With the stock SR crankset, you can try taking off the outer chain ring and run the inner ring as a single,but you are pretty much stuck with a 42t as the smallest you can go. Look for a 110 bcd crank and you can then run as low as 34t on the inner. Lets see some pictures of the bike ..driveside please..and the good folks here can help you more with your goal you have in mind..John