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BrandonRadtke
08-19-2020, 12:07 PM
I recently changed tires on my 250r the tires say they are 20” but they are 2” shorter than my old 20s. Anyways, I went for a top speed run and it only goes 43-44mph lol. My question is will it make a big difference if I go from the 13t stock front sprocket to a 14t? I can’t seem to find smaller backs but I found a 14t sunstar front sprocket.
oldskool83
08-19-2020, 02:17 PM
JT sprockets might make a smaller rear sprocket. If not a larger front sprocket by 1 tooth would be the same as making your rear sprocket 3 teeth smaller. Make sence?

Rule has been 1 took up or down up front = 3 teeth up or down at rear.
shortline10
08-19-2020, 03:47 PM
One tooth larger up front will give you approximately 6 more mph top speed .
Yamaha Tri-Moto
08-19-2020, 09:40 PM
I love my air foolers but man I wish they had a 6th gear. There's power to spare.
ATC King
08-19-2020, 09:51 PM
I love my air foolers but man I wish they had a 6th gear. There's power to spare.

Are there any gears from other trikes or motorcycles that'll work? It may be possible to build a wide ratio five speed.

I've got a bike with an XR600R engine, XR650L primary gears and first gear, NX650 second gear, and FMX650 fifth gear. Really wide ratio five speed transmission, all Honda parts.

Check out this vintage 50cc racer with 14 speed transmission: https://www.bikeexif.com/suzuki-rk67

Getting more crazy: https://advrider.com/f/threads/380-bhp-liter-40-years-ago.412922/
BrandonRadtke
08-19-2020, 11:12 PM
Thanks for all the info guys! And yes Yamaha Tri-Moto a 6th would make the world of difference��. ATC king that would be very interesting my fooler definitely has the power for a little wider spread gearbox. If it goes 44 ish now and I go from a 42 tooth rear to around 36-38 how many mph do you think I would gain? I’m only looking for around 55. It’s so short geared right now And in 5th it feels like you should have 1-2 more gears lol.
atc300r
08-20-2020, 02:21 PM
Contact PBI sprockets.I have a 15 front and 38 rear on my 83 300r with 18 inch rears.
BrandonRadtke
08-24-2020, 08:46 PM
Okay I like the way it is now I bought a 15 tooth front with the 42 in the back and it definitely made a big difference. If I end up wanting more speed I’ll look into them thank you.