42 tooth sprocket

[bowwow]

I just installed a 42 tooth rear sprocket. Does anyone know how much my mph will be off? Example: If it says I am doing 60, I am really doing.

 

[TruWrecks]

What's your front 18?

 

[BigBSBusa]

How much the speedo is off is different for each bike. Stock is anywhere from 7-10% and varies with the speed. Only way to really know is ride with a GPS or have someone pace with an accurate speedo (car of bike).

 

[bowwow]

Front is still stock. And I didn't think about turning my GPS on.Duh on me!

 

[SANDFLEA85]

either way you will need a speedohealer to correct it. i was off 18% with the mods i have

 

[kml]

Here is a gearing calculator
download it, change the values, and get the answers.

http://rapidshare.com/files/82572971/Suzuki_Hayabusa-gear-calc.xls

cheers
ken

 

[SAMBUSA]

+1 on the speedohealer. GPS isn't as accurate as everyone thinks

 

[gotgixers]

+1 on the speedohealer.  GPS isn't as accurate as everyone thinks

+1, I use a programable digital speedo on my '86. It uses the exact gear ratio and the circumferance of the rear tire in mm to the hundreth to calculate speed. It's a Veypor VR2. Had it checked by Laser @ 140, it was only .1 mph diff reading.

 

[proud dad]

mine with 17/42 and new M3...speedo..60........GPS......54

 

[BigBSBusa]

Agree that the SpeedoHealer is the way to go to correct things. Wasn't sure if he was asking for correction methods or just how far off the speedo would be.

 

[99'busa]

speedohealer $99.00