Chain jumping when riding under pressure

[mknash]

So, I bit the bullet after breaking a chain last week.

I bought a good book, a decent work-stand and some tools and set about learning how to fix this thing properly. Replaced the chain no problem and set to work tuning the transmission.

Now the gears are changing smoother than ever and I have eliminated all rattling that I was experiencing before.

Only rpblem is that the chain feels like it is slipping "goes crunch" when ever I apply hard pressure to the pedals. I can still do my commute so long as I start off in very low gear and cruise up through them smoothly. I do however seem unable to use the 4th cog without it clunking.

Is this indicative of worn cogs? They do seem kinda worn, but still mostly squared at the edges. The bike has done 5-6k on with these gears and had about 3 new chains.

Any other ideas what could cause this before i spend money getting a pro to look at it.

ta

 

[GrumpyGregry]

sounds like your cassette is worn too; new chain on old worn cassette = skippier than a bush kangaroo.

of course if only one or two ratios are worn you could just avoid them!

 

[Chrisz]

Worn cogs - betcha a tenner

 

[mknash]

thanks guys - has been my instinct on the matter, but a colleague told me they shouldnt wear out so quickly and sent me on a wild goose chase of problem finding.

Will pop to the LBS later and get them to check (not confident enough to do this myself yet - and lacking tools!)

 

[Globalti]

After 5-6000 miles your rings and cassette will be scrap. Change them now before the new chain gets ruined by wearing to the old parts.

 

[hulver]

My rear cogs needed replacing after 1000 miles.

I'm a fat bloke in hilly Sheffield, so it does depend on how you use it.

I was getting skipping on 1st gear (largest ring at the back) and it turned out that I just needed to adjust the cable a bit to make it a bit tighter, but it sounds like you've done that already.