Optimising my chain line

[wisdom]

Vids dont play comes up with this video is private

 

[RecordAceFromNew]

Oh, thanks. I have a spare axle, I think. I guess in that case, it doesn't matter if it's from the front or rear wheel, although I suppose for this purpose, the longer the better. So, do you manipulate the hanger with the axle, or do you just use the axle as an indicator and use something else to manipulate the hanger?

Front and rear axles aren't the same size usually, you are most unlikely to find a front one that fits. The axle would be a good indicator, and if the deviation is small I would use it to bent it back in one go if possible (because the hanger will weaken significantly if bent repeatedly). Ideally one should replace a bent hanger.

 

[Custom24]

Vids dont play comes up with this video is private

Cheers, fixed I think.

 

[Custom24]

Front and rear axles aren't the same size usually, you are most unlikely to find a front one that fits. The axle would be a good indicator, and if the deviation is small I would use it to bent it back in one go if possible (because the hanger will weaken significantly if bent repeatedly). Ideally one should replace a bent hanger.

Ok. The vertical alignment is now better. However, I am struggling to decide if this has made much difference to the noise. I am wondering about the horizontal alignment, but this is much harder to judge. Tomorrow, I might invert the bike and satisfy myself that the jockey wheels are straight. I will also try the original chain.

 

[Custom24]

Just to follow up. This went in for its first service at the LBS today, and I specifically made a big deal of this noise. But basically, they didn't fix it. One of them said it needed a new jockey wheel, but they didn't replace that either. When I picked it up, they said they'd improved it by cleaning/lubing the jockey wheels, but it sounded the same to me. They also said that it wasn't a big deal, some noise it normal, and that I wasn't wearing or damaging anything by riding it. I don't know if I believe that, because laziness or reluctance to do free work on their part would explain it.

So that was a bit of a waste of time.

Anyway, choices

1. Make more of a big deal of it. Meh - I don't really want the hassle.
2. Just ride the damn thing. I have been riding it anyway, but I have no real way of knowing if I am going to wear out the drivetrain quicker than I should.
3. Order a new rear derailleur, a new hanger and an alignment tool. Do it myself and see if the sound is any better. Derailleur is £30, tool is £25. There is someone selling hangers of all sorts of type on ebay for next to nothing, but I don't know if they are any good. Otherwise from Whyte the hanger will probably be silly money for what it is (£30 of something, probably).

What would you do? Option 3 if it doesn't improve things at least leaves me with spares and a useful tool, I guess. On the other hand I'm reluctant to keep feeding the bicycle money pit that has developed under my house of the last couple of years. This was supposed to be the bike to end all that

 

[totallyfixed]

If you were closer I would fettle it for you, born fettler I am, can't stand a noisy bike. A couple of things, the noise is coming from the rear mech area, so it is either your rear mech isn't perfectly lined up to deliver the chain on to the sprocket, in which case start by turning the barrel adjuster no more than a quarter turn anti clockwise and run through all the gears. If the noise does not go check that the chain is not being pinched slightly by the jockey wheel guides, the alloy is very easy to compress and conversely open out, particularly on the bottom jockey wheel.
Failing any of that it might just be that all the bike needs is more miles on the drive train, in other words it needs bedding in, a couple of hundred miles should sort it.

 

[Custom24]

Thanks
Doesn't matter what I do with the barrel adjuster. I can have the chain go all the way up or down a gear from where it should be, and the noise doesn't go away. To be clear, I'd expect a sweet spot where the noise was at a minimum, and this doesn't happen. All messing with the barrel adjuster does it to add a separate noise when it's not right.

Don't think it's a bedding in matter either. It's got worse since I got the bike, not better. I've already done probably 300 miles on it.

So, can you explain more about the jockey wheel guides? You mean the sides of the derailleur "cage"? I can't see the chain coming into contact with anything apart from the jockey wheels themselves and the cassette.

My feeling is that either or both of the jockey wheels is not aligned along the long axis of the bike, so that when the chain is moving from the bottom one to the top one, it's being pulled sideways at the same time. When I look from behind the bike, and put a metal ruler along the sprocket, top and bottom jockey wheels, they all seem in a straight line, but it's hard to tell visually. Other times I look at it and I think I can see them out of alignment, but I can't tell if just aligning the hanger better would solve it or I need a new derailleur as well.

I'm still head scratching, because the bike hasn't had any hardship, crash or knock to cause this. I'm pretty sure it wasn't there initially, though...

I guess if the sides of the derailleur are supposed to be completely straight and flat, I could take apart the derailleur and check this with a ruler or similar?

 

[RecordAceFromNew]

Did you try the chain which was not wrongly routed outside the cage for 15 miles? When the chain is off it is worth checking with your fingers that the jockey wheels do spin smooth under load, and there is no unusual play within the rear mech (compare with those on your other bikes), and of course check the top and the bottom jockeys haven't been swapped (top has sideway play), and don't forget to install the chain correctly given it is unidirectional.

If problem remains and shifting itself is not the issue you can leave the gear/chain on the 4th smallest sprocket well alone (here chainline should be close to perfect with either ring) and spin crank from dead slow to normal speed to try to examine really carefully for any unusual contact between parts or anything jumping. If in doubt compare with your other bikes (which presumably run much quieter).

If your other bike has a 9 speed rear mech (whether mtb or not as long as it is Shimano) you can try using its rear mech - the 10 speed chain is a weeny teeny bit narrower internally but shouldn't cause any problem with 9 speed jockeys on a stand.

 

[John the Canuck]

chain too long
mech appears to go waaaay back in video
top jockey wheel bouncing on cog teeth - ?

 

[Custom24]

Did you try the chain which was not wrongly routed outside the cage for 15 miles? When the chain is off it is worth checking with your fingers that the jockey wheels do spin smooth under load, and there is no unusual play within the rear mech (compare with those on your other bikes), and of course check the top and the bottom jockeys haven't been swapped (top has sideway play), and don't forget to install the chain correctly given it is unidirectional.

If problem remains and shifting itself is not the issue you can leave the gear/chain on the 4th smallest sprocket well alone (here chainline should be close to perfect with either ring) and spin crank from dead slow to normal speed to try to examine really carefully for any unusual contact between parts or anything jumping. If in doubt compare with your other bikes (which presumably run much quieter).

If your other bike has a 9 speed rear mech (whether mtb or not as long as it is Shimano) you can try using its rear mech - the 10 speed chain is a weeny teeny bit narrower internally but shouldn't cause any problem with 9 speed jockeys on a stand.

Yes, tried the other chain. No different.

I did not realise the chain was directional, but luckily it is on the right way. The logos should face outwards, right? I think I've never put it on the other way, not sure.

Unfortunately, the other bikes are 7 and 8 speed.

Thanks for the other suggestions. I will give them a go later.

 

[Custom24]

chain too long
mech appears to go waaaay back in video
top jockey wheel bouncing on cog teeth - ?

Chain same length as came with bike when new. Moving/pivoting the rear mech to simulate longer and shorter chain doesn't make any difference to noise. Neither does adjustment of B screw.
You mean "is the top jockey wheel hitting the cog teeth?". No.

 

[John the Canuck]

grasping at straws here

bought a NOS chain
chattering noise
it was hitting the adjacent teeth on either side of the cog it was on... IYSWIM
bought KMC Z7 chain [recommended by Pat]................silence
using digital calipers , it was slightly thinner

 

[JasonHolder]

Cross chaining is something to be avoided really.
Use the bigger half of the rear sprocket on the small chain ring.
And the smaller half of the rear sprocket on the big chain ring.
Let's be a little bit pro shall we.

 

[Custom24]

Cross chaining is something to be avoided really.
Use the bigger half of the rear sprocket on the small chain ring.
And the smaller half of the rear sprocket on the big chain ring.
Let's be a little bit pro shall we.

?

 

[JasonHolder]

Never heard of cross chaining?