Join Date: Sep 1999
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HELP with math-speedo question
Over the years I've collected several of those little speedometer gearboxes-little gearbox that attatches to the transfer case, and the speedo cable screws onto it-and it speeds up or slows down your speedo reading. So I take a couple apart and there are three gears-one driven from the transfer, an idler, and the one that drives the speedo. These have different tooth count combinations.
My question is does anyone know of a formula to use to figure out how much difference a certain combination of gear tooth count will affect the speedo reading?
I'm not the brightest bulb on the tree, but I did grad you ate kollege, and still couldn't figure out a formula. Trial and error got my 83 CJ-7's speedo dead-on, but I'd still like a formula.
Greg 89 XJ-stock, 83 CJ-7/4.0HO-t18-d300-locked-2.5" rancho-32 bfg mt, 79 Blazer/454-t400-np205-locked-3/4 ton axles-35 bfg, 67 CJ-5/231-t18-d18-4.88-front disc-rear 11" drum/front locked/30-9.50's