I modified a 12-25 to remove the 12, 13 and 14 and acquired a oneupcomponents.com mini driver and shark 10 tooth cluster (https://www.oneupcomponents.com/prod...t-cluster-1x11) so I'm running a 10, 12, 14, 15, 16, 17, 18, 19, 21, 23, 25. Nice close ratios with little steps until speed is really high, then we have big steps but a very high top ratio - like a 57-11.

The 39 was on the border of just usable with the 25 but the 36 leaves us hardly using the 25.