My latest and most difficult conversion Trek Top Fuel 9.9 Carbon.

[RobF]

I don't get it. What's your point?

Is there something that I wrote that you don't agree with?

The point is that no one - apart possibly from the manufacturers - has reliable failure rate information.

Your post - and mine - is little more than guesswork.

It does appear the Impulse motor is prone to fail, not least because Derby Cycles has all but coughed the job.

 

[RobF]

let me guess, RobF is bored and looking for a keyboard fight.

Not in the slightest, just pointing out the post is guesswork portrayed as fact.

As indeed was mine, the difference being I introduced it as such to prevent any reader being misled.

 

[Deleted member 4366]

The point is that no one - apart possibly from the manufacturers - has reliable failure rate information.

Your post - and mine - is little more than guesswork.

It does appear the Impulse motor is prone to fail, not least because Derby Cycles has all but coughed the job.

I'm not trying to guess failure rates. I'm just trying to point out that it's easy to get a false impression of what the failure rate is by reading a forum.

I still don't get the bit about posting guesswork as fact. can you be more specific by way of quote from my post?

 

[cwah]

All the bafang motors I purchased failed without exceptions:
- 3 bpm failed within 3 months only... but I have to admit I did overvolt them.
- the 2 bbs had defect under normal condition without programming or overvoltage.

Its enough for me to have my own opinion on the motors reliability... independently of the forum member posts

 

[Deleted member 4366]

Yes, but again you have to put that into context. Am I right that you had problems with every motor you ever had - Bafang or not?

What are you using now? Is it OK?

 

[Alan Quay]

All the bafang motors I purchased failed without exceptions:
- 3 bpm failed within 3 months only... but I have to admit I did overvolt them.
- the 2 bbs had defect under normal condition without programming or overvoltage.

Its enough for me to have my own opinion on the motors reliability... independently of the forum member posts

While I've never had a BBS, I've had about 15 Bafangs because I sort out all my mates bikes. BPM, CST and SWX. 7 of them were second hand, and a couple of those I have personally put 3000 miles extra on.

In all that time, the only problem I've had is one (very high mileage) that's a little bit noisy. I dare say if I opened it up and added grease it would be OK.

 

[trex]

in my personal experience, Bafang motors are very reliable more so compared with other components of the bike. Everything on the bike has a running cost, the motor's is way down the list, after battery, tyres, brakes, lights, other electrics, shocks etc.

 

[pn_day]

Just to wade in on this - I think it rather depends what you do with the motor. If you run within specs, never over-volt or use excessive current, and don't let it overheat then the Bafang motors are good bang for buck IMO.

Certainly I've been pleased with my CST motor - always run with 36V, and total peak watts never exceeding 900W.

That's not to say that other motor manufacturers don't also make good gear - just that some of the abuse that some folks here and on ES have put the BBS and BPM to might give a misleading view of the reliability...

Don't get me wrong. It's always an interesting thing to see a component tested to destruction. Just be honest if you've exceeded the recommended specs!
Phil

 

[cwah]

Yes, but again you have to put that into context. Am I right that you had problems with every motor you ever had - Bafang or not?

What are you using now? Is it OK?

Yes I did indeed have problem with all motors.... and not just bafang.

If I were to list issue by type I'd say:
- by far the biggest issue was clutch damaged. All my bpm had the clutch damaged after 3 months max
- second is blown hall sensor. It happened to my mac, a couple of Q100H and a leaf
- then wiring from fall on the axle
- and then the annoying issue such as the one I had with the bbs02

I have to be honest I may not give the best care to my motor and I tend to use throttle heavily and cycle on any weather even on heavy rain...

So a geared is an extra layer of maintenance and risk as every single part can break. A mid drive is even worse.

To date, I fixed my leaf motor 1000W (blown hall) and I'm exclusively using it for over a year... which is a record for me

 

[Deleted member 4366]

Yes I did indeed have problem with all motors.... and not just bafang.

If I were to list issue by type I'd say:
- by far the biggest issue was clutch damaged. All my bpm had the clutch damaged after 3 months max
- second is blown hall sensor. It happened to my mac, a couple of Q100H and a leaf
- then wiring from fall on the axle
- and then the annoying issue such as the one I had with the bbs02

I have to be honest I may not give the best care to my motor and I tend to use throttle heavily and cycle on any weather even on heavy rain...

So a geared is an extra layer of maintenance and risk as every single part can break. A mid drive is even worse.

To date, I fixed my leaf motor 1000W (blown hall) and I'm exclusively using it for over a year... which is a record for me

I now promote you to the position of pedelecs Chief Destruction Tester.

Just to make it clear to others, Cwah tends to run his motors at powers substantially above what was intended by the manufacturers.

I'm glad you finally got something that works for you. How fast does it go?

 

[Fordulike]

So a geared is an extra layer of maintenance and risk as every single part can break. A mid drive is even worse.

I don't quite agree with your statement that a mid drive is worse.

A geared hub motor is always stuck in the same gear, which means the motor/internal gears are fighting that load every time you move from a standstill. Open the throttle full on a regular basis, and you can see why gears/clutches don't last long.

I too had problems with a MAC 10T. The clutch had to be replaced twice.

A mid drive, if you ensure you are always in a low gear from standstill, has much less to fight against when moving off.

I've covered many more miles with the BBS02, only having to replace the controller. The newer controllers are more robust. The gear internals have weathered the beating so far.

 

[Deleted member 4366]

A mid drive, if you ensure you are always in a low gear from standstill, has much less to fight against when moving off.

Good point. This is what happened when I set off in too high a gear on my GNG mid-drive. It went with quite a bang and gives some idea of how much stress is on the final reduction gears in a crank-motor. Being in the right gear can be a bit of a problem with derailleur gears if a car or person jumps out on you, or if you have to do any other emergency stop :

 

[Fordulike]

Good point. This is what happened when I set off in too high a gear on my GNG mid-drive. It went with quite a bang and gives some idea of how much stress is on the final reduction gears in a crank-motor. Being in the right gear can be a bit of a problem with derailleur gears if a car or person jumps out on you, or if you have to do any other emergency stop :

Jesus, that's nasty

When I installed my BBS02, I tried to get an idea of how much force the drive would have to overcome in different gears, by riding the bike without motor power.

Using the 11T from a standstill was a no no, as I literally had to stand on the pedals to get going. Same went for the next two or three cogs. The Bafang wouldn't like them either from low speed.

Eventually, by riding up various grade hills unassisted, I got an overall picture of what the Bafang would be able to cope with.

If I'm ever in the wrong gear in a certain situation, I squeeze the brake cut-off slightly, change gear under human power, then release the brake.

I'd rather have a few moments of awkward pedaling, than put excessive force through the Bafang internals and bike gears.

 

[Nealh]

Though Cwah over amps/volts his motors and breaks them, I suspect the major factor is the throttle use. Unlike pas which commands less amps the throttle demands near full amps from the get go so straining the gearing and clutch at every opportunity. The BBS01 for instance draws 3 - 8amps generally through out the 9 assists of pas but using throttle only you will see 9 - 14 amps being drawn with a watt meter fitted.

 

[cwah]

I now promote you to the position of pedelecs Chief Destruction Tester.

Just to make it clear to others, Cwah tends to run his motors at powers substantially above what was intended by the manufacturers.

I'm glad you finally got something that works for you. How fast does it go?

My current leaf motor 1000W on 48v does 35mph max speed on city commute. I usually stay around 15-25mph in traffic.
It's almost perfect due to my low weight (60kg), however, during hot days or when I carry a passenger I have to be very careful with the wires/motor getting extra hot.

I'm planning to upgrade to a bigger DD motor at some stage.

 

[Deleted member 4366]

Can you spot the difference?

I guess you noticed the alarm and tracker, which was fitted after the bike was nicked, recovered and rebuilt. Also, the rear indicator light thingy and of course the uprated front brake, which hides a Q128 motor running at 52v and 20 amps to add another kilowatt of power. It's a 36v 328 rpm rpm motor. At 52V, it should spin to 459 rpm, which is 34 mph in a 26" wheel, but for some reason it goes all the way to 45 mph. The total now is 2500w, which takes it up to 41 mph. Imagine what it's like as you pedal past a 50cc motorbike and out-accelerate his mate on a 125. This bike is brilliant. It has perfect handling and masses of grip and braking. It's so sure-footed. I just wish they were legal.

The front Q128 doesn't come in disc version, so it had to be machined to accept a disc:



We started with one of these controllers, but had some problems with it, so eventually we changed it to a boxed Kunteng 20A sinewave one (not shown). I had to switch around the motor wires to get the right combination for smooth running:



The torque arms are yet to be finished. We're making special ones that have a shoe against the fork. Photos to follow.

 

[Nealh]

Awesome, great job not jealous one little bit .

 

[EddiePJ]

Dave, this isn't in any way a criticism, so please don't take it that way.

From reading the start of thread I got the impression that a rear hub motor would have been the owners preference, but couldn't be done because of the through axle and the carbon potentially not taking the stress.

I'm just curious to know that given the seemingly money no object approach to the project, that you/he didn't simply have a new rear end constructed with drop outs to suit.

As said I'm not criticising, but to me it just seems like simple and easy solution. Perhaps something to think about when the owner builds the next one.

 

[Deleted member 4366]

That's a good question. It would need a complete new subframe, which would be too difficult because you need special moulds and know-how to make one out of carbon fibre. It might be possible to make one out of steel and aluminium. Maybe we'll do that when we add a rear motor.

It's not exactly a money no object build because money is now being diverted into adding an electric bike shop to the premises. and stocking it.

I'm rolling around in clover at the moment. I get to build these fantastic bikes without having to spend anything and I'm helping the guy to start the electric bike shop - electric bike nirvana.

 

[nemesis]

That's a good question. It would need a complete new subframe, which would be too difficult because you need special moulds and know-how to make one out of carbon fibre. It might be possible to make one out of steel and aluminium. Maybe we'll do that when we add a rear motor.

It's not exactly a money no object build because money is now being diverted into adding an electric bike shop to the premises. and stocking it.

I'm rolling around in clover at the moment. I get to build these fantastic bikes without having to spend anything and I'm helping the guy to start the electric bike shop - electric bike nirvana.

What was the final cost of the build including the labour,quite high i presume.