Slipping chain after BB/Cranks/Cassette strip & clean

[RhythMick]

Today I stripped down my wife's pedals, cranks and BB. Gave everything a thorough clean, check and regrease before refitting. Not done this before but have the right tools and used the Park tools pages as guidance. Pretty sure I've gone slowly and carefully and got everything right. The bike is a women's Trek 4500, cranks are standard Shimano Alivio, 3 chainrings x 9 gears.

After fitting it rides ok, no horrible noises etc. Coming back up the hill it slipped. It wasn't a gear change (front or back) the chain slipped. While I was cleaning the front rings I thought they were starting to show wear, but they didn't slip before I stripped and rebuilt. She'll never let me near it again ... :-(

I've measured the chain stretch and it's showing fine (the 0.75% side drops about halfway down but not all the way in, the 1.00% side doesn't go in at all). Chainrings starting to look a little shark-toothed. However, it didn't slip before I stripped it all.

Only other thing I can think is I haven't followed torque guidance when refitting as I don't yet have a torque wrench (my old car wrench doesn't go to the range needed for the BB or cassette lockring).

Is it possible that the strip down and rebuild has uncovered a problem which was about to happen anyway ?

 

[Pauluk]

Only other thing I can think is I haven't followed torque guidance when refitting as I don't yet have a torque wrench (my old car wrench doesn't go to the range needed for the BB or cassette lockring).

That's a pain. If you have tightened these fairly tight then I doubt that errors in the torque have anything to do with it. I suppose it may be worth popping the cranks and the wheel off and just double checking the BB and cassette lock ring tightness if you haven't already.

Can you repeat the problem and if so does it slip on all chain rings or just one. Did your wife use all front cogs as much as each other so does any ring look worse than the other(s).

Failing any other advice on here I think if it were me, I would take it to my local LBS and see if they can tell from looking at it as to whether the chain set looked like the culprit, before I spent money on a new one. Unless of course you feel they are badly worn and need replacing anyway.

 

[RhythMick]

Thanks. I have a new chain set, chain and cassette all ready to go onto my Yeti. I think I'm going to pop those on now and get her to try it tomorrow morning.

Before I do that, I just want to make sure I've put the front chainrings on the right way around. Pretty sure I have, but it occurs to me that a slightly sharktoothed ring MIT be more likely to slip if on the wrong way around.

If the rings are on correctly I'm going to swap the lot, which will take her to a nice new Hollowtech II M590 plus HG50 11-34 cassette plus new chain. Only downside I can see is that I ordered the M590 for me with 175 cranks. If it all works well I'll order a 170 set for her and swap.

By the way, WoolyHatShop have some decent offers on right now with M590 crankset, HG50 cassette and a chain for £80 all in.

 

[RhythMick]

Ok so everything had been loosened earlier today, but 2 hours to take out the old square taper BB, swap to the new Hollowtech crankset/BB, swap out the cassette and install the new chain. Given that I hadn't done any of this before today I'm happy with that.

Tomorrow, check the indexing of the gears and give it a try.