Mechanics and Fixing Any Questions Answered

Having some trouble with a threaded bottom bracket. The drive-side is threaded fine, all the way against the frame but the left side needs to be very loose for the spindle not to seize. Simply threading it by hand just a bit more into the frame so it's not loose anymore will immediately seize the spindle. So when usually you can find that soft spot of no side to side play and smooth turning, in this case that soft spot happens when the left side cup is completely loose and can be unthreaded easily just by using your fingers on the inside teeth.

Is this a shit bottom bracket, could it be the frame? It's italian threading so I don't have another BB I could try. Should I just let it be and use loctite on the threads to hold the left side cup in place?

Is this a BB with loose balls? You should have a lockring for the NDS cup if so, if not then something else is quite wrong.

Yes sounds like bent forks.

A frame builder would be your best shout. I've just had some forks straightened by Winston Vaz at Varonha in Hither Green. Haven't collected them yet so can't comment on results but he's generally well respected on here.

Pro mech tip here: Don't spend 45mins of a scorching Sunday afternoon changing out a BB (and degreasing/lubing rest of drivetrain), after 50miles of constant clicking, without first checking you've tightened your rear QR properly first.

No, sealed bearings. It's one of these:

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Something else is quite wrong then.

How far is the NDS threading into the shell? Could it be a wrong sized Bb?

What is this meant for?

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looks like a robot hand

According to this thread it's apparently a caliper for measuring the over-the-locknut spacing on a hub. You open it so the ends touch both locknut faces, then bring it to a ruler to measure.

I guess you could use it for dropouts as well.

Yeah or an outside caliper. I'd like it to be first, but I'm afraid it's the latter. But for what? Googling 'Park Tool outside caliper' just gives me a bunch of hits on digital Park Tool vernier calipers.

Brillant, thanks!

I've found those miche bbs can be a pain in the arse.

The two halves seem to fit together with a really close tolerance so they are more likely to jam up than say, a Shimano unit.

I think the technique that I came up with was to fit the cups either simultaneously or in small increments, ie don't do the driveside right in then try and fit the nds.

I think they'll also sometimes come apart more than is ideal so that instead of having just a nds cup on it's own and the rest of all lumped together to go in from the driveside you get the bearing stuck in the nds cup and then its a bugger to get that to slide onto the axle nicely.

Assembling and disassembling everything off the bike a couple times and greasing any faces that need to come together or slide over each other might help?

Can any decent bike shop sort this? How much should I expect to pay?

Not really. You want one that specialises in frame building/frame repairs etc. Maybe a more established shop with older mechanics?

Vaz has already been suggested, there's also probably a few builders on here with the tools and skills to help you out.

Haha, you'll appreciate the clean drive train for the next 1 1/2 dry days we have.

Assembling and disassembling everything off the bike a couple times and greasing any faces that need to come together or slide over each other might help?

So yesterday I ended up doing this on the bottom bracket a total of 6 times. There was a lot of swearing and patience I didn't know I have. Weirdly it seems a lot better now, although it's still not as tight as I'd like it but at least it seems tight enough not to unthread itself or fuck up the threads. There are some things you just can't explain...

Grinding sounds and rear derailleur pulling forwards on each pedal stroke under pressure. Has been around for a while, getting worse to now where I need to deal with it.

This happens in any/all gears, but only under load. Just spinning on flat there is nothing. Start up a hill and put more pressure on the pedals, grinding on each pedal stroke and I can see the rear derailleur pulling forwards from the lower jockey wheel. I can’t replicate in a stand. Was happening with old chain between 0.75 and 1% stretch, so swapped it and it’s still happening with new chain. Chainrings or cassette don’t look worn. I have lubricated and cleaned up the derailleur.
There are no other issues, changes gear perfectly, does not skip over teeth under pressure, no undue looseness anywhere else on the bike.
Do I need a new rear derailleur? New cassette? Any other thoughts?

Did you disassemble the derailleur when you cleaned? Sounds like maybe the pulley wheels are sticking.

Edit - doesn’t really explain why it only happens under load 🤨

Maybe chainsuck? The mech cage pulling forwards would be due to tension between the cage and the bottom of the chainrings, I'd have thought.

While I did take it apart it was a time-limited clean, so I’m sure I could do a more thorough job. The (Hope) jockey wheels are relatively new compared to the derailleur, and were spinning very nicely when I played with them. Didn’t take them apart to clean more because they rolled well. Guess it wouldn’t hurt to take a look though. Thanks.

I think we have a winner! It occurred to me that while I said it happens in any/all gears, I only ever really use one chainring (only really need 4 gears where I am)… following your comment I rode around in the others a bit, and no grinding cage pulling strangeness…. Guess I’m cleaning up the middle chainring this evening then (edit) just in case it’s the filthiness rather than being worn which is causing the issue.

Thanks!

Maybe chainsuck?

Definitely. Only thing it can be. New rings and chain time.

So I've been having issues with my chain skipping when under load in the big ring.

I replaced the chain and cassette in March and this sorted it out but the skipping returned last week. My chain (new in March) is completely worn well beyond the 1 measurement mark, I've probably done 2500 miles on it and it's been cleaned and lubed in line with recommended good practice.

I've just put a new chain on but surely there must be something that's causing such accelerated chain wear, I don't normally wear chains out that quickly.

Could it be my chainrings (note only skips in big ring under load)? Pics of said chainring teeth below....

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Yeah, that chainring is fucked, although 2500 miles is plenty to wear a chain.

Little ring is fucked too.