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backspacing on 15x7 rally wheel

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Old 08-06-2003, 08:01 PM   #1
Old Vetter
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Default backspacing on 15x7 rally wheel

Can someone please tell me the backspace on original 68 15x7 rally wheels? I want to put a set on my 66. Also are the 68 to 82 trim rings the same depth? Thanks
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Old 08-06-2003, 08:38 PM   #2
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Default Re: backspacing on 15x7 rally wheel (Old Vetter)

Trim rings are all the same. I don't have a wheel handy.
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Old 08-06-2003, 09:09 PM   #3
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Default Re: backspacing on 15x7 rally wheel (Old Vetter)

I have a set of 15x7 corvette rally wheels that are stamped AG. I'm not sure what year they are, but they have 3 1/2" backspacing. Hope this helps, Byron
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Old 08-06-2003, 09:18 PM   #4
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Default Re: backspacing on 15x7 rally wheel (nitram)

I had a set of 15x7 Vette rallys I test fit on my 66. I didn't like how close they came to the rear fender lips. (with 205/75-15 tires). A 3.5 " offset gives you 3.5 towards the lip compared to 3.0 with standard 6" rallys.
There are some 15x7 rallys that were specific to 69 z-28 Camaros that had 4.0 backspacing which gives you the proper distance to the fender lip. 4" backspace is about the best you can do without having interference to the e-brake clips on the trailing arms.
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Old 08-06-2003, 10:07 PM   #5
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Default Re: backspacing on 15x7 rally wheel (joevette57)

I don't deal in backspacing, but their offset is -0.28". Beware that other Chevrolet seven inch Rallys used on other models have different offset. Because of their negative offset you can't put on a tire that justifies a seven inch wheel without shaving the horizontal fender lips on a C2.

The six inch Rallys have +0.60" offset and with a 215/70R-15 tire will normally have sufficient clearance to not hit the fenders. Setting front camber at zero to a bit negative and rear camber at at least -0.5 degrees should give more than adequate clearance. The only other issue might be front frame rubbing at maximum steering lock, but since you probably won't be at maximum lock above parking lot speed, it's not a big deal.

Duke
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Old 08-07-2003, 08:55 AM   #6
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Default Re: backspacing on 15x7 rally wheel (vettes1st)

Thanks for all the info. I've noticed that there are rally wheels with different back-spacing. I thought that I could get a 15x7 rally with a 4" back-space but I was concerned that a standard 68 trim ring would not fit. I measured the back-space on my knock-offs and they were 4"
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Old 08-07-2003, 12:55 PM   #7
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Default Re: backspacing on 15x7 rally wheel (Old Vetter)

68 vette = AG
-.3 offset
backspace ~ 3.5"

Monte/Z-28 = YH or FW
+.3 offset
backspace ~ 4"

Monte/Z ~.5" farther away from the lip, but closer to the rear spring




[Modified by 66427-450, 12:56 PM 8/7/2003]
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Old 08-07-2003, 01:02 PM   #8
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Default Re: backspacing on 15x7 rally wheel (66427-450)

15 x 7 's off a Monte Carlo will hit the brake cable brackets, the tire sidewall may rub the brake cable and the outside of the rim will hit the end of the spring. Believe me I know. If you jack the car up to allow full extension of the suspension and try turning the wheels the wheel weights and I think the rim itself WILL hit the end of the spring. On the road it is OK. On the front 15 x 7 will rub the frame behind the front suspension. The bolts that hold the steering box in place take a nice polish from the sidewall.
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Old 08-07-2003, 02:40 PM   #9
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Default Re: backspacing on 15x7 rally wheel (TheOman)

Duke -

Don't/didn't, you run 7" vette rally's and 225/70's on your '63? Seems like I remember you saying that.......
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Old 08-07-2003, 06:08 PM   #10
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Default Re: backspacing on 15x7 rally wheel (Old Vetter)

I run the 32-spoke Western Wheel Turbine wheels with center spinners (the look of Corvette knockoffs at a small fraction of the cost). They are 7 inches wide with 3-3/4" backspacing and fit my '64 perfectly with 225/60/15 tires. (They were used on Z-28 Camaros but mine are for Chevy/Ford/Chrysler with "slotted" lug holes.) I need to use a thin wheel spacer in front to clear the cailpers on the disks and even then, I can wipe the steering box carrage bolt shiny on a locked left turn.
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Old 08-07-2003, 07:55 PM   #11
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Default Re: backspacing on 15x7 rally wheel (66427-450)

Quote:
Duke -

Don't/didn't, you run 7" vette rally's and 225/70's on your '63? Seems like I remember you saying that.......
Yeah, but I had to trim the horizontal fender lips and front bonding strip. I did this back in 1968!!!, but I DO NOT recommend that folks do this today. I'm the original owner, and I doubt if I'll ever sell it unless they pry my driver's license away from me went I get senile, and I probably won't sell it even then - just park it in my living room.

I do have to admit that 225/70VR-15s on '68 seven inch Rallys look (and work) great. The wheel cover "Ben Hur" spinners stick out beyond the bodywork and can take out the kneecaps of daring pedestrians who stand on the curb if I clip the apex real tight. ;) The big wheels and tires really give it a hunkered down appearance.

Duke
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Old 08-07-2003, 09:15 PM   #12
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Default Re: backspacing on 15x7 rally wheel (SWCDuke)

Quote:
Yeah, but I had to trim the horizontal fender lips and front bonding strip. I did this back in 1968!!!, but I DO NOT recommend that folks do this today.
Yes, that was a popular mod way back then, lol...... I did the same thing to my '64, in about '73, when I was playing around with NCCC and SCCA autocross.

My '66 has had that done to it as well (front and rear)....... the guy did a really nice job, unless you knew what to look for, you'd think it was factory.

:seeya
PS: Same here on re my '66, not for any price...... I'd make them bury me in it, but I want the old beast to live on.
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Old 08-08-2003, 01:53 PM   #13
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Default Re: backspacing on 15x7 rally wheel (66427-450)

at one time i purchased a pair of rallys 15x7" from summit.
ordered a backspace of 4" these work well. i ran a 225/70x15 white wall.
one side is close and on hard bumps it rubs.
i recently upgraded to tork thrusts. custom part number CL205.
in 15x7 with 4" b/s all around. i am using 225/60x15.
still close on the same side. may be just my car. but other than that they look fine. no other rubbing that i can tell.(autocrossed twice now).
rubbing is on drivers rear. if i went with a 215 or 205 i'm sure it would be fine. but since there is no serious rubbing, i'll stick with 225.
d.s. in n.j.
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Old 08-09-2003, 08:19 PM   #14
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Default Re: backspacing on 15x7 rally wheel (STING67RAY)

I just ordered a set of rallys from Newstalgia. I ordered 15X7 with a 4" backspace. I'll let you know later how they work out. Thanks for the answers.
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Old 08-12-2003, 11:29 AM   #15
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Default Re: backspacing on 15x7 rally wheel (Old Vetter)

Quote:
I just ordered a set of rallys from Newstalgia. I ordered 15X7 with a 4" backspace. I'll let you know later how they work out. Thanks for the answers.
interesting...... do these repo's look the same? i've seen some that were configured significantly different in the lug nut area..... not true repos at all.

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