictures would be great if anyone has any.

[77poncho]

1 have a 78 trans am with 7" snowflakes and in front i run 225/70 r15, on rear 255/60 r15

[79TA455]

Originally Posted by 77poncho

1 have a 78 trans am with 7" snowflakes and in front i run 225/70 r15, on rear 255/60 r15

My brother can get 245 (or 255) all the way around on his '81 Formula with 15x8 snowflakes without clearance issues. I figured I might be able to get away with the same size.

[1lms]

If you want to run trim rings then the largest is 255/60. Without you can fit 275/60

[The Champ]

Originally Posted by 1lms

If you want to run trim rings then the largest is 255/60. Without you can fit 275/60

I'm not understanding what trim rings have to do with fitting a tire???

As to a 275/60/15 - tire manufacturers don't recommend that size be run on a 15x7" rim. They specify an 8" miniumum width.

[skullbucket]

Originally Posted by The Champ

As to a 275/60/15 - tire manufacturers don't recommend that size be run on a 15x7" rim. They specify an 8" miniumum width.

A 275/60 will fit but will also eventually wear out the center of the tire on a 7in rim.

[HWYSTR455]

Originally Posted by The Champ

I'm not understanding what trim rings have to do with fitting a tire???

As to a 275/60/15 - tire manufacturers don't recommend that size be run on a 15x7" rim. They specify an 8" miniumum width.

The trim ring contacts the bulge in the sidewall and pops it off.

If you go below the min wheel width, you run the risk of when under side loads, loosing the bead of the tire. Picture a high speed sweeping turn and having a blow out. That will cure you of trying to do that.

Why not upgrade to the 8" WS6 package wheels if you want to go to a 275?

255 all around is a great handling setup, Herb Adams recommended it back in the day. Only reason I can think of why to run a 275 is drag. Just run an aftermarket wheel for track days maybe?

.

[79TA455]

Thanks for the replies guys. I will go 255 all the way around.....when I have the cash to replace all four. Maybe I will just do the rears this summer since they need it but money may be tight as we are building a garage and putting an extension on the house.

[transam greg]

I also have a ‘76 trans am. When I got it back in ’90 the tires on the honeycombs 15 x 7 were 255/55/15 made by firestone. They fit real nice, and no rubbing the wells. Even with 14 year old saggy springs.
Now I can’t get that size in BF Goodrich so I use 255/60/15.

[76TA462]

I have a 1976 TA and ran 275/60/15 (BFG) for years on my OEM 15x7 rally rims with trim ring. A few years ago I changed to 15x8 Cragar SST on the rear and used the same 275/60/15 BFG, and a couple years changed to Nitto 275/60/15 NT555R. Never a problem and no mods. Currently waiting on 18 in rims from Summit and will try to get bigger on the back, an expecting some minor mods (seat belt hump).