Buick Rally Wheel Question?

[Roadmaster666]

Hi new here, saw this forum and you guys seem extremely knowledgeable.. so Im restoring some old buick rally wheels and just finally got to priming the middles so I can paint them... I just recently got the tires that came with removed from them so It would be easier.. While they where laying on my bench side to side I noticed something. one of the wheels looked smaller from the side... I got a measuring tape and measured the side of them and sure enough one wheel is 15x7 and the other three are 15x8 ..... now I had no idea of knowing that cuz the tires where on untill just recently... Now question is, will the 15x7 work with the other wheels or did I waste more than 15 hours restoring these wheels for no reason??

note that these are for my daily driver and I dont plan on going higher than highway speeds....

[carcrazyjim]

IMO, it probably won't hurt anything. But if it were mine, I would check the spare wheel. If it's 15X8 I would use it and put the 15X7 on the spare. OR, I would buy another 15X8 just so that all 4 were the same. A quirk of mine, I suppose!

Welcome to the board.

[N360LL]

having different size wheels can lead to a handling problem in an emergency situation or when driving with enthusiasm. The slip angle of the tirer is directly related to the rim width. So it you are using the same tire on two different width rims the tire will have a higher slip angle on a narrower rim thus causing a vague and unstable feeling in the hands and seat of the pants.

I would not use three of one size wheel and one of another as the daily configuration. As a full sized spare- yes.

[ragtops]

Sorry to tell you, that is not the proper way to measure wheels. The place to measure is the inside of the lip where the tire fits, where the tire is held in place to keep it on the rim. What you have are three 15x7 and one 15x6. They are for a big car with a 5" bolt pattern. You don't say what car they are going to be used on but they will not fit a Skylark size car.
I see "Roadmaster" in your user name, so hopefully these fit your car.
I can only give an opinion, based on the type of driving I do, which is definitely not aggresive. Having one different size wheel will make very little difference. I would use it on the rear if it was my car, and anyone who just cruises around would not know it was there.

Best luck,
Mike

[Roadmaster666]

IMO, it probably won't hurt anything. But if it were mine, I would check the spare wheel. If it's 15X8 I would use it and put the 15X7 on the spare. OR, I would buy another 15X8 just so that all 4 were the same. A quirk of mine, I suppose!

Welcome to the board.

Thanks for the welcome..



Sorry to tell you, that is not the proper way to measure wheels. The place to measure is the inside of the lip where the tire fits, where the tire is held in place to keep it on the rim. What you have are three 15x7 and one 15x6. They are for a big car with a 5" bolt pattern. You don't say what car they are going to be used on but they will not fit a Skylark size car.
I see "Roadmaster" in your user name, so hopefully these fit your car.
I can only give an opinion, based on the type of driving I do, which is definitely not aggresive. Having one different size wheel will make very little difference. I would use it on the rear if it was my car, and anyone who just cruises around would not know it was there.

Best luck,
Mike

Thx Yea I really had no idea I thought you just measure the damn wheel.. lol N yes they are for my daily driver 92 roadmaster limited which use the same bolt pattern.. I'm kinda strapped for time at the moment and really need these wheels on as my current tires are toast.. I was thinkin of putting it on the right rear cuz roadmasters have a side skirt over the rear wheels and it would hide any visual difference which i hear will be minimum..
Maybe I can use the smaller wheel for now and wait till I can get a replacement wheel... Does anyone kno where I could buy one rally wheel in fair condition? I only need the chrome around the edge on the lip to be in fair condition as the middles are being painted white to match my car...

[Jim Jones]

Thanks for the welcome..




Thx Yea I really had no idea I thought you just measure the damn wheel.. lol N yes they are for my daily driver 92 roadmaster limited which use the same bolt pattern.. I'm kinda strapped for time at the moment and really need these wheels on as my current tires are toast.. I was thinkin of putting it on the right rear cuz roadmasters have a side skirt over the rear wheels and it would hide any visual difference which i hear will be minimum..
Maybe I can use the smaller wheel for now and wait till I can get a replacement wheel... Does anyone kno where I could buy one rally wheel in fair condition? I only need the chrome around the edge on the lip to be in fair condition as the middles are being painted white to match my car...

A potential problem that should be considered is a difference in back spacing and wheel offset. Backspacing (sometimes called rear spacing) is the measurement from the back lip of the rim, to the mounting surface of the wheel center.

This dimension will determine location of the centerline of the wheel in relation to it's mounting surface (offset), and if offset is appreciably different on the 6" wheel than on the 7" wheels, it will alter the track measurement of the end of the car with the mismatched wheels. This may result in handling and drivability issues.

Typical steel wheels measure about 1" wider on the rim lips than on the bead seats. Thus a 15X7" wheel with a back spacing measurement of 4" is considered to be a zero offset wheel. The same 4" back spacing on a 15X6" wheel will result in a the centerline of the wheel being 1/2" indoard of the mounting surface. (-1/2" offset).

Ideally you would want 4 matching wheels, or at least a pair of matching wheels per axle. But in the event that one wheel is a mis-match, that mis-match should be in rim width and back spacing dimension only. Offsets should match. For a 15X6" wheel to have zero offset, the back spacing dimension should be 3 1/2".

[Roadmaster666]

http://www.kawasakiboeki.com/wheel_apgd/buick.html

I see... Well Im not saying im correct, but this chart says that the offset and backspacing are the same on the 63-78 Riviera (RWD) 15x6 & 15x7 wheels ( which Im sure is what I have) and I was told that I should be able to use half inch spacers on the 15x6 wheel to balance that 1/2'' offset you're talking about.. Does this seem plausible??

[Jim Jones]

http://www.kawasakiboeki.com/wheel_apgd/buick.html

I see... Well Im not saying im correct, but this chart says that the offset and backspacing are the same on the 63-78 Riviera (RWD) 15x6 & 15x7 wheels ( which Im sure is what I have) and I was told that I should be able to use half inch spacers on the 15x6 wheel to balance that 1/2'' offset you're talking about.. Does this seem plausible??

The chart you referenced seems to be in conflict with THIS (http://www.v8buick.com/attachment.php?attachmentid=158600&d=1264095216) one posted here on V8Buick. I do not know whether either is correct with regard to Riviera wheels, as I have never personally measured any of the big car wheels. I would recommend using either of these charts with caution. The only sure way is to measure the wheels yourself. Using the chart I referenced, I will calculate offset below.

15x6" with 3-7/8" rearspacing results in a negative offset of 3/8".
15x7" with 4-1/4" rearspacing results in a negative offset of 1/4".

Compare these two charts, and notice the differences. Then CAREFULLY measure your wheels to see if they match either chart. The following diagram may make it easier to identify measurement points.