I ride with a mid-drive Bafang 750w kit. I have to replace the rear sprocket at least three times a year which gets expensive. Does anyone else have this problem?
Sprocket wear
- Thread starter HughMorris
- Start date
How many miles per year, and how often is the chain replaced, and do you measure the chain elongation to judge when to change it?
The 750W if used at high power will be a big chunk of the cause.
I get 3,000 miles maximum out of a chain to 0.5-0.7% elongation, but that is a puny 250W 40Nm motor.
The 750W if used at high power will be a big chunk of the cause.
I get 3,000 miles maximum out of a chain to 0.5-0.7% elongation, but that is a puny 250W 40Nm motor.
Thanks for your reply Matthew.
I do about 2000 miles a year on steep hills hence the 750w motor.
Proper e-bike chain and rear sprocket changed together three months ago, slipping already.
Using proper tool to check chain wear. It's OK.
I guess it's a cost I have to accept. I've thought about hardening a new sprocket. Not sure it will work though.
I do about 2000 miles a year on steep hills hence the 750w motor.
Proper e-bike chain and rear sprocket changed together three months ago, slipping already.
Using proper tool to check chain wear. It's OK.
I guess it's a cost I have to accept. I've thought about hardening a new sprocket. Not sure it will work though.
Is your front ring ok? And chain length, derailleur tension? I've no direct experience of higher power and its effects, but my front chain ring only lasts 3 chains worth of miles.
All mid motor e-bikes with a chain drive will ALWAYS suffer more chain and sprocket wear, simply because all the motor AND the human developed torque travel via the relatively weak, chain drive.
Furthermore, certain failures of the mid motor unit on some designs, can also stop any torque from the motor or the rider, actually turning the rear wheel.
I call it "the single point of failure", which of course the mid motor brigade hate, because its 100% true, and for them, simply very annoying.
But any good engineer, taken as an average, will simply not buy a mid motor chain drive e-bike, just because they see and understand immediately, why this unfair strain on certain drive components, components originally designed for the level of torque that a human can produce, as being very obvious!
Of course there are also engineers that miss that problem completely, though I myself have yet to meet one!
And as someone else here, fully and correctly mentioned, the 750 Watt motor you have, just makes the chain drive wear problems even worse....a motor, assuming that you live in the UK, is of course totally illegal there. And as someone else here mentioned, apparently his 250 Watt motor, allows these components to have a longer life. If you are every stopped by the Police, or are involved in an accident, that motor may count against you legally.....
The chain component wear problems are only (very) simply physics, nothing more, nothing less.
So you either have to accept the wear effects as "running costs", or change to a hub motor system e-bike, where the torque of the motor actually tends to "reduce" the wear and tear to chain drive components, and they generally, provided they are of reasonable quality, which makes them last even longer than the same components on a traditional non e-bike system, due to the much lower torque being passed through these chain components, on a hub e-bike system.
A further problem with the "Single point of failure", is that if damage occurrs on the chain components, it will usually mean a walk home, or a pickup by a car, as the bike may not have any power drive, human or motor, to the rear wheel.
Whereas the hub e-bike owners, simply remove say the broken chain, get on the bike and simply do "air pedaling", to activate the motor, or simply twist the throttle, to drive home on any remaining battery power.
My first e-bike got me home with the "air pedaling", and the second can be got home with both "air pedaling" and/or "throttle", its a great system.
This same subject gets regularly addressed on Pedelec, with the mid motor e-bike owners, doing the job of being the "nay sayers", because they simply neither understand nor accept simple physics wear and tear, in a system that (in my opinion) was not properly designed for problem free long term riding.....!!
The mid motor owners, appear to be under the impression that as they paid many times the average price of most hub (because of far simpler hub drive mechanics = cheaper) e-bikes, that they bought something "BETTER"! But they really didn't, and they find this MOST galling.
They actually have bought something with many different possibly "built in" failures.....at a far higher cost. Not forgetting that some manufacturers actually install firmware that precludes an informed owner, from maintaining his own e-bike himself, like even replacing a battery,which I find totally appalling!
My second e-bike new, complete with two batteries, cost only a tad more than a replacement motor (may not even be new, just repaired!) for a Bosch e-bike, and where the owner is precluded from installing it himself, and if the guarantee is gone, even has to pay the bike shop to do the work, as well as the price of the motor, around 800 UK pounds plus work at an hourly rate!!!
I hope that you now have a far better understanding of "why", but if you have any further questions, please just ask us all here on Pedelec, as the massive amount of experience here, can help a fellow rider almost always.
regards
Andy
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A friend bought a 250w hub drive ebike, it burnt out within a week. Tough hills here in north Wales. I've owned this 750w mid-drive for five years now, love it and would never change.
Andy-Mat has an obsession against mid-drive.
They certainly get through chains and sprockets more than hub drives. A 750w motor used on hard hills certainly will though, I can't judge if your wear is beyond even what to expect from that.
The chain is also a single point of failure as he says; but only one of many single points of failure in any bike, and easily fixed if you carry a chain tool. There may be other failure points in a badly designed mid-drive units, or ones that are overstressed. As there are in badly designed hub motors.
He's also right about Bosch and other proprietary systems, most of which (but not all) are mid-drive, but that doesn't apply to your Bafang.
The benefits of crank drive are huge where you have tough hills.
They certainly get through chains and sprockets more than hub drives. A 750w motor used on hard hills certainly will though, I can't judge if your wear is beyond even what to expect from that.
The chain is also a single point of failure as he says; but only one of many single points of failure in any bike, and easily fixed if you carry a chain tool. There may be other failure points in a badly designed mid-drive units, or ones that are overstressed. As there are in badly designed hub motors.
He's also right about Bosch and other proprietary systems, most of which (but not all) are mid-drive, but that doesn't apply to your Bafang.
The benefits of crank drive are huge where you have tough hills.
I have had 2x 250 Watt rear hub e-bikes, they are the only legal ones here allowed.
The first bike was a cheapo, and I paid around 180 UK Pounds for it, 12 months old, and I covered around 30,000 Kms, over 8 years, riding in all weathers except snow and ice. I used 2 new chains and one new cassette, plus new tyres, tubes and brake blocks (Vee brakes) each year. I gave it away still running....It was still runnning over a year later (only one battery, correctly charged of course!), the last time I met the owner....
My second e-bike, also a rear hub, was brand new, I still have it, but I have not kept an accurate log of the distances covered, but I expect it to be about the same per year as the old one, and other than newt yres, tubes each year, and new brake pads about 2 to 3 times a year, nothing else has been needed.... I live in a very hilly part of Germany, about 25 miles north of Frankfurt, and I go "mountaineering" with my dog running beside me..... hard work for the motor and the brakes. It wears the dog out too!!
It sounds like your friend bought a crap bike if it only lasted a week, did he get his money back? I would have!!
The beauty for me about hub bikes is that the drive system, just by its nature, is more efficient and far simpler, therefore less power is wasted in the transmission system, as any qualified engineer will tell you, plus the motor is more open to the air, and far less likely to overheat, than a mid motor, and far, far less complex, and also less likely to have manufacturer's restrictive firmware.....
There are good and bad bikes around, both cheap and very expensive, as the old proverb says "You pays your money and you makes your choice!"
regards
Andy
The problem is chain alignment versus power delivery, the 750watt can eat a drive train in a couple of hundred miles set at 25 amps and high throttle use, or even snap chains 
My cube conversion now has a 250watt bbs01 [previous bbs02 tweaked to the limit ] the drive train is calmer and lasts far longer all the harshness has gone under load 12 amps max and only 80 nm .Just needs oil and not constant replacement
My cube conversion now has a 250watt bbs01 [previous bbs02 tweaked to the limit ] the drive train is calmer and lasts far longer all the harshness has gone under load 12 amps max and only 80 nm .Just needs oil and not constant replacement
My Haibike (mid drive, obviously) has done 6000 hard off road miles on 2 chains, 2 rear cassettes and original chain ring. I weigh 105kg and I am very hard on chains/sprockets
Your obsession against mid drive does not make sense at all.
Torque and its rapid inappropriate (mid gear) application kills chains and sprockets.(and poor maintenance as mentioned above) Modern pedelecs neither apply torque rapidly or at wrong time. The rider does. The torque produced by the most powerful ebike motor simply pales into insignificance at side of some heavy rider stood on a static crank pedal( or at mid gear change.) Perhaps you need to modify your gear changing strategy if your crank drive bike is destroying chains etc so prematurely.
I, ve tried hub drive (legal) ebikes and to be honest they simply can not compete with their mid drive legal counterparts. I actually found them bordering on useless for off road climbing.(and slow steep road ones)
Just completed 2000 miies on Giant Fathom e2..Original chain, chain ring, cassette and derailleur still fine.???
If crank drives are so poor in regards you mention why are they completely dominating the market, especially so in MTB. (I don't think top manufacturers are actually building any hub drive??)
Trek, Haibike, Giant, Turbo Levo, KTM, etc etc etc must all have got it wrong.
I, m afraid I strongly suspect anyone who chooses a hub drive has never actually ridden a crank drive. There really is no comparison on equal power motors, especially legal ones. . It really is a stark difference. One works fantastically, the other barely so. Go and hire a Haibike Flyon. You will never want another hub drive.
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Actually, my obsession is designed more to inform people, particularly newbies, of the pros and cons of the different styles and designs of e-bikes. I learned via friends who bought Bosch bikes, around the time that I bought my first e-bike (2nd hand) of the awful problems some were having getting problems fixed by Bosch representatives.
For anyone who can read German, there are plenty of problems from these bikes still around on some websites here, hair raising at its best!!!...
So I just did a very quick search, and even if you don't read German, the titles make it obvious I feel, these are all Bosch problems, some VERY recent, you should get an idea of just how unhappy some customers are:-
Apparently they do not expect Bosch motors to live much beyond 10,000 Kms, even today!! My first cheapo exceed that by a factor of three, just with my riding!
It was just good luck that I bought a hub, as a friend of mine wanted to get rid of one, and it appealed to me suddenly, and a test ride convinced me....and to an old Scot, the price was VERY appealing.
Plus, I simply did not even know of mid motor designs at that time (luckily for me!)
Ridden hard, I would guess that is simply par for the course, and has to be expected from both the illegal motor wattage, and the usage. Driven less hard would maybe reduce usage, but by how much?
A single point of failure on mid motors only, not on a hub. Reminder, losing the chain on a dark night, when its just starting to rain, is far less problemetic on a hub, as you get to ride home if you still have battery power....
Also I take my second battery if I am of the opinion that I may run out of power, and on my bike, as battery wap takes only 30 seconds to a minute at the most.
What other single point of failure are you talking about, between Hubs and Mids, I would be most interested to hear about them! from you, as all the ones I can think about, apply to BOTH styles of motor!!
Sad problem, where some manufacturers feel its good to screw the customer base to make more money.
Maybe you have only expereinced far less than perfect hub e-bikes (what makes and models please, to help our newbies to avoid them?), and I have been lucky with both of mine, but I have yet to see any difference with regard to my hub bikes compared to other riders and going up hill, and I am now 76 years old!
I switch down to the lowest gear and simply plug away, as I hate getting off and pushing! But one day it will start, I know......UGH!!
regards
Andy
You are comparing a human, who in fine fettle can supply about 100 watts continuously, to a 750 watt motor? Where are you getting your facts from???
See here:-
Could You Power Your Home With A Bike?
The discrepancy between what you personally can generate and what you personally use says a lot about what's happened with civilization and the planet in the past couple of centuries, says Adam Frank.
www.npr.org
Pedaling a bike at a reasonable pace generates about 100 watts of power. That's the same energy-per-time used by a 100-watt lightbulb.
If you doubled that for a fully fit bike racer, the facts still do not fit your thoughts!
If your aim is to put someone new off buying a hub bike, I can only say you need verifiable facts, not made up stories, with no meat in them!
Which is what I see each and hear every time from the people who bought a mid motor e-bike, and do not understand why it wrecks chain components, in comparison to simple hub motors..... To me personally its MOST obvious why, but not for everyone apparently, hence the obsession to inform people fully and accurately that I apparently have....
regards
Andy
bafang mid drives are the best as you can programme them parts are cheap and dont use fkn can bus but you want that power then it will wear parts at full amps and will hammer the batts capacity.
problem is like the diy ones that fit in the bb will fall to bits going down hill looks like a mess with all the wires on the outside but will only cost a grand for a hd motorkit and 17ah batt.
but even bafang is going can bus now which will mean no programming as want in on bosch bike prices and batts locked to there motors only.
but tbh if you gave me a bike with the new bosch smart motor on it that costs 15k to swap it for my bike no chance the only new bike id even look at is the yamaha motors that are still uart.
btw at full whack at 80-90rpm i can hit over 200w from my legs and in the kiox display is 20% of my input and 80% motor.
since 2014 if have only had 2 cassettes and about 6-7 chains as change at 0.5 seems to work for me but keep my bike super clean and will crash to avoid a puddle
but if you have a bosch bike peter can now do board repair if that can help anyone over there in Germany with shorted controllers.
Not many people know, but there are 73 different error code 500’s. What you can’t see on your handlebar display is the last three digits e.g. 500 111. Not that this would help as Bosch don’t tell you what these mean anyway.
The Ebike Motor Centre has teamed up with a local high-tech electronics company who had a team of engineers working with over 200 printed circuit boards, supplied by us, for over 3 weeks solid! Solving these software and hardware issues.
We can currently boast a 90% success rate of repairing all code 500 errors. This means it is no longer necessary to buy a new motor when it can be repaired. For the 10% that sadly can’t be repaired, we can usually offer a service exchange motor to keep you going.
www.ebikemotorcentre.com
problem is like the diy ones that fit in the bb will fall to bits going down hill looks like a mess with all the wires on the outside but will only cost a grand for a hd motorkit and 17ah batt.
but even bafang is going can bus now which will mean no programming as want in on bosch bike prices and batts locked to there motors only.
but tbh if you gave me a bike with the new bosch smart motor on it that costs 15k to swap it for my bike no chance the only new bike id even look at is the yamaha motors that are still uart.
btw at full whack at 80-90rpm i can hit over 200w from my legs and in the kiox display is 20% of my input and 80% motor.
since 2014 if have only had 2 cassettes and about 6-7 chains as change at 0.5 seems to work for me but keep my bike super clean and will crash to avoid a puddle
but if you have a bosch bike peter can now do board repair if that can help anyone over there in Germany with shorted controllers.
Not many people know, but there are 73 different error code 500’s. What you can’t see on your handlebar display is the last three digits e.g. 500 111. Not that this would help as Bosch don’t tell you what these mean anyway.
The Ebike Motor Centre has teamed up with a local high-tech electronics company who had a team of engineers working with over 200 printed circuit boards, supplied by us, for over 3 weeks solid! Solving these software and hardware issues.
We can currently boast a 90% success rate of repairing all code 500 errors. This means it is no longer necessary to buy a new motor when it can be repaired. For the 10% that sadly can’t be repaired, we can usually offer a service exchange motor to keep you going.
eBike Motor Repairs & Servicing - Homepage
eBike Motor Parts Repairs & Servicing, (formally, Performance Line Bearings) has become the “go to place” for all your e-Bike motor repairs...
www.ebikemotorcentre.com
The contents of my tool and spares kit are strongly influenced by 'single point of failure analysis' and has gradually grown from pump, puncture kit and tube to include gear cable, chain quicklink, chain tool and spare wheel sensor pickup.
Always had a bike shop close enough to bail me out when something I hadn't thought of broke, so far!
Always had a bike shop close enough to bail me out when something I hadn't thought of broke, so far!
Andy always seems to make his arguments in a combative style.
There are pros and cons to both systems. I own both, and really like both and appreciate their different attributes.
The can bus systems built into mostly the purpose built crank drive bikes serve nobody else but the manufacturer and are a right pita. They are effecting a lot of goods now.
I spoke to a mechanic of a very large crank drive selling bike shop recently and he said that the latest crank drive motors are built for performance and have got lighter and more powerful as a result. In his words they are brilliant to ride but not designed for a commuting role. This was born out when I chatted to Peter at Performance line bearings who told me the bearings on my 2015 Yamaha motor were much more robust than the latest motors. To make the motors lighter the bearings are now less robust than they were and the motors put out more power. If you are competent enough to take full advantage of their performance a high spec full suspension crank drive bike will offer an exhilarating ride. However like any high spec performance machine you need to understand the cost of maintaining such a bike and how long it will last.
I think that the problem is that crank drive bikes are now dominating the market place and someone new to electric bikes without a great deal of knowledge may buy one for a role that a simple geared hub motor bike would be more suitable, cheaper to buy, much cheaper to run, and much cheaper to keep running.
I don,t clean the drive trains of any of my bikes as often as I should. However I keep my chains oiled and keep an eye on chain wear and like soundwave tend to change chains around .5 wear point.
Interestingly, since I started measuring the wear of the chains on my bikes, I have found that although my geared rear hub bikes do take longer to reach this wear point than my crank drive bike, they reach it quicker than I had realised before I started measuring. I think before I measured the wear rate I just kept riding my bikes and the rear hub bikes can be ridden for thousands of miles further and sometimes years longer with a worn chain that a crank drive bike.
The Cassette on my crank drive Yamaha ridden mostly off road has completed 2,393 miles, 3,851km . I have swapped chains at wear limits but as my rear cassette must be getting pretty worn now have put back on a chain I previously took off when it just hit the .5 wear limit and will ride that chain until it is completely worn out. I expect it to get me through the winter. Then with the beginning of nicer weather I will put a new transmission on. This will involve a deep clean of the rear derailleur and replacement of the jockey wheels as well as a new chain, cassette and chain ring.
I like all my bikes to earn their keep but am not fastidious about their appearance. Change the brake pads, oil and change the chains at wear points, and change the tyres.
My Haibike Yamaha that I bought new in March 2015 for £1,750 is seven years old and has completed 16,732 miles.
My Befang rear hub Oxygen Emate that I bought new in June 2011 for £1,399 is eleven years old. The mileage is not recorded on that bike but it will be a lot as it gets used a lot. It did 6,000 miles by the end of its second year.
Note that my Haibike Yamaha was £350 more than my Oxygen which I thought good as it had hydraulic disc brakes rather than mechanical, 9 gears rather than 7, and an air adjustable front fork, all of which are really useful for serious off road riding.
My Yamaha crank drive is an infinitely better climber than my geared rear hub bikes. The rear hubs climb well up to a point, but beyond a certain gradient will bog down and drop out of their efficient power range.
There are pros and cons to both systems. I own both, and really like both and appreciate their different attributes.
The can bus systems built into mostly the purpose built crank drive bikes serve nobody else but the manufacturer and are a right pita. They are effecting a lot of goods now.
I spoke to a mechanic of a very large crank drive selling bike shop recently and he said that the latest crank drive motors are built for performance and have got lighter and more powerful as a result. In his words they are brilliant to ride but not designed for a commuting role. This was born out when I chatted to Peter at Performance line bearings who told me the bearings on my 2015 Yamaha motor were much more robust than the latest motors. To make the motors lighter the bearings are now less robust than they were and the motors put out more power. If you are competent enough to take full advantage of their performance a high spec full suspension crank drive bike will offer an exhilarating ride. However like any high spec performance machine you need to understand the cost of maintaining such a bike and how long it will last.
I think that the problem is that crank drive bikes are now dominating the market place and someone new to electric bikes without a great deal of knowledge may buy one for a role that a simple geared hub motor bike would be more suitable, cheaper to buy, much cheaper to run, and much cheaper to keep running.
I don,t clean the drive trains of any of my bikes as often as I should. However I keep my chains oiled and keep an eye on chain wear and like soundwave tend to change chains around .5 wear point.
Interestingly, since I started measuring the wear of the chains on my bikes, I have found that although my geared rear hub bikes do take longer to reach this wear point than my crank drive bike, they reach it quicker than I had realised before I started measuring. I think before I measured the wear rate I just kept riding my bikes and the rear hub bikes can be ridden for thousands of miles further and sometimes years longer with a worn chain that a crank drive bike.
The Cassette on my crank drive Yamaha ridden mostly off road has completed 2,393 miles, 3,851km . I have swapped chains at wear limits but as my rear cassette must be getting pretty worn now have put back on a chain I previously took off when it just hit the .5 wear limit and will ride that chain until it is completely worn out. I expect it to get me through the winter. Then with the beginning of nicer weather I will put a new transmission on. This will involve a deep clean of the rear derailleur and replacement of the jockey wheels as well as a new chain, cassette and chain ring.
I like all my bikes to earn their keep but am not fastidious about their appearance. Change the brake pads, oil and change the chains at wear points, and change the tyres.
My Haibike Yamaha that I bought new in March 2015 for £1,750 is seven years old and has completed 16,732 miles.
My Befang rear hub Oxygen Emate that I bought new in June 2011 for £1,399 is eleven years old. The mileage is not recorded on that bike but it will be a lot as it gets used a lot. It did 6,000 miles by the end of its second year.
Note that my Haibike Yamaha was £350 more than my Oxygen which I thought good as it had hydraulic disc brakes rather than mechanical, 9 gears rather than 7, and an air adjustable front fork, all of which are really useful for serious off road riding.
My Yamaha crank drive is an infinitely better climber than my geared rear hub bikes. The rear hubs climb well up to a point, but beyond a certain gradient will bog down and drop out of their efficient power range.
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@georgehenry - You are absolutely correct, thanks for the tip - it took about 72 miles for my new chain to wear into the old cassette, which saved my buying a new cassette.
It has always been said on this forum a hub bike is far superior in reliability for any riding bar sport mtb riding, they are in the whole pretty bullet proof.
It is brands , brand sellers and a verciferous few with very deep pockets who poo poo hub bikes. It's like buying a ferrari or maserati to use as a shopping car .
It is brands , brand sellers and a verciferous few with very deep pockets who poo poo hub bikes. It's like buying a ferrari or maserati to use as a shopping car .
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Thanks for the reply (assuming that you are replying to my question of course), but none of these are specific to a hub bike, as I asked. In fact they are applicable to any bike, electric or not, except the last one......
The very specific "single point of failure" I tend to mention, to fully inform e-bike newbies, on mid motor e-bikes with chain drive systems, is, as far as I can see, specific only to mid motor chain drive systems.....
Though there are a couple of mid motor systems with drive shafts, but tend to be even more expensive than the usual chain drive mid motor bikes......sadly!!!
If an e-bike company managed to produce a drive shaft version, priced below that of the chain drive mid motor systems, and kept nasty firmware away from the design, they really do have the chance to make some big money.....and have happy customers.
With the present mid motor designs with chains, due to the way the torque is transmitted to the rear wheel, I do not see much of a possible improvement in wear characteristic, in the forseeable future.
Now that statement will really get the mid motor "fans" up and shouting again, because they don't want it to be true. But physics, as einstein would say, rarely change as we might wish them to!
A possible "kwik-fix", might be with really heavy duty chains, running on fully hardened sprockets, all at least twice as wide as the present versions, plus instensive cleaning and lubrication as least once a month, or possibly an old fashioned, fully enclosed, chain guard, to prevent dust/mud/water getting on the chain. My first bike had one a great many years ago!!
Vintage Rudge Raleigh 26” Wheel Oil Bath Bicycle Chainguard Chain Guard • £26.00
VINTAGE RUDGE RALEIGH 26” Wheel Oil Bath Bicycle Chainguard Chain Guard - £26.00. FOR SALE! VINTAGE RUDGE OR RALEIGH BICYCLE OILBATH CHAIN GUARD IN DARK RED IN USED CONDITION NOT ROTTEN HAS SOME DINGS AND SCRAPES COMES WITH ALL FITTING ONLY PART MISSING IS THE OIL CAP SEE PICTURESFREE P & P UK...
picclick.co.uk
Enclosed chain guard removal | Vintage Lightweight Bicycles
I have been trying to remove the enclosed chain guard on my 53 Churchill De-Lux. That has been an interesting endeavor. The crank had been rubbing the chain guard so I figured it would be best to remove the chain guard and tweak the crank arm just a little. To do this the guard has to be...
thecabe.com
regards
Andy
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