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Question about gearing and hills

homers_doublehomers_double Posts: 7,293
edited August 2014 in Road general
Afternoon all, I'm off to Italy in a few months and there are some pretty horrendous climbs out there which will need to be tackled.

I'm taking my trusty Allez which is currently running a Tiagra drivetrain with a 50/34 compact up front and an 11-28 cassette (10 speed)

On chainreaction there is a Tiagra 12-30 for a minimal £13 or an ultegra 12-30 for £30, if I'm going to change some ratios then I'd spend the extra £17 and upgrade but am I going to notice 2 extra teeth up top and an extra tooth in the bottom end?

I'll probably get a new chain to go with it as well.

Because I live in the pennines I've always opted for a larger cassette on the MTB but not really had much experience swaping about on the roadie.

Advocate of disc brakes.


  • diydiy Posts: 6,473
    If you are currently running an 11-28 then you could probably get away with a 12-30, but might struggle with an 11-30 due to the range of the mech. You will notice it - its effectively 1 extra gear. approx. 1/2 mph at 80rpm or about 7% less work for the same rpm
  • GiantMikeGiantMike Posts: 3,139
    It's 2 teeth on top of 28, or 7.14% more in real terms.

    What kind of gradients are these climbs? 'Foreign' climbs are usually long but not necessarily that steep.
  • slowbikeslowbike Posts: 8,498
    Where in Italy?

    We went to Tuscany - between Pisa and Florence and the best route I found to ride was 18 miles and 2500 feet of climbing ... I was glad of the triple and 32-11 cog on the back ... didn't think I'd need 30/32 combination but at 16 miles it ramped up to 30% then eased for a "relaxing" 7% before going back up for a brief 27% ...

    If we go again I'll probably end up with the road bike but I'll get a 30-12 cassette - don't need the 12 tooth, but would certainly use the 30 tooth ...
  • homers_doublehomers_double Posts: 7,293
    We're staying in Menaggio on Lake Como.

    This is the view from our house up the road from the village, see that little point in middle of the lake? Thats the bit of land which holds La Madonna del Ghisallo, so pretty steep.


    View from down on the lake and turning the camera around slightly we'll be playing in those green things on the left...


    It isn't an out and out climbing holiday and one day will involve a full tour of the lake which is relativly flat.

    This little ride includes the climb back up to the house. 3077 feet of climbing in 21 miles which is mainly the ride back up the hill.

    A few of the lads I ride with spin faster than me on climbs at the same pace and I'm fine spending the £s but if its better spent elsewher then I will.

    Sorry for the ramble blah blah blah, I just wondered if I'd benefit from a few extra teeth in the extremes really.
    Advocate of disc brakes.
  • HertsGHertsG Posts: 129
    Continental tarmac is usually as smooth as a baby's bum. For me that usually saves one downshift.

    But, it's clearly playing on your mind - so I'd change the cassette to a 12-30.

    Whereas you might wish you had an 11-tooth top gear, you might need a 30-tooth bottom.

    Enjoy your trip!
  • Dippydog2Dippydog2 Posts: 291
    My ten speed Shimano had no problem with an 11-34.
  • diydiy Posts: 6,473
    I had a little look at the spec and while I couldn't find any published capacity figures it looks like you can go 11-30
  • ProssPross Posts: 33,471
    diy wrote:
    I had a little look at the spec and while I couldn't find any published capacity figures it looks like you can go 11-30

    Capacity appears to be 30t for a short cage and 39t for a long cage but still a maximum sprocket size of 30t. In either case, if my maths is correct, a 12-30 would be fine and to answer the OP's original question would probably make enough of a difference to be worthwhile in an emergency (whilst losing the 11 is likely to go more or less unnoticed).
  • homers_doublehomers_double Posts: 7,293
    Well some of my hard earned is on its way to Ireland this morning for an ultegra 6700 12-30 and a sram PC1071 hollow pin chain.

    I've always like Sram chains over shimano, zero problems and the powerlink is a piece of cake to use.
    Advocate of disc brakes.
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