I want to purchase a ToSeven DM01 kit to convert my Motobecane Night Train fat bike. it is the same frame that comes on the Sturgis.

It has a 100mm bottom bracket, but the chain stays are wide to accomidate large wheels.  I have the following quesions:

Should I get a 100mm or 120mm wide DM01.  Others with a BBSHD and my frame have stated that they had to use 120mm to have the cranks the proper distance evenly  With 100mm, they have to somehow shim one side and then they are not even. See pic for width.

From a gearing standpoint, I currently have a 10 speed 11-36 cassette.  I was going to upgrade to a 11-48 cassette and ordered the parts before I made the decision to convert the bike. Now, I am wondering if there is any value in going with 11-48 for an e-bike. Do I really need gearing that low? What size front sprocket is recommended? I am shooting for 25-30mph top speed. I don't think I need more than that.

My riding will be light commuting in the summer on 29er wheels and fat biking in trails in the winter on the fat bike wheels.

Thanks,

Tom