NwRecumbentRdr
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What's to most powerful FRONT hub motor you've ridden? How was the experience?
Front hub motor
- Thread starter NwRecumbentRdr
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Cornering works just fine with a front hub, there are 1000s of them out there and folks aren't falling over all over the place. But big high powered front hubs are a whole different and dangerous animal.
Traction of a front tire (whether it's powered or not) is very important. Completely lose that traction on a bicycle, motorcycle or any other two wheeled vehicle and you will go down as soon as your center of gravity isn't directly over the wheel.
On a front hub ebike you need to think about that traction. It's not a setup that is well suited to loose surfaces so serious off road isn't an appropriate use case. On pavement, dirt roads, or groomed trails (small gravel) that aren't too steep a front hub works fine. Even in the rain, snow or ice with suitable tires there isn't a problem.
I ride a 500w front hub bike which is capable of over 1000w using the throttle (Grin Technologies RTR kit with a Shengyi hub motor) with solid front suspension in an urban/suburban environment 365 days a year. My bike is well balanced and very stable. It's tuned to bring on the power smoothly, and it rides very much like a traditional unpowered bike. The only thing I've done to accommodate the front hub setup is to run slightly wider tires than I would normally. In my case that would be 650x50mm gravel/adventure type tires to handle a variety of surfaces but biased towards smooth pavement. In the winter I switch to good aggressive and studded winter tires.
Traction of a front tire (whether it's powered or not) is very important. Completely lose that traction on a bicycle, motorcycle or any other two wheeled vehicle and you will go down as soon as your center of gravity isn't directly over the wheel.
On a front hub ebike you need to think about that traction. It's not a setup that is well suited to loose surfaces so serious off road isn't an appropriate use case. On pavement, dirt roads, or groomed trails (small gravel) that aren't too steep a front hub works fine. Even in the rain, snow or ice with suitable tires there isn't a problem.
I ride a 500w front hub bike which is capable of over 1000w using the throttle (Grin Technologies RTR kit with a Shengyi hub motor) with solid front suspension in an urban/suburban environment 365 days a year. My bike is well balanced and very stable. It's tuned to bring on the power smoothly, and it rides very much like a traditional unpowered bike. The only thing I've done to accommodate the front hub setup is to run slightly wider tires than I would normally. In my case that would be 650x50mm gravel/adventure type tires to handle a variety of surfaces but biased towards smooth pavement. In the winter I switch to good aggressive and studded winter tires.
Catalyzt
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I only have 250 watts on my front hub drive kit bike, but I completely agree-- not only is cornering not a problem, but there are some really tight hairpins where the Trek handles better with the front hub than it did without. I think this is both due to balance and all-wheel drive.
My front hub can handle a short stretch of 15% grade-- maybe a block or two-- on pavement, and can handle maybe 12% on dirt. It's fine for bombing around even some of the steep hills near my house, and it can handle an 850 foot climb over the course of about 4.5 miles.
But think you'd want to be very careful with a powerful front hub motor. I wouldn't want more than 250 watts on my kit bike because it's just not set up for it, it wouldn't be balanced right. The smaller front-wheel kit is perfect for my class II mid-90s Trek 930. It's only 40 pounds, and has as much acceleration as I need on flat terrain, much more moped-like than my mid-drive.
harryS
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I've got a small hubmotor up front on one of my bikes. Nominally a 250W motor. It's only 4.5 pounds. The front tire will often slip starting out on loose surfaces, but I've not seen any loss of traction elsewhere because I ride it pretty mildly. It might pull at most 600-700W up a hill on 36V with a 20A controller, and I've never tried to pull it thru a corner under power. That would be asking for a crash.
indianajo
Well-Known Member
I had a 1300 W front hub motor. It really didn't have more torque than the 500 W Mac12t I've got now. Neither is a problem except on wet rock, wet or muddy steel plates, wet wood decks, ice. Have a brain, use it.
I use throttle only, PAS was a safety hazard. Too fast in PAS1 for 6" wide berms with 6" deep ruts next to them. Would whack me on the back of the ankle if I wound up the crank for a good start. Would kick in in the middle of a u-turn & throw me. Deleted the PAS pickup. Deleted the LCD display too, it was invisible in full daylight.
Front wheel will slip on steep uphill dirt. I don't ride on dirt.
I corner all the time at up to 35 mph on rolling hills. Not a problem. Usually don't power at the bottom, only uphill. I have knobby tires. Won't do 35 into a corner with gravel or water at the bottom.
I use throttle only, PAS was a safety hazard. Too fast in PAS1 for 6" wide berms with 6" deep ruts next to them. Would whack me on the back of the ankle if I wound up the crank for a good start. Would kick in in the middle of a u-turn & throw me. Deleted the PAS pickup. Deleted the LCD display too, it was invisible in full daylight.
Front wheel will slip on steep uphill dirt. I don't ride on dirt.
I corner all the time at up to 35 mph on rolling hills. Not a problem. Usually don't power at the bottom, only uphill. I have knobby tires. Won't do 35 into a corner with gravel or water at the bottom.
m@Robertson
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I use front hubs both on and off-road, but as part of a 2wd system. I have both powerful on-road twin hubs, much lower powered urban hub+mid drive and a powerful-but-adjustable off-roader.
talesontwowheels.com
The key to making a front hub work is judicious and independent power application. There are times when its best to turn the power off (like in a fast, sharp corner). On trails, if too much power via throttle or PAS to the front wheel, if a root pops your front wheel up, it likely comes down in a different direction and you shoot off in that new direction. A sub optimal result. Ideally on loose singletrack, stay in the ballpark of 250w to the ground. Thats the nexus/sweet spot I found for traction benefit vs. battery drain vs. safety, although thats on a 2wd assist system.
Regardless, I would prefer not use a front hub alone. If its all you can afford or are comfortable with as a DIY kit, its better than nothing. But generally you will be better served by putting a hub motor in the rear axle versus the front if you can swing it. If you want high power, put it in the back.
Dual Motor AWD Electric Bikes (the good and bad)
I like to build top-quality-component ebikes from the frame up. Quite a few of them are dual motor or AWD or 2WD or whatever you want to call them. Why would you build an AWD ebike?
talesontwowheels.com
The key to making a front hub work is judicious and independent power application. There are times when its best to turn the power off (like in a fast, sharp corner). On trails, if too much power via throttle or PAS to the front wheel, if a root pops your front wheel up, it likely comes down in a different direction and you shoot off in that new direction. A sub optimal result. Ideally on loose singletrack, stay in the ballpark of 250w to the ground. Thats the nexus/sweet spot I found for traction benefit vs. battery drain vs. safety, although thats on a 2wd assist system.
Regardless, I would prefer not use a front hub alone. If its all you can afford or are comfortable with as a DIY kit, its better than nothing. But generally you will be better served by putting a hub motor in the rear axle versus the front if you can swing it. If you want high power, put it in the back.
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tomjasz
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I do not agree, not at all. All of my bikes were mid-drives until I converted a Trek Pure flat foot frame. Lately converting the worn-out mid drives with MAC motors.
I just don't need the climbing ability.
A 1000W MXUS with a Grin controller and CA3. Super errand bike and the regen braking is great. Too often I think we tend to push our prejudices on n00bs. It's far and away better than nothing. Not everyone wants a build hobby.
tomjasz
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Horse pucky!
tomjasz
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I don't need to imagine. It corners just fine.
m@Robertson
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Well, I was thinking of this in the context of that noobie. And I think you misunderstood my recommendation, which I did not make crystal clear: I was not recommending a mid drive in the back. I was recommending a hub in the back. I'll edit my post to make more obvious.
If given the choice between a hub kit in back vs. a hub kit in front, I would always pick the back wheel. Its a little more work to install, but only a little. You get better performance (traction). You also have a MUCH lesser risk of destroying the front fork thanks to issues around torque arms and torque in general on the front forks. I have seen sooooo many destroyed forks where the dropouts have snapped because either the fork was not up to snuff or the builder didn't deal with the torque arm issue. And you have a safety issue with suspension forks and more powerful motors (plus 500w or so). I can remember having to do it in an emergency after *I* had destroyed my only fork (torque arms not installed properly). I watched my suspension fork blades flex outward as the motor tried to pull forward and pull the 2-piece blades apart. I ended up staying off throttle and limiting controller amps after doing some research and the fork stayed together while my new solid one got delivered.
For a low power build, it doesn't make much difference front or rear. A 250w 40Nm motor can go on steel forks just fine with no torque arms or undue concern. My 500w/25a could probably be ok as well since I set the controller to slow-roll on the power. But I knew to do that. Again, I'm coming from seeing this as a weekly occurrence on the DIY Ebikes group, or on Endless Sphere, where some poor noob doesn't know what he is getting into, snaps off or rounds his dropouts and posts to the group asking wtf he's supposed to do now.
EDIT: I decided to go to that group and see if they had another one happen. I only had to scroll back to June 12th. Three days ago. I know this can be done, but like I said I see one or more of these a week on a DIY group full of noobs (40k members in the group), so I am a bit gunshy with regard to recommending front motors to inexperienced builders.
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mschwett
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In addition to a mid drive, I have a front hub city bike, pedal assist up to 250w ish with a button that goes to 500w.
It’s really fun to hit the button while pedaling hard around an uphill curve. Totally stable. I do not see why two wheel drive with the rider putting down a couple hundred watts in the rear and the motor putting a couple hundred in the front is somehow bad. I agree that if your weight transfers rearward, and you’re not pedaling, you could lose traction. But it’s a bike, not a moped, so I pedal it.
It’s really fun to hit the button while pedaling hard around an uphill curve. Totally stable. I do not see why two wheel drive with the rider putting down a couple hundred watts in the rear and the motor putting a couple hundred in the front is somehow bad. I agree that if your weight transfers rearward, and you’re not pedaling, you could lose traction. But it’s a bike, not a moped, so I pedal it.
indianajo
Well-Known Member
One advantage of checking forums before purchase is finding out problems before the build. I read about torque on the front forks from hub motor, and the first set of torque arms were 30" long angle aluminum that also held up the 13 lb battery. That was a steel fork Huffy. Turned out I didn't like steering the battery on my rutted drive at the summer camp so I abandoned that $15 bike. Battery rides suspended from holes in frame on the front of the current bike.
Two trouble with rear hubs. One is it puts weight in the back where a cruiser bike is already overloaded. My MTB was weighing 120 lb rear 20 lb front with groceries, and that was causing unstable steering. Over the handlebars 3 times on my chin. Hence the stretch frame cargo bike. The second problem with rear hub motor is you cannot buy a 11 to 32 rear sprocket cluster in 7 speed. I have a collection of 8 speed sprocket clusters that will not fit in the rear fork. The 13 to 32 7 speed sprocket is on the manufacturer website, but nobody in the USA ever has one in stock. I need 32 to get up hills without power, so I deleted the rear DD hub motor and re-installed the 8 speed 11 to 32 sprocket the unpowered bike came with. Front hub motor now has 4" long torque arms made of bed frame rail. 6000 miles and not a problem with 1300 W or now 1000 W Mac12t front hub motor.
jdmvette
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Would an 11-28 or 11-34 work for you? 34T should help with the hills ¯\_(ツ)_/¯
Amazon.com : DRIFT MANIAC DNP E-Bike Freewheel 7 Speeds 11-28/11-34T Teeth EPOCH : Sports & Outdoors
Amazon.com : DRIFT MANIAC DNP E-Bike Freewheel 7 Speeds 11-28/11-34T Teeth EPOCH : Sports & Outdoors
www.amazon.com
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