Sunday, 18 February 2018

Shimano Polymer Coated Gear Cables Shifting Problems

Canyon Endurace CF with cat

I've had my Canyon Endurace CF for almost 2 years now and it had been absolutely faultless. A couple of weeks ago it suddenly developed a pretty dramatic shifting problem on the rear derailleur where it wouldn't go into the two highest or two lowest gears.

It came fitted with the Shimano Ultegra 6800 rear derailleur which is still on there now.

I had been out on a long and wet ride the day before so I thought it would just be some crud got into somewhere but after giving it a good clean the problem didn't get any better.

It would change between the middle few gears completely fine, it was almost as if both the limit screws had been turned in. Very strange.

After playing around with the cable tension for a bit I realised that wasn't solving the problem. To get into the largest sprocket I had to dial in so much cable tension that it would not shift into the smallest sprocket.

So I undid the cable and the derailleur dropped into the smallest sprocket as expected, and I could push it across to the largest sprocket without any issues. So the derailleur and limit screws were all fine.

I then noticed some fluff or something wrapped around the cable where it entered the outer casing on the chain stay. When I went to remove the fluff it was firmly wrapped around the inner cable and I could move it up and down the cable.

I could then see that it was part of the inner cable coating which had split, then unravelled and started to bunch up.

Shimano gear cables polymer coating unravelled

When I removed the section of inner cable this is what I found.

The coating (I believe this is the new polymer coating?) had started to unravel in several places and where it had bunched up at either end it was preventing the cable from moving beyond a certain point in either direction. Causing the shifting problems I had experienced.

Shimano gear cables polymer coating unravelled

I thought this was worth posting to see if anyone else had experienced the same problem, I could not find anything about it online but I can't be the only one.

It's worth noting that up until the shifting went I noticed no detriment in shifting performance from the rear derailleur at all.

No comments :

Post a Comment