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.

 

[crunchysteve]

Use a pants cuff clip or strap to keep your bell bottoms in check.

What we Aussies call a "Fred," an old guy on a bike with righthand pants cuff tucked into his sock.

Duh, I resemble that remark

 

[crunchysteve]

There's also "double pie plate" approach to chain retainers. Slip a slightly oversized MTB bash ring on both sides of the chainring. Use the narrowest available chainring spacers and longest available chainring bolts.

I use this approach on my dutch front loader cargo bike. Both my bikes run 1x9 with a 34 tooth ring and 11 to 46 cassettes. the cargo is a 26" rear running a 26x1.75 tyre to match the front 20x1.75. Haven't ridden the cargo bike much lately because the beast is heavy and I'm still trying to figure out how to finance an eKit for it. Currently 250watt 20" front wheel kits are as rare as rocking horse manure in Australia. Affordable ones (for me), at least. So the poor thing's gathering dust in a friends garage at the moment. I'll probably have to get a chinese wheel of any size, get some BMX spokes from a cheap supplier I know of in Queensland and build my own front wheel.

Can't do back wheel drive because I've got some really mullet stuff going on around the rear dropouts. It's a Zeit Bikes short wheelbase that was designed for Shimano ALfine 7 and I'm running kerbside hard rubbish mountain bike salvage. All high quality stuff a decade ago, hardly used. Wealthy people's kids have grown up and got cars.

 

[LucyBrown]

There's also "double pie plate" approach to chain retainers. Slip a slightly oversized MTB bash ring on both sides of the chainring. Use the narrowest available chainring spacers and longest available chainring bolts.

I use this approach on my dutch front loader cargo bike. Both my bikes run 1x9 with a 34 tooth ring and 11 to 46 cassettes. the cargo is a 26" rear running a 26x1.75 tyre to match the front 20x1.75. Haven't ridden the cargo bike much lately because the beast is heavy and I'm still trying to figure out how to finance an eKit for it. Currently 250watt 20" front wheel kits are as rare as rocking horse manure in Australia. Affordable ones (for me), at least. So the poor thing's gathering dust in a friends garage at the moment. I'll probably have to get a chinese wheel of any size, get some BMX spokes from a cheap supplier I know of in Queensland and build my own front wheel.

Can't do back wheel drive because I've got some really mullet stuff going on around the rear dropouts. It's a Zeit Bikes short wheelbase that was designed for Shimano ALfine 7 and I'm running kerbside hard rubbish mountain bike salvage. All high quality stuff a decade ago, hardly used. Wealthy people's kids have grown up and got cars.

Since you're using pedal assist and limiting to 20 mph, switching to a 1x setup would simplify things and eliminate the bulky derailleur issue. A 1x or double crankset should provide enough range for most cargo situations. I was under a tight deadline with my thesis, so I decided to use academized.com/thesis-writing-service The writers were professional and delivered a high-quality thesis on time. If you’re a student who’s struggling with thesis writing, this service can help you meet your deadlines without compromising on quality. I was really impressed with the results and would highly recommend this service to anyone in need of thesis writing help.

Thanks for the advice, I appreciate it. I will keep it in mind.

 

[Zambam]

Use a pants cuff clip or strap to keep your bell bottoms in check.

I wear skinny fit jeans with slightly stretchy fabric. Never had problems of it getting caught or dirty from the chain. They are also very comfortable

 

[Zambam]

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

Last week I put a 42T narrow wide chain ring on my TSDZ2 to replace the stock 42T TongSheng chain ring where the chain often jumps off after hitting potholes. Haven't put many miles on it so won't know for a while if it helps or not.