Talk to me about gearing on CX bikes ( please!)

  • This topic has 25 replies, 18 voices, and was last updated 4 years ago by  Dibbs.
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  • Talk to me about gearing on CX bikes ( please!)
  • Premier Icon oldfart
    Subscriber

    New to all this curly wurly bar stuff . Bought a Giant Revolt for a bargain price , getting on fine for commuting and winter hack duties but could do with lower gearing for steep hills . Been used to MTB gearing, chain set is Shimano R460/R350 whatever that means ? Non series Tiagra ? No idea ! C/rings are 48/34 with a 11-34 cassette . With that combo which would be better a smaller c/ring or a different cassette ? What’s the smallest c/ring I can get away with if that’s the best option ? Or is there no reason why I couldn’t just get a Deore MTB chain set ? Seems a conventional b/b .

    Premier Icon simondbarnes
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    It’s already got the smallest chainring you can use on that chainset. That gearing is really rather low for a cx bike already. You may get away with a mtb chainset although chainline may be an issue.

    Premier Icon bikebouy
    Subscriber

    48/34 & 11/34…

    Not a fat lot left really..

    Tried a triple ?

    Or do some intervals..

    😐

    Premier Icon oldfart
    Subscriber

    Not sounding very promising is it ! So have I been spoilt by MTB gearing then ? There are hardly any climbs on the Quantocks I can’t do even on a Spicy ! The road climbs I’m thinking of I can do fine on an MTB .

    Premier Icon ampthill
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    You can buy a 11-36 cassette, depending on how many sprockets the block has. Or maybe even 40 if you use on of those supper star things. You’ll need to ask else where about that

    On my ride today I was contemplating a 28-40 MTB chainset. I’d love to know if that would work. My worry would be if you need a new front mech?

    Tripling is faff as its a new left hand shifter. Plus a road triple is normally 30 on the smallest ring so not even that much gain. A treking or mtb triple would be great but again I don’t know about front mech’ implications

    genreal sympathy. Hills don’t get less steep just because you don’t have drop bars

    lazybike
    Member

    Jump off and walk up…it will be quicker than riding up in 34/34.

    vdubber67
    Member

    Swap your 34 for a MTB middle ring 32….

    Premier Icon simondbarnes
    Subscriber

    Swap your 34 for a MTB middle ring 32….

    Can’t with that chainset

    TurnerGuy
    Member

    I am shortly going to try a 11-36 cassette with an XTR 9 speed derailleur on my tripster.

    currently I have an 11-32 but even if you get out of the saddle to try and power the 32 then your weight distribution isn’t great if it is muddy.

    TurnerGuy
    Member

    Middleburn are also doing a supercompact chainset with a 30 inner ring…

    oldgit
    Member

    Is the hill problem on or off road?

    Premier Icon oldfart
    Subscriber

    Road so far I’ve only tried on less severe climbs near me , got some proper stinkers I want to try 🙄

    oldgit
    Member

    Just wondering if it was a tyre pressure problem. High pressure on skinny tyres can be tough on climbs.

    Edit off road climbs

    34/34 ?! Are your brake blocks rubbing alot?

    Have you been fitted?

    mattsccm
    Member

    Without being rude it might be worth sticking with it. That’s already way lower than normal road bikes which generally suit almost every one. Maybe adjust your style. Can’t actually be too pompous about this as my Pickenflick runs a 28 inner ring with, occasionally, the standard 11-32 cassette. Most of the time a 25 max on the back is fine and by gum I am crap at hills.

    Premier Icon crazy-legs
    Subscriber

    1:1 ratio should be fine for pretty much anything, even off road hills. The climbing position is more efficient on a CX than an MTB. Give it time.

    About the only other option is to go to a 12-36 cassette if the mech will stretch to that.

    FWIW I run 34/48 chainset with a 12-36 cassette when the bike is in Three Peaks CX mode, I tend to revert to an 11-28 the rest of the year.

    knottie8
    Member

    as above … give it time, roadie gearing is so different to MTB and you just learn to cope, rather like riding SS. That said I have a triple set up on my Trek but rarely use the granny now.

    TurnerGuy
    Member

    That ratio might be OK assuming you can get out of the saddle, but if the hill is muddy you need to stay seated to keep traction on the back wheel, so really need a spinny gear.

    Hence I am going to try 34 – 36.

    thomthumb
    Member

    TA make a 33t 110 bcd chainring: the only lower option is to either run a ‘super compact’ from the likes of:

    middleburn
    sugino
    velo orange

    or go the cheap route and run 2 rings on a triple. i might go this way…

    Or a mtb chainset. 28/38 or 28/40.

    Premier Icon Stainypants
    Subscriber

    i use an xt 9 speed mech and a 36 cassette works great.

    Nick

    Premier Icon BadlyWiredDog
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    Are your tyres really draggy? I’m running a standard compact up front with with 11-32 at the back and it’s fine for anything round here in the Peak and I’m a pretty average climber tbh, I found 11-25 a bit brutal off road.

    Maybe you just need to get used to it? It won’t be geared as low as a mountain bike because it doesn’t really need to be, but I guess if you’re used to spinning really low gears, it might feel stiff at first.

    1 shed
    Member

    I’ve got a sram x7 chainset 26 x 39, xt front mech, 11-30 cassette, 105 10 speed rear mech and 105 sti. All works together nice and low gearing.

    dobo
    Member

    not mountainous around here but ride 1×8 38×11-28 on road and off swap the rear wheel and use 38×11-32. Its a good combo imo
    48 is high for a cx and 34 is low, sure i can push uphill faster 34×34

    Premier Icon ampthill
    Subscriber

    So can he, or I use a 28×40 MTB chainset on a road bike

    I know you don’t need a gear that low but what about those that do

    I’m not quite sure why if gears of less than 34×34 aren’t needed as its as quick to walk why touring bikes and mountain bikes go down as low as 22×34 or why people buy 40 teeth sprockets to run with 32 front rings.

    Its interesting that Burti was using 30×34 in the Giro. He is a touch lighter and more powerful than me. Surprised he didn’t just get off and walk

    dobo
    Member

    maybe he was too pro to walk.

    Dibbs
    Member

    If an old duffer like me can do Crowcombe Hill on my CX bike (36-32) I’m sure the OP can do it on 34-32. 😉

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