I have a 29er MTB that I converted with a BBS02 and a Lekkie 40T chainring. 8 speed Shimano. I have an 11-32 cassette on the back and I'd like to get some lower gearing. I see that SRAM has an 11-48 cassette that's designed for e bikes but it's really expensive. Anybody have any suggestions? I don't care if I lose some of the top gearing- the bike is stupid fast. If I spring for the 11-48 am I buying myself some other problem that I'm not aware of?