When to replace rear cassette & rear de-railer adjustmen

paul the 6th

Eyup,

had my hardrock sport disc '09 for 2 years but only started using it properly this year (have covered 120 miles in the last 8 weeks, not much for some but it is for me )

When in a particular gear, say 4th or 6th, the chain seems to be skipping up or down when under load (always when setting off at the traffic lights or trying to pick up speed before a bus overtakes me and then promptly pulls over in front of me at the bus stop 20 yards down the road...

I inspected the rear cassette and noticed quite a few of the teeth are showing signs of wear


I did ask one of the guys at evans cycles york (great bunch! very helpful and friendly!) for a bit of advice about it - he reckoned there was an adjuster on the rear de-railer but I've looked and can't see one (maybe it's something which came in on the later '10 or '11 hardrock sports). I want to try cleaning and adjusting before going down the route of replacing parts.



Any advice on the above plz

nicklouse

yes the cassette is worn.

time for a new one and a new chain.

the adjusters are on the side of the mech but they are not the problem.

paul the 6th

cheers nick - overall the bike probably hasn't done much more than 200 miles - do they usually go in this sort of mileage? I must admit I'm a bit of a heifer at 6ft 2 and 18 stone, but I've always tried to reduce pressure when changing gear...

nicklouse

Mmm in that case just check that the mech hanger is not bent.

cooldad

Or a bit of indexing. (Adjuster on the shifter)

nicklouse

cooldad wrote:

Or a bit of indexing. (Adjuster on the shifter)

that is tension. if it was tension it would be the same all over the range.

ricardo_smooth

needs a bloody good clean too you dirty git!

paul the 6th

and yes, I'm going to clean it! Just been working all over the UK for the last month or so - gonna give it a good going over this afternoon

BigLee1

First job first, a bloody good clean!

try http://youtu.be/pfLHRIdMem0

then report back!

The adjuster I think you mean allows the derailleuer to pivot so the top jocky wheel is quite close to the rear sprockets so allowing the chain the maximum amount to go round the teeth. Don`t touch any with H or L on them unless you want your chain to fall in the spokes or off the smallest sprocket!

paul the 6th

yarp - mines one with H & L on it, just noticed the two little screws - it's always been very good but just in the last 20 or so miles it's started to get really bad (seems to be 4th and 6th are the main culprits, only when under increased load such as accelerating or climbing a hill)

How's this? Look at the shiny shiny! Runs a bit quieter but still skipping up and down.. rang evans and they said it'd probably be somewhere around £50 for a new cassette depending on what quality & brand I go for. You can see there's a tooth on the 3rd gear which is absolutely fuct. Any advice on how to avoid this or is it just par for the course?

rhext

paul the 6th wrote:

yarp - mines one with H & L on it, just noticed the two little screws - it's always been very good but just in the last 20 or so miles it's started to get really bad (seems to be 4th and 6th are the main culprits, only when under increased load such as accelerating or climbing a hill)

How's this? Look at the shiny shiny! Runs a bit quieter but still skipping up and down.. rang evans and they said it'd probably be somewhere around £50 for a new cassette depending on what quality & brand I go for. You can see there's a tooth on the 3rd gear which is absolutely fuct. Any advice on how to avoid this or is it just par for the course?

Is it skipping up and down a gear or is it coming off the sprockets under load?

If it's skipping up and down gears then it probably just needs adjustment. If it's slipping on a single sprocket then it's probably worn. I'd be gobsmacked if you'd managed to wear out chain and cassette with only 200 miles though, although I suppose you might have damaged it. The 'fuct' tooth might have been cast that way: I don't think they all have the same profile - to make for easier shifting.

rhext

When the guy in evans referred to an 'adjuster' was he perhaps talking about the barrel adjuster rather than the limit screws? Where the cable enters the mech, there's usually a barrel shaped plastic device which the cable passes through. Twisting it alters the cable tension. If your gears are tending to skip up/down, it usually means the cable tension is wrong: you get it up on a workstand (or turn it upside down), turn the pedals and twist the adjuster until it's running quiet and doesn't show any signs of skipping.

Have a look for an internet guide. Chances are you're going to have to do this if you replace chain and cassette anyway, so it's best to try it before buying any spares.

Something like this: http://bicycletutor.com/adjust-rear-derailleur/

BigLee1

Theres no chance you`ve worn out the chain and sprockets in 200 miles, more likely cable stretch is the culprit and 10 mins with someone who knows will sort your shifting. Does the chain sound like its wanting to change gear but not quite getting there?
If you have a look either on the shifter or derailleur there will be a barrel adjuster, if you keep a close eye on the mech and turn the adjuster either way a couple of clicks to see which way the mech goes depending on which way you turn the adjuster.
Then elevate the rear of the bike so you can turn the pedals while the chain is in the middle sprockets and see which way its trying to go, either up or down onto the next chainring.
depending on which way and now you know which way the mech goes compared to the barrel adjuster turns. Then while turning the pedals and watching the chain trying to change gear turn the adjuster either up or down to stop the chain from making that horrible noise

Then report back

madmole

Bottomish of range cassete + bottomish of range chain + lack of chain Lube + dirt + 200 miles does = excessive wear

I suspect the rear derailer needs setting up properly as well

Combination of both probable cause

Whats the middle rinmg at the front look like?

See loads of bike like this in the workshop, dirt does not a good lubricant make and 200 miles is not unusual for wear (normally middle ring at front and rear)

Use a wax rather than an oil lube and it will stay cleaner and last longer BUT only if you lube every ride

paul the 6th

yo dudes...

gave the chain and sprockets an even more thorough clean then headed out on my 11 ride - the chain behaved for 95% of the time all the way round my route until I got on the dusty gravelly path.... .about 5 mins further up the road and it started skipping into the next gear when in 4th & 6th. Dirt obviously brings the problem out and lots of the stuff makes it terrible..

Guessing it'll need either replacing or professional attention soon though.. Thanks for all the replies

supersonic

If it is skipping into the next gear, then your adjustment is usually out.

Clean and lube the cables, and readjust.