Never built anything that’s not an out+out MTB before… this going into mixed road/off-road commute duty next month. Started out with drops but changed my mind. All sorted anyway apart from what drive-train to run!

700C wheels, 35mm CX tyres.

Kona Dew by simonholehan, on Flickr

I have at my disposal – 1 pr LX 9spd shifters, its a given that its gonna be 9spd. M760 Rear Der. and a selection of fronts to hand.
I have a spare set of Deore HT2 cranks, no BB or rings.

I suspect that MTB 22/32/44 gearing will be too low?

I’d also need to purchase C-rings and a BB.

I also suspect a single 32 will also be too low and too limited given this bike should be able to lick along on the road a fair bit faster than a 6″ travel MTB!

In which case – If I purchase say a compact double, 39/50, will that leave it geared too high for climbing off road? And can I fudge it to work with a MTB shifter(got road and MTB front mechs spare)?

Final alternative, what about something like a Sora Triple? (There not that as I’d predicted though as you need a BB with the road versions)

Never ever had problems speccing a regular mountain bike, I’ve built stakcs of them, but as this style of bike is new to me I don’t want to muck it up by gearing too low/high, as its being built on a strict budget!

I would stick with MTB rings tbh
I can sort you out a cheap 44 9 speed and BB
It depends how hilly it is near you tbh and what you mean by offroad.
Quote hilly then triple IMHO not very double and a compact may do.
A MTB rear cassette tends to give a lower ratio anyway
Can you use a chainring from another bike to see what gearing seems right before buying?

I think I’d go for an MTB triple chainset and a 11 or 12-28 cassette. You should have plenty of coverage I would think.

Best bet would be to go for an MTB triple but opt for the 48,36,26T versions – if you go for a road triple the chainline will be wrong & you will need to use a road front mech which then won’t work with an MTB shifter (only the rear ones are mix & match) something like these?
http://www.rosebikes.co.uk/article/shimano-deore-crankset-hollowtech-ii-fc-m591-s/aid:368092

edit – 26T

I think your probably right – I wasnt fully au-fait with the compatibility ‘twixt road+MTB front mechs etc, just that there might be some – the difference in chainline I did not know.

I just found this though which seems reasonable seeing as I will need a cassette and a chain anyway, think I’ll go for it – Touring ratio an Deore HG53 bits are ideal for just grinding away on a commuter.

http://www.woollyhatshop.com/Chains-Cassettes-Crank-Deals/Shimano-Deore-Crank-Bundle-175mm-48T-Black-Chain-11/32-Cassette/prod_4431.html

Ta for the advice.

If you are mainly using it for road I would go for a closer ratio cassette 11-26 or 28 rather than the 11-32 but in the end it depends what sort of off road riding you are planning to do

You may well be right, but the 11-32 can go on the MTB if I find it too widespread and I’ll swap in a tiagra 11-26 or something.

Interested to know how I get on, looking forward to it.

That looks ace Si!