Bad gear changes - new chain & cables?

nunowoolmez

The gears on my Canyon have begun to slip & miss changes up & down & this is the first time this has happened & is happening on the flat & when climbing. I keep it well maintained & do all servicing myself so this has really thrown me. It had new gear cables fitted in the new year too, which the LBS fitted for me (this is beyond my skill level).

So I take it into LBS today having had no luck tweaking the cable tensioner & they had a look. They also played with the tensioner & had same results. No change. So he checked chain with chain tool & said it was probably on it's way out. Fair one, it's done about 2500 miles, so thats a good shout. He then said it will also most likely need new gear cables as the bends were quite tight & this would effect gear changes. Hmm, I was a bit taken aback with this one! Surely not.

Up til yesterday it was changing just fine. For info I run full Dura Ace componentry inc cables & chain & since installment of cables I have probably done roughly 1500 miles. The cassette has plenty of life in it.

What do you guys think?

I may just get a replacement chain & see if that does the trick.

wishitwasallflat

nunowoolmez wrote:

I may just get a replacement chain & see if that does the trick.

Do this - tight bends would not suddenly cause the symptoms you describe -but - be aware that if your chain is too far gone it would have damaged the cassette and so a new chain may also skip. You could leave it for a 100 miles or so to see if it beds in but personally I would put on a new chain and if it skips order a new cassette and put the old chain back on till it arrives and then refit new chain and cassette.

nunowoolmez

Thanks mate, reckon the new chain should work. Sound advice.

Monty Dog

Bad cable runs don't cause chain jump - it's down to a worn chain. LBS will always try and flog new cables - if they aren't kinked, frayed or damaged then a clean and relube should see you through - I've had gear cables last for 10 years.

francis666

Normally you change chains and rear cassette at the same time, as they directly relate to each other. Replacing one without the other will normally damages the newer part. Chain rings normally last much longer as the tension is spread over a greater amount or area. Think of the force that is spread over a small portion of the 11 tooth rear, compared to a 50T front!
Outer cable length at the rear mech can have an effect. Normally too long/too short (tight bend) = sluggish changes caused through too much resistance. Too much grease applied will do the same.
A loose rear mech will mess changes- check the bolt to the frame.
Cables last years and once stretched are more consistent, but a new cable will need to be indexed after a decent ride if not properly pre-stretched.
To me it sounds like chain and cassette (if nothing has become bent/loose or worn) and I'm glad I'm not forking out for the cassette!
so answer: if your LBS doesn't know this stuff, take it to another and get a decent answer!

ridgerider

Just to reinforce what Luke has mentioned, I was privilaged to watch a very good mechanic build my dream bike for me recently. He spent alot of time getting the gears right, in order...
1. Made sure the hanger was square to the wheel
2. Put new jockey wheels on the RD
3. Used the smoothest inner cables he could find
4. Used good quality outer cables
5. Made the routing as gentle as was possible
6. Adjusted the gearing focussing on getting small front ring/middle rear ring right
Changing gear is a dream!

wishitwasallflat

madasahattersley wrote:

Monty Dog wrote:

Bad cable runs don't cause chain jump - it's down to a worn chain. LBS will always try and flog new cables - if they aren't kinked, frayed or damaged then a clean and relube should see you through - I've had gear cables last for 10 years.

Bad cable absolutely do cause chain jump. If the cable is rusty/stiff/covered in debris then the derailleur will not be able to spring back toward its resting position. If it can't do that then it will basically be between 2 gears. It can cause chain jump in pretty much all 10 gears of a 10spd drivetrain.

In fact I'd go as far as to say that knackered old cables are the most common cause of cable jump, by an enormous margin. Second place would probably just be poor cable adjustment, third would be a bent hanger and then maybe worn chains.

Don't want to start an argument and each to their own and all that but IME cable problems do cause poor shifting but the symptoms are different from chain wear. Simple gear jumping (i.e. erratic/poor shifts up and/or down) is most often due to a worn chain. The OP says the chain has done 2.5k miles so my money is still on that. Won't do any harm to replace cables though.

pilot_pete

I started suffering from this on my TT bike, equipped with Campag Record.

I changed all the cable inners and outers, ferrules etc and tweaked all the adjustments. Did this again constantly over the next few rides as the cables stretched and bedded in. Some improvement but still not quite right. Hanger checked and confirmed straight. Chain checked with a brand new checker tool and not showing worn at all (only one season TTing on it - less than 500miles by me, but I did buy the bike second hand in 'nearly new' condition). The rear cassette is showing no signs of wear and the front carbon chainrings very little (big ring) and none (little ring). The chain is a KMC and the whole drive train was in my opinion a little 'noisy'.

I changed the chain last week for a Record 10sp and it has performed perfectly since then. Changes are crisp in both directions once more and the drive train much quieter. I really didn't think it was the chain, but there you go....

PP

desweller

Lots of things to go for.

1. It's quite easy to induce premature wear in cable housing by cutting tight radii - shifting will initially appear to be OK but will rapidly deteriorate. The loop to the rear derailleur is usually favourite for this.
2. Make sure all your housing caps are fully home, the exits of the housings are free of burrs and the housings are fully seated in the frame stops; a silly one but surprisingly easy to cock up
3. Some chains are just sh1t out of the box; I've had new ones that skipped or had poorly swaged rivets, upsetting shifting.

nunowoolmez

So i took the bike into the LBS today. They said they would check it over & let me know. I got a call from them a few hours later & they said all they had done was fit the new chain & tweak the tensioners. No cable issues & the gear changes were running smooth under load when tested, so all good! I am picking it up tomorrow so hopefully it will run fine. Thanks all for your comments & advice!