Try as I might, I can't seem to get a grip on this offset business. I simply don't understand it. I am trying to find a 17 inch wheel that is ""G Stock legal. My "stock" R85 S-lite has a off set of 50mm. The new wheel I am considering (14.1 lbs!) has a offset of 42mm. The SCCA rules allow for a maximum offset diffrence of +/- 0.25 inch variation from standard specs. Where the heck am I with this 8mm diffrence? Is there a way to adapt this wheel via shims etc into SCCA compliance?

 

Here's a link to look at the effect of offsets- http://search.netscape.com/ns/boomfr...heel+offset&pa

I think the wheel you're considering is beyond the .25in. allowed. (25.4mm=1in. so .25X25.4= 6.35mm.) I think you'll need a greater offset to fit the regs- like 44 or something like that- but I could be wrong!

 

Sorry, that link doesn't seem to work. Try this-
http://www.1010tires.com/WheelOffsetCalculator.asp

 

.25" = 6.35mm (may make a difference to you). OZ makes lightweight 17x7 wheels in ET44, which would work, although not quite as light as 14 pounds. Team Dynamics Pro Race 1 is also lightweight (17 pounds) and cheap, and has an offset of ET45. The latter wheel is the personal choice of Lohen for track days, etc.

 

Thanks. So, if I read the calculator correctly, they advise to "extend" offset an extra 8mm, which I could do with wheel spacers, if I could find somthing between 5 & 10mm. (good grief, that's a stretch lol!) Sound right? I will run this by the "G" stock site. Thanks for your help.

 

Dump the 17's and go with a 16's. Tire choices are better.

The only 16's that will work are $$R's or Rota Slipstreams 16x6.5 et45.

 

Yup. The Team Dynamics wheels will work nicely. Any one have any comments about the Pro Race 1 and the Pro Race 2 designs and reliability?

 

I have the Pro Race 1s with Toyo Ra1s. The wheels are flat black. 45mm offset. They look very good on a pure silver car. PR1 is lighter by a couple of pounds than the PR2s.

I think the real question is, what is considered stock offset? There is a range, I beleive, that opens the door for some interpretation...perhaps not.

My summer wheels are BBS RGRs. These have a 38mm offset...basically a 1/4" difference.