Hi having a little issue with my new bike.

Riding the new bike home and the bike kept jumping (skipping gears) so had a look tighten up cable etc was alittle better but still did it.. took it back to shop and they took care of it.. sorted!!

All seems fine until i ride on the trails or put the bike under load then it skips plays up… (one min fine the next a right git)

Had a look and i can see that the 2nd cog is ever so slightly out (could this be the cause)

looking normal
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then slight bend
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what do you think???

That’s the profiling on the teeth to aid shifting.
More likely to be a bent mech hanger or cable stretch.

cable stretch i though it was.. but after adjusting it seem fine goes through all the gear and down on the stand and even out on the trails…

just seems to be one min its fine the next its playing up…

bent hanger? how can i check this.. obviously it looks fine but even it being slightly out i must be able to check this..

Is the wheel square in the dropouts?

On a new bike I’d have said cable stretch. Check the cable routing too and ensure that it is secure and that the inner moves freely.

all moves fine no kinks in outers etc..
took cables out and lubed inside..

will try adjusting again.

Im prob being thick but surely if it was cable stretch i would have the problem all the time not intermittent..

Thanks for the suggestions though.

off to check again

is it all brand new? if its not worn together that may cause this issue.

User error?

Could be a number of things, most likely suspects are mentioned above, but yesterday we had a similar issue that turned out to be a loose nut on the axle allowing the freehub and cassette to slide back and forth along the axle. Never seen it before, but it may be worth checking that nothing’s moving on yours.

All checked.

Taken off and refitted lubed etc.

Goes through all gears up and down.

Now to go for a ride to test

If it’s 10 speed Shimano, check the joining pin in the chain – I found one had sheared (from its locating stud, as it should, on fitting) leaving a rough ‘end’ on the inside of the chain. It fouled the second sprocket in just enough to make it trip up and slip a tooth or so. A few minutes with a file was enough to sort it.

Have you checked for a stiff link or burr on the chain?

Have you lubed the chain. A lot of new chains come with a waxy finish to prevent rust. This makes them sticky & stiff and it needs to be cleaned off and replaced with a proper lube.