# Riding Lawnmower Setting up for higher speed



## chainsawmatt (Feb 20, 2011)

I want to make my riding lawnmower faster, what size pulleys do neeed to get a speed of about 30 mph in the highest gear, also if i change the pulleys how do i know what size belt i will need to get it going again


----------



## AllanJ (Nov 24, 2007)

A lawn mower cannot be run too fast otherwise it won't cut the grass properly. Only the outer two inches of the blade (the part you sharpen) does the cutting. The blade must complete a half revolution (come around in front again) for each two inches or less of forward movement.

Meanwhile there is a safe top RPM limit for the blade rotation so you don't have the danger of the blade's shattering from centrifugal force.

Let's say the blade rotates at 3000 RPM.
Equals 50 rev. per second, 100 blade swipes per second, 200 inches forward movement per second, 16.66 feet per second, 59976 feet per hour, 11.36 mph maximum speed.


----------



## chainsawmatt (Feb 20, 2011)

I'm not talking about deck, i want it to be a racing mower, how do i determine the size pulleys for the motor and the transaxle, also how do i determine the right size belt for the new pulleys, so i can achieve 25 to 30 mph


----------



## Tom Struble (Dec 29, 2008)

google can help Matt

http://www.instructables.com/id/How-to-make-a-racing-lawn-mower/


----------



## chainsawmatt (Feb 20, 2011)

Is there a way to determine what size belt i will need once i change the pulleys


----------



## Tom Struble (Dec 29, 2008)

you mean the length?use string


----------



## boman47k (Aug 25, 2006)

Reverse pulleys and use the same belt! :jester:


----------

