Chain Slipping on new Ultegra, no idea why...? (Video)

[cgfw201]

Hi,
Have a 1 year old Canyon with Ultegra 6800. Bike's done around 3800 miles and gets looked after well.

On a ride at the weekend the chain started coming off under pressure, usually when getting out of the saddle accelerating out of a corner or up a hill, only when in the big ring.

Thought this was a sign I needed a new chain, so have put a new chain and 11spd Ultegra cassette on the bike.

Alas, same problems are persisting.

Only thing I assume it could be is the big ring has worn down too much, but surely I should be getting more than 3900miles out of it?!

The strange thing for me is how suddenly this has come on. 3800miles and then 60 miles into an 80 mile ride on Saturday without problems, then instantly coming off at every opportunity (no crashes/interference to the mech.)

Could there be a spring in the rear derailleur gone or something?

Just taken a slowmo video of the chain coming off and put on youtube which may help understand the problem. (Skip to 40s for best example of problem)

https://www.youtube.com/watch?v=cnwbvGK ... e=youtu.be

The big ring has some signs of wear, but I've seen a lot worse with bikes still working ok. Pic below of it next to a brand new one.

Any advice appreciated, otherwise will go shopping for a big ring at the weekend...

 

[Yellow Saddle]

Hi,
Have a 1 year old Canyon with Ultegra 6800. Bike's done around 3800 miles and gets looked after well.

On a ride at the weekend the chain started coming off under pressure, usually when getting out of the saddle accelerating out of a corner or up a hill, only when in the big ring.

Thought this was a sign I needed a new chain, so have put a new chain and 11spd Ultegra cassette on the bike.

Alas, same problems are persisting.

Only thing I assume it could be is the big ring has worn down too much, but surely I should be getting more than 3900miles out of it?!

The strange thing for me is how suddenly this has come on. 3800miles and then 60 miles into an 80 mile ride on Saturday without problems, then instantly coming off at every opportunity (no crashes/interference to the mech.)

Could there be a spring in the rear derailleur gone or something?

Just taken a slowmo video of the chain coming off and put on youtube which may help understand the problem. (Skip to 40s for best example of problem)

https://www.youtube.com/watch?v=cnwbvGK ... e=youtu.be

The big ring has some signs of wear, but I've seen a lot worse with bikes still working ok. Pic below of it next to a brand new one.

Any advice appreciated, otherwise will go shopping for a big ring at the weekend...

Chainrings don't wear evenly and wear is concentrated at the power stroke strongpoints. If you look at the chainring from the right, the wear area will be at the top of the chainring when the right crank is in the ten-past position and another one at the top of the chainring, with the left crank in the same position. The photos above don't show enough of the ring to judge it, but I do think that the tooth furtherest to the right is worn away.

However, wear first manifests as sharkfin patterns and only later as the one on the right. Let's see the full ring.

 

[Yellow Saddle]

First stage of wear.

Second stage of wear.

A chain typically only slips when it gets to the second stage of wear. During the first stage, it simply makes a rumbling noise under pressure.

 

[cgfw201]

Few more pics (not great definition I'm afraid) of it in here. Hard to tell with it on the bike with the frame as a background.

https://plus.google.com/photos/1021...ms/6122492045568674145?authkey=CPagyK3Xu9Cpag

 

[SatNavSaysStraightOn]

I had something similar when my indexing was just ever so slightly out.

But if you compare that outer chainring with the visible inner chainring on the last photo, there is considerable wear and it could be time for a new one. The valleys are nowhere near as deep for starters.

 

[cgfw201]

I had something similar when my indexing was just ever so slightly out.

But if you compare that outer chainring with the visible inner chainring on the last photo, there is considerable wear and it could be time for a new one. The valleys are nowhere near as deep for starters.

That's kind of how they look when new though isn't it?

http://www.chainreactioncycles.com/...OZOro7njdWi2Og8mO8KSvhoCNWvw_wcB&gclsrc=aw.ds

 

[Yellow Saddle]

Few more pics (not great definition I'm afraid) of it in here. Hard to tell with it on the bike with the frame as a background.

https://plus.google.com/photos/1021...ms/6122492045568674145?authkey=CPagyK3Xu9Cpag

OK, that pic says it all. Ring is worn too much. Replace it. It's an expensive ring, being hollow and fancy.

Also measure your chain before riding and don't use a worn chain on your nice new ring.

What you have there is classic stage two wear but without the cross-chaining damage I showed in my stage 2 photo. Cross chaining makes the rings thinner by wearing away the sides and eventually they are too thin to handle the pressure effectively and squash out like in the photo.

 

[Pale Rider]

I had something similar when my indexing was just ever so slightly out.

But if you compare that outer chainring with the visible inner chainring on the last photo, there is considerable wear and it could be time for a new one. The valleys are nowhere near as deep for starters.

Aye, looks a bit blunt to my untrained eye.

Have you been using it to cut wood?

 

[cgfw201]

Aye, looks a bit blunt to my untrained eye.

Have you been using it to cut wood?

Weirdly I've not used it to cut wood.

As I say, only 3800 miles and I clean and lube the chain pretty regularly as well as clean the cassette, jockey wheels and chainrings.

One thing that changed a few months ago was the LBS taking a few links out of the chain which I thought was odd, as I didn't think Canyon would supply a chain the wrong length? If the chain is too short, could this accelerate wear on the components?

 

[Yellow Saddle]

Weirdly I've not used it to cut wood.

As I say, only 3800 miles and I clean and lube the chain pretty regularly as well as clean the cassette, jockey wheels and chainrings.

One thing that changed a few months ago was the LBS taking a few links out of the chain which I thought was odd, as I didn't think Canyon would supply a chain the wrong length? If the chain is too short, could this accelerate wear on the components?

No, a short chain would not do that. A short chain has the effect though, of wearing the tension pulley (bottom pulley) thin to the side. This is because in big/big combinations the jockey would be bent forward by more than 45 degrees with the effect that the chain enters it sharply from the right, abrading the left side. This is a noisy affair.

 

[raleighnut]

The big chainring looks quite badly worn to me.

 

[Deleted member 35268]

Looks a gonner i'm afraid.

 

[Travs]

I'll go with the far greater knowledge than me on here - but the pic on CRC of the new one does look ropey too compared to the small ring teeth. The chain issue may also be that Canyon supply a chain with extra links for various different applications and they just need to be removed to fit specifics - rather a couple to many than not enough, or manufacturing lots of different ones for various models/setups.

 

[wam68]

As Monty Python would say...... It's dead, no longer of this world, ceased to be,

 

[cgfw201]

Thanks for opinions...does any of this explain though why I had 3,810 miles of skip free cycling, and then from nowhere 20 miles of totally unrideable chain skipping?