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What is a good wheel offset?


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I have a 72 Monte and I have recently visited a few tire shops around town. I kept getting asked the same question. "What offset do you want?" I have no clue what they mean I thought these guy's are suppose to be able to help with this. Anyway I'm looking to put 18's in the front and 20's in the back. Is there any king of modification that needs to be done prior to buying? Does anyone out there have this set up?

Thanks for your replies!!

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Thats a tough one with that large of wheels...

 

You might have to revive this thread once and awhile till someone with that combo comes across your post...here you go... take it to the top. lol

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Not 18's, but some numbers from my car to consider...

 

I run 15x8 Rally's, which are zero offset, or 4" backspace. I am running 235/60-15 fronts & 245/60-15 rears. Go to a tire sizing site (Tire Rack?)to figure the overall width and diameter these would be. On my car, the right front rubs, but nose is low and sheet metal is shifted over to the left a bit. This is more pronounced with a passenger. Rears don't rub (I have urethane bushings, so side-to-side motion is reduced) except when carrying passengers in back, and then minorly only on left. Back is also lowered. Front and rear fenders are stock, upper inner fender retaining bolt on front fenders has been removed on both sides.

 

I feel 4-1/2" backspacing would cure most of these rub issues, as well as raising the car up. Most aftermarket big Rallys (15x8 and 16x8 from Stockton) are recommended to be 4-1/2" backspace for a Monte. However, I like the way my car looks with the wheels pulled all the way out.

 

Just some thoughts.

 

Best,

Tom

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Tom is correct. 15"x8" rally wheels with 4 1/2" backspacing were created in order to better fit 8" wide rims on the midsize "A-body" cars, as the 15"x8" Corvette rally wheels have less backspacing and there tend to be clearance issues unless the car is raised up and/or smaller tires used with them.

 

I read an article about a year ago in a car magazine that basically said they wouldn't ever put anything larger than 18" diameter wheels on older cars. Their suspension systems weren't designed to handle the additional size and weight that larger diameter wheels bring along with them, as well as the fact that you then have to run such a super-low profile tire that the shock absorbing characteristics of the tires are pretty much eliminated - meaning that the rest of your suspension pieces will have to endure the additional stress and wear.

 

Handling-wise, an in-depth article in Super Chevy magazine several years ago where they tested various wheel and tire sizes on a '70 Monte Carlo proved that bigger is not always better - at least up to a certain point. Their best slalom times were achieved with 17" diameter wheels and reasonably-sized tires.

 

Steve (Monteman71), a member of the FGMCC, has stated that his current '71 402/4-speed car with 17"s rides better than his previous car which had 18" wheels (and slightly lower profile tires) on it.

 

Personally, if you want to go for a "plus-size" wheel diameter, I'd save your money and your suspension components and wouldn't recommend going with anything bigger than 17". As far as backspacing and tire sizes for a 17" wheel go, I can't say because I'm a 15" diameter w/beefy tire fan - because to me nothing looks tougher than some serious rubber in the wheelwells of a classic musclecar. Steve would know about what to use with 17"s, though, and I like the way his car looks with them. He "plus-sized" by 2" and he did it right.

 

Well, that's my take on it - and I hope it is of some help to you. smile

 

Dave

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Front BS Use 4.25(Stock) to 4.5"

 

For the Rear you can go to 5.5" and if the rear is exactly centered in the chassis you can go 6" BS but it is getting very close to the lower shock mount.

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