Heymow - Lawnmower Racing Forum

Mower Building / Setup Help => Chassis => Topic started by: Schiveley89 on June 04, 2021, 04:27:47 pm

Title: Help with gearing
Post by: Schiveley89 on June 04, 2021, 04:27:47 pm

Looking for help on getting a base line set up for my gearing on my fx mower. Vanguard 35 built,pushing 6500 rpm,noram star clutch 15 tooth
1/10 mile track,8" rear wheel ,need that middle speed and torque set up.

Title: Re: Help with gearing
Post by: PJG56 on June 06, 2021, 12:03:42 pm

 I would start with a final ratio of about 6-1 and work from there

Title: Re: Help with gearing
Post by: Schiveley89 on June 06, 2021, 07:50:59 pm

Paul,my last one was a 5:1
It went...15 to 30 then
16-48

Now it's a smaller track,150-180' straights..clutch will most likely be a 15 tooth
Any sprocket tooth ideas?
Horizontal Briggs twin

Title: Re: Help with gearing
Post by: PJG56 on June 08, 2021, 08:57:15 am

Quote from: Schiveley89 on June 06, 2021, 07:50:59 pm

Paul,my last one was a 5:1
It went...15 to 30 then
16-48

Now it's a smaller track,150-180' straights..clutch will most likely be a 15 tooth
Any sprocket tooth ideas?
Horizontal Briggs twin

Your math is wrong.The ratios you quoted =6-1 (30 divided by 15=2,48 divided by 16=3 ,2x3=6-1 final ratio

Title: Re: Help with gearing
Post by: PJG56 on June 08, 2021, 09:14:16 am

15-30 and 16-48 =6-1 final ratio
15-30 and 15-48 =6.4-1 final ratio
15-30 and 14-48 =6.86-1 final ratio

Engine rpm divided by final ratio = axle rpm x tire rollout x5 divided by5280 = mph

example 6500 rpm divided by 6 =1083 x 48=51984 x 5  =259920 divided by 5280 =49.23

Hopefully you can do your own gear ratio's now