I am going to use a 21 to 1 gear ratio on my flywheel but I don’t know what would be good wheels for a flywheel. Could some one help me? 
I have some high traction wheels but they are small. Will it make a difference if its small or nah?
You will need a higher rpm to get the same speed with a smaller wheel. I would recommend at least experimenting with different gearings and wheel sizes till you find what’s best for your specific robot.
we have the 21 to 1 and are using 5in wheels
Thank you! Im gonna use 5 inch wheels
I got a 5 in wheel with a 28:1 ratio and it seems to work well. I just got to adjust the amount of friction.
Currently our team is utilizing a 25:1 gear ratio with 4in wheels. With the reduction of friction in the moving parts of our flywheel, we are able to shoot the ball well across the field and over the net.
The main issue with a flywheel with large gear ratios, is the removal of torque from the wheel. Which when the ball is shot, takes longer for the flywheels to spool back up.
It does work. However when attempting to fire shots consecutively, the wait time between spooling up and firing again takes its toll. :mad:
I am thinking that a big issue this year is gearing flywheels too high. A 25:1 gear ratio is way too high, even our 15:1 gear ratio is too high with 4" omni wheels. The optimal setup for a dual flywheel is around 13:1 (this gearing is virtually impossible, so you could go up to 15:1 like we did) with high speed motors (turbo gears are geared to high and are more prone to burning out) with 4" omni wheels (to help reduce momentum the start up is working against). With 4 motors on this gearing you can get your flywheels to ramp up from shooting a ball in about 2 sec. That is, from out testing.