Hi!

I have just changed my chainrings (shimano 105 5703) and chain (KMC X9.99) on my specialized allez elite 2007.
I originally bought this bike used several months ago and it looks like the owner never changed any parts except the chain (all the other components seem to be originals)
When I cleaned the cassette (SRAM 9-speed), it was looking good enough that I didn't change it.

Since I changed the chain and the drivetrain, I experience shifting problems :
- First of all, I have experienced what I think was chain skipping (although i didn't see it, just felt like it)
- Second, when shifting, even after adjusting my derailleur (shimano 105), it has somewhat trouble from going form a cog to another. I don't have a picture, but it looks like the chain has a hard time to "seat" on the cog and therefore goes toward the next cog but before reaching it, goes back and only after jumps to the next cog (I hope it's not too confusing)

It looks to me from this and from what I have read that I should change the cassette.
Could it also be the chain length (too long) ? I am certain I have correctly checked the chain length but I could be wrong

You should get a new cassette.

the cassette is usually changed much more frequently than the chainrings

generally
the chain is changed most often
but eventually the cassette will wear out too
especially if you go too long between chain changings

chainrings can go years and years if the drivetrain is maintained properly

I decided to change my cassette, hopefully that will fix my problem

Thanks for your help!

Hello how are you. How do you measure chain length. I have one road bike i have by used chain is was too long i take in bike shop is cut the chain but stay now the chain looks long to me. On my bike now i have 53/39 crank and 12-25 cassete 9 speeds. You think is good combination. I ride in trail have 900 feet elevation. What cassetes is good tight or wide 25 cog is enough or is need lower gear like 28 or 30 or maybe 32. I try setup my bike for century. Do you fix your cassete? My bike used do the same skip as your bike i replace cassete used too but the skip is stop. I know the cassete is used. Now if the chain try jump cog adjust the gears with the barrel adjuster. That way i adjust my gears. I adjust first the screw limits i be sure the chain no jump off. Then i i put the shifter in the higher gear position example on my bike on the 12 cog. The i do the adjuster i be sure is all the way in. counter wise. Then i lose the screw hold the cable i pull the cable with my hand. then i tight the scres. After i start move the shifter in the next gear and i turn the pedals. I have the real wheel on stand. If i see the chain is not go in the next cog i turn the barrel adjuster counter clock wise until the chain is go on the next cog.

I wanted to let you know that I have replaced my previous SRAM cassette with a Shimano CS-HG50 9 speed and it fixed my shifting problems.
I guess the SRAM was worn out and I couldn't tell by looking at it.
As always, thank you everybody for all your help