View Single Post
Old 02-15-2012, 09:32 AM
Skarrd's Avatar
Skarrd Skarrd is offline
Motorized Bicycle Elite Member
Join Date: Oct 2010
Location: Chandler, AZ
Posts: 495
Default Re: what did you do to your motor bike today?

Originally Posted by 5-7HEAVEN View Post
JMO, I think you're in for a disappointing ride with those gears. You will definitely know this when you're stopped at the bottom of a steep ramp or hill, and try to climb it.

Ask me how I know this.

With a 3-ish hp 10,000rpm engine, you'll be making less than 2hp @ 6,000rpm.

If your engine has 10,000rpm capabilities, you'll be shifting @ 10,000rpm, not 6,000rpm. No one shifts 4,000rpm short of the redline.

My 2.8HP Tanaka 47R engine is rated @ 7,000rpm redline. With the pipe, I'm shifting @ 8,000rpm or a little less. If I'm putting around, I shift @ 5500rpm.

Here's how your gearing works @ high rpm.

First gear.....22.9mph @ 8,000rpm.....28.6mph @ 10,000rpm.
Second gear.....32.5mph @ 8,000rpm.....40.6mph @ 10,000rpm.
Third gear.....35.4mph @ 8,000rpm.....44.3mph @ 10,000rpm.
Fourth gear.....38.9mph @ 8,000rpm.....48.7mph @ 10,000rpm.
Fifth gear...43.3mph @ 8,000rpm.....54.1mph @ 10,000rpm.
Sixth gear.....48.7mph @ 8,000rpm.....60.9mph @ 10,000rpm.
Seventh gear.....55.6mph @ 8,000rpm.....69.5mph @ 10,000rpm.

You will run out of road in second gear.

In comparison, here's my gearing @ 7,000rpm redline and 8,000rpm:

First gear.....12.1mph @ 7,000rpm.....13.9mph @ 8,000rpm.
Second gear.....15.9mph.....18.1mph @ 8,000rpm.
Third gear.....17.9mph.....20.5 @ 8,000rpm.
Fourth gear.....20.6mph.....23.6mph @ 8,000rpm.
Fifth gear.....24.3mph.....27.7mph @ 8,000rpm.
Sixth gear.....27.5mph.....31.4mph @ 8,000rpm.
Seventh gear.....31.7mph.....36.2mph @ 8,000rpm.
Eighth gear.....37.5mph.....42.8mph @ 8,000rpm.

Hmm, good point. I'll see how it handles, right now the first reduction is 6t to 40t, i can always get a bigger gear from i think they have it up to 70t or something crazy. Like that.
They see me rollin'
they hatin'

Originally Posted by biknut View Post
Traditional bicycle riders think we're cheaters. Non riders think our bikes are toys. Bicycle shops think we're a threat. Tree huggers think we're polluters. The police don't know what to think.
Reply With Quote