Slip on one cog - chain wear ?

DCR00

Afternoon all

Chain has started slipping in one gear. Has been happening every now and again for the last few weeks. Put it down to crappy gear cable i used when i moved to the Scale frame, however i replaced said cable at the weekend with a ptfe coated goodridge cable.

Shifting is now much smoother with less resistance from the cable, and meach moves up and down the gears just fine, but i now get slippage in the 2nd to last gear (the one i use the most)

The chain is a few months old now, and does around 40 miles per week

Reckon this slippage is due to chain wear ?

nicklouse

more likely to be a worn cog if it is only on that one cog. (and as you say you use it the most).

cavegiant

The solution to this is easy, just do not use that gear!

If you put a new chain on a worn cassette you will get more slip; so if you wish to burn cash replace both.

Arkady001

Sounds very much like that cog is worn... Replace that and the chain asap otherwise the chain will stretch to accommodate the wear and cause further wear on the other cogs and chainrings as well...
One of the reason more expensive cassettes come apart is so you can replace individual cogs instead of the whole block.
It's a good idea to replace chains very often as they're the cheapest component in the mix and suffer from the most wear - if you ride regularly off-road in dirt (weekly or more often) then quarterly isn't kicking the arse out of it.
Just clean it every ride, hose it with WD-40, wipe it dry and bung some Finish-Line Century Lube on it. Every ride.
As a roadie I'd replace the (budget) chain on my commuting/training bike every other month as that was getting about 50 miles a day.
The XTR chain on my MTB stayed on the bike a while longer, but not much. I found that chainrings and cassettes lasted a lot longer that way.

DCR00

new cog and chain coming up i guess

wildthyme

Hey, i'm having this problem on about a third of my gears and i just got a new chain and if anything the problem is worse so it looks like i need a new cog as well, the middle one is where is slips real bad.

Arkady001

wildthyme wrote:

Hey, i'm having this problem on about a third of my gears and i just got a new chain and if anything the problem is worse so it looks like i need a new cog as well, the middle one is where is slips real bad.

The problem stems from keeping chains on for too long: they stretch a bit and the links wear because of the grinding paste they're constantly immersed in.
This causes uneven wear on the cog teeth and chainrings - do a google for 'sharks teeth' in reation to uneven tooth wear and you'll see extreme examples of what I mean - in bad cases the teeth can develop a hooked appearance.
Once this has happened, then you need to replace cogs, chainrings (if affected) and chain as merely putting a new chain on will do nothing: the spacing of the teeth is now slightly out, so the spacing on the chain is now out of alignment causing it to skip under load.

Nice little vid that explains it all:
http://bicycletutor.com/chain-wear/

Chains are relatively cheap: treat them as a throway, consumable item. Even the costliest are only £70 (only worth buying if you're a racer, IMO) and most are about £25-£30...[/url]