I picked up some cheap 15x7 ET37s for my '86 c900 with 88+ axles. Looks like they'll work up front (springs are narrower than stock) but not in back: at full droop I've got maybe 1/8" @ the lower control arm and contact at both the upper link and the body, by the shock.

For 15x7s, how much clearance works, or, put another way, what ET works in back?

I can't answer the question directly but a friend of mine bought some 15x7" wheels for his '90 900T and I helped test fit them. We put one on the left rear (with the car jacked up it would have had the most clearance at this point) and you could barely squeeze a pinkie finger between the wheel and body. When we test fit the front the wheel looked OK until we turned the steering wheel and found that the wheel went under the spring perch. Keep an eye out for that...

I have a set of 15x7's sitting on the shelf, no tires on them and I haven't test fit them yet... so I don't have an answer (well that wasn't much help) but I could try them Not sure if I'll have more/less or the same space with the very early rear setup (but 900 axle). I'll take a look later today. I've had the wrenching bug recently so it's a good excuse to get out there..

I have a set of 15x6.5 Panasports with 35 offset. They just touch the lower front spring perch. They touch when the steering is cranked all the way to either side. I run a set of 1/4 inch spacers on them. Just make sure the spacers are properly centered. One hell of a vibration if not. Ebay has a variety of spacers that range from about 1/4 inch up to 2 inch. I was looking at a set of 1 inch spacers so I can run my Shelby's on my E/F Prepped car. Im gonna be running 15x8 steel wheels on that with 0 offset. That is 4 inches of backspacing. By comparison, my stock Saab steelies have 5 inches of backspacing. The Ventus slicks Ill run on the 15x8's bulge past the bead a fair amount. Thus requiring the 4 inch backspace instead of the 5. The flares on the car will be made to fit the 15x8 setup, so stock wheels will look goofy without spacers behind them to push em out to the edge.

I looked at mine today. I believe they are 37 and at full droop they seem to fit. Very close though - max 1/4".





Just for giggles I figured I'd mock up the front wilwoods as well

Thanks for checking, and for the pics, Jordan. Are your rims stamped with ET37? Interesting that they're the same offset as mine but yours have clearance. Maybe the upper link attachment point is different on pre-88 axles?? The other thing I'm realizing as I write this is I have an adjustable panhard bar; also, I measured on the RH side. If I'm visualizing this correctly, in droop, wouldn't the p-bar pull the axle closer to the car as it goes lower, and push it away on the LH side?

@SwedeSport: Thanks for the info. I have read about people using narrower springs up front to accommodate wider rims. I have a set-up like this that I have yet to install (lazy). Meanwhile, I read somewhere that this car supposedly has narrow springs: http://www.youtube.com/watch?v=ickba42_rDw and there's at least one other person out there doing it: http://web.archive.org/web/200410200719 ... +seats.htm. An advantage to using narrower springs is that you can use rims with an offset that's less likely to mess with the scrub radius.

The only thing I saw on one of the centers was stamped 37...but I was just guessing that was the offset. I can look at the rest and see if there are any other labels. I actually don't have the rear panhard in yet so not sure if that would cause the issue when it does get installed. Luke owes me an adjustable one

I tried to search through old posts to see if I mentioned it anywhere but I didn't see it. I did find previous discussion where we figured out 32-35 would be ideal.

The nature of the panhard rod will make the axle shift left-right when it goes up-down.

Up = axle goes to the left
Down = axle goes to the right

Funny, I just noticed that not all of the wheels have dual bolt patterns... One looks like it was started to be drilled, but from the back...but way too big.. maybe they were *oops* wheels. I better check they all fit. They were like random ebay $100 wheels with the right bolt pattern , close offset , center bore and 15x7. We shall see...

OK, I'm confused. The axle's lateral motion is controlled by the arc of the p-bar, with the axis at the body. At rest, the p-bar slopes down. Viewed from behind, as the axle goes up, the p-bar's arc will move the axle to the right; going down, the p-bar moves it to the left. Or not?

(I'm trying to simplify this by ignoring the fact that, technically, when cornering, the car is actually moving with respect to the axle, not vice versa.)

You have it drawn correctly. I think what Geoff was saying was that as the car body lifts up (suspension unweights), the axle goes left...compress the suspension and the axle moves right.

Yeah that's where my mind was at.

* Googles "boobs" *