Cycling UK Forum

Yes all gears work, plenty of clearance between chainstay and cage in granny ring.

Rings are 48/36/26 I use M591 in winter for the extra mudguard clearance and M590 when mudguards come off

M591 in middle ring 2mm over big ring

M591 in big ring

M590 in middle ring 1.5mm over big ring

M590 in big ring

Brucey wrote:I use a piece of software called 'MB-ruler' for such tasks. Seems to work OK.

My guess is that your FD that doesn't match the curve of the chainrings is meant for smaller chainrings than those you have

cheers

The one that doesn't match is Deore LX M581A 44-48t, the one that does is Deore M591 44-48t, my large chainring is 48t.

I thought this might help anyone who wanted to measure the chainstay angle of their bike.

Using a graphics editor called GIMP and a picture of your bike you can measure the chainstay angle by selecting the measure tool, draw a line from rear axle to bottom bracket, then hold SHIFT and draw a second line from the bottom bracket to seat collar along the middle of the seat tube like illustrated below


Here is a 66-69 degree front mech on a 65 degree chainstay angle frame


Here is a 63-66 front mech on the same frame, see how the inner cage follows the curve of the middle ring.

The exploded view pdf shows compatibility with t4060 and m430, which means m390, m530 and m590 rings should fit too.

Sweep wrote:

pwu wrote:
Yes I physically tried it, the shoulders of the right crank that the rings sit on are compatible. The spec sheets are usually limited to the year of print, M530 chainrings should also fit.

Have you concidered this? https://bike.shimano.com/en-EU/product/ ... 300-3.html

Thanks - will bear that in mind.

On the fraught question of bits compatibility/matching, if Shimano techdocs are somewhat compromised as you say, is SJS the best source of info?

Re that last suggestion, thanks, but that's external bearings isn't it?

And have decided to get all my bikes onto square taper if possible.

Could live with Octalink if chainrings match some of my other bikes.

SJS is probably a better source.

Square taper can result in chainring wobble so when chainreaction were selling the M430-8 for £11 I bought one and a ES300 bottom bracket (reused the 48/36/26 M391 rings, didn't use the 44/32/22 it came with) and it was smoother and stiffer with no wobble. I liked octalink. I saw the M590 for £39 with 10% off code and top cashback it was £35 and quality 9 speed stuff is disappearing so I bought it.

If you pry off the 'do not disassemble' caps and fill the bearings with grease (they come with hardly any grease from the factory, I used TF2 red grease) they should be fine. I used a topeak beam style torque wrench to tighten the preload cap to just under 1nm and the bolts to 12nm it spins about 5 revolutions by hand unlike some videos on youtube where people overtightened the preload cap which kills the ungreased bearings.

https://photos.app.goo.gl/UqWuEAV84RScFnQi7
https://photos.app.goo.gl/5W1nPgzJuxirPMCY8

Here are some pictures of the m430 rings on the M590
https://photos.app.goo.gl/ZRkFHr3yJYVPY9iE6
https://photos.app.goo.gl/kgtKA6MSzUeYoenp8

Sweep wrote:

pwu wrote:I have M391, M391-8, M430-8 and M590 and the rings are interchangeable. The middle rings are identical deore quality. Inner rings on square taper and octalink have a little plastic removable guard to prevent the chain getting stuck in the bottom bracket.

Thank you pwu - this is useful info.

Very - as a quick search hasn't turned up too many 391 spares - though the 22T seems easier to find.

er, edit - are you sure?

Or is chiselling involved?

For found this:

https://www.rosebikes.co.uk/shimano-deo ... _size=22+t.

For the 590. At the bottom it has an extensive list of what it is compatible with but doesn't mention the 391.

Yes I physically tried it, the shoulders of the right crank that the rings sit on are compatible. The spec sheets are usually limited to the year of print, M530 chainrings should also fit.

Have you concidered this? https://bike.shimano.com/en-EU/product/ ... 300-3.html

I have M391, M391-8, M430-8 and M590 and the rings are interchangeable. The middle rings are identical deore quality. Inner rings on square taper and octalink have a little plastic removable guard to prevent the chain getting stuck in the bottom bracket.

Here are some weights of rings:

22t = 43g
32t = 59g (Never used but heard its weak)
44t = 185g
26t = 63g
36t = 97g
48t steel = 234g
48t alu = 98g