Gear Ratio Change

robtom Posts: 8
edited May 2014 in Workshop
My 2014 Cannondale Synapse 105 disc has a compact 50 34 matched to a 12 - 30 cassette. This is fine for general roadwork, however, as a 55+ year old recreational cyclist, this doesn't give me a low enough ratio for the persistently hilly roads and the more challenging climbs on some back roads in N.Wales. What is the cheapest way to convert or achieve a ratio of less than 1:1 e.g. my other bike, a Cube Nature Pro, has a 26 small chainring to a 32 on the cassette and this lets me climb anything. For example, could I simply try and fit a triple chainring ...presumably this would entail changing or modifying the front deraullier? Is there a 10 speed cassette with a megarange cog e.g. a 32 or 34 "granny" gear?


  • dj58
    dj58 Posts: 2,221
    The answer is in this thread:

    If you wanted to fit a triple crankset you would have to change the FD for a triple compatible, the LH shifter and possibly the BB, not cheap.
  • robtom
    robtom Posts: 8
    Pushed myself over a 19 mile hilly back road route this evening and the current Cannondle Synapse set up got me through it OK, but just not as comfortably as my 2nd bike, a Cube Nature Pro, would have done. There is no doubt that, generally, the Cannondale is quicker, however, given the ~2.5 Kg weight difference, and the advantages the Cube has in carrying extra gear, it's greater feeling of safety from much better hydraulic disc brakes, there is very little in it in terms of performance and average speed over a 20 mile mixed back road route. I think that I've learned that, despite the bike shop hype, there are some bikes better suited for certain type of routes and riding styles and a so called compromise bike has it's limitations depending upon the routes that you are likely to face where you live ..still, the Cannondale was comfortably averaging 22/23 mph on slightly undulating road stretches and it certainly accelerates faster short, I think that, given the probable expensive modification, I will learn to live with it and it's riding charecteristics.
  • dj58
    dj58 Posts: 2,221
    Rob, another option to consider if you still want a lower bottom gear is an MTB cassette and a GS medium cage derailleur, have a look at this thread: viewtopic.php?f=40042&t=12969018
  • keef66
    keef66 Posts: 13,123
    Well I'm a recreational cyclist coming up to being 57, and living in gently undulating Suffolk / Cambs. When I bought my first road bike for my 50th birthday I'd just had knee surgery so I specced a 105 triple chainset with a 12-25 cassette, thinking the 30t chainring would allow me to spin up the hills while the 12-25 would still give me fairly close ratios. It worked out pretty much as planned; now the knees are OK and I spend 90% of my time in the middle 39t chainring, but it's nice to know I have the others when required.

    If I lived in Wales I'd definitely have a triple, and probably a bigger cassette. Not a cheap upgrade though if you currently have a double chainset since you'd need crankset, front mech and new LH shifter at the very least. MTB cassette and longer rear mech are the cheaper option, frequently supplied on touring bikes, but you do have some bigger gaps in the cassette as a result.

    Last year I bought a carbon frameset and built it up with bits off the internet. Ended up installing a Tiagra standard double crankset, so my smallest chainring is 39t. Paired with the 12-25 cassette it came with, I'm in the same situation as the middle chainring of the triple, but with no bail out option. I can manage all the 'hills' round here, but several I can only get up by standing. Definitely wouldn't work if I lived where you do :shock:
  • robtom
    robtom Posts: 8
    Thanks for all the responses and suggestions. At present, I'm learning to live with the C'dale Synapse 105 set-up.

    I did an early morning 30 mile circuit of the Rival (Yr Eifl) hill range on the North Lleyn Peninsula earlier and got around comfortably in just over 2 hours 10 mins. Nontheless, I did deliberately avoid the other possible quieter routes which have the challenging climbs! Only on one section, after~22 miles did I wish I had one lower gear, otherwise the bike is quick and comfortable on the other mixture of A roads, narrow back roads and cycle paths. A change to the MTB cassette is tempting, but it would be a shame to sacrifice the performance on the lesser gradients etc.

    The other half of the Rival hills involves an ~450 foot ascent over 2 Kms from Llanaelhaearn towards Llithfaen, with one really steep section...I think I'll take the Cube Nature Pro for that one!
  • Downward
    Downward Posts: 179
    You can get the MTB/Hybrid rear gear set up - New Derailleur and cassette. The cassette is a 11-34.
  • simonj
    simonj Posts: 346
    If you can learn to live with what you have that would be the best option and obviously free. A 12-30 is considered pretty low geared anyway, with many relaxed bikes normally having just 11-28. If you really can't get on with 12-30, then a longer rear derailleur with a 11-32 MTB type cassette would be a good cheap option - you may also need a slightly longer chain. You will not loose out on performance as such, the gear shifting 'may' not be quite as slick - although you may not be able to tell, you'll just have a wider spread of gears which may mean the jumps in between gears are slightly too big which may result in at a give speed one gear may be slightly high for what you want, but dropping down one gear is slightly too low. Not the end of the world, but if you prefer to stay at a particular cadence then big jumps can make it a little trickier to do. As I say, if you can practice and get used to what you have, I would imagine what you have is ok. You may find you can't live with it and change to a MTB cassette, but then after 3-6 months discover you've improved and want to move back to the previous cassette. It's not always good to 'default' to the lowest gear at the first sniff of a hill and spin up it and if you can learn to attack the hill in a slightly higher gear that may be a good trick to practice if your legs can handle it. :)