Lowering gearing on Cannondale Synapse - GX-1000?

I'm looking to lower the gearing on my 2013 Cannondale Synapse. It's got a FSA 50/34 compact / 68mm BB30 bottom bracket combo on the front (with a Shimano Tiagra shifter) and a 10-speed 12-30 Shimano Tiagra cassette on the back. This is fine on the flat but on steeper hills results in me dropping below my natural rhythm and grinding away, not good for my 58 year old knees (as I've just confirmed after a week cycling in The Yorkshire Dales and Lake District).

My friend has a similar bike and picked up a MTB double crankset on eBay that had a similar effect, albeit he had to fit a mounting bracket to lower his front mech to work with the smaller chain rings. He found it much easier going up the hills (helped no doubt by being fitter, but the gearing played a part too).

I don't think my FSA crank will accept smaller chainrings, so I've been looking online for a compact double crank compatible with BB30 and unfortunately there are few with smaller chainrings. One option is SRAM's GX-1000 2x10, which is a few years old but claims BB30 compatibility, comes with 38/24 or 36/22 rings (the latter may be too low) and isn't too expensive.

If anyone has experience with the GX-1000 - especially fitting one to a road 68mm BB30 (I can't find whether the GX has a 68mm or a 73mm BB length) and / or using it with a Shimano front mech - I'd love to hear how it was.

Additionally, if you have any other advice on lowering my Synapse gearing (other than 'pedal harder' and the like - I'm 58, thanks!) I'd appreciate it.


  • lesfirth
    lesfirth Posts: 1,382
    Ok ,I am just about old enough to be your Dad! My solution and not expensive, would be to use your existing chainset, fit a Shimano 9speed mountain bike rear mech and a cassette with a 36t big sprocket e.g. CS-HG50. To me the whole point of climbing the hills is to fly down again. The 11T cog means you can fly.
    A guy on here recently said hills were for free wheeling down. When you think that you are really old. I hope I never get that old!
  • paulbox
    paulbox Posts: 1,203
    Wiggle sell a Tiara 10 speed 11-34 cassette for £27.99

    Just make sure that your rear mech will handle it.

    XC: Giant Anthem X
    Fun: Yeti SB66
    Road: Litespeed C1, Cannondale Supersix Evo, Cervelo R5
    Trainer: Bianchi via Nirone
    Hack: GT hardtail with Schwalbe City Jets
  • dj58
    dj58 Posts: 2,221
    You could also use a Wolftooth roadlink (standard), to reposition your RD to use either a 11-34 or 11-36 10 speed Shimano cassette plus longer chain.