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Deleted member 4366
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None of that is necessary if you install the motor the right way up with the cable going down.
Long-Term, Reliable FW Kit - does it exist?
- Thread starter Warwick
- Start date
Ya can lead a horse to water, but ya can't make it drink - unless ya shove its head under water!
That makes sense. Is there any other reason a hub motor should be a particular way up? I'd guess the manufacturer intended it to be installed cable up, but they tend not to think too much about things like long term water ingress. I know mine came with the anti-turn washers set up for cable up installation, but it's easy enough to turn them round.
Whilst I take the point that it is up to the installer to ensure their kit is installed in a waterproof state, I would counter that it is up to the manufacturer to do a lot more to make their kits much more watertight.
I'll admit that the rain that caused my latest issues was heavy and prolonged, but this is Britain, after all; rain is not unheard of. If a rear hub/integrated controller machine is vulnerable to moisture ingress, what chance do we have of a kit being up to the job without having to do some additional waterproofing as detailed above?
I'll admit that the rain that caused my latest issues was heavy and prolonged, but this is Britain, after all; rain is not unheard of. If a rear hub/integrated controller machine is vulnerable to moisture ingress, what chance do we have of a kit being up to the job without having to do some additional waterproofing as detailed above?
yes, that's what we do too. The problem is that we only know about the problem after someone has experienced it. It sounds awful, doesn't it?
We add into the installation manual where to add grease.
Factory built bikes are better in this respect because cables are typically run inside the frame and downtube batteries are mounted on a flat surface on the downtube.
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Deleted member 4366
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How many times do we tell people on this forum to install their motor the right way up, and still we see that most people get it the wrong way!
The problem with instructions is that many people don't read them.
If I were selling kits, I'd probably make print a single A4 piece of paper with key points on:
The problem with instructions is that many people don't read them.
If I were selling kits, I'd probably make print a single A4 piece of paper with key points on:
- Cable from motor must exit downwards.
- Do not pull cable ties too tight.
- Make sure the motor connector is inserted all the way to the line.
- When riding the bike, don't use full power at less than x mph (x depends on motor winding speed,but something like 6 mph).
- Do not use a pressure washer on this kit..
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Deleted member 4366
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I keep telling people. I never charge anything for anything to do with ebikes. Do what you want with it.
Given the limitless supply of electrical niggle questions on here, the short answer to your question is no.
Hub kits tend to sell on price, which is part of the problem.
More than a million Bosch crank drives have been sold, and you rarely hear of any electrical problems, which is quite a testament given it must be the most popular system by some way.
There's no equivalent quality hub kit of which I'm aware.
If Bosch - or Yamaha or Shimano - made a premium hub kit it would probably be reliable.
It would also probably be twice the price of what is currently available.
only correct to a certain extend.
Hub kits are cheaper than CD kits because of the simplicity and low loading of its planetary gearbox in comparison with the CD gearbox which has been typically designed for 4 times more loading.
Think about it this way: a typical 2.5kg motor without gearbox can only produce about one fifth of the torque needed for 20mph on a 26" wheel.
If you put a gearbox at the wheel, you will need a reduction of 5:1. If you put it at the bottom bracket, assuming you have 44 teeth on your chain ring and 11 teeth at the rear, you have to have a reduction of 20:1, which necessitates big steel cogs and probably a second stage reduction. That is why Chinese CD kits are comparatively heavier than geared hub for the same power output. They have to have strong gearbox, put 5 times more loads on the chain etc and end up costing £100 more for the motor position.
A second issue is that CD kits use square taper bottom bracket design with ballbearings sited inside the 68mm BB shell. Most of the Chinese CD kits supplement the two ballbearings with extra needle bearings but they are not sufficient for the 5x rider load, none of them have external ballbearings. A fundamental design deficiency.
Bosch fix the issue of 20:1 reduction with a small chainring at the front but still load the chain with 5 times what an average rider puts in.
Think also of unsprung weight distribution. The motor and the battery on an average bike weigh roughly the same and have their centre of gravity roughly equidistant from the bottom bracket.
It's easy to lift up the bike in a normal way. If you lift up a CD bike with battery on the downtube, you'll notice that the centre of gravity is shifted to the front.
In conclusion, a 3kg motor at the rear and downtube battery gives the best weight distribution. The smaller, lighter loaded planetary gear is also more energy efficient and lower wearing than CD kits.
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Hub v crank is not the discussion here, but to my simple mind '5X load on the chain' makes no sense.
Last weekend I did a hilly ride with some fit roadies.
One liked to attack hills and routinely went past me quite quickly.
I'm climbing steadily in low gear in Sport on a Bosch bike.
My rig - me in particular- weighs more, but given he reaches the top of the hill a lot faster than me it's hard to accept there is more load on my chain than his.
Probably less.
Some people like to say 'crank bikes eat chains', but the combined grunt of a legal crank motor and relatively unfit ebike rider is a lot less than the grunt which a fit push cyclist deploys, albeit in short bursts.
Last weekend I did a hilly ride with some fit roadies.
One liked to attack hills and routinely went past me quite quickly.
I'm climbing steadily in low gear in Sport on a Bosch bike.
My rig - me in particular- weighs more, but given he reaches the top of the hill a lot faster than me it's hard to accept there is more load on my chain than his.
Probably less.
Some people like to say 'crank bikes eat chains', but the combined grunt of a legal crank motor and relatively unfit ebike rider is a lot less than the grunt which a fit push cyclist deploys, albeit in short bursts.
if it doesn't to you, an experienced pedelecer, then it probably doesn't to a lot more members looking for a conversion kit.
Unlike normal bikes where you have more than one ring at the front and 10 at the rear, converted e-bikes with a CD kit has only 1 at the front and 8 at the rear. The worst case scenario for that bike is not so much when the bike has to climb a steep hill with the rider pedaling hard to help, but when it is derestricted and the rider pedal at the highest gear/lowest rear cog at the rear.
Without the motor, the chain will have a load of what the rider puts in, about 150W load.
With a CD motor like the BBS01 or GSM then delivers about 600W mechanical, their maximal output. The chain will have 600W + 150W from the rider = 750W load, or 5x load on the chain.
For a geared hub motor, the load on the chain is limited to what the rider puts in, 1x.
When people convert their bikes with a CD kit, they don't think of upgrading their chain and cassette.
I have in my workshop right now a bike for conversion with a BBS01. It has an Alfine 8-speed IGH and a 34T chain ring. The ballbearings gives concern - the customer did not notice, he's been riding like that for a long time. It's OK when it's him who pedal but it won't last 5 minutes with a BBS01.
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A fit rider can put out 400W.
A legal crank kit at peak power plus the rider is, as you've observed, around 750W, which doesn't amount to '5X'.
As a comparison, Froome - when he was accused of cheating - released data showing his peak power as 525W.
Clearly weight plays a big part, because Froomey would vanish into the distance on a climb against the ebike rider with his total of 750W.
A legal crank kit at peak power plus the rider is, as you've observed, around 750W, which doesn't amount to '5X'.
As a comparison, Froome - when he was accused of cheating - released data showing his peak power as 525W.
Clearly weight plays a big part, because Froomey would vanish into the distance on a climb against the ebike rider with his total of 750W.
he/she is then an exception. I've read somewhere that an athlete can output 1,200W in short bursts.
You, yourself, could be an average pedelecer in term of pedal power. How much power do you think can you put out yourself continuously for say 15 minutes?
BTW, most donor bikes I have seen are ordinary bikes. Their chains are usually of ordinary quality.
That seems to be my conclusion too, sadly. The fact that there are so many caveats - mentioned on this thread & many others - about the user needing to take extra precautions underlines this. It is relatively new market, I'll concede, but waterproofing really should be a fundamental requirement, IMHO.
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Deleted member 4366
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.. and how much experience of installing or running kits do you base all that on Rob? I've never heard so much rubbish. Just about everybody that owns an ebike, gets "niggles". Whether a niggle is important or not depends on the owner's ability to interpret and sort it. People with all these Bosch, Yamaha and Shimano bikes get all sorts of problems with derailleurs, chains, drive sprockets and cassettes, often after very short mileages. Some would see that as expected wear and tear. For others, it renders their bike useless until they can get it to the dealer. They nearly always get their bike back with at least a new chain and cassette and a bill for about £100. Attention to those parts is inevitable. It's just a question of when.
Compare that with somebody who bought a cheap Chinese bike and gets water in the LCD. It's a relatively rare occurrence (not inevitable). It would be the same for the owner: Buy and install a new LCD for about the same cost as a chain and cassette, or take it back to the dealer and get it fixed free if under warranty or £100 for a replacement part.
MY kit has done 4000 miles with absolutely no attention to anything, so it is possible to have a problem-free kit/installation. No Bosch bike can run 4000 miles with no attention.
Even Bosch had trouble with bearings wearing out and water in the LCD.
Don't forget that Panasonic make hub-motors and so do Sanyo, though not DIY kits. There's also premium kits like Bionx. I guess that as soon as I tell OP that he can solve his problem with a BIONX kit, he'll jump straight onto Google and find a supplier. Will he buy one? I 'm pretty sure that the answer will be no.
One of the reasons you don't hear about electrical problems with Bosch kits, etc, is that they are not installed by inexperienced self-builders, and secondly, most people with problems take them back to the dealer to get fixed instead of seeking help here. I know that some notable forum members have had problems with their bikes fixed by dealers, but they've never mentioned that here!
One thing that I do agree with you is that the DIY kits are very cheap. You can buy a complete kit (less battery) for less than what a bike shop will charge for fitting a new chain and sprockets for your Bosch bike. If you had to replace the entire kit twice a year, it would be even-stevens - maybe!
I just fixed a 20" wheeled Powabyke for somebody today. It must have been 10 years old and very well used. It had a niggle: The ignition switch was worn out. It cost £7 for two switches specially ordered from China as they're not standard. I ordered 2 from different supplies because I wanted to get one ASAP. They came in about 10 days and now the bike is back on the road and a happy owner. £7 for 10 years isn't bad.
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I have seen loads of Bafang SWX motors doing 10,000 miles without servicing.
Is it reliable enough for you?
Those that need servicing, it's usually 4 ballbearings to replace or a clutch unit. No complicated electronics to worry about.
My Rose/Bosch bike has done more than 4,000 miles on the original chain.
It's nothing special, just a Bosch bike, albeit a well-made one.
You might also want to ask Croxden about mileage and Bosch motors.
Any reader of this forum can see Chinese electrics are routinely unreliable.
Not being able to use the bike in the rain is ridiculous.
The stuff may be cheap and - for someone with your experience - relatively easy to fix.
But we are not all hobbyists.
It must be possible to design and manufacture what the OP wants - a reliable hub kit that is not allergic to water.
RobF, I think warwick is the current record holder, he went through 3 or 4 bikes in a year.
I wonder if he would want to test the Karoo to destruction.
I wonder if he would want to test the Karoo to destruction.
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