Chain jumps since new chain/cassette/chain rings

[SatNavSaysStraightOn]

I have recently ditched one LBS for making my bike worse and have tried another one BUT..
I picked the bike up last night from the 2nd LBS and all seemed OK at the time.

It has had a new chain, all 3 chain rings (terminology) at the front & new rear cassette - all at my request because they were well worn out. I had asked that if anything else needed it, to do so after contacting me... The front derailleur was replaced about 500 miles ago (read 5 weeks), so I left them to decide on it - it was not changed. The rear derailleur has never given any issues and seems fine - I think the LBS has replaced the free wheels (terminology yet again) on the rear derailleur - they have that new look about them. There is no question that the parts requested to be replaced have not been.

But riding to work this morning, the chain is jumping/slipping in 2/7, 2/8, 2/9 & 3/9. I assume that it is going to be evern worse on the inner ring set (which I label as 1) but my commute (cross country/bridle paths and then road) does not require it. I think the chain is slightly longer than the one I had on (I had taken 4 links out of it after the last attempt with the other LBS), the reason being that I could hear something metal to metal over the tree roots on the faster sections of the bridlepath and this may be the problem for all I know.

The bike is a £1,500 MTB with excellent parts and everything replaced was like for like.

Before I speak to the shop, I was wondering if anyone has an ideas please.

 

[PpPete]

When you say chain jumping/slipping do you mean a) skipping between gears, or b) just not transmitting power to the wheels?

If b) I'd be thinking it's the freehub needs attention or replacement. If a) it could be anything from chain length, as you suspect, to gear hanger alignment or simply cable tension - but the shop really should have sorted those when they fitted the new parts.

 

[Davidc]

It can be chain over long if there's jumping on new kit. Misalignment of the rear derailleur can also cause it.

I'm not going to describe my method for adjusting chain length as I learnt in the days of 5 speed freewheels and 2 chainrings max, so there are probably quicker methods!

As the LBS has put the new bits on why don't you go back to them? you've paid for the bike to be made to work properly.

 

[SatNavSaysStraightOn]

Sorry for not getting back to people yesterday - I do appreciate the help - work just got manic and I didn't see daylight for hours and hours.

When you say chain jumping/slipping do you mean a) skipping between gears, or b) just not transmitting power to the wheels?

If b) I'd be thinking it's the freehub needs attention or replacement. If a) it could be anything from chain length, as you suspect, to gear hanger alignment or simply cable tension - but the shop really should have sorted those when they fitted the new parts.

The chain - jumping/slipping - don't know the correct term, but it stays in the gear, just not on the gear, the pedals move forward without power going to the wheels - it feels like the chain is not sitting on the teeth properly at certain irregular intervals - it is not constant and only happens 3 or 4 times in 10 minutes in those certain gears, but you get the impression of moving the chain without moving the rear wheel.

As the LBS has put the new bits on why don't you go back to them? you've paid for the bike to be made to work properly.

I would normally go back to the LBS, but the shop is in the opposite direction to going home if I am at work, they are not open on Sunday's and I am not able to get to them this Saturday when I could use the car and bike rack - in fact the bike is actually in use all of this weekend relating to work - I work in a school and this is a Duke of Edinburgh's award weekend where I use my bike (if I took the car, my other half would have no motorised transport for the weekend to do what he needs to get on with and we live in rural surrey which means no public transport of any kind), so I need to be able to look at it myself hence me asking about chain length becuase that is something I can do myself (I don't have full use of my left hand which makes some tasks rather more difficult than they really need to be).

thanks again