Brand new bike and my chain is not sitting properly on the largest cog on my 1 x 10 set up. Seems like the chain is not staying on the top cog for long enough and is sliding off too early which is causing vibration etc

Any ideas what could be causing this?

Thanks

The screw with ‘L’ marked next to it might need turned anti clockwise about 1/4 to 1/2 a turn. Try it small amounts to begin with and see how it goes.

Should I undo the tension bolt cable before doing this?

The L limit screw is there to stop the deraileur dumping your chain over the top of your cassette into the spokes, so if to tight the deraileur will not quite move in far enough to allow the chain to settle comfortably and will instead try to ride up the out side ode the sprocket. As said above just 1/4 of a turn anticlockwise of the l limit screw ( don’t touch barrel adjuster yet) and see if this helps. If not check out the park guide.

This link is the best guide I found on the subject , take a minute to read and understand it then give it a go.
It’s not rocket science and quit straight forward once you understand what you are doing .

Park guide

Okay I tried what you suggested but it didn’t make any difference to the noise/vibration. I think the mech is set up properly and the problem lies with the angle of the chain as it looks pretty squint in the big cog. Is there any way to get a straighter line between the big cog on the cassette and the chainring?

With my 1×10 set up I don’t notice any more noise from the cassette since the change but the NW ring is definatly noisier but I am guessing that is normal due to longer teeth with greater contact with the chain.

is it a brand new bike, could you ask the shop where you bought it or failing that an lbs.

Chainline?
You want the chain ring to line up with the middle of the Cassette to minimize the bend in the chain. If the chainring sits too far outboard this could cause issues in the biggest sprocket.

Surely a brand new bike supplied with a 1×10 should be good to go as far as chain line is concerned.

You would have thought so – but I would check anyhow. someone in the shop/factory might have put the BB spacers on the wrong side…?

68mm shells should have 2 spacers drive side and 1 none drive side
73mm shells should have 1 spacer drive side only

….unless its press fit of course

I changed it from 2 x 10 to 1 x 10 so maybe I went wrong somewhere although I don’t really see where. Very annoying.

I changed it from 2 x 10 to 1 x 10

This is def chainline then.
The Outer chainring of a dedicated 2 x 10 chainset is centered on about the 2nd or 3rd smallest sprocket. A dedicated 3×10 chainset or 1 x 10 chainset centers in the middle of the cassette.
So when in the biggest sprocket you have an undesirable bend in the chain

Moving a bottom bracket spacer across to the non drive side should sort your problem although its not ideal. But the alternative is new cranks.

Thanks for your help but I’m not too sure how changing my cranks will change the angle of my chain.

OK brand new bike? From a shop? If so go back to the shop and get them to set it up properly.

Thanks for your help but I’m not too sure how changing my cranks will change the angle of my chain.

I just explained how???

yep but on a brand new bike I would be back off to the shop for them to sort it, either spacers are wrong or the crank is not the right one for the frame in which case they can replace it.

But its not a brand new bike is it……

I changed it from 2 x 10 to 1 x 10

2 x 10 cranks are not properly compatible with 1 x 10.

If I were him I would go back to 2 x 10 – Not a fan of all this 1 x 10 silliness

missed the bit where he went from “Brand New Bike” to “I Changed stuff”

I moved 1 spacer to get 1×10 working right, much better than the front mech sillyness.

anyway advice as stands, if you don’t get the explanation seek professional advice.

I moved 1 spacer to get 1×10 working right

So you missed the bit where I suggested this bodge too

nope I saw it but though the OP had a brand new bike like he said in the first post. The advice to return to a shop was the sensible thing to do, do it first then let them deal with the fact it can’t be sorted. When someone doesn’t get what your suggesting then going somewhere with they have tools and knowledge isn’t a bad idea.

whatever man

OP – Just make sure they don’t try and flog you a chain guide or a new saddle to fix the problem 😉

I took the cranks off and I don’t appear to have any bb spacers? The bb is a press fit. What can I do now?