34/42ish Double Chainset

Berk Bonebonce
Berk Bonebonce Posts: 1,245
edited September 2010 in Road buying advice
Anyone using an unconventional chainset, like a 34 inner and 42 outer? If so, can you recommend a suitable chainset.

I guess it would need a compact-style front mech mounted suitably low enough on the seat tube whilst still allowing it to function without fouling the chainstay.


  • Okay ... I'll talk to myself.

    Just how often do the vast majority of cyclist actually use their big ring? I mean, I used my 53 ring when I was in my twenties and when I was fit, but not now. In fact, I am sick of the sight of my 53 ring. Reminds me of when I was young and carefree. I dislike my 53 ring so much, I even refuse to put the chain on it on those long descents.

    So, big ring ... be gone.

    I'm going back to my schoolboy set-up of 42/34. Get me up any hill, that.

    Can't understand why so many bikes these days come with impossibly big outer chainrings.
  • I mostly ride a 46/36 by 11-25, 7 speed groupset
    For me the gearing is perfect for riding at 15-18 mph average, mostly on the 46 ring.
    A 46x11 gear is virtually the same as a 50x12 gear (inches) which is the biggest gear on most compact chainsets.
    My "average" gear is around 70 inches. With a 46 "big ring" I ride with the chainline more central/straight on the rear cassette. When I ride a different bike with a 52 ring I find that I ride more with the chain bent over to the inside of the cassettte with a more bent chainline. This just creates more wear on the chain and drivetrain.

    With a 46 outer ring you can just get away with using a braze on mech on the lowest setting on most frames. Band on aren't an issue as you can stick them as low as needed anyway.

    You can buy stock 36/46 chainsets, they're usually labelled as cyclocross chainsets.
    Failing that you could just put custom rings on your crankset to suit your riding style. This may mean that you need to adjust your chain length but it's not that difficult to do to have an ideal gearing set up.
  • rake
    rake Posts: 3,204
    jazzkailey wrote:
    I mostly ride a 46/36 by 11-25, 7 speed groupset

    A 46x11 gear is virtually the same as a 50x12 gear (inches) which is the biggest gear on most compact chainsets.
    :? why not ride a compact then? :? you must have large steps between gears.
  • Monty Dog
    Monty Dog Posts: 20,614
    Whilst it is perfectly possible to run a 34/42 chainset by adapting a compact chainset, you may have difficultly finding an outer chainring in that size - modern chainrings have ramps and pins to aid the shift. I run a 34/46 for cyclocross - occasionally it gets a run on the road and only on fast descents does it make any difference.
    Make mine an Italian, with Campagnolo on the side..
  • I love my 39/53, wouldn't be without the 53 and 39 coupled with my 23 at the back is the lowest I need and yes I've got hills, live right next door to snowdonia,

    What your asking about as others have suggested sounds like a cyclocross chainset or even a double mountain bike chainset (I know midddleburn made some), they do list 42 on there website, although not sure if outer or not.
  • anto164
    anto164 Posts: 3,500
    I have a triple, and use the big ring (50t) about 80pc of the time.. Was about 60pc of my ride today done in the big ring because there was a bloody strong headwind.. :/ Where i cruise at 20mph, i was struggling to keep 11mph today.

    As for mountain bike rings, they've got the same BCD as compact cranks, and there are lots to choose from.
  • I've tracked down a Stronglight Impact 34/42. It's got pins and is 10 speed compatabile and is a road chainset.

    I have a couple of choices in the front mech department, but it will be interesting to see how well I can get these schoolboy ratios working.

    Frames with braze on front mech fixings are limited in respect of chainring size, in as much as they outer one cannot bee too small. With a band you can get the front mech lower down the seat tube.
  • rake
    rake Posts: 3,204
    have you thought about a junior cassette with 13t top sprocket.