Originally Posted by
Leisesturm
I have a 2015ish Giant Expressway with a 53T x 11 - 32 and I hate the 33" low gear and top gear if IRC is around 93" which isn't all that useful. I spend all my time in the bottom gear or the one above. The o.p. is right, the SA hub is pretty reasonably priced for what it is, but unfortunately for me I got the urge to build mine during Covid and no one had these hubs. I found a wheelbuilder who was going to convert my existing rear wheel but he didn't have a source for the hub either. 18" is the low gear on my cargo bike and also the around town tandem I commute DW (blind) to work on every day. We use that 18" on every trip. I'm pretty sure the SA hub is up to handling the torque from the primary reduction. However, if my experience with my 33" low is any indication, a low of 22" to 24" might be just the ticket. A folder is not usually pulling a 100lb trailer up 8% grades.
Not quite that heavy, but my folder is typically 55 lbs + perhaps 20 groceries + fat me, and I do 10% hills all the time, some short 15%.
If the Expressway is 20"/406, you can get lower gearing, either by going mega-cassette 11-42 like Ron Damon and others, or 2X gearing as I note in the post above. Just shrinking your chainring will get you lower but not enough top end with just under 300% I think, I believe 400% is minimum in hill country, I'm not fast enough now to need over 85 gear inches.