Motorcycle Gear Calculator Part 2) This adds a little more to my post yesterday. A club member asked me about the gear calculator and the tire slip I would expect at 170 to 180 mph. He has not built the bike yet, but he is figuring out if he can afford to make it achieve the record he wants. He is a smart fellow to think before making the plunge. I never use that kind of logic and I pay the price in lots of hours and $.
My bike puts down a mighty 50 horses on a bad day and maybe 60 on a good'un. Naturally, I do not know about tire slip or 170 -180 mph. The fellow that asked me the question is reading this, if anyone sees errors in my thinking or has anything to add, type up.
As mentioned yesterday, I put a combined factor in the gearing equation to account for tire slip, tire growth, tachometer error, etc. It is based on the calculated speed versus the measured speed through the mile. My tachometer is not calibrated so I do not know how much of the difference I see is tire slip or tach error. My factors are good for comparing runs and setting my gearing, but not much else.
The tach error factor can be neglected for theoretical calculations. My bike runs relatively narrow steel belted radials. I do not see how they can expand. The belts would not allow it. I do see, in my imagination, how the flat spot at the bottom of the tire where it contacts the pavement can disappear it high speeds. Centrifugal forces in the spinning tire would make it more round. I always assume the tire is fully round in theoretical calculations. Tire slip is where I do not know much. I figure my gutless wonder is good for 5 percent slip, maximum, in theoretical calcs. This is about all I know.
