Tire size help - '65 GTO

[PT Goat]

I am finally ready to order tires for this thing and I cannot make up my mind. Wheels are 17x7 front and 18x8 rear, 4.75" and 5" backspacing. It's lowered about 2" in the rear and 2.5" up front.

On the rear, I'd like a 255, with the aspect ratio depending on the front, but maybe a 255/45/18. Was shooting for a 27" tall tire in the rear.

For the front, I'm all over the place. 225, 235, 245, I can't decide. I don't think I want to try a 245, but maybe I could be talked into it.



Thoughts?

[DriverzInc]

On a 7" wide wheel, and with running a 255 on an 8" wide wheel, you want to stick to a 225 -235 wide tire. This way your tire bulge on the rear won't look smaller than your front tires.

A 255/45/18 measures 10.16 (according to Nittotire.com)
An 8" wheel measures 9" overall in width. So your tire bulge on each side will be .58".

A 235mm wide tire measures 9.3" wide. On a 7" wide wheel that measures 8" overall, your sidewall bulge is .65".

A 225mm wide tire measures 8.9" wide. On a 7" wide wheel that measures 8" overall, your sidewall bulge is .45".

So you see how the math breaks down, and what you'll potentially be left with in sidwall bulge. Last thing you would want is your front tire too look fatter on the rim than the rear.

Now.. overall diameter is another big part of the equation. My suggestion, for a 17x7 and 18x8 set up on a 65 Goat, try and keep your overall diameter at least 1" greater in the rear than in the front.

Call if you need help finding the right tire. We sell almost every Nitto tire on ebay, and we list all the specs for each tire in every auction if you are looking for the best price on Nitto. If you are interested in any other brand from Falken to BFG, give us a call. Good luck!

[66SuperSport]

On our '66 Chevelle SS convertible I went with 245/45/17s and 275/40/18s. Has the 1" stagger in height and are stock sizes for a C-5 Corvette so there are LOTS of tire choices.

[PT Goat]

Thanks for the replies so far - Jon I sent you a PM.

I never thought about sidewall bulge, just another calculation to factor in. Also trying to make the sidewall heights similar.

Having a hard time finding matching front and rears, but I do see options with the BFG KDW and Nitto NT555.

[PT Goat]

I've done a lot of research and here are the two options I've come up with to go along with my planned 255/45/18 rears, which are 27" tall:

Nitto NT555 - 235/45/17 - 25.28" tall with .67" sidewall bulge.

The Nitto 255s would be 27" tall / .65" bulge.

BFG KDW - 225/50/17 - 25.9" tall with .60" sidewall bulge, or
BFG KDW - 235/45/17 = 25.4" tall with .65" sidewall bulge.

The BFG 255s would be 27" tall / .55" bulge.

[PT Goat]

Finally got my tires and couldn't be happier - BFG KDW 225/50/17 and 255/45/18. Only have the rears mounted up now and they are perfect. I think a 275 would fit but inner fender would need some hammering and a little wheel lip trimming. A few teaser pics until I can get it outside for a full shot.

[a73formula]

that looks really sharp, I like those wheels with the red lines on pontiacs.

[BA.]

yeah, those wheels will look great on the 65 Goat!! Nice job!

[19 usac]

who did the red lines? thanks Jim

[PT Goat]

who did the red lines? thanks Jim

Diamondback is the only one doing custom redlines that I know of - I have three sets.

www.dbtires.com.

[19 usac]

thanks.

[[email protected]]

beautiful rims pt, are those vistas? Remininisant of the hurst wheels. Definately fit the gto image. I have v-rods on the way! I almost went with the matrix, similar to vista. I hope I made the right choice. Ill post pics next week. They should be here by then. I was also looking at a 255/45-18 for my rear. I like the bfg kdws. Cant wait to see your pics with all your shoes on!

[Murf]

Looks great, Matt. I'm working on a Mayfair Maize 65 vert and am trying to decide on tires & wheels. Could you post a pic or two of your car with these wheels on it? Thanks!

Murf

[PT Goat]

Hey Murf - I'll get a pic up asap but I've got the front fenders off right now trying to sort out a few issued before I close her up for the last time. As soon as it's together, I'll throw the fronts on and shoot some pics!

[PT Goat]

Here are a pair of pics, obviously I've still got some work to do but it's getting closer. Sorry for the poor pic quality, by the time I got them bolted up it was almost dark.

[gearheads78]

That looks soooo good

[Murf]

Thanks Matt, Beautiful car! Mind if I PM you sometime for some specific's on your car?

Murf

[eric1967]

That looks great. I am building a 1964 Lemans. This is some great info that will come in handy. You sould post more pics with the front end on & some more info on the car. Thanks Eric

[eric1967]

What back space did you go with?

[PT Goat]

What back space did you go with?

Eric - Fronts are 17x7, 4.75" BS, rears are 18x8, 5" BS. If I had to do it again, I'd go 5.25" in the rear, its pretty tight to the fender, plenty of room to the frame. As for the other specs, I did a build thread back in the day, I guess I should pull that up and update it.

Murf - fire away!