Bob,
You do mean Backspace not offset don't you. Offset is the distance
that the hub is from the center of the wheel width. If the hub is offset
towards the outside it is positive offset ala front wheel drive, if
towards the inside it is negative. Backspace is the distance between the
hub and the rim.
Peter.
Charlotte NC
Bob Spruck wrote:
>
> Interested Listers:
>
> I have been searching for a set of wheels for my ' 67 Midget vintage race
> car for a while now. I use 5.5" wide Western alloys with Hoosier A70s when
> I race with HSR. I have begun to race with VDCA, a new group that is
> much more concerned with period authenticity and to comply with their rules, I
> can only use street radials on a 5.0 " wide wheel. Most of my fellow
> vintage racers use the Panasport Minilite replicas but I want something
> different and cheaper. In my search, I've looked at wheels from all the
> stock Spridgets, Chevy Vega, and BMW 2002 and thought some of you might be
> interested in my findings.
>
> Assuming we are only talking about 13", four stud, 4.0" bolt circle wheels,
> all the non Spridget wheels seem to have problems. Not insurmountable, but
> challenging, nonetheless. The two problems are center hole size and rear
> offset. The Spridget has a rather large "cone" on the front hub and rear axle
> "mushroom" on the flange that have to fit inside the center hole of the
> wheel in order for the
> wheel to sit flush against the front hub flange and the rear drum. If the
> center hole on the wheel is not large enough, the wheel is not brought up
> tight to the mating surface by the wheel nuts, it wobbles and you have
> serious problems. A 1/4" thick wheel spacer will solve this problem, but
> the spacer
> may throw the wheel/tire too far out so that it
> interferes with the fender on a square wheel arch car. It may also cause
> the studs to be too short for sufficient thread engagement with the lug nut.
> This interference shouldn't be a problem on round wheel arch cars.
>
> Another detail to consider is the configuration of the lug nuts and the
> wheels. Spridget wheels and nuts have a different bevel than American
> wheels. Some alloys use shoulder nuts and washers so there isn't a problem.
> I installed 7/16 " studs from Pep Boys on the race car and had to use
> American nuts to fit them. When I temporarily used Rostyle wheels, the
> bevel of the American nut did not match the bevel on the British wheel. I
> had to take 16 stock chrome lugnuts, drill the right size hole all the away
> through, and tap them for the 7/16 x 20 studs. Also make sure the studs are
> long enough to fully engage the nuts. With the spacers, I have to convert
> again from the 1 1/2 " long studs to the 2 1/8" studs and use open nuts.
>
> The other problem in non-Spridget wheels is the rear offset. As you can
> tell by looking at the following dimensions for the non-Spridget wheels,
> the offsets can be quite different than stock. If the offset varies from
> stock too much, you
> once again have clearance problems with the sheet metal. The smaller the
> rear offset dimension, the further the wheel protrudes towards the outside
> of the
> car and the inside of the fender. I have found that any wheel with a rear
> offset between the stock 3.0"
> and about 4 3/8 " fits fine on a SWA car.
>
> I have determined that Vega wheels won't work on my SWA car, so they are
> available if anybody wants them for a RWA car.The BMW 2002 steel wheels
> look like they will work fine. They are 100 mm bolt circle but otherwise
> seem to
> fit. Of course, I will have them tested for cracks and trueness before I
> sandblast and paint them. I hope the information below helps and you don't
> have to accumulate all the wheels I have before you finally find something
> that fits.
>
> STYLE WIDTH REAR OFFSET
>
> BUGEYE ? ?
> SPRIDGET, STEEL, SOLID 3 ½ 3
> SPRIDGET, WIRE 4 3
> ROSTYLE, EARLY, 8 SLOTS 4 ½ 3 3/8
> ROSTYLE, LATE, 4 SPOKES 4 ½ 3 3/8
> VEGA, STEEL 5 2 5/8
> VEGA,GT, STEEL 6 ?
> BMW 2002, STEEL 5 3 11/16
> WESTERN, ALLOY 5 ½ 4 3/8
>
> Regards,
>
> Bob Spruck
> Sharpsburg, GA
> ' 67 Midget Vintage Racer
> ' '72 Midget Weekend Car
> 4 parts cars in the woods
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