New chain and cassette

[blinker24v]

hello all,

this may have been covered elsewhere, sorry if it has.

have just changed my Shimano HG73 chain and Shimano HG 50 cassette for new ones. All seemed fine for a couple of weeks but now the chain slips. only seems to slip when, in the front middle or front lower and not the largest front, doesn't seem to move change rings (gears) on the back,only when under pressure / load going up hills.

any ideas.

many thanks

[Bill]

If you try and shift into like a large front chain ring with the biggest cassette gear then it is highly not recommended... here is a video that will explain... http://bicycletutor.com/gear-shifting/

IF THE ABOVE IS NOT THE CASE THEN:

If I am reading correctly your front derailler may need slightly adjusted which this video shows how.... http://bicycletutor.com/adjust-front-derailer/

Second if you just replaced your cassette then you may have to re-adjust your rear derailler which this video shows how... http://bicycletutor.com/adjust-rear-derailleur/ .

[cyclerUK]

Is it worse on the smallest ring?
If so then I would suspect worn chain rings.
It's not slipping yet on the big ring as there are more teeth to grip too.
(or it's not used as much.)
Less teeth on the middle/small rings and the chain can ride over them easier. ??
Worn chainring teeth tend to be pointed like a shark fin.
http://www.bikemagic.com/news/images/chainring_lo.jpg

Make sure first that the front dérailleur is set properly.
Any misalignment could cause "ghost shifting".