drive train help needed

[Ihatehills]

Hi all , hoping someone can help

Changing gear on my bike has become an issue in that some times it doesn't want to shift properly.
i had a go at adjustment yesterday but cant get it right, in that if I adjust so that the derailleur will smoothly shift up the cassette then it wont drop down the cassette on a couple of gears, half to three quarters of a turn on the barrel adjuster will get it shifting down but then it wont change up onto the gears that were giving trouble the other way.

The bike is around 5 months old and has done 1200 miles in the wet and muck and I haven't cleaned the drive train as often as I probably should. Are my indexing issues likely to be due to a knackered chain and cassette and how can i tell?
If not what else can it be ?
Hope this is clear, thanks in advance

 

[T.M.H.N.E.T]

Clean cassette chain and chainrings, if any teeth resemble shark fins - bin and replace then look after the next ones a bit better

 

[screenman]

Rear mech alignment is the place most good technicians will start from.

 

[Tim Hall]

Rear mech cable is another favourite. Changing to a lower gear is done using the mighty strength in your hands, changing up uses the spring in the mech. A worn or mucky cable adds to the friction, throwing the shifting off.

 

[screenman]

I was just typing that.

 

[kevin_cambs_uk]

To me that sounds like the cable is getting stuck somewhere in that it has friction somewhere that stops the cable from gliding out as you release the cable from the shifter.

I would look at the cable guide under the frame if it has one.

I doubt very much it has anything to do with wear and tear yet but more a case of something along the cable route is stopping the cable moving freely.

HTH

 

[raleighnut]

To add to @screenman and @Tim Hall 's comments the short length of cable between chainstay and mech is notorious for this kind of trouble but I'd check the hanger and replace inner and that section of outer cable,

 

[Racing roadkill]

Check the amount of wear on the chain. If it's had it, you'll need to change the cassette at the same time, or the new chain will almost certainly jump about, when you are on the smallest sprockets.

 

[Citius]

Check the amount of wear on the chain. If it's had it, you'll need to change the cassette at the same time

No. You won't. New inner/outer cable is probably all that is needed. If the issue was with the chain and cassette, there would be more than just minor shifting issues on one or two gears.

 

[gbb]

At 1200miles , I'd have to agree with Citius, I wouldnt be considering changing the cassette.
At 1200miles, I would change the chain TBF, its all I get out of them...this goes some way to protecting/prolonging the life of the cassette. But thats my world, not neccessarily OPs. Measure chain wear anyway...you need to know how its doing before it wears too much, even if it has nothing to do with the shifting problem.

 

[Ihatehills]

Thanks for the replies, I've measured my chain with a rule and and it does seem to be worn but not by loads, less Than a 16th of an inch over 12 inches, I haven't got a measuring tool to be more accurate and there is no obvious wear o the cassette or chain rings that i can see.
@screenman I've no idea how to check rear mech alignment I'm new to this any help is appreciated

@User no real knocks that I'm aware of although I don't know how delicate these things are so it is possible, I assume its a bent hanger that I'm looking for ?

I don't really know how to check if the cable is moving freely, it makes sense that it could be sticky I'll have another look later

 

[Racing roadkill]

At 1200miles , I'd have to agree with Citius, I wouldnt be considering changing the cassette.
At 1200miles, I would change the chain TBF, its all I get out of them...this goes some way to protecting/prolonging the life of the cassette. But thats my world, not neccessarily OPs. Measure chain wear anyway...you need to know how its doing before it wears too much, even if it has nothing to do with the shifting problem.

If you change the chain and not the cassette your new chain will slip. You can change the cassette with an old chain, but not change the chain without changing cassette.

 

[Citius]

If you change the chain and not the cassette your new chain will slip. You can change the cassette with an old chain, but not change the chain without changing cassette.

Complete and utter nonsense. Are you deliberately trolling?

 

[Doyleyburger]

f you change the chain and not the cassette your new chain will slip

Definitely no need to change the cassette. As mentioned the bike is relatively new so even if a new chain is needed I think the general rule of thumb is to change the cassette every three chains or so unless you can tell its absolutely knackered.
(Be happy to be corrected on this one but this rule has worked for me so far)

That being said you really need to look after your drive chain more. You'll get a much better ride if you keep it clean and lubed.

 

[gbb]

If you change the chain and not the cassette your new chain will slip. You can change the cassette with an old chain, but not change the chain without changing cassette.

Completely against the general concensus I'm afraid. Generally, 3 chains can be fitted to one cassette, IF the chains were replaced at a sensible point. Ive been doing it for years.
In reality though, you COULD end up with a situation where your cassette would need changing...ie if you allowed the chain to wear to an extent where it destroys the cassette...but that should be considered the exception... not the rule.