2x10 chainlines

hard-rider

I've just installed a 2x10 (24/38) crankset and am busy setting up the gears and indexing. Everything is working fine except that I'm getting a lot of rattling noise when on the largest and second largest sprockets and large chain ring. The shifting up and down the cassette is fast and clean, it's just the rattling which sounds like it's from the from the front rings that bothers me. I've checked to make sure that the cranks have been fully inserted in to the BB and it is. The large ring looks in line with the middle of the cassette.

It was my understanding that with a 2x10 set-up you basically run on the large ring all the time (treat it like a 1x10) and drop to the smaller one only when necessary. Is the rattling noise expected when running large / large combo? I don't remember hearing that noise on a 2x10 bike I once demo'ed.

Drive train is full XT 24/38 front and 11/36 rear and press fit BB92-41A.

freshe

I have fitted xt triple just few days ago and my only problem was fixed by adjusting either limit screws or barrel adjuster when on middle ring. If you inspect the chain and me h carefully in good light on each gear you should see if there is any contact. It could also be the rear mechs jockey being too close to cassette sprocket ? Or as a pure guess a stiff chain link perhaps ?

hard-rider

Thanks for the reply. I looked at the front more closely and the chain is definitely not rubbing on the mech cage. The noise is from the chain links catching on the chain ring teeth.

I'll play with the b-screw adjustment as I have set the jockey wheel quite close to the cassette's large sprocket. I read the closer it is the better the rear shifting. I'll try wind it out a little but don't see how that will really make a difference as the noise is from the top of the chain rings not the bottom side.

freshe

Is that derailler with the bb mount ? You also need to remember that the height between rd and chainring is 1-3 mm for shimano. Not sure whats for other brands but i bet its the same.

And I think there will always be some sort of noise of moving chain - not sure how loud it is in your case. But thats all I could think off given my inexperience.

I know that youll get ratyling noise when RD needs some adjustment with the barrel - it aligns the cage with the sprocket. When that line is off chain wants to go up or down depending which was cage leans toward - but the sound is very much ratling.

And if none of above works maybe other colleagues here could help.

hard-rider

freshe wrote:

Is that derailler with the bb mount ?

Not sure what you mean by that question. The rear dérailleur hangs off a X12 dérailleur hanger (my rear axle is a X12 142mmx12 Syntace axle). I mentioned the BB in case it had any relevance to the chain line.

freshe

Sorry I thought the noise was in the front.

And I meant derailler like this one http://www.bike24.com/1.php?content=8;n ... pgc=83:275

Where Im not sure if and how you adjust the veryical position of the mech.

thelonegroover

hard-rider wrote:

I've just installed a 2x10 (24/38) crankset and am busy setting up the gears and indexing. Everything is working fine except that I'm getting a lot of rattling noise when on the largest and second largest sprockets and large chain ring. The shifting up and down the cassette is fast and clean, it's just the rattling which sounds like it's from the from the front rings that bothers me. I've checked to make sure that the cranks have been fully inserted in to the BB and it is. The large ring looks in line with the middle of the cassette.

It was my understanding that with a 2x10 set-up you basically run on the large ring all the time (treat it like a 1x10) and drop to the smaller one only when necessary. Is the rattling noise expected when running large / large combo? I don't remember hearing that noise on a 2x10 bike I once demo'ed.

Drive train is full XT 24/38 front and 11/36 rear and press fit BB92-41A.

Not sure where you got the idea of running only the 38 on a 38/24 chain set. I have a 38/24 with 11-34 cassette, I'd really be strugling with only the large chain ring. Mine also makes a noise when running large and large, as most bikes will.

The Rookie

Thelonegroover wrote:

It was my understanding that with a 2x10 set-up you basically run on the large ring all the time (treat it like a 1x10) and drop to the smaller one only when necessary.

Not sure where you got the idea of running only the 38 on a 38/24 chain set.[/quote]
He hasn't got that idea though has he?

paulbox

hard-rider wrote:

It was my understanding that with a 2x10 set-up you basically run on the large ring all the time (treat it like a 1x10) and drop to the smaller one only when necessary. Is the rattling noise expected when running large / large combo? I don't remember hearing that noise on a 2x10 bike I once demo'ed.

Drive train is full XT 24/38 front and 11/36 rear and press fit BB92-41A.

I have almost exactly the same set up as you and have similar noise, I don't think you're going to get away from noise if you're trying to run big ring to big ring. I think my noise comes from the chain rubbing the front mech though.

And I spend more time in the small front ring than the large.

thelonegroover

The Beginner wrote:

Thelonegroover wrote:

It was my understanding that with a 2x10 set-up you basically run on the large ring all the time (treat it like a 1x10) and drop to the smaller one only when necessary.

Not sure where you got the idea of running only the 38 on a 38/24 chain set.

He hasn't got that idea though has he?[/quote]

Not sure what idea he has, but running large and large will cause the chain to rub on the teeth.

The Rookie

That indeed can be true, depending on the rear wheel......

hard-rider

It was on a forum somewhere that I read that a 2x10 should be ridden mostly on the larger ring as the chainline was optimized for that. Cleary that wasn't correct. I noticed that when my rear mech is up on the biggest cog, the cage and bottom jockey seem to point outward and the chain rubs on the side of the cage. It doesn't look right to me and I want another opinion. I'll take a photo of it and post it later when I'm back home.

The rear wheel is a stans arch ex 29".

The Rookie

hard-rider wrote:

It was on a forum somewhere that I read that a 2x10 should be ridden mostly on the larger ring as the chainline was optimized for that. Cleary that wasn't correct. I noticed that when my rear mech is up on the biggest cog, the cage and bottom jockey seem to point outward and the chain rubs on the side of the cage. It doesn't look right to me and I want another opinion. I'll take a photo of it and post it later when I'm back home.

The rear wheel is a stans arch ex 29".

That sounds like a rear mech issue, if anyhting it should 'look' like it's the other way round.

Thats the rim, the hub is?

hard-rider

The Beginner wrote:

hard-rider wrote:

It was on a forum somewhere that I read that a 2x10 should be ridden mostly on the larger ring as the chainline was optimized for that. Cleary that wasn't correct. I noticed that when my rear mech is up on the biggest cog, the cage and bottom jockey seem to point outward and the chain rubs on the side of the cage. It doesn't look right to me and I want another opinion. I'll take a photo of it and post it later when I'm back home.

The rear wheel is a stans arch ex 29".

That sounds like a rear mech issue, if anyhting it should 'look' like it's the other way round.

Thats the rim, the hub is?

Sorry should have said, the hub is a 142x12mm DT Swiss 350.
Here are some photos of the rear mech when I'm on the large / large combo. It's difficult to capture and doesn't look as bad on the photos but you can still see what's happening. the cage is kinked out from the vertical and also rotated outward about it's axis.



Here you can see that the lower jockey wheel is almost climbing on to the outside of the chain.


When cranking the chain rubs on the inside of the cage at the lower jockey wheel.
Is this normal or is something wrong with my dérailleur or hanger. The hanger is an X12 type so quite meaty and unlikely to be bent.

I compared it to my 3x9 setup with XT rear dérailleur on large / large combo and it doesn't 'kick out' like this nearly as much. It remains almost vertical and aligned with the sprockets.

thelonegroover

Right, I think I see what you mean. When I compare my 2x10 XLS to my sons 3x10 XT it's tending to be the same, but not as pronounced as yours. Could the bottom part of the cage be bent at all?

Chunkers1980

Can't really tell from the photos, the angles could lie. But the pully cage does look bent. What does it look like half and fully slack rather than at full like those photos?

hard-rider

Chunkers1980 wrote:

Can't really tell from the photos, the angles could lie. But the pully cage does look bent. What does it look like half and fully slack rather than at full like those photos?

It's still kinked out but not as severely. I'll double check the derailleur when I get home.