Bought a kart from a friend with flathead engine 5hp with 9 inch tall rear tires. Gear ratio is 12/72 but I changed engine to animal 12hp with 2400 rpm clutch. Is the 12/72 ratio still ok or should I gear it different? We just parking lot race to have fun. It has great top end would like a little more on take off. Any thoughts? Thanks
Gear ratio question
- Thread starter Funkart1
- Start date
Brianator
Gettin' er done!
You're gear ratio seems spot on (6:1) for what I'll assume is not a big heavy kart with a 5hp and 9" tires. A torque converter should give you the best of both worlds, a sprocket change can gain you torque but you'll lose top end in the process.... a higher engagement rpm clutch will get you closer to your torque peak at launch but driveability will suffer some.
I'd go for the TC if you have the space, you wouldn't regret it!
9" rear wheel diameter? odd!
frankly, I think you misread something there,
since a #35 sprocket with 72 teeth is 8.6" in diameter,
with the chain riding on it it grows by 0.395 inches to 8.995"
even if you use steel wheels that are 100% unable to collapse
a 0.0025" gap is going to catch on every rotation.
So, take a photo, and or read us the sidewall marking please.
maybe even recount the teeth on both sprockets.
'sid
frankly, I think you misread something there,
since a #35 sprocket with 72 teeth is 8.6" in diameter,
with the chain riding on it it grows by 0.395 inches to 8.995"
even if you use steel wheels that are 100% unable to collapse
a 0.0025" gap is going to catch on every rotation.
So, take a photo, and or read us the sidewall marking please.
maybe even recount the teeth on both sprockets.
'sid
Do You mean the whole wheel is 9" tall ? Or just rims ?
If the whole wheel Your gear ratio 12/72 is very good. I wonder if te clutch is ok for such power (12hp).