wheel backspace question
#903072
01/12/11 08:17 PM
01/12/11 08:17 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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first of all, back space is the amount that the center of the wheel is offset towards the outside of the wheel, moving the tire towards the inside of the car. is this correct?
on my car, there is a good 1/2" or more of difference between the two sides on the rear, so that my left wheel is that distance towards the inside of the car, and rubs on the inner wheel well when going up a curb at an angle. not that big a deal, but it is the side where i'm most doing that.
i have 5.5" backspace 15X10's on there now, and i was thinking of getting another set of wheels, one to put some good gripping tires on, and one to put the radial t/a's on for looks. my idea was to get a set of 5" backspace wheels, and mount a set of tires on each, with the 5" on the left side and the 5.5 on the right.
does anyone else do anything like this, or is there a way to more evenly center the rear axle? scatpk mentioned loosening everything up and just giving the differential a good kick on the side that is outset, and moving the whole thing over. seems to me that it is firmly set in place by the position of the front hangers, the shock mount plate, etc...
any thoughts?
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Re: wheel backspace question
[Re: ahy]
#903074
01/12/11 08:48 PM
01/12/11 08:48 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
As far as adjustment, all the mounting holes and locating holes have some tolerence and are slightly oversize. Loosening everything up - including the U bolts - and giving is a shove may help more than you think. Its worth a try.
I didn't see what car you have but on about any Muscle Mopar, 10" wheels are pushing it if its not tubbed and 5.5" backspace is on the high side also.
How close is the tire on the outside left and right? Would a little less backspace help without causing a problem? You could mock it up with a wheel spacer to simulate less backspace.
Mounting the same size tire on a different width wheel will impact tire profile, width at the bulge and even overall efffective diameter. You could get into some handling inconsistancies.
I'd suggest plan A is give it a shove, plan B is the same width wheel with less backspace and plan C is slightly narrower wheels (and tires?) with less backspace. I wouldn't stagger wheel widths left and right.
i'm talking about using 15X10 on both sides, but with a 5.5" backspace on the right and a 5" on the left.
the 275's will fit under there, i just want to get it to a point where it doesn't rub, so i'll try moving the rear axle first.
narrower tires are a no go, and i have a hard enough time getting traction with the 275's.
scatpk graciously gave me a set of 275/50 bf goodrich drag radials, and i'd like to make use of them. but they don't have the raised white letters like the radial t/a's. i'd like to make use of those, get them fitting under there a little better, but also be able to quickly and easily switch back to the t/a's.
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Re: wheel backspace question
[Re: babarracuda]
#903076
01/12/11 09:17 PM
01/12/11 09:17 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
I had to put in 3/8" spacers to get the left side to clear on the inside.
that is the point i'm making i think. if you have to use a spacer, it's really the same as using a wheel with that much difference in the backspace.
in my case, i need to move the wheel out, so a 5 as opposed to a 5.5" backspace wheel will do that.
if i can't move the rear end over any, of course.
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Re: wheel backspace question
[Re: mickm]
#903077
01/12/11 09:51 PM
01/12/11 09:51 PM
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Joined: Jan 2003
Posts: 104,346
Garden Grove, CA
OzHemi
Penguin-hating Ginger
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Penguin-hating Ginger
Joined: Jan 2003
Posts: 104,346
Garden Grove, CA
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If you are going to use 2 piece wheels, having each wheel made to take full advantage of the room on the car is not a big deal to me.....we've done it a bunch of times. (especially on some old cars that aren't too even  ) The wheels on my Torana I had made locally and each one is build to it's spot on the car to center it right in the wheel opening. I remember a couple years ago we built a set of billet wheels for a customer, and his where about 1/2" different offset on the back to solve an issue he had with a poor 1/4 panel replacement sometime in the past If you are not going to rotate the wheels, it really is no problem in the least IMO.
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Re: wheel backspace question
[Re: mickm]
#903078
01/12/11 11:06 PM
01/12/11 11:06 PM
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Joined: Jan 2007
Posts: 7,664
IN
ahy
master
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master
Joined: Jan 2007
Posts: 7,664
IN
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Quote:
Quote:
As far as adjustment, all the mounting holes and locating holes have some tolerence and are slightly oversize. Loosening everything up - including the U bolts - and giving is a shove may help more than you think. Its worth a try.
I didn't see what car you have but on about any Muscle Mopar, 10" wheels are pushing it if its not tubbed and 5.5" backspace is on the high side also.
How close is the tire on the outside left and right? Would a little less backspace help without causing a problem? You could mock it up with a wheel spacer to simulate less backspace.
Mounting the same size tire on a different width wheel will impact tire profile, width at the bulge and even overall efffective diameter. You could get into some handling inconsistancies.
I'd suggest plan A is give it a shove, plan B is the same width wheel with less backspace and plan C is slightly narrower wheels (and tires?) with less backspace. I wouldn't stagger wheel widths left and right.
i'm talking about using 15X10 on both sides, but with a 5.5" backspace on the right and a 5" on the left.
the 275's will fit under there, i just want to get it to a point where it doesn't rub, so i'll try moving the rear axle first.
narrower tires are a no go, and i have a hard enough time getting traction with the 275's.
scatpk graciously gave me a set of 275/50 bf goodrich drag radials, and i'd like to make use of them. but they don't have the raised white letters like the radial t/a's. i'd like to make use of those, get them fitting under there a little better, but also be able to quickly and easily switch back to the t/a's.
Ok - got it. Agree different backspace L/R shouldn't hurt anything. A spacer with long studs added may be easiest/cheapest unless you need new wheels anyhow. If you do decide to try loosening and shoving, I'd love to hear the results.
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Re: wheel backspace question
[Re: ahy]
#903079
01/12/11 11:56 PM
01/12/11 11:56 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
Ok - got it. Agree different backspace L/R shouldn't hurt anything. A spacer with long studs added may be easiest/cheapest unless you need new wheels anyhow. If you do decide to try loosening and shoving, I'd love to hear the results.
as i mentioned, i want to get a second set of wheels anyway, so i can swap the t/a's with the drag radials w/out having to pay for mounting/balancing each time.
i will post when i get a chance to play with the rear end.
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Re: wheel backspace question
[Re: mickm]
#903080
01/31/11 02:31 PM
01/31/11 02:31 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,179
California
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Quote:
i will post when i get a chance to play with the rear end.
i removed the shocks from the lower mounts, and loosed the u bolt nuts. did as much as i could to try and move the rear end over to the driver side, didn't get anywhere. i didn't think it would, as this is a dana that i have in there now, which replaced an 8 3/4. when i put in the dana, there was no difference in the position of the tires in relation to the body, so i think it is in a fairly fixed position.
so on with my plan, getting another wheel with a 5 instead of a 5.5 backspace for the left side.
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Re: wheel backspace question
[Re: mickm]
#903081
01/31/11 02:42 PM
01/31/11 02:42 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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loosen up the shackles and F&R spring hanger bolts, too....
yes, a 5.5" BS wheel with a 1/2" spacer is the same effectively as a 5" BS wheel. personally, I'd probably go with a spacer and longer wheel studs, so I could rotate the tires l/r...
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