Replacing old 8spd XT with XT M870

porschenut911 · Apr 30, 2017

My current bike is 8speed with Mid 90's XTR mechs and ti cassette, STX shifter pods and middleburn Cranks with pace rings.

The shifting isn't great, especially the front, and the rear is beginning to show wear. Looking online, there are good deals on 10speed XT M870 components - I used to love the more boutique components like the Cranks and rings, but to be honest, nowadays I just want perfect shifting without the exclusivity - I am thinking of replacing the whole lot with brand new XT870- mechs, cassette, Cranks chain and shifters. I assume this would solve my shifting and drivetrain woes in one hit?

legrandefromage · Apr 30, 2017

Just a refresh of cables and cassette / chain would probably be better? Flush and lube the mechs/ shifters first? Even just changing to a chain with different beveling can help with the shifting

You may have missmatched the front mech with the shifter too which will mean that it would never been satisfactory from new - Shimano front ends are fickle if you dont match up cable pull,reach and leverage. STX and XTR M900 span two different eras - 110bcd and 'compact' 94bcd - the mechs had different pulls/ leverage/ reach/ accent/ reverse parking skills/ Nectar points etx etc

Just bear in mind you may be changing pretty much like for like but with less tolerance - narrower chain, closer spacing etc. Chainline can be an arse on older wider frames with thick stays when trying to fit new, heck it was bad enough the first time round for some!

Go for it but just do it well otherwise you may end up just swapping one headache for another.

Splatter Paint · Apr 30, 2017

Re:

Yep - but it won't look retro!

A complete strip-down and de-grease plus new cables may help things no end on the existing set-up. You could buy a modern 8 speed cassette for under a tenner: http://www.chainreactioncycles.com/shim ... -prod68154 and then some rings for about £35 from Spa: http://www.spacycles.co.uk/m2b0s149p0/P ... tronglight with a new chain for another tenner you could keep it all looking largely retro and cheap too.

SP

legrandefromage · Apr 30, 2017

Stuff 'retro' - its more coincidence than anything else that all my stuff is old 8spd as it just works, then carries on working, plus it works a little bit more. Cassettes are cheap, chains are cheap. Rings not so but then theres lots of BCD to choose from and road going 110bcd a few years ago helps too.

Thinking further - if your XTR mech is M950 series, the grease in the pivot bolt can dry out. It very easy to rebuild, I've just done this for a neighbour as his was almost seized and was causing mayhem, but not Mountain Mayhem. *and check the jockey wheels too!

porschenut911 · Apr 30, 2017

legrandefromage":114k1ynn said:
Just a refresh of cables and cassette / chain would probably be better? Flush and lube the mechs/ shifters first? Even just changing to a chain with different beveling can help with the shifting

You may have missmatched the front mech with the shifter too which will mean that it would never been satisfactory from new - Shimano front ends are fickle if you dont match up cable pull,reach and leverage. STX and XTR M900 span two different eras - 110bcd and 'compact' 94bcd - the mechs had different pulls/ leverage/ reach/ accent/ reverse parking skills/ Nectar points etx etc

Just bear in mind you may be changing pretty much like for like but with less tolerance - narrower chain, closer spacing etc. Chainline can be an arse on older wider frames with thick stays when trying to fit new, heck it was bad enough the first time round for some!

Go for it but just do it well otherwise you may end up just swapping one headache for another.

I'm sure the mismatch is part of the problem - it's never been great, xtr m950 rear with Stx shifters and compact ti cassette. Front is non compact 110 bcd pace rings with no shift ramps whatsoever. Just looked and jockeys are worn, cassette is worn too. My other halfs bike with five year old deore is fantastic in comparison.

It will be a wholesale change, everything new and XT 870. (I presume 10spd will fit my disc hope xc hubs). It's a 2001 pace with asymmetric rear stay so clearance would hope to be good.
Is there a chance that hollowtech2 bob may cut down on the usual pace BB creaking

And yes I'm not at all bothered about retro, I just want it to work, then I may use my bike more than once a year!!

legrandefromage · Apr 30, 2017

Check the Hope freehub body: Ti or Aluminium will need a cassette with an aluminium spider otherwise you can really damage the freehub body. Other than that theres not much to worry about. The BB will have rings to space the chainset and set the chainline.

However, new jockey wheels, cassette and chain will probably do the same thing!

Replacing old 8spd XT with XT M870

porschenut911

Retro Guru

legrandefromage

Splatter Paint

legrandefromage

porschenut911

Retro Guru

legrandefromage

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