what is the backspacing on an 86/87 GN wheel?

[novaderrik]

i was confronted with the idea of trading the slots on my 74 Monte for a set of GN wheels- an old friend just got a 66 Chevelle that has GN wheels on it, and he wants my slots. i just want to know how they will sit in the wheelwells of the Monte.

 

[toofastforyou]

i was confronted with the idea of trading the slots on my 74 Monte for a set of GN wheels- an old friend just got a 66 Chevelle that has GN wheels on it, and he wants my slots. i just want to know how they will sit in the wheelwells of the Monte.

Back spacing on a stock 15"x7"GN wheel is 4".

Claude.:smile:

 

[SNOWBIRD]

It seems that a 4 inch back space is the magic number for a good fit but many of the wheell companys will offer a 4.5 and not a 4 inch WHY

 

[toofastforyou]

It seems that a 4 inch back space is the magic number for a good fit but many of the wheell companys will offer a 4.5 and not a 4 inch WHY

Choosing the correct back spacing depends on how wide is the wheel, but usually, it's somewhere between 3.5" and 4.5"...Also, keep in mind that the car's rear axle is never centered perfectly under the car and often varies from one car to another which can affect the clearance between the tire and frame...I have some 15"x8"s with a rear spacing of 3.5 and they fit ok. I also have some 15"x10"s with a rear spacing of 4.5" which also fit ok...Both these wheels have the same P275-60-15 tires on them.
What happens is that when you go to a wider wheel (like going from 8" wide to 10" wide), assuming you're using the same tire size, the sidewall of the tire gets a little more "stretched" to seat on the wider rim, reducing the sidewall bulge, and therefore increasing the clearance between the tire and the car's frame. So you can select a wide wheel with more rear spacing than you would on a narrower wheel...
I dunno if I explained correctly though...:redface:

Claude.

P.S: as for why some manufacturers don't offer wheels with a rear spacing of 4"...I dunno for sure, but it's likely to be a question of demand...

 

[SCOOBY DOO]

It seems that a 4 inch back space is the magic number for a good fit but many of the wheell companys will offer a 4.5 and not a 4 inch WHY

That's a good question. Grumpy uses a rim with a 4.5" BS on his daughters car with a 1/2 spacer.

 

[SCOOBY DOO]

Choosing the correct back spacing depends on how wide is the wheel...I have some 15"x8"s with a rear spacing of 3.5 and they fit ok. I also have some 15"x10"s with a rear spacing of 4.5" which also fit ok...Both these wheels have the same P275-60-15 tires on them.
What happens is that when you go to a wider wheel (like going from 8" wide to 10" wide), assuming you're using the same tire size, the sidewall of the tire gets a little more "stretched" to seat on the wider rim, reducing the sidewall bulge, and therefore increasing the clearance between the tire and the car's frame. So you can select a wide wheel with more rear spacing than you would on a narrower wheel...
I dunno if I explained correctly though...:redface:

Claude.

P.S: as for why some manufacturers don't offer wheels with a rear spacing of 4"...I dunno for sure, but it's likely to be a question of demand...

Claude, have you rolled the fender lips on your car?

 

[toofastforyou]

Claude, have you rolled the fender lips on your car?

Yes...I forgot to mention that, but I don't think that it is a big modification that should stop you from choosing the wheels you like...

Claude.

 

[novaderrik]

Back spacing on a stock 15"x7"GN wheel is 4".

Claude.:smile:

ok.. thanks.. that would put them inwards a bit far on the Monte. i was actually hoping the answer would be 3" or so.

 

[toofastforyou]

ok.. thanks.. that would put them inwards a bit far on the Monte. i was actually hoping the answer would be 3" or so.

Mmmm...I dunno...Being another "G" body, I thought that the Monte Carlo was about the same width as a GN...so wouldn't the GN wheels look ok? ...

Claude. :redface: