Motorcycle Gear Calculator

[Uncle Jimbo]

Thanks Panic   I don't know how I did it but the file that I got downloaded is written by Tom Nichols. I substituted the sprocket numbers, tire dia. and bingo everything is there, speed at projected rpm and even rpm's at a given speed. This saves us tons of guess work.
You guys are great. Thanks You made this cyber neanderthols day.
uncle Jimbo

[Jack Hester]

I know that there have been several calculators listed.  Here's one more.  It can be opened from the website, to memory.  Or, can be downloaded for use offline.  No installation needed.

http://www.terra-glide.net/pgms/WheelSpeed.exe

Jack

[Jonny Hotnuts]

Jack that is a cool calculator.....but it is missing 5th and 6th gears!

 

[Jack Hester]

Jack that is a cool calculator.....but it is missing 5th and 6th gears!

 

Jonny -

Here's a little beta program in the works: http://www.terra-glide.net/pgms/LSRutil.exe .  See if this takes care of the missing gears.

Jack

[wobblywalrus]

Usually I remember my engine rpm through the mile during my first run and I calculate how fast I should go assuming no tire slip.  Then I look at my timing slip and see how fast I actually went.  The actual speed divided by the calculated speed is my combined slip/tachometer inaccuracy/tire growth, etc factor.  It is specific for my bike at that meet.  I make further gearing calculations and adjustments using that slip factor.  All works OK as long as the salt conditions stay the same as they were during my first run.

[Tonerjockey]

Here's a few sheets for the 2 or 3 of us that don't use sprockets.

I don't remember where I got this, but if it's yours and you don't want this posted, lemme know and I'll take it down.

Fun to play mix n' match.

Tonerjockey

[wobblywalrus]

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.