I have a SRAM double chainset (120bcd) with 10 speed on the back. I’d like to convert to 1×10 but the push fit bottom bracket and direct mount front mech are proving troublesome. I am not convinced that I will like it so I want to try it in the cheapest possible way. I figure I have 2 options:
1) Buy a Renthal 36T unramped chainring and adjust my current front mech so that it functions like a chain guide. The potential problem here is that the 36T may be too big, but it is the smallest chain I can buy with 120bcd.
2) Buy a new bottom bracket that will fit my oldish XT chainset (I prefer shimano to SRAM), fit a 30T unramped chain ring that a friend of mine has given me, and use my front mech as a chain guide as above. The potential problem here is that the 30T chainring may be too small and I may need to replace the chain ring anyway.
I understand that the push fit bottom brackets are not designed to be replaced, so if a go down the second option it would be a right pain in the backside (and costly) to go back to option 1.
Any help would be appreciated.