FABO Gold Member
FABO Gold Member
- Nov 28, 2008
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I realize I'm digging an old thread up, but there's some great info here... wanted to see if anyone could shoot holes in my thoughts?
I've got a 76 Scamp currently with 10" drums and a 7.25 rear end. I just bought used some OEM disc spindles. Also just ordered a ton of suspension components to rebuild the front (tubular UCA's, rebuild kit for LCA's, sway bar, adjustable strut rods, new torsion bars, and about every rod end and bushing imaginable)... also have the Wilwood Dynalite Big Brake kit on its way.
The car currently has SBP but I'll be swapping the front to LBP with the Wilwood kit. For the rear, I anticipate pulling my axles and drums and running them up to the machine shop to have the LBP added to them.
But now I've gotta figure out wheels/tires... I'm leaning toward this set of 18x8 with 4.5" backspace...American Racing 51088012400: VN510 Draft Series Vintage Silver Wheel 18" x 8" - JEGS High Performance. my point of concern is that the car currently has the SBP 14x5.5 rallys on it (they appear to be about 3.5" backspace) and I've had a time or two where I've been backing out of the garage at full lock (kinda uphill) and heard the front tire scrape I believe the top of the fender lip...
If I'm doing the math right, the new wheels would be 2.5" wider than my existing ones. 1" of that would be to the inside (difference between 3.5 and 4.5 backspace) and the remaining 1.5" would be to the outside, which theoretically would make my steering lock/tire scrape issue worse... however, I also tend to think the lower profile tires probably don't bulge out as much beyond the width of the wheel as the current 14" (215/70/14) ones do, so maybe it will be less than 1.5" closer once it's up to the outer diameter of the tire? Sound right, or am I completely off base?
Which Wilwood kit? Some alter the track width, which will change the backspace you need. Also, some of their kits have a VERY large hub diameter, which will seriously limit wheel options.
In general, if you want to run an 8" wide wheel up front and put a tire on it that's worthwhile, you need at least a 5" backspace. 18x8" with a 4.5" backspace will probably be too close to the fenders on most cars even with a fairly modest 245/40/18. That combo would be 15mm further out than the 275/35/18's I run on 18x9's, and my fenders are rolled and pushed.