Gearing for a hub driven e-cargo bike

[smitty2k1]

Working on my first ebike conversion - Xtracycle Edgerunner with a Grin All Axle rear hub motor (20" wheel). This bike started life as an analog bike with huge gearing for getting cargo up hill - triple 9 speed with 48/36/26 crank and 11-34 cassette.

I'm thinking I should replace the triple front with a double or maybe even a 1x crankset. I'll probably stick with the 9 speed 11-34 cassette in the rear. I don't think I'll need the gear range of the triple and the stupid front derailleur constantly catches on my pants because of the very wide chainline and low end components being rather bulky.

I'll mostly be using this in pedal assist mode and will likely speed limit it to 20 or so mph. Wondering what appropriate gearing may be?

Thoughts? Worth swapping out the crank for a double or 1x? Just keep it a triple until something wears out?

 

[Chalo]

That's a good donor bike for conversion.

I would keep the crank and front derailleur you have, and just leave it in the big ring unless you need to deal with loss of power or extreme riding conditions. Use a pants cuff clip or strap to keep your bell bottoms in check.

When/if you use up those chainrings, maybe a full sized road double (53/39) or compact road double (50/34) would be a more suitable replacement. You can use a shorter BB to reduce Q factor; the very long chainstay makes chainline almost irrelevant.

 

[smitty2k1]

That's a good donor bike for conversion.

I would keep the crank and front derailleur you have, and just leave it in the big ring unless you need to deal with loss of power or extreme riding conditions. Use a pants cuff clip or strap to keep your bell bottoms in check.

When/if you use up those chainrings, maybe a full sized road double (53/39) or compact road double (50/34) would be a more suitable replacement. You can use a shorter BB to reduce Q factor; the very long chainstay makes chainline almost irrelevant.

Thanks I'm now seeing that some other off the shelf e-cargo bikes with hub motors and 20" wheels come with 50T front chainrings (Specialized Globe). Not many 1x configurations with chainrings that big. I suppose standard chainrings work but lose the narrow/wide tooth profile.

 

[Chalo]

Thanks I'm now seeing that some other off the shelf e-cargo bikes with hub motors and 20" wheels come with 50T front chainrings (Specialized Globe). Not many 1x configurations with chainrings that big. I suppose standard chainrings work but lose the narrow/wide tooth profile.

Narrow-wide rings are available separately, but they are part of a system and not fully effective by themselves.

The other part of the system is a clutched derailleur that resists paying out more chain. The only reason new single ring MTBs can do without a chain keeper or front derailleur is because they use both a narrow wide ring and a clutched rear derailleur.

On my single ring bikes, I use a simple old front derailleur with flat side plates, pushed down to capture the chain on top of the chainring. It doesn't need to be connected to a shifter. There are dedicated chain keepers that do the same thing.