Massive pothole comprehensively frocks BPM

[Kabbage]

Oh my. Back on the bike after about a year off, and on my third (count'em: 3) trip to work, I've encountered a massive pothole on Victoria Parade at about 40km/hr. It snuck up on me, and the rear wheel took a very big hit (and my battery is over the rear wheel too...)

Well, it's comprehensively frocked my BPM; it was running beautifully - I was only thinking yesterday how much better I like it than the Crystalyte for the type of commute-riding I do - and *BAM*. Now it sounds and feels like something is *SERIOUSLY* wrong in there, perhaps I've stripped some teeth off the planetary, or something has gone cactus in the clutch, due to the hit.

I hope BenMoore carries spares, or something.

And I'm certainly glad that I've kept the Crystalyte as a 'swap-out' spare, which will make getting back on the road while I deal with this little setback a much easier process....

bugger.

 

[bowlofsalad]

Having spares is pretty nice. I am curious, what sort of wheels were you using, what was the psi for the wheels, that gauge are your spokes are on the wheel, and what sort of suspension suspension was going on with your bike when the pothole event occurred?

 

[full-throttle]

Don't worry, should be fix-able
AFAIK Ben is away, but I have a spare gearset if you need.

 

[d8veh]

For anybody that needs spares for Bafangs. If you look down the list, they have gears, clutches and side-plates:
http://www.greenbikekit.com/index.php/accessories.html

 

[Kabbage]

Don't worry, should be fix-able
AFAIK Ben is away, but I have a spare gearset if you need.

Thanks for the offer FT - It'll take me a little time to get my self sorted out to fix this, so perhaps BM will be back by then - otherwise I might have to take you up on your offer!

I also saw your kind offer re: Nickel sheet for my Commuter No.2 battery build - I am pretty sure I will take you up on your offer there as well! Stay tuned.

Having spares is pretty nice. I am curious, what sort of wheels were you using, what was the psi for the wheels, that gauge are your spokes are on the wheel, and what sort of suspension suspension was going on with your bike when the pothole event occurred?

I decided a while ago, when my Crystalyte's stock rim & spokes were comprehensively shitting themselves after just a few months, that if I was going to get something reliable, I had to have a backup. Hence the change to the BPM.

I have now had both my Crystalyte and BMP motors laced into Mavic EX325 downhill rims by a nice wheelbuilder at the LBS, and they've been excellent. The Crystalyte is on 11/12 double butted spokes from JRH (Holmes hobbies), and the BPM which has just mostly carked it, is on Sapim 13 or 14 spokes.

see http://endless-sphere.com/forums/viewtopic.php?f=6&t=39940&hilit=avanti#p695544 for photos of the wheel pre-pothole.

Tyre pressure is around 70-80PSI. Hardtail - so no rear suspension. Surprised I didn't damage the rim (although I haven't had a good look), or the tyre with the hit.

Anyway, I did ride it home tonight, and apart from being horribly horribly noisy and having a nasty grating stickiness when I pedaled, it got me home with almost no fuss. I suspect it actually improved a little on the way, which makes me think there's been some burring of either the clutch or the planetary gears which has worn a little.... Still - now have to swap out for the Crystalyte and work out how to get the cover of this sucker prior to getting parts and fixing.

Good thing bike No.2 is on the way as well...

 

[bowlofsalad]

Eep, no suspension on a 1.5" marathon tire filled to a rock with the battery over the wheel no less, sounds like exactly what I was running with for a while with exception to suspension.

Something that inspires a lot of my doings is a phrase, "The only difference which makes no difference is no difference." I cannot state that having a fatter tire, lower PSI, suspension or any combination of these would have resulted in just a hard landing across the bump instead of a busted hub, but I think if I was busting motors by going over potholes, I'd consider trying to soften the blow.

Is that one of those auto-turn on brake lights?

How much weight is on your rack and what rack is that?

 

[Kabbage]

Eep, no suspension on a 1.5" marathon tire filled to a rock with the battery over the wheel no less, sounds like exactly what I was running with for a while with exception to suspension.

Something that inspires a lot of my doings is a phrase, "The only difference which makes no difference is no difference." I cannot state that having a fatter tire, lower PSI, suspension or any combination of these would have resulted in just a hard landing across the bump instead of a busted hub, but I think if I was busting motors by going over potholes, I'd consider trying to soften the blow.

Perhaps, as my work colleagues have suggested, having a 20-25kg lighter me on top of the bike would be the best thing... which is why they mock me for riding a bike with a motor in the first place, rather than one I (really) have to pedal, for exercise...

Is that one of those auto-turn on brake lights?

Nah. If I wanted brake lights (and turn indicators), I'd have a motorbike (again). It's just the 'standard' ebikes.ca/grin fully moulded rear light. It's perfect.

How much weight is on your rack and what rack is that?

It's a topeak rack. It's beautiful too - it's got two top bars, so that you can hang the panniers without having to buggerise around trying to get it under the top bag - and because my brake calipers are the newer 'in the triangle' type, it has the standard connection at the bottom too - not those weird-ass looking ones that have to stick out around the brakes.

How much weight? Well there's a 16cell 12Ah Headway battery in that bag, so, it's probably about 7kg or so, I've never weighed it - but it's NOT light over the rear end. See comment above about my weight as well...

 

[Kabbage]

Did I say the topeak rack was beautiful? Yes....



This is what I discovered tonight, when trying to get the wheel off - see that middle bar, it's supposed to go straight through - but it's bent to buggery. I've managed to bend it back by putting a shifter onto it, but aluminium being what it is, I've basically snapped it like a paperclip.... bugger. I wonder how long it has been like that? I've never noticed before!

At first I thought I thought maybe this was the problem - the rack rubbing on the tyre - but turns out the motor is still frocked.

You can't quite tell in the photo, but there'd also been some axle rotation in the dropouts, which sort of clamped it in there. It took me about an hour to get the wheel out - in the end, I was using an *enormous* shifter onto the flats of the axle each end in turn to try and rotate it around so the axle-flats lined up exactly with the dropout, and even then, had to resort to the 'everyman-tool', yes, the hammer which I had to use to beat the crap out of the end of the shifter to rotate the axle enough.

I'm not sure, but I have possibly managed to twist the axle in the process - but it wasn't coming out any other way.

The other bugger that I've discovered with the BPM is that, because the cable is on the freehub side, I had to cut the bloody Anderson's (on the phase) and the 5-pin hall connector off in order to get the nuts off, in order to get the freehub tool on, to get the freehub off, to get to freehub and expose the coverplate. That's gunna be a pain to fix up again...

And. After all that, I couldn't 'swap in' my Crystalyte anyway. UGH!. I'd taken the cog from it to off to go on the new Bafang, I tried to put the Shimano 6-speed freewheel on, but it turns out that I need one of those funny big washers that you put against the spindle of the freewheel to stop the outer edge rubbing on the motor housing. Bugger again.

 

[Kabbage]

Well, I've just had the BPM taken apart...

The other bugger that I've discovered with the BPM is that, because the cable is on the freehub side, I had to cut the bloody Anderson's (on the phase) and the 5-pin hall connector off in order to get the nuts off, in order to get the freehub tool on, to get the freehub off, to get to freehub and expose the coverplate. That's gunna be a pain to fix up again...

Actually, in retrospect, I think I could have got it apart without taking any of this off - just sliding it along the cable a bit... oh well.

Anyway, now I've had it apart, I pretty much couldn't find anything wrong with it; the planetary gears all looked fine, the clutch seems to be working fine. The only tiny thing I found was the little thin metal washer that adjoins the silicone washer/gasket at the non-cable side bearing was a little wonky, as though the shaft had hit against it, so I bashed it flat with a hammer.

It all seems to be ok. sort of good, but annoying as well, as I hope I don't now go to the effort of re-terminating it all and then having the problem re-manifest itself....

Perhaps it is the clutch? Although it seemed fine - I put it on the spline backwards (with the gears facing out) and swung it around with the planetaries, and it all seemed to run reasonably freely - not *completely* freely - what are these supposed to feel like? are they completely free?? it felt like it had some grease in it or something just giving a bit of resistance. Oh well....

 

[full-throttle]

I think it's the wiring
Internal short

 

[Kabbage]

I think it's the wiring
Internal short

OK. Interesting... Only one way to tell; re-do the wiring and put it back and see if anything has changed... Otherwise, I guess it's a new BPM...

If I do get a new one, do you just rip the guts out of the new one and put into the cover of the old one? Or would it be best to lace the 'whole' new motor into the rim?

I'm not fully convinced it's an electrical problem, as I'm pretty sure it was making weird noises just rolling...

 

[Kabbage]

How about an update on this one, while I'm in a posting mood?

Well, with the benefit of Commuter No. 2 on the road I finally got around to putting the BPM back in the Avanti, and guess what?

It works fine. No apparent problems. So perhaps it was just that washer that was cactus.

The cables are now a bit weird, because of the dodgey re-termination due to cable length restrictions... but you get that.

 

[Tench]

Could it have been the tyre rubbing on the bent rack? and the motor is fine.