New wheelset and cassette - chain/gear skipping

[misternapps]

Hi,

I have a 2008 tarmac elite. About two months ago, I (an LBS) replaced the stock 105 front and rear dérailleur after the front der gave out on me. At that time, I also upgraded the chain to an ultegra chain.

I recently put on a new (ultegra) cassette and wheel set, upgrading from the SRAM cassette and stock mavic CXP22 wheel set. Both the original SRAM and new ultegra cassettes are both 11-28.

Since I installed the new cassette and wheel set, when I shift from "gear 5 " through "gear 8" (forgive my naiveness.....not sure what cog it is, but counting upwards from the 11 cog, where the 11 cog is "gear 1" and the 28 cog is "gear 10") it seems like the gear is slipping. My thought is that the rear der needs adjusting, but why would I only notice it in those three gears?

I looked through the chain and it doesn't appear there is any 'hard' links in it....I'm pretty bad about diagnosing or doing technical things with my bike, so forgive any ignorance. I can't replicate it (I don't have a stand and cant tension the cable while pedaling and shifting....). However, I posted a couple videos on the 11cog; one pedaling forward, the other backpedaling, in case it might help diagnosis....

http://www.youtube.com/watch?v=L2-JbZEFk-U

http://www.youtube.com/watch?v=lS7_JRn7nHg

I have a standard double (53/39).

[Surly LHT]

Try to tension the rear cable a little and see if that helps.If not take it to your LBS they may adjust it for free for you.Never hurts to ask.GL.

[trevgbb]

If you are having problems after a repair/replacement take it back, any worthwhile LBS will want satisfied customers and would rather they sorted it than you "mess around" yourself and make it worse.
But, what is the noise on the videos? I originally thought it was the chain/Rd mis-aligned, but it continues after they have stopped turning, is it your wheel bearings? if so, they don't sound very healthy to me.
Also, are you satisfied that all the transmission parts, including the shifters, are compatible, you only need small discrepancies in a 10 speed set up to cause problems.
Just re-read you post and see you probably did the work yourself, may be even more of a case for visiting your LBS, especially if you bought from them.