Brian Matheis

I think I asked this question a couple years ago (but I'm getting older) :yesnod: I've got 15" X 6"s on my car, and it sure doesn't look like there is an overabundance of room anywhere. In fact, there is a small frame rub on the left front rail. Is anyone running 7" Ralleys with the OE backspacing?? Any problems?? If so, what size tires?? I've already got Ralleys on my car (see sig pic, they are under the hubcaps) but they are not running true. I'm thinking about putting 7s on the rear to spread the tire out a little and help with the "contact patch" (not that my 300 hp PG needs it!!!) but 7" are easier to find and cheaper!! Thanks boys, Brian

TheOman

I had 4 15 x 7 Monte Carlo Rallys on my 66SB. On the rear when the car was jacked up and the diff was hanging down the rim rubbed on the end of the transverse spring ever so slightly. A little grinding on the spring out near the eye hole for the bolt fixed that. Sittin on the ground everything was OK even before the grinfing. I don't jump the car so the grinding really was unnecessary. Up front the 15 x 7 with the 205s rubbed at max right or left turn on the frame kickout under the area where your feet would be. This was with 205 x 70 15 Eagle GTs on the car.

I switched the front to 15 x 6 Wheel Vintiques with 3.5 backspacing and retained the 205 X 15 x 7's on the front. The decreased backspacing on the Vintiques makes the 15 x 6 look as deep as a 15 x7 when viewed from the side and at the same time pulls the tire out and away from the frame.

Spring height was not an issue for me as far as fender clearance with either the 15 x 6 or the 15 x 7. My rear spring is new and the fronts are in good shape.

Crazyhorse

That's what these are, If I remember correctly I used 4.5" backspacing.
I can check tonight. Using 70/215's but I prefer the 65/215's.
No rub problems unless I go up a steep driveway at a sharp angle, then I can hear a front rub.







[Modified by Crazyhorse, 1:28 PM 11/18/2002]

toddalin

I run 15x7 Western Wheels with 3-3/4" backspacing on my '64 with no problems. 225 tires will rub on steering box carrage bolt on locked left turn, but no big deal.

jump150

I am running Ralley 15" x 7" front and rear on mine. The rear Ralley's are code AG with 255/60 15's.. soon to be 235's (for appearance) and the fronts are code FW with 205's soon to be 215's or maybe 225's will fit with little frame rubbing at full lock..

SWCDuke

I installed '68 7" Rally's (-0.28" offset) on my SWC in 1968 with
205HR-15 Pirelli Cinturatos. I HAD to trim the horizontal fender lips, but
the outside fender contour is unmolested. I now run 225/70VR-15s. I
would not trim the fender lips today, but I'm not going back to OEM
either.

Wheel/tire combinations are a function of tire size and wheel offset and the
individual cars. If you want good handling, a '67 6" Rally wheel, KOs or Bolt-ons (all +0.06 offset) with 215/70WR-15 Pirelli P4000 Super Touring tires will clear, except for some front fender lip interference when the suspension goes into jounce with a lot of wheel lock, so you have to be careful entering steep driveways at an angle.

Duke

Brian Matheis

So.....the concensus is....yes and no!!!! Since I can't change the backspacing on the OE wheels, and I don't want to worry about trimming a spring, or a fender, or rubbing anywhere, it looks like I'm staying with the 6"s.

I called my uncle last night ('64 vert) and he said he has 7"s on his, but had to trim his spring, has "rubs" once in awhile, and has to be carefull at times. To me, that's not worth it, I'll stay with the 6"s. Thanks guys. Hopefully for X-mas I'll get some trim rings and centers, and I'll have a whole new look for the vert :D :D Thanks again, Brian

toddalin

No, you don't need to trim the spring. Just use a 1/8" wheel spacer to move the wheel out a hair.

Brian Matheis

Thanks for the advice about the spacer, I had actually thought about that, but it's not gonna happen here :nono: I know I'm just a dumb old Indiana boy, but I learn from my mistakes.

I helped a friend get a set of wheels to fit his car using spacers once, and while we were doing 70mph on the interstate, the wheel passed us up :eek: :eek: :eek: It was interesting, there were some sparks and "BIG EYEBALLS", but we got it slowed down and off the road. I think I'll play it safe and stick with the 6"s. Brian

Dyna

Hey Brian,

I run 16 x 8 in American Racing Hopsters on my 66 and it is a little tight, but no rubs. I think the back spacing is 4.5 in. Wheels are 55 series Goodyear Eagle HPs, 205 wide. I like the look. Sticks to the road real well.

Dyna

MassVette

Brian, I fit 15x7 rallyes on the rear of the '67, and the backset was fine. They cleared the spring and e-brakes. I dunno about the rear fender lip clearance (for obvious reasons), but the offset is the same as the 6" wheel, I believe.
:yesnod: :chevy :chevy :yesnod:

Brian Matheis

Dyna, 16" X 8" :eek: :eek: WOW!!! Obviously the backspacing has a lot to do with it, but I didn't think an 8" would work at all!!!! You need to get a picture of that thing on here :D :D Brian

SWCDuke

No; '67 6" Rallys have +0.06" offset; '68 7" Rallys are -0.28", and 8" Rallys are -0.50".

The offset moved in the negative direction as the wheels got wider because of inside clearance issues, but the Shark body has more outside fender clearance to handle the increasing negative offset. That's why the 7" and 8" Corvette Rally wheels won't fit on a midyear without fender mods unless a narrow and short sidewall tire is mounted, so you end up with a tire that has insufficient load capacity and a odd look.

Duke

MassVette

The GM wheels I found have the same -offset as the 15x6 Corvette wheel. The '67 trim rings fit and look the same.The difference is in the backset. Rear spring and swaybar clearance is OK.
The tires are Goodyear Eagle ST's, P225/70R15. Overall tire dia. is 26". Tread width is 6". Inflated sectional tire width is approx. 8".
I'm just a hobbyist, not a pro; but the tires and wheels seem to fit and look OK.

:chevy

TCracingCA

There is a place I think called Stockton Rims in Northern California that will customize stock type rims (widen, backspacing, etc..). They work with the Rally type and other brands from Mopar and Ford. I know that a set of American Torq-thrust D's 15X7 with 3-3/4" or 3-7/8" backspacing depending on whether they are the modern ones or the vintage ones (the modern ones are listed as 1/4" negative offset) fit a stock 63-67 without any problems with a 215/60-15 BFG. No offset trailing arms, no emergency brake relocation, no rubbing on the rear spring, no shaving of the fenders. Only at full lock in a slow parking lot manuever will you get rubbing on the front but that was with one coil cut off of the front 550lb springs. This setup looks really good. The car has a slight rake depending on your rear spring bolt adjustment and the tires set inside the wheel wells perfectly. You should definitely check that your body isn't mounted on the frame crooked. Also there is no problem with wheel spacers if you have the appropriate thread engagement into the lug nuts and the proper torque on the lug nuts. :cheers: My recommendation is a true 7X15 Rally with a 3-3/4 backspacing. Offset can be deceiving and I am not going to get in a discussion on this topic. Always go with the backspace measurement from spindle to rim mounting surface (safer). Offset is the distance from the center of the rim to the mounting surface. Far easier to take two rulers and do the backspacing. Also keep in mind that a true 7 inch rim is usually actually 8 inches wide (edge to edge). This should make you happy. If this is the way you would like to go? I will dig up that Company Name and address, phone for you, if not hope my input narrows down your fears and good luck with your project. :cheers:


[Modified by TCracingCA, 5:50 PM 11/23/2002]

bondo478

I'm running 15x7 ralleyes on my 66 with 215/65/R15 with no problems. Maybe a little frame rub up front at full lock, but not so you would notice.

Vetterodder

I'm running TT2's, 15x7, 3.75 backspacing, with 225/60's, unshaved wheelwell lips, and the car has been lowered 1 7/8" front, 1 1/8" rear. At full right lock, the right front tire will contact the lip upon the slightest suspension bound. As a result, I have to take entry/exit of steep driveways real slow, otherwise, no problems. No problem on the left side due to my `65's body being off center of the frame by 1/4" to the right side, front and back..

At the rear, the tires barely clear the lip on the right side (but they do clear), and only because of the camber change as it squats. With stock trailing arms and the parking brake cables in the stock position, there is 5/16" clearance between the sidewall of the tire and the parkng brake line. If the body were perfectly centered, there would be another 1/4"of clearance and I'd be using 235/60's on the rear.

I think the outfit that TCracing mentioned is Stockton Wheel Service (209-464-7772). I think they have an 800 # but it's not listed (doh) in my local directory. Unlike the minimum wage idiots selling wheels in most places, these guys do KNOW wheels. If you want your stock rims widened or repaired, they can fix you up. If the alloys on your wife's Camry gets a boo-boo, they can fix that too.

Backspacing vs offset: They both provide the same information but from different perspectives. (Yeah, I know that most of you already know this but not everyone does) Offset is the distance from the outer part of the rim to the centerline of the rim. Backset is the distance from the part of the rim that mounts to the hub from the inner edge of the rim ("inner"being the part that is towards the differential and outer being the part that is towards the fender). For a given rim, increasing or decreasing backspace will result in an equivelent change in offset. Because the differences in distance between the hub mounting surface and the ceterline of the wheel can vary between different types of wheels, you can't always rely on published specifictations when trying to determine what will work best for your application.

Before changing wheels, take some measurements of what you already have so that you understand the effect that a different wheel will have on clearance. The same thing applies if you are changing tire size. Due to the shape of disc braked C2's and c3's (they stick out farther than others), neither measurement will indicate if the wheel will clear the calipers.

TCracingCA

Amen, nice summary. Offset is harder to understand than backspacing. I didn't feel like giving as detailed a write up as you but you probably saved this guy some grief which is the benefit of this forum. Compliments to you! :cheers: