Getting higher gears?

[garage sale GT]

Im 176cm tall and i started raceing road bikes at 15 im now 34, i can hold that kind of rate for something like 5min depending on how i feel. and no its not the most efficient way to ride, i only do spinning like that to train. according to my gear calc thats just over 120rpm?

Did you measure the actual circumference of an MTB wheel? I am assuming you do that with small street mtb tires though I did not account for the possibility that you are going down a hill with fat MTB tires. I assumed 81".

I also assume that taller people can't spin as fast although the crank length may have far more to do with it.

 

[garage sale GT]

Here , courtesy of the 'bent crowd, are instructions and drawings of how to make your own big sprockets if you want a combo not commercially available.

McMaster-Carr has steel 60t sprockets but you have to finish the bore yourself. I am sure there are other industrial sprockets.

Boy, recumbents just got interesting if they have need of a 68t sprocket.