thoughts on road STIs, road front mech, MTB chainset

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Fettling my latest build at the moment, a Planet X Uncle John CX frame... with wheels yet to arrive I've put together a few bits & pieces - do you guys think this drivetrain set up will work ok?

  • Ultegra ST-6510 STIs (9 speed)
    105 double front mech (FD-5600)
    cheap s/taper Acera compact MTB cranks with inner removed and running 9 speed 32/44 rings
    long cage XT RD-M750 rear mech
    11-32 HG50 9 speed cassette
The LH STI has five positions which is going to be helpful, but I'm thinking the front mech will struggle to push out far enough to run smoothly in the higher gear while on the 44 ring, and I'm going to need the shortest BB possible.
 
Front mech and shifters will work together fine.

Chainset with front mech - may give some issues but probably OK. Try it.
 
I run an Ultegra front mech and a long cage XTR rear. Miidleburn duo on the front with, I think something like 29/44 chain rings. I've got a pretty big range on the cassette as well!

Generally works OK despite the odd mix!
 
CAS":2ijbe07u said:
I run an Ultegra front mech and a long cage XTR rear. Miidleburn duo on the front with, I think something like 29/44 chain rings. I've got a pretty big range on the cassette as well!

Generally works OK despite the odd mix!

Cheers CAS.. is that a compact crankset? How long is your BB? Al :)
 
Oh.. hard questions ....I'll hang my head and confess that I'm not sure what a compact crankset is. BB was fitted by the LBS as it was a new frame and the threads needed a bit of cleaning out so I fondly imagine it's whatever the Middleburn website recommended! Not much help really - that's women for you!
 
CAS":1ktsni0b said:
Oh.. hard questions ....I'll hang my head and confess that I'm not sure what a compact crankset is. BB was fitted by the LBS as it was a new frame and the threads needed a bit of cleaning out so I fondly imagine it's whatever the Middleburn website recommended! Not much help really - that's women for you!

no I'm new to the compact thing too... I think it's just the gaps between the chainring bolt diameter holes are smaller - enabling one to use smaller rings :D
 
Road mechs run fine with compact cranks - I run a Campag Record double with a 42/32/22 setup.

Personally I'd go for a Campag 10 road lever with Shimano 8 mech and cassette. Completely coincidentally, Campag 10 pulls exactly the same cable per click as Shimano 8.
 
Ive got this feeling guys, that bike frames are designed around the components, so its unlikely that it would work better with non standard kit.

however, Im not sure if this is true as where would off the shelf frames stand?

there must be a way of checking the tradjectory of the front chainset to the rear?
 
I've swapped the cranks for compact road double now, which has brought the rings inwards quite a lot... no problems as yet :D
 
The Acera cranks will weigh a bomb, so if weights a concern...?

Your probably better off with a road compact 34/50 like Tiagra (with outboard bearings) or the square taper Stronglight Impact.
 

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