Inner chainwheel removal on FC-M5909

[jimlews]

Simple question:
With this triple chainset and it's ilk, the right hand crank/spider seems to be integral with the bottom bracket axle,
Is it necessary to remove the whole assembly when changing the inner chainring ?

[Jdsk]

Have you already got the Shimano diagram and guide?

Jonathan

[jimlews]

Have you already got the Shimano diagram and guide?

Jonathan

No.
This is really a question about this type of chainset.
I'm thinking of a potential touring scenario where chain has become tangled or trapped behind the inner C/W. (It can happen)
With a square taper C/S, if the spider needs to be removed, it is a simple operation, especially if a "one key release" has been installed.
So it is a question about whether this type of chainset is suitable for an expedition touring bike.

[Eyebrox]

You would release the chain by slackening off the left hand crank bolts and tapping the axle a few mms through the bottom bracket. Just do the reverse once the chain is freed and placed on one of the chainrings. Not much more than releasing and tightening a crank bolt at the other end.

[colin54]

FC-M590-9 speed presumably ?
https://si.shimano.com/en/pdfs/ev/FC-M5 ... -2926B.pdf
I remembered I'd got one of these that I took off a bike, the little 'safety-keeper' on one of the bolts on the non-drive side crank is something to be aware of, it needs to be flipped after loosening the two allen screws and before pushing the crank spindle across (item 4 in the link) There's a little plastic tool required to enable removal of crank and adjust the bearing on reassembly (all in the picture if you zoom in ).
My only experience of this type of chainset was taking the one pictured off, and that was a while ago.

Eyebrox's answer above seems about right to me, you'd only need a little clearance to free a jammed chain.
Edit, In answer to your first post I think you would have to remove the crankset from the frame to change the inner ring, but I think you're almost there once you remove the non-drive side crank anyway, from memory it's all pretty straightforward.
and... there's a good account of the adjusting procedure in this tech doc as well.
https://si.shimano.com/en/pdfs/si/0093A ... 02-ENG.pdf

[jimlews]

Thanks fellas,
Really interesting and informative replies.

I think in this case, I'll not upgrade.

[Brucey]

when shimano launched HT2 I wasn't exactly holding my breath; after all, the predecessor (octalink) had been distinctly underwhelming. However, in hindsight, HT2 is a good piece of design. I've gone on record before as saying that is pretty much how I would have done it, and I stand by that. It is not that I can't think of ways to make it better, it is that they have got the fundamentals about right. So what would I change? In no particular order;

1) upgrade the bearings to DFC spec. (you need to obtain a load of 3.5mm balls for this).
2) eliminate the trapped volume; a pinprick in the centre sleeve is enough.
3) improve the lubrication arrangements. A suitable port(*) in the BB shell would allow both cleaning and relubrication to be carried out in situ.
4) improve the seals
5) improve the design of the 'top hats'.
6) routinely use bearing fit compound (or similar) between the 'top hats' and the spindle.

(*) for a standardised port here I propose that an M5 tapped hole is made in the BB shell, 34mm from the RH side and at least 1/3 of the way round from the bottom. This would normally be blocked using an M5 screw (which could be metal or plastic) ~8mm original threaded length but sharpened to a point, so the end of the screw pokes into the BB shell and makes a rudimentary seal on a ~2mm drilling in the BB sleeve. This port would allow both cleaning solvent to be introduced, as well as SBG (solvent-borne grease). This would be conveniently carried out using pressurised containers (eg. Aerosols).