only 12 motors for fat bikes & all are bad choices

[xtinctionRebeller]

I've studied 11 mid-drive kits for fat bikes (listed here), as well as the Stokemonkey (which is unlisted due to being discontinued). I'll probably abandon the project because there are just no good options.

Hacking budget-- It's sensible to nix anything over ~$1.5k because there are bikes with frames that are properly designed as an e-bike around & above that price. The conversion kits are a hack & it doesn't make sense to spend more on a hack than a proper design from the beginning.

Pedal ergonomics-- they suck all around. Muscle bikes already ship with excessively long crank arms as it is (a majority of riders are probably not over 5'9"). E-bikes call for shorter cranks simply because there is a motor helping, and fat bikes could use extra clearance as there's a good chance they're used off-road. The kits not only include cranks that are too long by default, but they don't even give the option for sensibly sized ones. And most kits have the design defect of right-shifted pedals. Only two kit makers thought to correct the asymmetry by increasing the q-factor on the left.

Low-maintenance use case-- There are some decent high-power options for those who would throttle around but that's not my use-case. I was looking for a PAS hill-climbing-only motor that's not as loud, messy, and high-maintenance as a chain drive.

My comments on some of the kits (bold = short listed):

• Bafang BBSHD - I could almost be tempted but after replacing the crank arms with sensible ones it's about double the cost of a TSDZ2, and yet still no torque sensor.
• Bikee Bike - $1.2k is expensive for a kit without a torque sensor.
• CYC x1-pro gen1 - the gear option makes this attractive, until you realize that they stopped offering a gear option in gen2 because of all the issues it has. Overpriced compared to the torque-sensing gen2.
• CYC x1-pro gen2 - tempting despite the chain drive. It's torque sensing and it's the only kit to come with sensible crank arms (165mm). It's perhaps the best documented and presented motor kit on the market, and the vendor is responsive.
• Cyclone - no positive qualities really, unless you're simply looking for high-power for the money.
• L-faster - only sold by one vendor exclusively in Aliexpress. Aliexpress harrasses Tor users so that's a non-starter for me.
• Lightening Rods - PAS option is at least $130 more, likely cadence; better to spend ~$250 more on a torque-sensing CYC x1-pro gen2
• Tongsheng TSDZ2 - on paper this is clearly the best option even despite the fragility of it in general (motor cases breaking). However, the fat bike version is very unsafe. I cannot accept a BB spindle that would snap all of the sudden while standing on the pedals. Make sure you have a decent healthcare plan before putting a TSDZ2 on a fat bike.
• Binova Flow - $2k for a very low power hack? Granted the market is for the European street rider but at that price you can probably have a well-designed complete e-bike fully featured.

I'm leaning toward keeping the fat bike as a muscle bike. If the wiki is missing any please let me know.

 

[HazEbike]

If all else fails, one thing I've learned building and blowing my hub motor a few times has been to go with the best documented option. CYC mid drives seem powerful, cost effective for what you are looking for, and the main product support (the non company based) is the real contributor to longevity aside from build quality. I read your post last night and thought on it a bit yesterday. Based off of your needs, it seems as though with the attributes listed the CYC with the backing of community-based documentation and testing will be the best option. Don't feel bad when something doesn't fit right, sometimes solutions to small problems like the crank arm length can be solved by buying something that wasnt necessarily engineered for your application, but does have the strength, functional, and safety you need.

 

[john61ct]

Everyone has their own priorities and criteria.

Besides the strength issue, what would make a mid-drive unsuitable for fat tires?

A proprietary bike is not an option at all IMO, completely different market.

Better to pay triple the pricing for something where you have free choice of mix and match components, ability to modify stuff etc.

I agree many kits are too big a compromise, they generally won't have any intelligent designer or awareness of subtleties behind them.

**You** are the designer, better to buy each component individually.

A CAv3 is IMO required unless you get a truly sophi$ticated controller, either will get you good torque-based PAS.

Everyone has their own priorities and criteria.