Front Hub Drives Can't Climb

richj8990

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The first in a multi-part series to show just how terrible front-hub drives are offroad. Unless of course they have a DHR II up front :)


 

matt4x4

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Front hubs can climb just well, all depends on how much juice your dumping into the motor via the controller.

Whats the controller voltage and amperage rating that is on the bike?

The trail in the video, yes certain aspects the front hub would have way different handling characteristics then a rear hubbie.

Rear hubs are better then front, no need to buy a front hub motor unless you find it for ultra cheap. Like at YESCOMUSA, I scored a front hub ebike kit, except battery for C$125 delivered! Sure its a wimpy controller, the motor could probably handle an extra 10A above the stock controller and the motor still stay cool. Its a good cruiser ebike on a bso ccm from department store.

A trail like in the video, a bbs02 or bbshd mid drive system or a rear mxus/qs hub then you could power up them trails with ease and minimal pedaling. Helps conserve the battery wh.
 

Bigwheeler

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I was working at a shop that installed kit systems a few years ago for a bit and a customer came in that wanted to convert his old Specialized mtb to a front hub. He uses the bike as a commuter and during the winter months his commute, 90% on dirt, can get pretty greasy and he lives at the top of Forest Park in PDX and his office is in the NW part of town also and thought it might help his ability to ascend at the end of the day. Just had word from his associate the other day that two years in he loves it and has no issues and ended up using it year round. Just a simple 350w nominal geared front hub motor running @ 48v/15A.

After several thousand miles on my drop bar front hub eX bikes and experiencing how well they climb, even with 40/45c tires, you can't convince me that a front hub bike won't do the job. Considering weight bias on my eX bikes having a front hub motor, centrally located battery and my weight biased towards the rear with me pedaling in the appropriate gear along with feeding the right amount of power to the front motor it is pretty easy to maintain traction on both ends creating a nice little 2WD scenario. As opposed to a rear hub system that I have never gotten on with as the rear bias is not to my liking and it is too easy to overpower your input.

For single trail use I do prefer a mid drive with torque assist and some low psi tires but I have always been intrigued by the idea of a small efficient front hub mounted on an mtb but have yet to do so because I am pretty satisfied with my setup as is.

To me any e system has to out weigh the benefits of the system weight in order to make sense for it's intended use. Also it is important that the system not affect the bikes handling characteristics as well as my desired input at the cranks. That is why I only use a throttle with cruise control on my eX bikes for the higher cadence I use mostly with them and a torque sensing PAS for mtb and the lower cadences associated with its use.

Cadence sensing systems like the Bafang kits drive me nuts trying to ride even on the street, much less trails as they don't feel at all natural to me and minimal pedaling is not my goal when riding a bicycle in any situation.
 

richj8990

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Here's another one, 5 separate inclines, the 4th is the hardest even though the 2nd one looks hardest.




I'll do some longer, gnarlier ones later. Ones that on a normal bike the KOM by a pro XC racer is only 5.6 mph uphill, and my goal is to get like 4 mph on the e-bike. Look up McGinty Complete on Strava (Jamul CA), it's pretty brutal.
 

ironbrewer

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What front hub kit are you using, and where did you get it? I'm currently researching to find an affordable kit with a big battery for self retrieve paragliding. I need to be able to go about 12 miles with 1500 foot elevation gain.
 

matt4x4

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Hub motors are a dime a dozen, most based off a single design. What width of magnet do you want, tells you how much power the motor can handle.
20H 25H 30H 35H 40H 45H
^Small low power tooooo^Very high powered

There is a dilemma though for front hub motors placed on a fork. The fork can only handle so much power, even with beefy torque arms on both sides. One bonus is its easy to replace a flat on a front hub. You will be A-OK with a 250W (UK) hub, but the sellers will tell you a 5000W motor is 250W just to sell you a motor, thats just their culture, profit. Its all based on the controller, so that 5000W capable motor, can be tamed by a 36V10A 360W controller, or you can buy a 72V40A 3000W controller (not legal) for that 5000W motor. So back to 360W. You'd burn the 250W 20H motor quickly with 72V40A3000W controller. Magic smoke, burnt a few myself.

Next up do you want a direct drive (DD) motor or a geared motor.
Do you want regeneration of power back into the battery (DD), or do you want a freewheeling motor, geared motor.

Sources for ebike kits from reputable sources
https://www.ebikes.ca/
https://lunacycle.com/
https://em3ev.com/
https://evfittinggreentime.aliexpress.com/store/313864
https://ebikessf.com/
https://www.mxus-motor.com/ Also on Aliexpress or Alibaba straight from the factory! Custom wound motors, 3T/4T.....9T whatever.
 
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richj8990

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OK gentleman, this is it. Or should I say, was, is, and will be, because with a 17% grade on the 2nd section, it makes an excellent testing area for what works and doesn't for climbing. I tried this mountain a few times before and stopped pretty early on the middle section, this time I made it about 85% up before I took the wrong line and the front tire slipped. I was also exhausted. I'll have to get in better shape to complete it, but it's 100% doable. About 400W, as mentioned in the YouTube notes I'll later vary the watts by +/- 50W and the seat height as well. Too high of a seat and the front tire gets really squirmy, so you either sit down with a higher wattage, or you lean forward with a lower wattage, probably 300-350W at most. Would a mid-drive do better? Maybe. I'll try one up this one day I'm sure.

The first section is probably about 8-10%, a lot of eroded sandstone that's actually fun. The 2nd section is just brutal, period. The top section is impossible, and since it was completely foggy I decided to head back down this time.

I'll post a video later on the other side of the mountain, that's pretty steep too.
 
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