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Old 01-03-2012, 12:50 PM
5-7HEAVEN 5-7HEAVEN is offline
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Join Date: Aug 2008
Posts: 1,912
Default Re: Will shift kit help with strong headwinds?

Originally Posted by The_Aleman View Post
Having optimum pedal gear ratios and the willingness to pedal will greatly enhance the riding experience on these!
Gear cluster and 50+T crank sprocket, keep pedaling at 28

As for shift kits, setting a shift kit up so that you can contribute your pedal power at the optimum time is the way to go. By default, the shift-kit puts your "pedal" redline way below the HP peak. To counter that you must run a huge (60+) outer crank sprocket to increase the engine gear reduction.

HOWEVER, the inside chainring is the pedalling one. Having one with less teeth results in low gear ratio and good pulling power for the engine. Unfortunately, not for pedalling power and engine power simultaneously. I haven't measured it, but I don't think a 50t will fit on the inside chainring position. It will hit the chainstay frame. Also, a large bicycle chainring REALLY screws up the gear ratios for engine application. Compare these figures:

Use the 24t chainring and 9t jackshaft for stump-pulling low gear (45.43:1, like a 111t rear sprocket) and 15.62:1 in 8th gear (15.62, like a 38t sprocket).

Use a 30t chainring for 36.35:1 (88t sprocket) and 12.49(30t) in 8th gear.

Use a 36t for 30.29:1 (74t) and 10.41:1 (25t) in 8th gear.

Use a 50t for 21.8:1 (53t) and 7.5:1 (18t) in 8th gear.

In retrospect, this 21.8:1 first gear w/50t sprocket is similar to 6th gear (21.3:1) with a 24t chainring.

To summarize, if you could get a 50t bicycle chainring to fit a bike w/shift kit, it would not be a good choice for engine power.

But hey, that's only my calculated opinion. We can all agree to disagree.....until someone actually installs a large sprocket as their bicycle chainring.

A 60t engine chainring? Lemme do more pencil-scratching, lol.

Ok, with a 60t engine chainring and 9t jackshaft, that's 31.02:1 in 1st gear w/34t sprocket (like a 76t rear wheel sprocket).

In 8th gear, that's 10.22:1(like a 25t sprocket).

You can pedal well in 8th gear, but will that 50t fit in there?

Last edited by 5-7HEAVEN; 01-03-2012 at 01:20 PM.
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