Cycling UK Forum

Nothing beats that silky smooth gear change offered by modern derailleur systems.

Nothing beats having a chain in perfect harmony with the cassette.

However, when these go out-of-sync - its horrible.

Currently the movement of the chain on the sprockets is - what only can be described as - very rough and changing gears is far from silky.

I know there are upper and lower limit screws and an adjuster just above derailleur.

But where do I even start? Any tips would be great?

(It's a Shimano Deore btw)

I suggest starting with the relevant sections of the Sheldon Brown and Park Tools Repair Help sites:
https://sheldonbrown.com/derailer-adjustment.html
https://www.parktool.com/blog/repair-he ... adjustment

But don't assume that the problem lies in the changer: check the cables, the chain, the chainwheels and the sprockets.

Hope it's all smooth again soon.

Jonathan

Do not adjust the limit screws to start with!!! Chances are they are OK.

Put the chain on the front in the biggest chainring, and on the rear on the 3rd sprocket from the outside (regardless of the number of sprockets on the cassette) - turn the pedals at a steady speed (ideally with bike in a stand - or off the ground at the least) - turn the adjuster on the cable at the derailleur in VERY SMALL increments . . . try either way until the chain/sprocket interface is running smoothly. That's very probably all you need to do.

What you can also do is:
1 Rear derailleur on biggest chainring and smallest sprocket - check derailleur is hanging vertically and the chain is centred
2 Do the opposite test - smallest chainring and biggest rear sprocket - ditto check

If the derailleur isn't vertical you my have a bent mech hanger - or if they are vertical but not aligned then you might need to adjust the limit screws, again with very small increments.

As suggest the Park Tool technical stuff - especially the YT videos - is pretty good. Just remember - SMALL adjustments!!

ok thanks jdsk and robgul.

The adjuster on the deraileur - what does that actually adjust?

jacobean wrote: ↑7 Sep 2021, 8:17pmThe adjuster on the deraileur - what does that actually adjust?

Is that the B screw or the barrel adjuster on the cable outer at a stop? Or something else?

Jonathan

If you haven't already got one, I thoroughly recommend getting a stand - almost impossible to adjust disraeli gears without one...

simonineaston wrote: ↑7 Sep 2021, 8:25pm If you haven't already got one, I thoroughly recommend getting a stand - almost impossible to adjust disraeli gears without one...

Me too. And in that thread about favourite tools IIRC I nominated a stand and a web browser,

Jonathan

And don't even bother starting if the cable outers are more than a couple of years old and / or unlubricated. Sticky cabling is generally at the heart of the problem.

>>Is that the B screw or the barrel adjuster on the cable outer at a stop? Or something else?

I mean the adjusting barrel.

I have a stand but it's terrible because it holds the bike up by the frame - meaning you have to take one of the pedals off to hand turn the wheel. Or maybe I'm just doing it wrong.

btw, the bike is only 2015

jacobean wrote: ↑7 Sep 2021, 9:05pmI have a stand but it's terrible because it holds the bike up by the frame - meaning you have to take one of the pedals off to hand turn the wheel. Or maybe I'm just doing it wrong.

Can you add a photo of it with the bike on? Then we'll tell you... : - )

Jonathan

Jdsk wrote: ↑7 Sep 2021, 9:10pm

jacobean wrote: ↑7 Sep 2021, 9:05pmI have a stand but it's terrible because it holds the bike up by the frame - meaning you have to take one of the pedals off to hand turn the wheel. Or maybe I'm just doing it wrong.

Can you add a photo of it with the bike on? Then we'll tell you... : - )

Jonathan

Well, its like a single bike version of this.

https://www.bike24.com/p25884.html

jacobean wrote: ↑7 Sep 2021, 9:49pm

Jdsk wrote: ↑7 Sep 2021, 9:10pm

jacobean wrote: ↑7 Sep 2021, 9:05pmI have a stand but it's terrible because it holds the bike up by the frame - meaning you have to take one of the pedals off to hand turn the wheel. Or maybe I'm just doing it wrong.

Can you add a photo of it with the bike on? Then we'll tell you... : - )

Jonathan

Well, its like a single bike version of this.

https://www.bike24.com/p25884.html

Thats a storage/display stand not a work stand!

this is a workstand https://www.bike24.com/p2164238.html

Thanks Foxy .

I got it free from a friend who was moving abroad. Now I know why I got it free...

The limit stops are mainly for friction shifters & their function now is merely a safety thing to stop the chain accidently flying off the end of the block.
Index gears should shift safely onto the extreme gears without needing the stops. These stops therefore have no effect on the quality of the gear change.

Assuming there is no damage to the derailleur & it was working well before, bad changing can be a result of:

Alignment of the derailleur to the sprockets has changed needing adjustment of the barrel adjuster (but this is unlikely to have come unadjusted without a reason see below)

Worn or frayed cables which can easily be hidden from view.

A worn chain and block.

Worn out jockey wheels that can be rocked from side to side especially the top one.

Derailleurs with a pulley wheel for the cable run can sometimes have an obstruction in the pully groove that upsets alignment (MTB bikes usually)

Correct all of those & there isn't a lot else can stop it changing properly.

jacobean wrote: ↑7 Sep 2021, 7:18pm Nothing beats that silky smooth gear change offered by modern derailleur systems.

Nothing beats having a chain in perfect harmony with the cassette.

However, when these go out-of-sync - its horrible.

Currently the movement of the chain on the sprockets is - what only can be described as - very rough and changing gears is far from silky.

I know there are upper and lower limit screws and an adjuster just above derailleur.

But where do I even start? Any tips would be great?

(It's a Shimano Deore btw)

Aside from the first two statements (off hand I can think of about fifty things all of which are better than a smoothly operating bicycle) some more information may help. Do you have a single chainring or a chainset? When you say the gears feel rough, is it only when you select a different gear or is it when you are simply pedalling along? If you are having difficulty selecting gears is it the rear which is causing issues or the front. Does when you change gear is the gearing change not happening, or happening slower or when you're not expecting it, or making strange noises?