Chain Slip when out of the saddle on one rear gear

[DAZLIN6]

Hi I`m new to this forum, sorry if this has been asked before, I just can`t seem to find a good answer.

Recently I put a new chain on my 10 speed 105 shimano set up. My old chain was showing just about 1% wear. When I get out of the saddle the chain skips on the 5th gear only all other gears are good. My Cassette doesn't seem to be overly worn. The Chain jumping only happens under severe pressure.

I went to my local bike shop this morning, he looked at the cog and suggested that it may be due to a small burr on said cog. He suggested I file it down. Job Done cog nice and smooth, problem is still there. Do I :

1) Put some miles on the new chain and see if it beds in?
2) replace the cassette?
3) any other suggestions?

Thanks in advance for any help

[cyclerUK]

Chances are it's a worn cog.
Possibly the one you use most.

How do you know you had 1% wear on the old chain?
Did you replace like for like chain?

[DAZLIN6]

I checked it using my park tools chain checker.

Yeah the guy in the bike shop said it was prob the cog I use most.

I replaced it with a shimano cn 5600 chain, I think its like for like

[ultrarunner]

(09-06-2010, 10:15 AM)DAZLIN6 Wrote:  I checked it using my park tools chain checker.

Yeah the guy in the bike shop said it was prob the cog I use most.

I replaced it with a shimano cn 5600 chain, I think its like for like

I'd suggest you re-check that chain. It just sounds to me like that chain is worn. A worn chain will cause it to skip on a cog under tension/torque. I just today changed my chain on my touring bike as the chain was skipping and that resolved the problem.

[DAZLIN6]

the chain is brand new....I have put about 150 miles on it and seem now to have settled down thanks