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Gear inches

Discussion in 'Touring and Adventure Cycling' started by rickangus, 19 Apr 2008.

  1. rickangus

    rickangus Über Member

    Location:
    west sussex
    I'm beginning to think that my gear ratios are less than optimal. I'm running a 24/34/46 chainset with a nine speed 11-32 cassette.

    This gives me 20.3" through to 112.9" and the jump between certain gears is too great. I find I hardly ever use the highest gear unless I'm racing someone down a hill. I think I might be better off with a 12 or 13 through to 34 cassette. More usuable gears without a pointlessly high gear that I hardly ever use. This would offer 19.1" through to 95.5" or 103.5" respectively.

    What sort of top gear ratio do folk here use for touring - and indeed lowest gears. Responses here will largely determine my choice of new cassette.

    Thanks
     
  2. Crackle

    Crackle Pah Staff Member

    Location:
    Wirral
    What sort of cadence do you ride at. A 95" is good for 25mph at 90rpm, 23 at 80 and 20 at 70.

    Your lowest gear setup is akin to my mtn bike and I've ridden some quite steep slopes on that.

    Gear spacing is a bit more personal. For general riding I like close spacing but for out and out touring I would've thought gaps of 2 to 3 teeth would be better.
     
  3. simoncc

    simoncc New Member

    I'm not sure what your problem is. Most tourists complain about their lowest gear being too high rather than their highest gear being too low. Hardly any tourist uses their bike's highest gear, but nearly all of them use the lowest. Most off the peg bikes are too highly geared. If your lowest gear ever needs to be lower, then the MTB chainset is the way to go, but this route means you cannot use an STI brake lever to operate the front mechanism for it.
     
  4. Dave5N

    Dave5N Über Member

    Clearly not.

    If you can use the triple to give you range, keep the ratios at the back as close as you can. A three-tooth jump is a very big difference.
     
  5. Danny

    Danny Legendary Member

    Location:
    York
    You could use a cassette with a narrower range of gears, but also slightly increase the size of your large chain ring so you still have a high gear when needed.

    On my tourer the top gear on my cassette is 13 and my large chain ring is a 48, which must be a similar gear to your 11 to 46. Like you I don't use it very often, but it is nice to have it available for long downhill runs.
     
  6. ASC1951

    ASC1951 Guru

    Location:
    Yorkshire
    In my sprightly touring youth 32/42/52 and 12/28 used to get me up pretty much anything here or in the Alps. I know fashions change and with the influence of mountain bikes there are much wider-ranged set-ups around. Even so, 24 x 34 really is a very low gear for anything on the road - if you actually need that, I wonder if you are carrying too much stuff?

    I'm with Dannyg. I'd leave the chainset alone and go for something like 13-30 or 13-32. Too wide a cassette is a pain on hills and a 112" gear for touring is just a waste of a useful sprocket mid-range.
     
  7. Tim Bennet.

    Tim Bennet. Entirely Average Member

    Location:
    S of Kendal
    Hi Rick,

    You have a couple of issues here. The main one being that the 11 tooth cassettes have been designed to give mountainbikers using compact chainsets a high top gear. The problem is the 12 to 11 tooth jump is about a 10 percent difference, and although it serves the needs of its intended market, it is very crude and not that useful on a tourer.

    So a reduction to a 12 tooth top will be significant and gives you an extra ratio in the range. This is just as well as finding a reasonably priced, decent quality 13 -34, 9 speed shaimano cassettes is not easy. (If you do, can you get me one).

    But 20 to 100 inches is a pretty reasonable range for loaded touring including the Alps.

    (Be a little wary of some of the advice you have got above as it appears to be based on understanding your problem completely arse about face. Or is it me?)
     
  8. piedwagtail91

    piedwagtail91 Über Member

    i have a 48,36,26 chainset and use a 14-25 cassette . top gear is plenty high enough and because of the closer ratios there are no big jumps between gears. bottom gear is low enough for me. i find if i go too low then it's quicker walking!
     
  9. OP
    OP
    rickangus

    rickangus Über Member

    Location:
    west sussex
    Thanks for the responses especially to Tim who understands my poorly phrased op!

    The only cassette I can find that might meet my objectives are the Cyclo Touriste ones from Harris Cycle Surgery here: http://www.sheldonbrown.com/harris/k7.html but which might not fit Tim's reasonably priced criteria. Mind you, the $:£ exchange rate isn't too bad at the moment...

    The Gear Chart from the same site suggests that the 12 toothed version appears to offer a more consistent spacing between gears.

    At the top end 46x12 gives 103.5" and 46 x 13 gives 95.5".
     
  10. Paul_Smith SRCC

    Paul_Smith SRCC Über Member

    Location:
    Surrey
    What you need to do is work out what gear ratios you actually want and then try and achieve them, making sure they are correctly positioned, no point if mathematically you can only get your most common used gear in largest ring largest sprocket.
    By way of an example that is all I have done on my tour bike, I use a 13-29 Campagnolo 10 speed set up with 26-36-46, which gives me all that I am after

    [​IMG]

    In my case for example I like gears of around 60”, you will see that I have got those on both middle and outer ring. I have done this essentially because this is a bike I use for two roles, solo rides of 15-20mph and touring rides of 12-15mph, to save repeated chain ring changes I can essentially use the big ring mainly for solo rides and the middle ring for more sociable rides. Even though it only has a 96" top gear I find that easily high enough for a mid 20-25 mph work out, for 15-20mph cruising I have ratios that I like available mid cassette on the 46 ring, this I find is the perfect set up for me. Of course everyone is different, some prefer a lower low gear and a higher high gear, horses for courses as they say.

    It does take a bit of thought as to what you need both in terms of ratios and then equipment choices to achieve them, but it can nearly always be done. In my case for example I did invest in a high quality chainset to get the ring combinations I wanted, as for me personally I find many road specific triples to large for me and the ATB chainsets to small for what I want.

    Paul_Smith
    www.bikeplus.co.uk
     
  11. OP
    OP
    rickangus

    rickangus Über Member

    Location:
    west sussex
    Paul,

    Thank you very much. Btw, I have found your contributions to this and the CTC forum extremely helpful and am very appreciative for the detailed responses, info and pics you supply.

    I've printed out your gear chart for a more detailed study; I will be doing a 50 miler on Friday so will try and monitor my most frequently used gears and undertake a comparison.
     
  12. SelfUnderEmployed

    SelfUnderEmployed New Member

    9 speed 13-34 cassette

    Just reading through these posts and have spent the last couple of weeks brainstorming the gearing on my bike. It was built as a seven speed set up on a triple crank (52/39/30 married to 13-34 7 speed). The gearing is pretty good and I have 7 speed indexed bar end shifters. Recently, I bought "new" wheels for my ride. I was running 32 spoke wheels and the rims were showing too much wear (bought the bike used). I was lucky in that I found a pair of good used 36 spoke rims (Velocity Dyan and Razor) on Ultegra hubs. I now could make my bike 9 speed if I chose and expand the gear range. After much screwing around, I decided to leave it as a 7 speed for the sake of general compatibility and the fact that it is theoretically a more durable drivetrain.

    I had a hard time finding a new 13-34 cassette in a 7 speed. I was considering going to 9 speed 13-34 and found both at Harris Cyclery (via sheldonbrown.com). A 9 speed 13-34 cassette is 105.00 (it's a Harris exclusive, made by Shimano, designed by the late Sheldon Brown himself RIP). The 7 speed was $31.00, which made my decision to stay 7 speed easier.

    Your gears sound okay to me. The high gears are a little high, but if you want to drop a hundred bucks, you could have a nice close ratio touring set up. You wouldn't gain much on the low end though, just slightly smaller jumps.
     
  13. OP
    OP
    rickangus

    rickangus Über Member

    Location:
    west sussex
    Thanks SUE,

    I think I went through a similar iteration as you, also ending up at Harris Cyclesurgery. I like the idea of their cassette spacings but, as you say, it's quite a lot of money for a relatively small gain.

    At this point in time I'm successfully resisting temptation...