I’ve got one of the last US made S Works M4 hardtails that’s in need of a bit of refurbishment, or more specifically a new drive train. I’m so out of date with groupsets etc that I’m struggling to pick out which bits will work.
Firstly its got a square taper bottom bracket which I love but it seems that getting square taper chainsets is rather difficult nowadays. So what are my options? Which is of the current crop of BB designs will a)fit and B) last?
Also I need a rear mech, cassette and chain. I have nine speed LX shifters which I think are still okay.

Middle burn rs7 crank arms if you want to stay with taper
But your frame will take a lot of modern stuff just not bb30 /pf30 chainset a
But even the new xtr 11 speed will fit.

10 speed cassettes will fit a 9 speed hub but will need new matching shifters and mech etc

Yes, you can use the external bottom bracket, just not the press fit BB30 type, and any 8,9 or 10 speed groupset (or 1 speed)

I’m running mine with a XT ht2 chain set and a mix and match of 10 speed components, it’s the one frame I could never bring myself to get rid of!

Same here, that’s why I want refurb it 🙂

Is the back wheel offset the same for 9 and 10 speed?

Yep, exactly the same freehub – as with 8/9 they made the sprockets closer together. Shimano have done the same with 11 speed too, although SRAM is totally different.

Middle burn rs7 crank arms if you want to stay with taper

Still likely to need a new BB though, so a more expensive way to go. I’d fit external as others have mentioned.

As long as one of the external bb alternatives is reliable then I’d go that way although my first square taper one lasted seven years!

Deore external bb have been rubbish for me but hope or gusset ( from ison ) work very well and last a long time

Shimano do not make a xt level taper bb anymore just a un56 which is ok
Phil wood still make nice taper bb as do Royce but lots of money

Praxis external BB are good.

Still have an M2 Stumpie with ST bottom bracket – not sure what I’ll do when it expires..

Could someone possibly advise me if this lot will a)fit my bike and b) work together!

Shimano Deore LX SL-T670 10 Speed Rapidfire Pods
10 Speed Silver

Shimano Dyna-Sys Deore XT 10 Speed Cassette
11-36 Silver

Shimano Deore XT M786 Shadow Plus Rear Derailleur
Long Cage SGS Black

Shimano XTR M980 HollowTech II Bottom Bracket Cups
68/73mm

Shimano SLX M670 HollowTech II Triple Chainset
42/32/24 – 175mm

Shimano XT HG95 SIL-TEC 10 Speed Chain

All of that should be fine (Although the shofters are they LX? Didn’t think they made LX in 10 speed?)

But a full XT Groupset from Ribble, Merlin, or one of the German sites might represent better value

Do you find you need all 3 rings on the front? You could save a lot of money and weight by running a new single ring on a chainset for a nice quiet 1 x 10 setup.

XT 2 x 10 or 3 x 10 chainset with BB (sell the rings) http://www.merlincycles.com/shimano-xt-m780-10-speed-triple-chainset-54992.html
Zee 10sp shifter for rear mech http://www.merlincycles.com/shimano-sl-m640-zee-10-speed-right-hand-gear-lever-59281.html
Zee 10sp FR rear mech http://www.merlincycles.com/shimano-zee-m640-shadow-rear-derailleur-59278.html
Superstar narrow/wide chainring http://www.superstarcomponents.com/en/i-o-chainring-narrow-wide-style.htm
XT 10sp chain and cassette(11-36) http://www.merlincycles.com/shimano-xt-10-speed-cassette-49363.html bundle deal available

Those shifters are from the LX touring group set, I’d get SLX ones.

Hadn’t considered the groupset idea – Merlin have an XT triple for £299 and an SLX triple for £199 which to b fair is around the same price as the bits I picked above.
Cheers re the shifters, I’ll pick the SLX ones.

I’ve got am M5 s-works from the last year before they went to carbon in need over end red. It’s on loan to a mate until my kids are big enough to ride it! After that it’ll go on the wall somewhere..,

They did both for a while. The 2006 M5 was a completely new design, alongside the carbon one.

Final question! Will the bottom bracket need facing?

Nah, I’d not worry about it.

So I’ve been and bought a Deore XT ten speed triple group set from Chain Reaction for only £150 which I thought was rather good. Fitting day will this Saturday. Anything I need to know about fitting the Hollowtech 2 bottom bracket as I’ve never done that kind before?

You will need to use 2 or 3 of the plastic spacers between BB and frame. 2 one side and 1 the other. Then just screw the BB shells into the frame. Then fit the cranks.

The bottom bracket will need a special c spanner to tighten up, your local bike shop might do it while you wait if you take them a box of Jaffa cakes and go at a quiet time.

You will need to use 2 or 3 of the plastic spacers between BB and frame. 2 one side and 1 the other. Then just screw the BB shells into the frame. Then fit the cranks.

2 on the drive side one on the NDS if it’s a 68mm BB shell, one on the drive side if it’s 73mm.

Thanks ever so much for all the help. As luck would have it I’ve got the correct c spanner – I bought it by mistake quite a few years ago now and kept it just in case.

Pictures when you’re done!

You may have a tough time getting a square taper BB out of the frame if it’s been in there for a few years…

The external type BB are much better. The XT BB you’ve got may only last a year though, replace it with hope when the time comes (mine has been on four bikes, and is 7 years old now, still going strong!!).

It has been in there a while but i did change it about four or five years ago and I’m fairly sure I was liberal with the coppa slip when I did it!
I’m amazed how light the new BB is though.

That’s because it has no axle, that’s the heavy bit!

I realised that I was making a cuppa!