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Discussion Starter #1
Hey everyone,

I need new tires for my 67 GTO and would like to get some larger rims if they will fit. I currently have 15" rims that are 7" wide with 4.5" backspacing. I would like to go with 15" rims from wheel vintiques that are 8" wide. The big question is...will they fit in front without rubbing? The wheels are offered with 4.5" or 5.0" backspacing. According to my measurements the 5.0" backspacing should work better...but I'm not really sure! Tires will be 235/60/15 in front...again if they fit. Not sure about the back...maybe 255/55/15 or 275/50/15....but BFG does not make that size. Can anyone help?

Hollie
 

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Hollie, If you go on Tirerack.com, thet have a drop down that you can fill in. This will give you the height, width, ground contact width, recomended wheel width, load range, etc. This info should help you with measurements, that will help you decide which size tires to buy. Eric:cheers
 

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Discussion Starter #4
Unfortunately tirerack.com only lists the recommended tire size for my car. With a 15" rim they recommend 225/60/15 tires. I still don't know if an 8" rim will fit in the front, and I'd like to run a 235/60/15 tire because the total height is exactly the same as the original tires.
 

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Attached is an image showing front and rear side clearance from RS Racing;

Click here for a Tire Spacing and Offset calculator from; Autolounge.net

If you can get the correct backspacing the low profile 50 or 60 aspect ratio should not rub the front fender directly in front of the tire. Hope the information is helpful.
 

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Discussion Starter #6
Thanks for the info Randy. You've given me excellent advice on how to measure my wheel for clearance. However, having never done this before I don't really trust my measurements 100% on the front wheels as they are much closer to the fenders and suspension than the rear wheels. I believe 8" wheels will fit, but I'm tempted to order just two in case they don't. In that event I would put the 8" wheels on the rear and buy 7" wheels for the front.

I would still like to hear from someone who has 8" wheels on a 66' or 67' GTO! Is there anyone out there who has advice on this?

Hollie
 

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Hollie, On the Tire Rack site. there is a spot to shop "tires by size". between Randy's info and the tire dimension info, you should do alright. Personally, I would sacrifice width for suspension travel/rubbing issues. Nothing sux worse than driving down the road worrying about dips, curves, and are my tires gonna hit!!!!!!!!!!!!!!! Eric
 

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You don't want a 235 on an 8" wheel. The sidewall will stick out beyond the tread and look like a ricer.....:willy:
The recommended wheel width for a 235 is 6-7 inch. Keep the 7" wheels you have for the front and get 8" for the rear.
 

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Discussion Starter #11
Thanks for all your help guys. What started all this is one of my tires came apart and went flat. After investigating I discovered my tires were 19 years old! They all need to be replaced, so I wanted to entertain the idea of new rims and bigger meats. This week I will get a BFG 235 / 60 / 15 mounted on one 7" rim and see how it looks and if it clears OK in the front. I'll let you all know what I find.

Hollie
 

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Under the RS Racing link above, I have always had trouble trying to understand the "Backspace to Offset Conversion Chart". First it says see the chart on the right...on my computer it is to the left??? But, I think what it is saying that for a 7" rim, 4" is the correct backspace indicated by a "0" offset, 8" rim= 4.5" backspace??? If for example keeping with the 8" rim, with a backspace of 5 then the answer is 12? 12 what??

If it is 12mm then converting = .4724" ??
 

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I have 17x8s up front with 245/45s and no rubbing.....and my car is lowered about 1.5" (front). Backspacing is 4.75". You probably know this already, but just in case, an 7" rim measures 8" outside to outside, 8" rim measure 9" outside to outside, etc. I think this is because wheel widths are measured from the tire bead location, not from the outside edges.

65gto,
Offset is measured from the center of the rim, so 12mm offset means the hub flange (the plane where the wheel mounts to the hub or rotor) is 12mm towards the outside of the wheel from the centerline. I think positive offset is towards the outside of the wheel and negative offset is towards the inside of the wheel. Combine this with the extra 1" width from outside to outside and the numbers should work out.

Here's some pics of my car with the wheels and tires mentioned above.

Hope that helps,
Jeff
 

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Very nice Jeff, how does she ride with the 17's? What brand of tires did you put on?

Hollie
She rides fantastic! Although I have a mild pro-touring setup from Savistke Classic and Custom.....so lowering springs, Bilstein shocks, front upper and lower control arms, and a rear sway bar. The Bilstein shocks really make it ride nice......I had crappy KYB gas-adjusts before (no offense to anyone that has them.....an economical choice, just not a real high end shock).

I'm running the Nitto 555r tires, which are pretty sticky, so it hooks well and corners amazing. 285/40s in the rear and the 245/45s up front.

Thanks,
Jeff
 

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When I bought the 15" for my 67 I couldn't seem to get the help I needed. I called Summit and one of the guys there has a 67 and I let him talk me into 15x7. I put 215/65on the front and 255/60's on the back and they look great.

Just my opinion but I am really happy with them
 

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Discussion Starter #19
Hey Jim,

Wow...you managed to get a 255/60/15 on a 7" rim? Now you have me rethinking my plans! Can you please post a photo of your rear wheels? Curiosity is killing me!

I have the same size tires on the front now; 215/65/15. They look fine, but I think a slightly larger 235/60/15 would look and handle even better.

Hollie
 

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When I bought my car it had 275/60/15s on a 7" wide rim and they worked fine. If you get on it alot and like to do smoky burnouts (who doesn't?!?), then plan on them wearing out in the middle......I mean, more so than a tire on a properly sized rim. And I'm sure you sacrifice some handling performance as well. I ran those until they wore out, then I put on 255/60s because I don't care for the overly "raked" look. Before putting the 17s on and installing my pro-touring setup, I ran the exact combination you're looking for.......I had 235/60s up front.

Here's some pics of 255s. Why are they so worn in the middle? :lol:

See next post for pics of the 235s.....for comparison.
 

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