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

joey100 · 28-08-2018 09:13AM

What's the best way to figure out what BB a crank is? Have an old power2max power meter I forgot I had, on a set of rotor 3d+ cranks, I think it's for BB30 but not 100% sure. Any tips on how to figure it out??

ridelikeaturtle · 28-08-2018 12:26PM

outfox wrote: »

What's the consensus on front wheel skewer arrangement on disc brake bikes? Lever on left or right?
I've mine on the right, to 'balance' the disc, but I've spotted a few bikes lately with the lever on the left. This arguably looks better, given that the rear skewer lever is always on the left.

I'd always have the front wheel's lever on the left, to match the rear, which is always on the left to be opposite the drivetrain (and not be in the way of the rear derailleur).

CramCycle · 28-08-2018 01:53PM

ridelikeaturtle wrote: »

I'd always have the front wheel's lever on the left, to match the rear, which is always on the left to be opposite the drivetrain (and not be in the way of the rear derailleur).

I have always had them opposite, I dislike them on the same side although I see no reason not too.

Macy0161 · 28-08-2018 03:23PM

Following on from all the dynamo talk - I'm not missing anything in thinking that a 28" wheel will fit a road bike? Minimum recommended tyres are in the range of what I have had fitted in the past (1.1inch, which is 28mm)?

tnegun · 29-08-2018 09:09AM

Dropped the bike to to my LBS, first time using them, needed a cassette and chain I mentioned it should be a 116 link Shimano HG-X chain but they fitted a 114 link Sram chain now I've some slippage on the front and the chain drops onto the lower ring under load. LBS is recommending replacing the chain rings on the front now saying the chain doesn't matter, bike has about 5k kms on it should the chainrings last longer? I'm thinking put the correct chain on it first then lets see about the chain rings?

CramCycle · 29-08-2018 09:16AM

Put the chain into large front and large back and see what strain the derailleur is under. It sounds more like the chain is too long rather than a chain issue. SRAM chains are my preference over Shimano but that's a personal thing. I think they last better but pretty sure its all in my head.

tnegun · 29-08-2018 09:21AM

Its almost horizontal in that position

seven stars · 29-08-2018 09:23AM

tnegun wrote: »

Dropped the bike to to my LBS, first time using them, needed a cassette and chain I mentioned it should be a 116 link Shimano HG-X chain but they fitted a 114 link Sram chain now I've some slippage on the front and the chain drops onto the lower ring under load. LBS is recommending replacing the chain rings on the front now saying the chain doesn't matter, bike has about 5k kms on it should the chainrings last longer? I'm thinking put the correct chain on it first then lets see about the chain rings?

I'm certainly no expert, so hopefully you get a better response from someone else. But I thought SRAM and Shimano chains were completely interchangeable, so I wouldn't have a massive issue with what they've done there. In fact, SRAM have a magic link or powerlink or whatever they call it, making it easier to work with.

In terms of the number of links, if there's slippage with 114, you'd expect it to be worse with 116, no? It's certainly true that a brand new chain (even with the correct number of links) on a worn cassette or chainrings can cause problems.

tnegun · 29-08-2018 09:30AM

The chain seems too short to me as on the biggest rings the derailleur is pulled fully forward. The slippage is worst the more strain placed on the derailleur so big front, big rear is most likely to slip. I was also unsure the difference Shimano v Sram would make so thought this might add to it as its a Shimano chainset.

magicbastarder · 29-08-2018 09:58AM

if you're running big ring up front to the biggest at the back, that's known as cross chaining as is generally best avoided.
chainrings should last longer than 5,000km though - usually much longer, unless your chain is badly worn.

tnegun · 29-08-2018 11:16AM

Would only accidentally run large on large but the last chain didn't stretch the derailleur to the same extent would being the chain being too short cause issues?

ridelikeaturtle · 29-08-2018 11:19AM

tnegun wrote: »

Would only accidentally run large on large but the last chain didn't stretch the derailleur to the same extent would being the chain being too short cause issues?

To quote Sheldon Brown: "If the chain is too short, it will be at risk for jamming and possibly ruining the rear derailer if you accidentally shift into the large-large combination. Never run with a chain that is too short, except in an emergency."

CramCycle · 29-08-2018 02:01PM

Can you put up pics, one of the chain in the big big combination, and one of the teeth of the chainring, easier than examining possibilities.

mloc123 · 29-08-2018 02:07PM

SRAM/Shimano chains are interchangeable, I always used SRAM chains as a few years back Shimano had a reputation of snapping.

A chain being too short (I suspect most bike shops know how to size a chain - it isn't that difficult) won't cause slippage. Is this the first time you have replaced the chain and did you clean the old one on a regular basis?

tnegun · 29-08-2018 02:33PM

Pic attached first chain had the bike in for a service out 9 months ago and chain was ok, this time round the LBS said it was very worn so had left it late. Kept pretty clean but if we had a few wet weeks might of left it too long to clean up.

tnegun · 29-08-2018 02:41PM

Should be attached now!

mloc123 · 29-08-2018 02:47PM

tnegun wrote: »

Should be attached now!

It looks a little short from that angle, you should have a little "bend" in the chain on both pulleys but the chain looks almost straight through one.

Throw up a picture of your large chain ring too, see if it is worn.

tnegun · 29-08-2018 02:52PM

Sorry missed that chain ring pics attached too.

ridelikeaturtle · 29-08-2018 03:09PM

Yeah, to me that front big ring is gone.

Also, the chain is too short... unless it's too long when on the smallest cog on the back. While cross-chaining should be avoided, it's my belief that you should be allowed to do it (e.g. by accident, or just because you want to) without breaking something.

CramCycle · 29-08-2018 04:42PM

It's a big rear cassette but yep, chain looks short but because of the cassette, it may be misleading.

Large chainring is near the end of life, a few teeth are badly worn so may account for some slipping. A few of the inner ones look worn as well.

seamus · 29-08-2018 04:51PM

Chain could definitely do with two extra links to relieve the pressure a bit. The upper jockey wheel isn't engaged, which is going to make the chain a bit slippy in terms of changing down but also keeping the chain on the big sprocket. And as above, your big ring is on the way out.

You might be able to give yourself a little bit of give by tinkering with the end adjust bolt, also known as the "B" tension screw.

Page 17 here: http://si.shimano.com/pdfs/dm/DM-MBRD001-04-ENG.pdf

Edit: Also look at Page 11 to familiarise yourself with the low/high screws. You don't want to touch these.

If you can loosen this enough that the upper jockey wheel doesn't come into contact with the cassette, you might get a few more mm of slack in the chain.

tnegun · 29-08-2018 09:27PM

Picked up a 116 link chain on the way home and fitted it derailleur looks much more comfortable now on big big and no issues on small small combination either. Both quick releases were a little looser than I would like so reseated both wheels and tightend those.

No slipage on the second chainring from the quick test cycle. Slipping on the second was a new issue since it had been serviced it went in for slippage on the big one but was told it was fine just chain/cassette needed doing. I did noticed when I had it on the stand the cassette has a very slight wobble to it when free wheeling e.g. instead of being at 90 degrees sways a couple of degrees either side not sure what that means also something is catching the cassette on each revolution it catches on moves slightly. Will find out on the commute tomorrow if I've improved or worsened the situation.

riclad · 29-08-2018 09:59PM

I have a mens 26inch mountain bike thats fine, apart from the chain ,Its left outside
for years, the chain is brown,it might be rusty.
How much does it cost to buy have a new chain fitted.

Type 17 · 29-08-2018 10:10PM

Oil it first, you might not need a new chain.

Most LBSs should charge about €20-€25 to supply & fit a suitable chain (if the old one was also worn out (km's) as well as rusted (weather), then you might also need a new freewheel or cassette).

magicbastarder · 29-08-2018 10:20PM

tnegun wrote: »

I did noticed when I had it on the stand the cassette has a very slight wobble to it when free wheeling e.g. instead of being at 90 degrees sways a couple of degrees either side

That sounds odd. From what you're saying, it's loose? Could explain rapid chain wear.

tnegun · 29-08-2018 10:33PM

It didn't feel loose but was getting dark so I didn't investigate too much pretty much as in this video

https://www.youtube.com/watch?v=lxbNvj10eZg

07Lapierre · 29-08-2018 10:40PM

tnegun wrote: »

It didn't feel loose but was getting dark so I didn't investigate too much pretty much as in this video
https://www.youtube.com/watch?v=lxbNvj10eZg

Nothing to worry about...it's a very slightly "warped" hub. Won't do any harm really. The only answer is a new wheel, but it's not doing any harm, so I'd live with it if I were you.

tnegun · 30-08-2018 04:41PM

Much better today with the longer chain but still slipping on the big ring so will get that sorted. Still a bit early to tell only 20kms this morning. Have a vibration coming from somewhere in the drive chain now when up to speed, at a certain cadence and effort. Reducing or increasing effort/cadence seems to stop the vibration any ideas?

Type 17 · 30-08-2018 07:44PM

tnegun wrote: »

...Have a vibration coming from somewhere in the drive chain now when up to speed, at a certain cadence and effort. Reducing or increasing effort/cadence seems to stop the vibration any ideas?

Worn chainrings with new chain?

tnegun · 30-08-2018 09:28PM

Maybe but wasn't noticable with the short new chain. Its going back to the shop on Saturday so will have a list of issues for them now.

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

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