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

tnegun

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

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

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

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

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

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

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

Should be attached now!

mloc123

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

Sorry missed that chain ring pics attached too.

ridelikeaturtle

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

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

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

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

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

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

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

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

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

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

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

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.

John Hutton

Folks, I fitted a new front derailleur and had to break my chain in order to do so. I then reconnected the chain with the same pin. Friend of mine said to me today that I'm just begging for it to break and should replace the pin with the special one Shimano give you or if I can't locate the pin in question get a new chain.

Chain is a ten speed Shimano.

Opinions? Am I ok doing what I did? I think my mate is overreacting.

magicbastarder

if you've not got a joining pin, you could use a quick link. should only be a few euro.

John Hutton

magicbastarder wrote: »

if you've not got a joining pin, you could use a quick link. should only be a few euro.

Well I've already put it back together with pin that I took out, I had a look at that chain and now can't tell which pin I had taken out.... Should I replace the chain?

Type 17

Sorry, but your mate isn't overreacting - on 10 & 11-speed chains (and some 9-speeds), the pins are stamped to spread the ends (note the dimple in the centre of each pin-end), to prevent the link-plates from slipping off the pins.

When you push out the pin with a chain tool, you tear off the spread end-part of the pin, making it vulnerable to slipping off under heavy load if it is re-closed.
If you can find the pin you opened/re-closed, you can replace the whole link (two pins and outer plates) with a speed link, but if you can't, a new chain might be a good idea because if it snaps, you will fall off, if you're lucky - if you're less lucky you might smack your privates off the stem or top tube :eek:

John Hutton

Type 17 wrote: »

Sorry, but your mate isn't overreacting - on 10 & 11-speed chains (and some 9-speeds), the pins are stamped to spread the ends (note the dimple in the centre of each pin-end), to prevent the link-plates from slipping off the pins.

When you push out the pin with a chain tool, you tear off the spread end-part of the pin, making it vulnerable to slipping off under heavy load if it is re-closed.
If you can find the pin you opened/re-closed, you can replace the whole link (two pins and outer plates) with a speed link, but if you can't, a new chain might be a good idea because if it snaps, you will fall off, if you're lucky - if you're less lucky you might smack your privates off the stem or top tube :eek:

It's a touring bike and I'll be hauling panniers so I'll have to replace it so...

Why do so many front derailers no longer unscrew so you can slip the chain on? Annoying.


Thanks folks.

Type 17

John Hutton wrote: »

Why do so many front derailers no longer unscrew so you can slip the chain on? Annoying.

The screws used to come loose over time, which led to a different set of problems.

Mark the outside side of the old chain that you remove, and keep it - one of the pins on the outside will be missing its edge, and you'll see it if you examine each one closely...

iwillhtfu

John Hutton wrote: »

It's a touring bike and I'll be hauling panniers so I'll have to replace it so...

Why do so many front derailers no longer unscrew so you can slip the chain on? Annoying.


Thanks folks.

Just buy a quick link and when it does let go stick in the quick link. Buy a couple while you're at it they're handy to have although they usually come in packs of 2.

TychoCaine

iwillhtfu wrote: »

....when it does let go....

Yeah, but a chain letting go will usually pitch you off the bike. I've had it happen once, and it didn't end well. Fit the quick link ASAP. And if you can't find the spot, change the entire chain.