My Crank Bearing has Dissolved! (Wisper Bike)

[karl101]

Setting off to work today, things seemed rather strange in the pedal department, I duly took it back home and took the long walk. Having just gotten home and taken the crankshaft to bits, I found the bearing on the chain side to be absent.

I've only done 1500 - 2000 miles on this Wisper 905sel and I'm surprised to see this happen. Can't take it to a wiper dealer, as they're too far away. It takes me two trains to get to the one in Garforth, near Leeds. Apart from this unexpected failure, its a very good bike.

I am right in thinking this is a standard part, and amy competent cycle shop will sell me one? The two ends with the bearings and the plastic tube that goes down the middle. Obviously the chain wheel has the magnets for the Hall Effect sensor so I would rather not replace that.

Some Pics:
The chain side of the crank:


The other side, this is what the bearing is supposed to look like:


And here are the ball bearings:


Karl

 

[banbury frank]

Hi Just take it to a local bike shop it is only standard bike bits



Frank

 

[eddieo]

if an SEL does it have a hollow crank, should be covered by warranty.

David in Germany sure he will advise when he sees this...

 

[karl101]

if an SEL does it have a hollow crank, should be covered by warranty.

That's the thing, the warranty requires a visit to the place I purchased the bike from. For me a cheap day return is £9.90 to Garforth, and assuming that I would need to leave the bike overnight (at a minimum). That's two trips, cost £19.80 plus the hassle plus having to use Northern Rail.

Now, at this moment in time I don't know how much these crankshaft parts will cost, but for me they would need to be of a fairly high value, say £80+, for me to suffer the trip out to the dealer.

Karl.

 

[Deleted member 4366]

Buy Shimano BB51 Deore Hollowtech II External Bottom Bracket at Tredz Bikes. £12.44 with free UK delivery

 

[karl101]

Hello,
I've cleaned up the crankshaft, removed the melted on bearing ring, the melted plastic from the bracket and the embedded ball bearings. You can see in the picture that the plastic is a little melted. The question is do I put a washer between the plastic magnet ring and the new bottom bracket?



I got a washer from the bike shop, its 3mm thick and is 26mm in diameter larger than the 24mm crank and is 3mm wide. If I were to fit a washer I think I'd prefer something thinner and wider.

Thanks
Karl.

 

[Deleted member 4366]

The bottom bracket bearing is designed to have a flat surface against it. I'm not sure that I like the idea of the uneven plastic pedal sendor being pulled against it, but I guess it's tried and tested by Wisper. I think I'd prefer a shim between them of about 0.3 to 0.5mm. 3mm is much too thick. I think you'd have to make yourown if you want one.

When you get your replacement bearings, pay attention to match the spacer arangement on your existing ones. The spacers are behind the red bearing holders. There's normally three spacers: two go one end and one the other, but yours is probably different because of the pedal sensor, and if you fit a washer, you need to compensate for that too.

 

[karl101]

Thanks for the info.

I've installed a new bottom bracket and re-used the spacers that came with the bike. Instead of a washer for the magnetic disc, I've made a shimmy from an old stainless steel bowl, this is quite a bit less than 1mm thick.

Karl

 

[Deleted member 4366]

Excellent. I make mine out of an old stainless breadbin - you know the one with a curved front that slides upwards.