[Closed] Road Drivetrain on a MTB

can i ask why?

If you're using shimano stuff you'll only need the chainset, front mech to match, and a really the rear mech and cassette would transfer over, if you were being tight about it, the MTB shifters would be fine as well

I kind of did the opposite to this with my Surly Cross Check. I fitted a full MTB drive train complete with triple chainset. I even managed to get down tube shifters to work OK with a Deore rear mech and an LX front. As long as you are using Shimano kit you should find that you don't have any shifter compatibility problems (if it says it is 'Mega 9' compatible it should just be a case of mix and match).

The BB length could be another issue though. I found on the Cross Check that the chain line was all wrong and the only way around it was to miss off a spacer and the plastic sleeve that fits inside the BB shell as the Surly is too narrow compared to the sort of frame the chainset and BB was designed for. Not sure how this may affect you as you'll be using road kit on an MTB frame but it might require a bit of head scratching to sort out.

All fine. As you mentioned, chainring clearance is the biggest issue.

Not sure why you'd bother though. If you want higher gearing, just fit bigger chainrings.

The main reason being that I currently only have 1 ring up front (and only 1 shifter!).

Therefore if I get a bigger ring to increase top end speed I'll lose my easier gears.

The drivetrain is a few years old so needs replacing anyway so figured it wouldn't cost that much more to replace it with road stuff.

Good to hear the cassette and mech should be ok.

bb shell would def be an issue i would have thought, know someone who fitted road chainset to a mtb but as said above needed to skip spacers

Still doesn't quite compute... why not fit eg an [url= http://www.chainreactioncycles.com/Models.aspx?PartnerID=79&ModelID=23102 ]XT M771[/url] chainset with a 48-tooth big ring...?

Mainly use on the road so why not replace with road stuff?

I looked at doing this and there was an issue with fitting a chainset. IIRC it was the the "Q factor" which meant that there would be no clearance between the chainrings and chainstays.

My LBS recommended the 48t XT chainset as suggested by elliptic. Alternatively just fit a bigger chainring

I ran a 48t chain ring up front with 32-11 cassette on the back, gave me all the gears I wanted to get around Edinburgh (commute was loanhead to city centre, so there were some hills to be passed).

Yeah think I too will have issues with clearance of stays 🙁

So you do mainly road miles but have a MTB? And now you want to change the MTB drivetrain to a road drivetrain...on your MTB...because you do mostly road miles?

No problem with that, there have been a few magazine articles about doing that to get 10-spd on the MTB - it's possible but depending on what you are after i.e. 10-spd it won't be cheap - but it is possible.

If you need a double (or triple) ring up front then yes a new chainset will be required...front mech shouldn't need to be changed if you have one already. Rear mech is likely to work as well if all Shimano kit so that would just leave your shifters and cassette (which would both likely work)...so not sure if you need to go the whole hog. A road cassette will be smaller so you might find the easier gears aren't as easy as the ones you have now...and if you go back to a MTB cassette, the road rear mech may not handle the larger cogs.

I'd have a think about what you want to do and decide then what kit actually needs changing...sounds to me as though all you really need is a new chainset up front - Middelburn do a double ring job that looks rather tidy.

I've done this on one of my old bikes, an old 16in alu GT, it's quite simple...

48/36 chain rings up front. chainrings bolt straight on to XT cranks -Works fine with deore front mech & shifters, wind the screw in on the mech so it doesn't go over to granny position.
23 or 25-13 rear cassette and shimano 105 short cage rear mech. Works fine with mtb shifters.

fit some flat bars if you want and some skinny tyres. I ran Spesh Nimbus on mine, got some Panaracer Rimbos which work really well too.

Job done.

I've done the same on a Giant Xtc but haven't bothered with the larger chain rings this time so I can use it off road too by just swapping the tyres. Riding off road with 48/36 up front is doable but it's not as nice as the usual 44/32/22. The 23-13 block was also a bit too close, 25-13 works well enough on and off road.

Kev

have a look at chainsets aimed at tourers and triple chainsets, they often use the old 5-arm compact chainrings (like old MTB's) so its easy enough to pick up rings from right down to 24t, right upto 53t.

More usefully it means you can go 2x9 with sensible ratio's. 28t (granny gear on a tourer) and 38t (middle ring from a tripple).

So what your after is turning a 1x9 into a 2x9 high ratio Manly Grrr machine…

What is your current front ring and Cassette setup? 11-32 cassette with a 32 or 36t Chain ring Perchance?

Ok, OK you've convinced me to look at sticking with mtb stuff (that and the fact that the tiagra chainset I was looking at is silver and the rest of the bike is all black so would look stupid!)