BMC One way bearing failure * Best Supplier?

Hi

I think after many years of hard abuse that the one way bearing in the clutch plate is finally failing on one of my bikes, its not done bad to be honest as it has moved my hefty old self along well in those years, I don't know how many of you have experienced the one way bearings fail on the BMC? the symptoms are that it will sometimes work fine and then other times you will be rolling along and when you apply the throttle the motor just spins freely almost like its going backwards, it has started doing this intermittently but its getting worse so my assumption is that the bearing is on its way.

Back in the day I would simply rob one from Mark at TH but these days he isn't tinkering with them any more, so where do you guys go for spares for your BMC/MAC motors? I am after the new clutch if possible the V3, I have spotted this one http://ebikessf.com/V2-vs-V3-clutch has anyone had any dealings with them?

I am in the UK however I would doubt that there are any suppliers supplying parts over here? there was a thread somewhere where somebody changed just the one way bearing?

I don't think it will be too long before all of the bearing pawls are broken and the motor just spins, I have my X5 bike as a backup but love the BMC as its soooo much lighter so don't want to be out of action for too long.

knoxie,

Ilia is the person running it. He was great to deal with and his prices on the BMC are pretty low. I thought the Mac used the same parts? Couldn't you pick up one from cell man if that is the case? I know the latest BMC clutch is suppose to be stronger and Ilia would definitly have it. If you don't need it to freewheel I've heard people welding it to get by. I've been very happy with my BMC, and even have a spare so I don't have to wait. Some of your earlier posts influenced me on getting one for my trail bike, even going to put one as a middrive on my latest dh build.

Hi

Yes the MAC is a clone of the BMC although the BMC is considered to be the better built motor by many, its funny you know because I know how much we paid for the motors from way back, they were only $75.00 per motor so it scares me a little having to spend $150 on just the clutch, looking on Alibaba I can get a complete motor delivered for less so I may go that way.

The BMC is a great motor though and this is the first bearing that I have had go on me so not really had to deal with it before, I should have hung on to the box of spares that I had from Mark ahh well, I might see if the factory are interested in selling a few clutches direct, I see that one US site were doing the whole thing for 30 dollars, even if it were the old clutch I would be happy as I dont run more than 1.6KW and you can of course weld them, welding wouldnt solve this problem though this is the one way bearing itself, its broken, probably down to a few pawls inside the bearing then it wont work at all.

Jozzer has offered me a few old motors to play with, pretty sure I can get something out of them I can also get a go in his electric car too either way I will post some pictures of what I find when I open and repair the motor.

I do recall someone on the forum had posted pictures of the clutch taken apart. I don't remember if he was able to rebuild it?

$150 for a clutch is insane. BMC really rapes you for parts and the motor. If you need a new clutch, just get one from cell_man. My original almost 2 year old MAC clutch has lived at the 2500w power i now run it at.. it's taken abuse at 4000w.. it's taken intentional stalls at ~3000w up a hill with a 240lb rider to test controllers.. and there is a new generation of clutch from MAC that is even stronger.

There was a period where BMC was the better motor and MAC was the underdog, but that's not really true anymore.

I've never had a Mac to compare it with. It would be nice to know if the parts are truly interchangeable. I have been happy with the quality of the BMC and it was the best choice for me when I looked around 3 years ago. Picked up a spare for $300 when it was on sale last year with upgraded phase wires. Now that the Mac comes in black I would probably go that route if I needed another and I was sure parts could be swapped with the BMC.

kfong said:

I've never had a Mac to compare it with. It would be nice to know if the parts are truly interchangeable. I have been happy with the quality of the BMC and it was the best choice for me when I looked around 3 years ago. Picked up a spare for $300 when it was on sale last year with upgraded phase wires. Now that the Mac comes in black I would probably go that route if I needed another and I was sure parts could be swapped.

Click to expand...

I have not seen the new clutch, but i know that BMC / MAC clutches / gears have been interchangeable forever. The MAC motors now also come with gray gears, which are equivalent to whatever rainbow color gear BMC is using

3 years ago, the MAC wasn't all that great from what i've seen, but they have really caught up in the last year and the price is still damn good. I don't know why people are still buying BMC. The cost premium is just not justified anymore.

That's good to know, sounds like the quality of the Macs have caught up with the BMC. I will definitly go that route when I need another.

Hey Knoxie,

I'd just weld it up. Easy to do. Once you take it apart you'll see what I mean.

Welding wont work as I want it to freewheel, what price does cellman sell them for? I know that the gears are the same size but I wonder if the clutch is the same dimensions between the BMC and the Mac? anyways I will take it apart to have a look and post up some pics

there was an issue with some chinese bmc freewheels, it wasn't the actual freewheel causing the problem,
from memory the big gear ? is pressed onto the freewheel, the fix was small tackwelds stopping the pressed part rotating.
if lucky it is same problem on yours, tack welds were used to fix the problem successfully

The new design clutch WON'T fit without new gears!

The new clutch is thicker so the gears have to be thinner, but I don't think it will effect their strength. Cell-Man seems quiet confident in it. I should have it either by the weekend or next week sometime, I can't wait to get the mac back!

Ilia at ebikessf.com sells mac clucthes. The gears are wider and seem to fit fine. The bmc guy camdu or what ever. Don't give support. Call him if you buy a new clutch with money he will sell it to you but customer service ? He does very little to support his vendors. A good motor with bad Q.C. keyway's fitting ect. The ever going clucth problem's so now they offer a $165usd. v3 clucth as the fix. Call him and they and get a keyway or a c-clip or good luck. B.M.C. cvanjani@aol.com and there is a ph# on the wheel ( 818) something.

If you got a mac from cell-man, his new gears are wider so the new clutch won't fit in the mac, without slightly thinner gears. But best person to ask is Paul himself, you surely won't find better support!

The motor is a BMC not a MAC.

OK well I should have sorted this at the weekend but had other things on, the motor had been making a nasty sound but was still working, albeit sometimes it would spin and other times it would engage, anyway been riding it like this for a week or so and at lunch time I said to the missus, I really must strip the motor tonight and see what wrong with it, I went out of the door and in the first few seconds it went with some style.

There was a nasty gnarling sound and that was it, so I peddled to work and home (that nearly killed me) ha ha and then got the motor apart, this motor is old over 6 years old and has never been touched, has been used every day pretty much and has never had any maintenance, luckily all of the screws came out OK (used to grease them back in the day) which is great as the heads on them are easy to strip. The motor came apart quite easy, see picture below, for an old motor that is kept outside and ridden in all weathers its remarkably clean inside.



It was evident from looking at the gears that they were badly damaged in 1 place only, they looked in really good condition otherwise, my suspicions were the one way bearing, anyway got my old puller out and after a bit of pratting about getting the circlip off I started to pull, my god it was hard work (I found out later why) It wouldnt shift, I had to get a really old pair of pipe grips to hold it whilst I had 2 spanners for leverage trying to pull it off, eventually it came off with a mighty crack, shortly followed by the sound of ball bearings falling about the place.





The one way bearing was mashed, the casing had cracked, the sharp bits of metal had got sucked in to the gears and destroyed them should have done this at the weekend oh well, anyway you can see from the photos the bearing is toast, notice apart from the bit where the gears have been damaged the other parts of the gears are in amazing shape, this motor has done 8,000 miles or so at 1.6KW



Here you can see the backside of the one way bearing, its mangled, I am taking the plate in to work tomorrow to see If I can take the top clamp plate off, I have some gears from another motor that are OK and I have found a supplier for the bearings in the UK too at only 10 pounds its much cheaper than a new clutch.



The reason the clutch assembly was so hard to pull off the motor was the casing of the bearing was driven between the key in the shaft and the clutch, see how the edge of the key has been deformed by the puller as I used all my strength to get it off.



Here is the topside of the clutch, as you can see its very different to the MAC clutch, this is why I would rather try and repair this one than fit a new one.



Here is the super clean windings, as you can see from the nice colour of the windings they are like new!! these motors happily chug along with up to 2KW, most DD motors would be in much worse state for the same performance.



Now before the DD motor lovers rain on my thread, I also love DD motors, my X5 Trek bike is my saviour as this one is going to out of action for a week or so, I will post pictures and details of it going back together, if you are in the UK check these guys out for bearings or sprag clutch bearings.



http://tinyurl.com/c7p5chc

I might get a new set of gears, the sun gear in the motor casing is in such good shape, there isnt a mark on it, I think the bearing has been on its way out for a long time now I think about it as there have been strange noised coming from it for a while now. Anyway I am hoping I can repair this motor for pennies, it should be good for another 8000 miles I reckon

Well I contacted they very helpful Ilia at ebikes sf, He assured me that the one piece MAC clutch would fit the motor as snowranger had fitted one to a BMC and it has been working fine, well its got to be a lot better than the gears that I had in it!! ha ha, anyway he is doing the whole clutch for 75 dollars which is reasonable considering the new price of the motors these days.

Totally recommend Ilia he responded instantly as was very helpful, he will ship worldwide as well which is a bonus, so for UK 75 pounds delivered I can get my bike back on the road, the motor has been amazing so I owe it to the machine to keep it on the road

I intend to clean the grease and shrapnel from the inside of the motor to make sure I dont damage the new gears, it will have the green composite gears with the one piece clutch, the way I run the motor it should be fine, I will post pictures of my progress, the new clutch should be with me within a week or so.

This video explains the differences with the clutches

[youtube]6kcLWncvx5o[/youtube]

knoxie said:

Well I contacted they very helpful Ilia at ebikes sf, He assured me that the one piece MAC clutch would fit the motor as snowranger had fitted one to a BMC and it has been working fine, well its got to be a lot better than the gears that I had in it!! ha ha, anyway he is doing the whole clutch for 75 dollars which is reasonable considering the new price of the motors these days.

Totally recommend Ilia he responded instantly as was very helpful, he will ship worldwide as well which is a bonus, so for UK 75 pounds delivered I can get my bike back on the road, the motor has been amazing so I owe it to the machine to keep it on the road

I intend to clean the grease and shrapnel from the inside of the motor to make sure I dont damage the new gears, it will have the green composite gears with the one piece clutch, the way I run the motor it should be fine, I will post pictures of my progress, the new clutch should be with me within a week or so.

This video explains the differences with the clutches

[youtube]6kcLWncvx5o[/youtube]

Click to expand...

I have know Chandu for 7 years now as I have worked in the same building designing microscope systems. He designs the motors and distributes to sellers like ilia. He does not want to deal with the public so go through one of the suppliers when you need something. I still do work on the side for him from 85 miles south. I have a spare set of white, green, and blue planetary gears. I could give you the green or white ones just pay the shipping. So glad to hear your motor lasted so long. I used to ride my bicycle to work there but it was only .8 miles away so I never needed a motor. Now I am 58 and have many hills to climb to get to work. The v2t does this for me. I have the blue gears in it and it is much quiter and free wheels better then the green gears. I believe the original design was Chandu's and it is made in India and the MAC's in China. Look at all these motors. Makes me drool.

Nice vid! the new clutch looks quite a bit beefier, but up the version 3 looks identical as to what MAC motors have came with up until maybe a few months ago.

The MAC gray gears might save you some $.

And yes, MAC motors are made in China.

knoxie said:

Well I contacted they very helpful Ilia at ebikes sf, He assured me that the one piece MAC clutch would fit the motor as snowranger had fitted one to a BMC and it has been working fine, well its got to be a lot better than the gears that I had in it!! ha ha, anyway he is doing the whole clutch for 75 dollars which is reasonable considering the new price of the motors these days.

Totally recommend Ilia he responded instantly as was very helpful, he will ship worldwide as well which is a bonus, so for UK 75 pounds delivered I can get my bike back on the road, the motor has been amazing so I owe it to the machine to keep it on the road

I intend to clean the grease and shrapnel from the inside of the motor to make sure I dont damage the new gears, it will have the green composite gears with the one piece clutch, the way I run the motor it should be fine, I will post pictures of my progress, the new clutch should be with me within a week or so.

Click to expand...

Sounds good Knoxie,
+1 on Ilia's helpfullness, knowledge and response. I can't say enough good things about him. Also, good to know you've had many good years of service from that old BMC motor (and with those original white nylon planetary gears too). The new blue gears should be even better and the new clutch should freewheel better and be quieter too. Is that you're only geared hubmotor? For some reason I seem to remember you running a PUMA.

Ilia is the best.

Hi guys

Thanks for the offer of the gears any yes Ilia has been amazing to deal with, he shipped out the new clutch within a few hours on me sending him the funds, he also threw in a new key,circlip and grease for free!! what a top guy, so yes anybody who is reading this thread and needs a new clutch get in contact with him, very highly recommended.

As far as other hub motors I have the BMX which has the Puma motor in it, I also have another spare motor in a 26 inch wheel with a BMC copy very early design, that one also needs a new clutch I think so may be in contact with Ilia again :lol: its funny because i took it off the bike a few years back because it was slipping and couldn't find the problem, at the time I didn't know the 1 way bearinig was in the clutch now I know I think that motor can be repaired as I had tested the usual sun gear slipping, rotor slipping etc, so that will resurrect that motor, that motor was a torque motor not a high speed wind but the wheel was cool as it was spoked in a radial array.

The other bike is an old school xlyte X5 5304, a monster of a motor and the bike that I am using at the moment whilst the BMC is out of action, I also have the KMX of course with the modified Currie unit, so in total 4 working ebikes

The beauty of the BMC or MAC is just how light they are and so very powerful at low voltages, riding my X5 in to work its like a tank, its a good motor but the weight is almost unbearable especially when you compare it to a geared motor, I am not interested in going over 30mph or having mental acceleration this is why I love the BMC/MAC in my opinion its they very best compromise any ebiker can get, until you try one you don't know what you are missing out on.

Hows this for service!! Clutch, Grease, Circlip and Key arrived today.

US to UK in 6 days just as promised Very pleased, will post pictures when I get it sorted in the next few days, Thanks again to Ilia as ebikes.sf for your great service I may just order another one as well as I have 1 more spare motor that I think also needs a new clutch

Here are the pictures of the new clutch.

Its a little different to the old clutch as you can see, the old one is deeper, anyway its all in the bike and is working, used the supplied grease too, the new key was slightly smaller so had to use the old key, because the design was slightly different the keyway was exposed at the top once the gear was on, I fixed this with a supporting washer pushing down on the key, fitted the circlip against that so should never move.

Thumbs up for ebikes.sf

The gears look darker than previous ones. I wonder if they changed the composition.

Knoxie,
What's the inside diameter of that keyed shaft bore?