Strange noise when turning pedals on new bike

[berty bassett]

I still think it may just be clipping front mech - it seems to go away when in middle of cassette , that’s what I would tinker with first
And I do think the rear mech limit screw does something , else there would be no point of having one , when in smallest cog it could be trying to get over just a smudge to far , but noise wouldn’t happen in other gears , it would make a noise if in big ring and too far up cassette though
Just an opinion

 

[MikeJD]

No, it isn't possible. It is a function of the lateral distance the chain has to cover to cross over to a far-side sprocket and the length of the chainstays. You can't change either of these two factors.

Further, limit screws only limit the two final travel positions of each derailer. For example, if the indexing is perfect, you can actually remove the limit screws and it will have no effect on the gear changes. Also, adjusting a limit screw at one end changes nothing at the other end. They only work on the side they're intended to work on.

I still can't figure out enough from your video to decide what's wrong, if indeed there is anything wrong. I think without extensive video-ing with the help of an assistant and a steady camera, we can't help. It is up to you to physically look for contact between components.

Cross-chaining is an absolute no-no, it causes all sorts of noises and undesirable wear in the chain, sprockets and bottom jockey pulley. Just don't do it.

Yeah I definitely won't be cross-chaining during riding, I'd only done that to try and get the front derailleur set up 'correctly'. My aim was to set the trim positions so they can handle the extremities, but also preserve no contact when in high/low and low/high (straight chain), which seems like it isn't an easy thing to achieve.

I'm confident in saying there's no contact between the chain and any parts of the FD, then noise is coming from lower down. Now someone mentioned it, it does sound like the chain is touching the chain ring ramps and that's what's causing the noise.

This would be unusual on a new bike, but check that the chain isn't riding on top of the tab between the jockey wheels on the rear mech. That makes a similar sort of noise and it isn't beyond possibility that it was fitted wrong on assembly.

I'll give this a check but pretty sure I'd of noticed that, also this sound is coming from the area amount the middle of the cranks/bottom bracket.

That was my first thought, but after he changed gear the noise pretty much went away.

Yeah it goes away in the centre of the cassette, it doesn't worry me isn't doing it in the low front/high rear combination, it's that I can still hear it to a lesser degree in the low front/high rear (straight chain) combination.

Thanks for the responses

 

[Yellow Saddle]

I'll give this a check but pretty sure I'd of noticed that, also this sound is coming from the area amount the middle of the cranks/bottom bracket.

I'm pretty sure it is an easy thing to overlook. Most of use here, even hardcore mechanics, have made that mistake. Show us a photo of the RD cage so that we can see the chain routing.

 

[MikeJD]

I still think it may just be clipping front mech - it seems to go away when in middle of cassette , that’s what I would tinker with first
And I do think the rear mech limit screw does something , else there would be no point of having one , when in smallest cog it could be trying to get over just a smudge to far , but noise wouldn’t happen in other gears , it would make a noise if in big ring and too far up cassette though
Just an opinion

Oh for sure the rear mech screw does something, but in my understanding that's for the indexing of the rear cassette (getting the chain moving in the correct increments per gear change). I'll triple check, but contact with the front mech is always the first thing I'd look for, in addition to that, as mentioned above, the sounds doesn't seem to be coming from that area.

Thanks

 

[MikeJD]

I'm pretty sure it is an easy thing to overlook. Most of use here, even hardcore mechanics, have made that mistake. Show us a photo of the RD cage so that we can see the chain routing.

I've made the mistake myself on a previous bike. Sure as soon as I get in tonight I'll get a picture taken.

 

[MikeJD]

I'm pretty sure it is an easy thing to overlook. Most of use here, even hardcore mechanics, have made that mistake. Show us a photo of the RD cage so that we can see the chain routing.

I've attached those images of the RD.

I'm still pretty sure it's coming from the front crankset, it seems as though as soon as the chain straighteners out, the sound goes, which is concerning as when the chain's in high rear, low front, the chain should be straight? So confusing.

 

[Yellow Saddle]

I've attached those images of the RD.

I'm still pretty sure it's coming from the front crankset, it seems as though as soon as the chain straighteners out, the sound goes, which is concerning as when the chain's in high rear, low front, the chain should be straight? So confusing.

OK, that's perfect. Not the problem.

 

[Milkfloat]

I assume the FD is totally straight? If it is not then you will increase the number of gears it rubs in.

 

[berty bassett]

Oh for sure the rear mech screw does something, but in my understanding that's for the indexing of the rear cassette (getting the chain moving in the correct increments per gear change). I'll triple check, but contact with the front mech is always the first thing I'd look for, in addition to that, as mentioned above, the sounds doesn't seem to be coming from that area.

Thanks

the limit screws on the rear mech adjust how far the chain can travel up and down the cassette to stop it going over the top or off the bottom , nothing to do with correct increments
there are two screws on the front mech that do much the same and allow it to move alittle in or out that could be the problem - also like milkfloat said , if it has been put on alittle on the scew then it will touch chain as you pedal - and its not always easy to see it happen but the noise sends you nuts !