the 'there's no such thing as a stupid question' bike maintenance thread

cletus · 08-05-2020 10:35AM

mirrormatrix wrote: »

Hi. I've a kids bike that seems to have a through axle that is also the cranks, so both cranks and axle are one continuous piece (if you get me!). I'd not seen something like this before. Anyways, there was a bit of play in the bottom bracket and it seems as though the locknut had come loose.

On these sorts of systems, do you just tighten the bottom bracket (as it were) finger tight and then use a spanner to tighten the locknut as much as possible?

Cheers
MM

Pictures?

mirrormatrix · 08-05-2020 11:01AM

ONE_PIECE_CRANK_CHROME_21329.jpg

Will try to get some later. It's basically like this photo though.

CramCycle · 08-05-2020 11:11AM

mirrormatrix wrote: »

Will try to get some later. It's basically like this photo though.

Is it like a Shimano Hollowtech crankset then? Is there a shell for the through axle bit to rest against? Is that loose or disintegrating. If it is not, then yes, simply tightening it up should do the job but I'd prefer to see pictures fo the specific set up before putting any money down on it.

Type 17 · 08-05-2020 11:14AM

Yes, it's a Thomson BB, AKA Ashtabula). Common on older BMXs and cheaper American bikes

You can tighten it and lock the locknut against it like an older, threaded headset, but note that it is a left hand thread

Roger the cabin boy · 08-05-2020 11:18AM

mirrormatrix wrote: »

Hi. I've a kids bike that seems to have a through axle that is also the cranks, so both cranks and axle are one continuous piece (if you get me!). I'd not seen something like this before. Anyways, there was a bit of play in the bottom bracket and it seems as though the locknut had come loose.

On these sorts of systems, do you just tighten the bottom bracket (as it were) finger tight and then use a spanner to tighten the locknut as much as possible?

Cheers
MM

BMX's have these.

Its the same principle as any cup/cone bearing. Clean them, make sure the balls and races are in good order and then reassemble

However, there is a knack to tightening them.
Too loose is better than too tight, but neither is great.

My advice is to tighten everything up finger tight, then, back of the locking cone a 1/4 turn, then, tighten the lock ring. As the lock ring tightens,it will affect the tightness of the locking cone (due to play etc,) and you may find that tightening the lockring, tightens the lockcone too much.

Just keep adjusting it until the crank run smooth. A trick here is to tighten the lockring somewhat and then back off the lockcone a small bit whilst still holding the lockring.

Its a trial/error thing really. Easy but takes a few goes...

mirrormatrix · 08-05-2020 11:18AM

Type 17 wrote: »

Yes, it's a Thomson BB, AKA Ashtabula). Common on older BMXs and cheaper American bikes

You can tighten it and lock the locknut against it like an older, threaded headset, but note that it is a left hand thread

That's it exactly, thanks!! Yes, it's also left hand thread. Was just unsure whether I needed to hold the cone in place while tightening the locknut to prevent overtightening, but i'll just play around with it a bit and see what works on that front. I might as well regrease the bearings while i'm at it.

Gasco · 09-05-2020 08:58AM

So, replaced the freehub body on Pave 28 wheel, easy job. But there is a lot of freehub drag, as in it takes effort to get the freehub moving. Took off the new one and reinstalled the old, same thing. Have not used the wheels in a while so cannot remember if this was the case when they were on the bike.

Scratching my head on this - before I tighten the hub cap it spins fine but once these are tightened up then not much moving. Am I over tightening these? they were pretty tight prior to removal.

Did I lose a spacer between the freehub body and hub shell? Looking at the novotec manual, there only appears to be the large metal spacer that fits over the axle - which is in place.

Are the hub bearings the problem? They are cartridge but I presume once the end caps are tightened there is some compression.

Or is this a thing with these hubs / wheels???

Lockdown is causing me to obsess about these things...

Tony04 · 09-05-2020 10:50PM

On my ride this evening the bolt holding in the mech hanger seems to have fallen off.

Is my only option buying a new hanger? Or is there any other cheaper options or even temporary bodges?
Cheers in advance

cletus · 09-05-2020 11:47PM

Is the bolt on the right in the chainreactioncycles link? If so, I think you're going to struggle to find a generic replacement. Have you any idea of size or thread pitch

CormacH94 · 10-05-2020 12:38PM

Do internally routed cables usually have a thinner piece of outer for the section of cable inside the frame?

I've seen carbon builds where the bare frame usually comes with these pieces already installed and the ends are taped to the frame to serve as guides but how would one go about replacing these, as I imagine they also wear.

Would trimming an outer section down to the center piece of sheath work for this?

Any tips for routing internal cables without the specific kit would be greatly appreciated!

Deano12345 · 10-05-2020 08:12PM

CormacH94 wrote: »

Do internally routed cables usually have a thinner piece of outer for the section of cable inside the frame?

I've seen carbon builds where the bare frame usually comes with these pieces already installed and the ends are taped to the frame to serve as guides but how would one go about replacing these, as I imagine they also wear.

Would trimming an outer section down to the center piece of sheath work for this?

Any tips for routing internal cables without the specific kit would be greatly appreciated!

I use this stuff from eBay.

https://www.ebay.co.uk/itm/401630605331

Personally I don’t leave them on the cable when I’m done, but no reason you couldn’t. Generally I just feed them through the internal routing holes, tape them to either side, then feed the cable through and all sorted!

CormacH94 · 11-05-2020 07:59PM

Deano12345 wrote: »

I use this stuff from eBay.

https://www.ebay.co.uk/itm/401630605331

Personally I don’t leave them on the cable when I’m done, but no reason you couldn’t. Generally I just feed them through the internal routing holes, tape them to either side, then feed the cable through and all sorted!

Yeah, changed it out today, thought it might be covered the whole way through the frame, was just where it came out at the bottom bracket.

Troubleshooting chain drop when back pedaling at the minute, figure it could be due to the grease on the new chain gunking it up a bit? Any other reason why a new chain might drop when backpedaling? 99% sure I sized it correclt against the old chain

Type 17 · 11-05-2020 08:46PM

Usual reasons for slack chain when back-pedalling are stiff freewheel or stiff jockey wheel in the rear derailleur.

The new chain would want to have very thick grease on it for that to be an issue.

CormacH94 · 11-05-2020 09:02PM

Type 17 wrote: »

Usual reasons for slack chain when back-pedalling are stiff freewheel or stiff jockey wheel in the rear derailleur.

The new chain would want to have very thick grease on it for that to be an issue.

Pretty much stripped the bike down to clean/degrease, would a bit of lubricant on the jockey wheels make much of difference? Or back off how tight the bolts are?

Should probably say it's only happening when the bike is in largest rear cog and smallest front, every other combination is fine for backpedaling

Type 17 · 11-05-2020 09:07PM

CormacH94 wrote: »

Pretty much stripped the bike down to clean/degrease, would a bit of lubricant on the jockey wheels make much of difference? Or back off how tight the bolts are?

Should probably say it's only happening when the bike is in largest rear cog and smallest front, every other combination is fine for backpedaling

If it's only in top gear, then that's probably fine...

For the record, jockey wheels can get gummed up with crud, but it's relatively unusual. Check it by holding the swing-cage forward to let the chain slacken and see if you can move the jockey wheel with your finger.

PS: Keep the bolts tight, if you loosen them, you'll lose a jockey wheel on the road.

CormacH94 · 11-05-2020 09:14PM

Type 17 wrote: »

If it's only in top gear, then that's probably fine...

For the record, jockey wheels can get gummed up with crud, but it's relatively unusual. Check it by holding the swing-cage forward to let the chain slacken and see if you can move the jockey wheel with your finger.

PS: Keep the bolts tight, if you loosen them, you'll lose a jockey wheel on the road.

Yeah quite a bit of play when I move it with my hand, probably would have been an idea to replace them with the chain...

Any tips for checking the wear of jockey wheels or do they usually wear with the chain

Type 17 · 12-05-2020 12:36PM

Jockey wheels should last through a good few chains, but not forever.

Check for sideways wobble and if it’s more than a few mm, they’re toast. Note that the top pulley on most Shimano derailleurs are designed to have a few mm of lateral movement across their pivot (straight, lateral movement, not wobble).

crosstownk · 12-05-2020 08:23PM

Type 17 wrote: »

Jockey wheels should last through a good few chains, but not forever.

Check for sideways wobble and if it’s more than a few mm, they’re toast.

My 105 5800 RD lasted over 20,000km (probably 4 or 5 chains) before the jockey wheels went exactly as you describe. The easiest solution was to just order a new derailleur rather than faffing around for the correct jockey wheels which would have been almost half the price of a new mech.

Type 17 · 12-05-2020 08:39PM

True, high-mileage derailleurs get sloppy around the parallelogram pins, so the swing cage goes out of alignment and the indexing goes wonky - new jockey wheels aren't going to help.

Edit: I found a vid I did a while ago: https://youtu.be/ARPDaWjU3j4

CormacH94 · 12-05-2020 09:33PM

Type 17 wrote: »

True, high-mileage derailleurs get sloppy around the parallelogram pins, so the swing cage goes out of alignment and the indexing goes wonky - new jockey wheels aren't going to help.

Edit: I found a vid I did a while ago: https://youtu.be/ARPDaWjU3j4

Jesus your bottom bracket video is horrific, what did the customer say when they brought it in?

Type 17 · 12-05-2020 09:37PM

CormacH94 wrote: »

Jesus your bottom bracket video is horrific, what did the customer say when they brought it in?

Something along the lines of: it's got worse recently, maybe time to get it looked at...

Stuff that bad is not uncommon, but the auto-shifting 'feature' made it extra special.

Cee-Jay-Cee · 14-05-2020 10:34PM

CormacH94 wrote: »

Yeah, changed it out today, thought it might be covered the whole way through the frame, was just where it came out at the bottom bracket.

Troubleshooting chain drop when back pedaling at the minute, figure it could be due to the grease on the new chain gunking it up a bit? Any other reason why a new chain might drop when backpedaling? 99% sure I sized it correclt against the old chain

I had the same problem with a new chain a few years ago and couldn’t figure it out so left it into LBS to sort. They told me my chain was one link too short (even though I sized it off the old chain) anyway they fitted a new chain and problem solved.

Tony04 · 15-05-2020 07:13PM

Was out cleaning the drivetrain on my road bike today and am just wondering... Should you/do you grease thru axles? Is there any need to spray lube pivot points and pedals in the summer?

cletus · 16-05-2020 09:20AM

Weepsie wrote: »

My genesis frame has an unbranded headset.

I've no idea which cup goes is for the top and which one is the bottom cup.

I presumed the one with the longer lip/insert part for want of a better word, is the bottom one but not sure.

It's a fairly big standard headset anyway, so if I wreck it it's not the end of the world but still.

Any idea?

I'll attach pics later

Are you replacing a set, or reinstalling the same set?

cletus · 16-05-2020 10:36AM

I am by no means an expert, but if I was installing, the order you have in the first picture is how I would do it.

magicbastarder · 16-05-2020 10:46AM

Reckon it's the same headset that might be in my equilibrium? You're welcome to take a look at that.

cletus · 16-05-2020 02:56PM

Right, quick question. So far on all assembly jobs requiring grease I've used Holt's Blue Lithium grease.

What do other people here use, and is there any advantage to bike specific grease, or is it all so much marketing wånk?

cletus · 16-05-2020 07:49PM

Mate of mine was out for a cycle, shifted down gears and somehow fouled the derailler. He's too far away for me to go have a look

Any ideas or suggestions as to the problem, or possible solution?

CramCycle · 16-05-2020 08:02PM

Clean his chain, cassette and derailleur, looks like they are gunked up which would explain it

Type 17 · 16-05-2020 11:13PM

cletus wrote: »

Mate of mine was out for a cycle, shifted down gears and somehow fouled the derailler. He's too far away for me to go have a look

Any ideas or suggestions as to the problem, or possible solution?

That hanger looks bent - tell him not to ride it, and to go to his lbs unless the can change it himself.

the 'there's no such thing as a stupid question' bike maintenance thread

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