Hi folks. I recently bought my first ebike, a 1000w 48v hub drive fat tyre. It suits my purposes well, but part of my needs is to climb a steep hill without having to pedal, and the bike doesn't do it without pedalling, which is not what I want to do. I am now learning more about ebikes and realize that what I need is torque. My bike is rated at 54nm, which is probably less in effect. I need more torque. I wonder if I could fit a mid drive kit, which could be awkward to make fit. Would that help? BUT I have also noticed that I could maybe fit a left chain drive. Would that help?
Would a left chain drive help me?
- Thread starter duggie
- Start date
Scrambler.......I think you are right, to just get a high torque mid drive. I'll just have to bite the bullet with the price.
JRA...........well, i don't mind gentle pedalling, I enjoy that, but I live where it is very hilly and to get up this particular hill I have to pedal assist in an energetic way and this is too tiring for me. I wanted something to take me up the hill with no effort. I only want it to get me to and from my allotment, which involves a steep hill. To use a car or motorbike is not possible. An electric bike which can handle muddy paths and steep hills is ideal. I have noticed such mtbs are very expensive, too expensive. Perhaps I could fit a high torque mid drive conversion kit like the bafang ultra max to an ordinary bike I have, if that would give me the torque, at a sane price, to get me up that damn hill I can't avoid.
JRA...........well, i don't mind gentle pedalling, I enjoy that, but I live where it is very hilly and to get up this particular hill I have to pedal assist in an energetic way and this is too tiring for me. I wanted something to take me up the hill with no effort. I only want it to get me to and from my allotment, which involves a steep hill. To use a car or motorbike is not possible. An electric bike which can handle muddy paths and steep hills is ideal. I have noticed such mtbs are very expensive, too expensive. Perhaps I could fit a high torque mid drive conversion kit like the bafang ultra max to an ordinary bike I have, if that would give me the torque, at a sane price, to get me up that damn hill I can't avoid.
Yea, we'd all love to have the perfect bike - high powered climbing ability, throttle when it's too tiring to pedal, light weight, infinite range, comfortable, and yes, let's make it cheap, too. Oh, and maintenance free...
Unfortunately, life, and bike purchases are full of compromises. What did you do before your ebike? And what prompted you to get a fat tire hub drive if you knew you had a steep hill to climb?
Sounds like you need some serious advice. Are there any ebike enthusiasts locally that can help advise you? A trustworthy bike shop?
D
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A ‘left chain drive’: like on a motorcycle?
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tomjasz
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- USA
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- Minnesnowta
No, but a BBSHD kit would likely do the job.
tomjasz
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- Minnesnowta
Which ebike do you have? Gearing? Motor? Heat sensor?
Which model brand is your bike to convert?
theres no escape from due diligence. Read research BEFORE buying an eBike. You could have avoided the fail. Places like EBIKESCHOOL.COM can be frustration freeing and money saving too. That said my first build had me pulling hair out. I had to buy a new bike to kit. I have felt your frustration.
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retiredNH........
harryS.......Sorry, I must not have made myself clear, a motorbike will easily climb it, but it is in a place where I can't use a motorbike.
I had to use my van, but had to leave it in an awkward not allowed place. In hindsight I should have got good advice first, but I just didn't expect, well, I feel a bit tricked because I thought a 1000w motor would have twice the climbing ability of a 500w, and a pal had a 350w that was apparently almost good at hills, so it is a bit misleading for the uninitiated. Really they should headline both wattage and torque......but they don't, you have to know, and when you do know you have to pay for the stuff that will turn wheels, and pay a bit more over the odds.....they are a bit overpriced. 6 grand for a bike, etc, I mean. But it's just learning. My bike will do for now, and the next bike I get I will know what I am doing. Yes, there is a good shop, locally.
harryS.......Sorry, I must not have made myself clear, a motorbike will easily climb it, but it is in a place where I can't use a motorbike.
Hi David. Yes. It is a motor with a drive sprocket which is bolted to the left hand side of the frame, and this goes to a sprocket on the back hub. So you have your cog train on the right of the rear hub as normal, and then an additional cog fitted to the left-hand side of the hub, and it has its own chain, all independent of the bike's usual gears.
You raise some very good points, especially with regard to wattage and torque. Neither is relevant in and of itself. "Wattage" is the worst, given the lack of standards and universal understanding of what it means. It could mean peak, sustained, average. It could mean input or output (but in almost all cases the former) and neglecting efficiency. Torque could be peak or sustained. It means something very different, in practice, when comparing hub versus mid drives.
As you can see, I don't agree that "they should headline both wattage and torque" because neither is very relevant to real life riding - there are more important factors like the bike and drive train design.
I strongly encourage you to work with a decent local shop that can show you a variety of bikes, both mid and hub drives, to find something that works for you.
tomjasz..........thanks, I'll look up that BBSHD kit. Well, my bike is branded Keteles, a 1000w 48v hub drive with no internal gears, just a normal shimano gear train and just 50Nm of torque.
The bike is comfortable, it folds, it feels very stable in mud. It's a lovely bike. But if it had a mid drive 160Nm on it I would be over the moon. Know I should have done more research. I took a bit of a chance. But, well, on the up side i have a bike i can still use to a fair degree, and it didn't cost crazy money, and it has taken me well along the learning curve. I'm going to have a good look at that kit you mentioned now. Could be just the ticket.
The bike is comfortable, it folds, it feels very stable in mud. It's a lovely bike. But if it had a mid drive 160Nm on it I would be over the moon. Know I should have done more research. I took a bit of a chance. But, well, on the up side i have a bike i can still use to a fair degree, and it didn't cost crazy money, and it has taken me well along the learning curve. I'm going to have a good look at that kit you mentioned now. Could be just the ticket.
PedalUma
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- USA
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- Petaluma, CA
Sell it fast and take the hit like a man, calling it the high price of tuition. In my opinion @duggie, a small, lightweight mid-drive with a moderately low bleed out rate and moderately high torque with a throttle on a light gravel bike is what you need. The bleed out rate is Watts. Beginners think that a high number is better. With a lower rate of bleed out you can use a smaller, lighter battery and go farther. A mid-drive will power through the gears so it will be far more efficient. And be a better climber. I do very large hills and mountains in the region of California where the mountain bike was invented and perfected. Heavy bikes don't cut it on those trails. Here is one of my bikes. It is 350Watts with 85Nm. I have found that more than 90Nm leads to drivetrain problems. This bike normally uses a three pound, 1.3Kg battery. It also uses adult sized wheels.
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indianajo
Well-Known Member
The motor on the back of that bike doesn't look 12" in diameter. If it whines when you push it backwards, but makes no sound when you push it forwards, then it does have internal gears. If it doesn't, gearless hub drives are fairly useless for climbing steep hills. The torque doesn't reach rating until about 100 rpm. The geared ones are useful. The rotor inside runs 5 times faster than the bike wheel. Torque is much higher at low speeds.
All the mid drive mania above glosses over a huge pitfall. Unless the sprocket on the back wheel is bigger than the one inside the mid-drive, it does not have torque multiplication. Only speed multiplication. As you notice, bikes with 48 or 50 tooth rear sprockets cost mid $$$$. Or LLLL in your case. I couldn't even find a 32 tooth 7 speed freewheel to fit my rear hub drive. In the catalog, never in stock. 28 teeth wouldn't get me up the hill when the rain took out my throttle, even with a 32 tooth front sprocket.
What mid drives do better than geared hub drives, is climb 1000' in an hour without overheating and shorting the windings. There is not a 1000' hill in the UK IMHO.
You may be able to use the same frame controller & battery, but buy a power wheel (with the same connectors) that is geared. I'll wager a Mac12t geared hub motor will climb your hill with a 25 A controller, if you plus bike weighs less than 150 kilos. https://www.alibaba.com/product-detail/Mac-bldc-hub-motor-6T-8T_60512780782.html I'll not wager that UK customs won't confiscate either at the port or airport. Its still legal to buy these things in the US, but not to ride them on road in about 48 states. Mine had a top speed of ~23 mph on 48 v (54.6 max) but the deadly 750 w limit means its not a bicycle motor under the 3 class system. Domestic retaillers have stopped selling them here. What mine would do is start 150 kg me+bike+groceries up a 15% grade, and accelerate to about 9 mph uphill, without help. Retired bIke riders riding 9 mph uphill: we may as well be displaying Uzis!
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IJ, you've said this before, and it is just NOT TRUE. Please check your biases. You should know by now that the whole issue of "torque" is a can of worms because of the many ways it's defined. Worse, for your favored hub drives, torque is hardly constant. It varies with speed (RPM) and with hub design. At least with a properly designed mid drive, the motor is working within a much narrower speed range, so a rider can, within the range of the rear gearing, always get maximum torque out of the motor. That's the whole point. And that's why the best climbing bikes are mid-drive.
m@Robertson
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- USA
Hub drives are at an inherent disadvantage in hills. Period. There is no gearing pitfall.
Want to test this? Ride ANY bicycle and leave it in one gear. 17T would be about right as thats typical for a hub motor'd bike. Go up a hill. How'd that turn out? Now ride up a hill shift up thru the gears with a derailleur. Did it get easier? Of course it did. Thats why fixies are only used by hardcore types. Hub motors also are running at a fixed gear thanks to the fact they power the bike thru the axle, not the gears in the bicycle's drivetrain.
If you are in the UK and concerned about legality, an 80 Nm BBS02 is available in a 250w version, although its limited to a 68-72mm bottom bracket installation unless you get hold of one thats been modified for wider (fat) bikes... if you have such a bike. That 80 Nm can then be applied efficiently to the task at hand by upshifting prior to hitting the bottom of your hill... and you'll toodle right up the thing without even straining that motor. Which as you already have learned is not going to happen with the hub motor.
If you need something wider, a BBSHD is commonly available for bottom brackets as wide as 120mm. Dial that motor back in power so it only runs at a fraction of its potential (over 1600w on a 48v system) and dialed back like that it will last forever.
Want to test this? Ride ANY bicycle and leave it in one gear. 17T would be about right as thats typical for a hub motor'd bike. Go up a hill. How'd that turn out? Now ride up a hill shift up thru the gears with a derailleur. Did it get easier? Of course it did. Thats why fixies are only used by hardcore types. Hub motors also are running at a fixed gear thanks to the fact they power the bike thru the axle, not the gears in the bicycle's drivetrain.
If you are in the UK and concerned about legality, an 80 Nm BBS02 is available in a 250w version, although its limited to a 68-72mm bottom bracket installation unless you get hold of one thats been modified for wider (fat) bikes... if you have such a bike. That 80 Nm can then be applied efficiently to the task at hand by upshifting prior to hitting the bottom of your hill... and you'll toodle right up the thing without even straining that motor. Which as you already have learned is not going to happen with the hub motor.
If you need something wider, a BBSHD is commonly available for bottom brackets as wide as 120mm. Dial that motor back in power so it only runs at a fraction of its potential (over 1600w on a 48v system) and dialed back like that it will last forever.
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