Chainring Slippage - link to video

[Dexradio]

Hi all,

I wonder if you could try and help me understand what's going on with my chain as it goes over my front Chainrings.

I've attached a link to a short video of what's happening. This started last week so I checked my chain and it was worn. The chain in the video is a new one, but the problem is still happening. I've done what I am technically comfortable with in terms of trying to diagnose the problem. I've checked the cables, limits, indexing and all the basic stuff. I've "played" around with adjusting the B Limit screw in a somewhat desperate attempt to make this problem go away, all with no joy.

I wonder if it might be a "wear" issue? But any thoughts, guidance, advice etc. would be very much appreciated before I give in and take to my local bike shop.

Video of my problem on Vimeo

Thanks for any thoughts you have,

Dex.

[Painkiller]

it is hard to tell from the video, But suspect a worn big ring. does this happen in the smaller/inner chainring? How many miles aprox. on the drivettrain?

[Dexradio]

No it doesn't happen on the smaller Chainring (39T) and I would guess about 5000 miles on it, it doesn't do a high mileage annually, but I have it since 2006.

Dex

[Joe_W]

You could start by measuring the chain length (Alex has a tutorial on this site). I guess the chain is worn out and you waited too long with replacing it, but this is hard to tell without seeing the bike or you measuring the chain length.

[FredS]

The video shows the chain rising up on the top of the chainring and going around so it could be a bad tooth on the chainring or the chain is stretched.

[haykong]

(04-20-2013, 03:57 PM)Dexradio Wrote:  Hi all,

I wonder if you could try and help me understand what's going on with my chain as it goes over my front Chainrings.

I've attached a link to a short video of what's happening. This started last week so I checked my chain and it was worn. The chain in the video is a new one, but the problem is still happening. I've done what I am technically comfortable with in terms of trying to diagnose the problem. I've checked the cables, limits, indexing and all the basic stuff. I've "played" around with adjusting the B Limit screw in a somewhat desperate attempt to make this problem go away, all with no joy.

I wonder if it might be a "wear" issue? But any thoughts, guidance, advice etc. would be very much appreciated before I give in and take to my local bike shop.

Video of my problem on Vimeo

Thanks for any thoughts you have,

Dex.

Since you mentioned that it doesn't slip on the small 39T ring..... yeah it seems you might damaged the 52T big ring by waiting too long to change out your chain.

Question did you also change out your cassette yet too? normally cassettes wear out faster than the big chain rings.. but if you wait out too long.. both will have to be replaced...

And since you have Dura-ace components that is not going to be cheap. yeah it's an expensive lesson to learn if you did not know about chain wear and when it's too late.


However, you also mentioned on your video posting on vimeo that it only happens at 52tx12 and 52x13

well maybe all is not lost yet....

I would replace the cassette first if you haven't done that yet.... and see if it still slips..... then replace the front ring... but first just do the cassette..

[Dexradio]

Thanks all, for the input.

Looks like its most likely a wear problem then. It's a brand new chain in the video, and I do keep an eye on the wear, and replace them once they stretch beyond the .75 mark on my chain measuring tool. The new chain has the same number of links as the old, so is the same length.

The cassette and crankset are all original, so looks like I may just have to replace them, as you say an expensive exercise indeed.

Thanks for the help.

Dex.