Devon76

Okay guys I need some help. I have a 1976 Cutlass "S". I would like to put bigger rims on it without having trouble with steering and such. Now I have been told that my car will have the 5 on 4 3/4 Chev bolt pattern. I was told that I should be able to go up to 22" without trouble. Now I am not sure if this is rim size or total size with rim and tire. Weather it is or not I am intrested in a set of 18" rims from Boyd Coddingtons collection. Now i dont want to order anything this expensive with out knowing if the back spacing will affect my steering or anything like that. They are 18x7 with a 4" BS. Now will i have problems with the 4" BS (Back Spacing)???. They are also available in the 18x8 with 4.5" BS. If anyone has any information that could help me please do so. I appologise that I am not very knowlegable in this field at all. I could go and measure but I would never trust myself. haha. Thanks a million!

joe_padavano

Yes, your car has the GM midsize 5 x 4.75" bolt circle. Don't confuse rim diameter with tire diameter. The measurements that matter are TIRE outside diameter and width and WHEEL offset. For example, you can buy 20" (wheel size) tires with a smaller outside diameter than the 15" tires that came on your car originally (but PLEEZE don't do it - "rubber band" tires don't look good on these cars). Unless someone has prior experience and can recommend a particular tire size and rim offset, you probably are stuck with measuring. Every car magazine runs an annual wheel and tire issue and usually has the stock article about how to measure.

Devon76

Yea I was not sure if the 18'' rims would force me into a "rubber band" style tire. I just wanted to have somthing a little out of the ordinary and very flashy. maybe I should go down to some 17's or somthing to allow more tire room. I was affraid i was gonna go have to do some measuring. LOL. I guess i just figured that someone on here would have the same style body that I do and could tell me what my limitations are. Thanks so much for your help and fast responce Joe.

daverbmxer

An 18" rim isn't all that big. It's only 2 inches taller than our stock 16" rims. That's only an inch difference on each side which isn't all that low profile.

Now, I haven't measured, only eyeballed it, but I think you could fit a fairly large tire in there as long as you watch your backspacing. You don't want it sticking out so far that it will hit the fender.

This guy here has a 77, which will be the same as your 76 and he's running 22's.

http://www.cardomain.com/ride/492255

I'm not sure how much backspacing he's running (didn't bother to read far, I'm off to class here in a minute) but as you can see from the close up of his tire/rim shot, if they stuck out very far he'd be in trouble if he hit a bump.

And by the way, if it matters, I completely agree with Joe that it doesn't suit our cars at all to have "rubber band tires." It's an all right look if you do all the right stuff to the car but I'd take a thicker BFG/Kelly/Dunlop any day over a low-pro.

joe_padavano

A 76 Cutlass would have come with 14" rims stock with 15" rims optional. There were no 16s then. As I noted above, the rim diameter isn't the issue, it's TIRE diameter.

daverbmxer

My '77 came with 16's stock.. Nearly the same body style. And yes, I know its the tire diameter, but I'm just saying that he can have larger rims if he wants, still allowing the outside tire diameter to be the same as it is now if he buys a low profile tire for a bigger rim.

It's not rocket science.. my bad if it sounds like I messed my statement up.

joe_padavano

I guess I'd like to hear more, since I'm not aware of GM using 16" tires and rims on any car prior to the late 1980s. Even Corvettes had 15" rims in the late 1970s.

Devon76

Just ran out and measured my rims. They appear to be 16" on my measuring tape. They look like pretty standard cutlass rims. I think they are stock but im not 100% positive.

joe_padavano

What size is printed on the tire mounted on this rim?

The dimension that sets the rim size is not the outside diameter of the rim, it's the diameter of the hole in the tire. Since the bead of the tire needs to seat on the edge of the wheel, there's about a half inch of overlap (or an inch total difference in diameter). Thus a 15" wheel will measure about 16" across the rim. If you could measure the diameter of the wheel where the beads seat, that's where you'll get 15". As another test, find a car with 15" tires on it and measure the diameter of the wheel. You'll get about 16".

Devon76

Came to me to search for the markings on the tire. Its R-15. Sorry about the confusion. Im just gonna have to find someone local thats done it and can make sure im not messing up my measurments.

Oldsguy

I know it is a personal taste issue, but I don't think that the white '77 car given as an example looks good at all with rims that large. The car will handle like a lumber wagon too if you put rims on it that large. I visit a website for older cars and they are "nose in the air" for any tire other than bias ply wide whites (30s, 40s, and 50s cars). Don't want to be that way or discourage anyone from what they want but just be careful. The fenderwells in the 70s era cars just weren't as big as they make fenderwells now, I have seen ford fusions with 35 series tires on 18 inch wheels and they fit. Don't know if that is stock or not but...... At any rate back to your car, I would just guess, this is a guess, that you won't be able to go any larger than 18 inch wheels with 3" backspacing, and 40 series tires max, and that might be too large. With 14" or 15" original wheels on the Cutlass's in the 70s I don't think they looked good if you got any bigger than 50 series tires like Mickey Thompson Drag Radials.

Devon76

Im gonna have to get some more info i guess on the rims that im wanting. All it simply says is that they are a 5 on 4 3/4 pattern. and they are available in an 18x7 with 4" BS. and 18x8 with a 4.5" BS. I know im gonna have to get a bit of a low profile but im hoping i could stay away from the elastic band look.

joe_padavano

This is where your high school math comes in handy. The original tires on that car were probably in the 27" diameter range. A 235/50-18 tire has a 27.25" diameter and should fit fine. A 245/45-18 is about 26.75" in diameter and also should fit fine, though that starts to get a little short in the sidewall.

The other problem with monster wheels on these cars are the tiny brake rotors and drums that you can now see. Looks pretty rediculous (though not as bad as the Civics with monster rims and the stock 8" rear drums...).

Devon76

I want to thank everyone for the help on this subject. The business that is selling me the rims got back to me with some information. They say that I can definatly go with a 17x7 with no problems. Plus, as some people on here have allready stated. Bigger rims do not always look good on this car.

daverbmxer

Glad to hear that you got it all straightened out. 17's will look nice on there. You're still going with a tire diameter near stock though?

joe_padavano

Call my cynical, but I'm always worried when somebody who's trying to sell me something says "it'll fit with no problems..."

Seriously, if the backspacing is about 3.5" there should be no problems with the wheels. Of course, the wheel vendor doesn't know what size tires you're planning to run. A 235/55-17 or 245/50-17 should be about right. Both are commonly available sizes at www.tirerack.com (but not cheap).

Devon76

They are 17x7 with a 4" BS. Im still wondering if its gonna work??? im lost. I can see that they probably wanna make a sale. Humm. what to do ?

Oldsguy

Let us know what happens...