• This topic has 31 replies, 15 voices, and was last updated 12 years ago by mboy.
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  • Road bike gearing advice please
  • Sue_W
    Free Member

    OK, I am rather a numpty when it comes to road bike gearing, so I’m after some advice.

    I have 2 bikes which I ride on the road – a Specialised Tricross and a Dolce. The gearing on the Tricross is perfect for me, especially going uphill where I can reduce knee strain by spinning, while I love the lighter weight of the Dolce.

    So ideally I’d like the same gear configuration on the Dolce as I have on the Tricross. They both have a triple at the front – 50x39x30. But very different rear cassettes – the Tricross is 34×11, while the Dolce is 28×11. Is it possible to put a 34 x 11 cassette on the Dolce (shimano 105)? Or is there another, better way to obtain the same gearing for going uphill?

    druidh
    Free Member

    The 11-34 is a “Mountain Bike” cassette. You can use one of these with your existing 105 shifters if you also fit a 9-speed rear mech (e.g an XT).

    Sue_W
    Free Member

    Thanks druidh. So if I wanted that gear ratio on the Dolce I could keep the current shifters and front chainring, and replace the rear cassette AND the rear mech with a mtb one, and that would all be compatible? Would XT give me the same level of performance as 105?

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    druidh
    Free Member

    Yes, yes and yes.

    I run Ultegra and XT on my Tourer/CX bike.

    Bianchi-Boy
    Free Member

    You would probably need a longer chain as well. Your original chain will be fine for 30*34 but if you ever try 50*34 it will almost certainly be a bit short.

    Ian

    forzafkawi
    Free Member

    As you already have a triple chainset on the Dolce, it’s likely that you have long cage rear mech also. Druidh is correct about the 34-11 being an MTB cassette but your existing long cage road mech on the Dolce might still work with the 34-11.

    I would suggest swapping the rear wheels on your two bikes and see how you get on with the 34-11 on the Dolce. It might save you having to buy a new rear mech.

    If you do try this then you will need to test the gearing at 30 on the front and 34 at the back as well as 50 on the front and 28 at the back to make sure the chain (and mech) can accommodate the gearing extremes. You may need to adjust the length of your chain even if the mech can handle the stretch of the lower gears.

    billysan
    Free Member

    You wont be getting a smaller front chainring than the 30t you already have. Therefore to lower the gearing further you’ll need a different cassette.
    Druidh’s advice on rear mech choice is also correct. 9spd shimano mtb mechs have the came cable pull ratio to shimano 10spd road mechs. Just choose one that covers the rear range you want, ie 11-34. You’ll need an SGS mech too (long cage) to take up the chain slack you’ll have with this large a gear range.

    What sort of hills do you ride anyway if you need lower than 30×28 to get up comfortably?

    billysan
    Free Member

    A 30×34 gives 23.2 gear inches! 😯

    Sue_W
    Free Member

    Cheers guys!

    Right, trying not to get confused – xt 34 x 11 mtb cassette will be fine, might need a new ‘long cage’ / xt mtb rear mech (but check current one first), will need a longer chain – can I add extra links to my current one or would I need a new chain?

    billysan – I ride in Snowdonia so steep hills are commonplace. I know most of the guys I ride with manage with “standard” gears, but they usually then have to stand and grunt up the hills. The gearing on the tricross just works for me, and despite it being a heavy bike I can often hold my own or go faster uphill than some of the local roadie boys. Withl the Dolce I just have to struggle more, am often slower uphill, and put more strain on my knee joint.

    druidh
    Free Member

    Sue – if you are fitting a new cassette, a new chain would be worth it anyway. Depending on wear, you might find you have problems with the old chain.

    njee20
    Free Member

    A 30×34 gives 23.2 gear inches!

    Good lord, I may faint at such nonsensical measurements.

    Maybe she’s doing multi-day rides, or touring, or audax, or just isn’t as hard as you, or just wants lower gears.

    billysan
    Free Member

    Fair play Sue. My other half has a triple and an 11-28 on her giant. She manages with this in the Chilterns and around Bath, but much more and she might need easier. Snowdonia would certainly warrant it! Excuse my third post (in defence, Im an engineer, so quantify everything!).

    Regarding chain, I’d get a new one to go with the new cassette. Its a recipe for much accelerated wear otherwise for minimal cost.

    druidh
    Free Member

    I was generally happy with 28 on the back until I started to do more stuff off-road.

    breatheeasy
    Free Member

    A bit left field maybe, but how about dropping a 28t front chainring on instead of the current 30t? Will probably get the gear ratio close to the Tricross and it’s less than a tenner for an inner ring to try it out. Shouldn’t even need to change the chain either, though the front mech might need a fiddle with.

    njee20
    Free Member

    Excuse my third post (in defence, Im an engineer, so quantify everything!).

    It was more your “OMG IT’S X INCHES” that I found odd, does anyone really think in gear inches, being as it’s a completely meaningless way of measuring!

    Will probably get the gear ratio down to the Tricross and it’s less than a tenner for an inner ring to try it out

    Not quite, I’m not using inches, because it’s stupid, but that would give a 1:1 bottom gear, 30/34 would give 0.88.

    A 26t inner would give very similar, but I’m not honestly sure about BCDs on road triples and how low you can go.

    billyboy
    Free Member

    Are they both 9 spd systems?

    If The Dolce is a 10 spd shimano 105 setup then you will need to use a 9 spd mega shimano mtb rear mech with a 10 spd SRAM mtb cassette and a 10 spd shimano road/sram rd/mtb chain, and it will apparently work with a 10 spd shimano road shifter. Not my wisdom…comes from Juden in the CTC mag…I’ve not tried it.

    I’m with you. There’s no way I’d want to do road riding around the Lakes for any distance with any road geared bike. You do a couple of passes and you are whacked. Given a touring set up, 48/36/26 with a 9 spd 11/34 cassette out back you can just keep it going without blowing yourself up.

    Several folk will now tell me I’m a wuss etc etc

    aracer
    Free Member

    You wont be getting a smaller front chainring than the 30t you already have

    You can swap the 30 for a 28, 26 or a 24 – that being the standard size for Shimano chainsets doesn’t mean you can’t replace it with an aftermarket one. As above, I’d recommend trying a smaller inner ring – we have 52/39/26 on the tandem which works just fine.

    billyboy
    Free Member

    njee 20

    I’ve tried a 26T (TA??? I think!) chainring on a shimano 105 10 speed chainset and it worked ok. That was on a Tricross.

    davidtaylforth
    Free Member

    I’d try a smaller front chainring since it’ll be less hassle and its hidden away – then you wont get other people laughing at you for using mtb gears on sportive rides.

    billyboy
    Free Member

    I think you can now get shimano tiagra 10 speed road cassettes in an 11/30

    billysan
    Free Member

    njee20

    a; My comment was made in jest, not in oneupmanship as it may have come across (in hindsight).

    b; I find gear inches useful, and yes I know what size each actual gear is. Further more, I know what size gear I can hold over certain sizes and shapes of hill. ie I know I can hold a 50″ gear over a certain hill, but not a 52″. This then helps me pace myself, adapt to both my road bikes which have very different gear sets, and benchmark myself.

    A bit off maybe, but then I think of everything in numerical terms. Each to their own and all that.

    cynic-al
    Free Member

    gear inches are meaningless?

    What alternative do you use?

    druidh
    Free Member

    billyboy – Member
    If The Dolce is a 10 spd shimano 105 setup then you will need to use a 9 spd mega shimano mtb rear mech with a 10 spd SRAM mtb cassette and a 10 spd shimano road/sram rd/mtb chain, and it will apparently work with a 10 spd shimano road shifter. Not my wisdom…comes from Juden in the CTC mag…I’ve not tried it.

    It doesn’t have to be a SRAM cassette – a Shimano one works just fine. My wisdom. Comes from druidh on STW. He’s tried it.

    stevewhyte
    Free Member

    I must be an old fuddy duddy, as i still think about inches when you talk about gear ratios.

    “Back in my day” ‘n all that.

    My gear range on my road bike with Alfine is 23 to 72 which is ok for me right now, find that im not useing 1st that much any more.

    Bear in mind the bike weighs 30lbs and i weight 210 !!! I need all the help i can get going up hills.

    GW
    Free Member

    does anyone really think in gear inches, being as it’s a completely meaningless way of measuring!

    I’m not using inches, because it’s stupid, but that would give a 1:1 bottom gear, 30/34 would give 0.88.

    the only thing that’s stupid here… 🙄

    simply stating the ratio is far more meaningless than using gear inches.
    (clue: gear inches includes how far the wheel will roll and so is transferrable throughout wheel sizes)

    billyboy
    Free Member

    As long as you know that a mega 9 mtb system on 26″ wheels does 17 to 104 gear inches and you ride that a lot then it’s a good base to start from in understanding what other gear systems are going to do for you. If you don’t have that experience to go with the gear inch figure then it ain’t much use

    but

    wot else is there?

    GW
    Free Member

    Njee’s blinkered decimal system, looks tidy, neat and precise but in reality is of very little use. similar system to most of his forum posts. 😉

    njee20
    Free Member

    Haha! You’re suggesting that my posts aren’t helpful!? That’s rich! Isn’t it time for you to piss someone else off with your ‘honesty’ and get banned again?

    I can accept that gear inches are useful if you’re changing wheel size or comparing between the 2. It doesn’t tell you how far a bike will travel in a gear, just serves as a comparator between gears, as will ratios or any other metric. Multiply that by wheel circumference and that will tell you how far you’ll go for a revolution of the pedals…

    I know inches is the ‘de facto’ measurement for old roadies, don’t get it myself. I know what 50-25 feels like, its the same as 32-16 or 22-11, not got a clue what 48″ feels like though! Certainly couldn’t tell you what gear inches my MTB runs, know that I’m happy with my 1:1 bottom gear though, but can find 3.27:1 a bit limiting at times.

    Can anyone actually work out gear inches in ones head? Serious question, or does it require a roll-out chart?

    cynic-al
    Free Member

    I can…today’s youth appear to have rubbish mental arithmetic 😉

    Sorry but gear-inches is closer to a more universal system than ratios, that’s a simple FATC.

    GW
    Free Member

    Njee, forget roll out charts, you, yet again you’re causing this kind of roll 🙄

    MrSmith
    Free Member

    It was more your “OMG IT’S X INCHES” that I found odd, does anyone really think in gear inches, being as it’s a completely meaningless way of measuring

    for people who ride fixed/SS on the road or fixed/track it is the only way to converse and makes perfect sense when different chainring/sprocket combinations can have the same gear inches.

    it’s also a way of seeing overlap or gaps in double/triple systems and is easily understood once you have an idea of what 70 gear inches feels like (63-72 being common fixed GI’s for road use)

    mboy
    Free Member

    I know inches is the ‘de facto’ measurement for old roadies, don’t get it myself. I know what 50-25 feels like, its the same as 32-16 or 22-11, not got a clue what 48″ feels like though! Certainly couldn’t tell you what gear inches my MTB runs, know that I’m happy with my 1:1 bottom gear though, but can find 3.27:1 a bit limiting at times.

    I don’t have a clue what Gear Inches each gear (or any gear) on any of my bikes are, but to dismiss it as being totally useless or irrelevant is a bit silly. Yes, it’s an old roadie/fixie hangover system of measuring rate of progression per crank revolution, but if it still works for some people who are we to say it’s any less relevant than the metric gear ratio system you and I prefer to use? I prefer talking about ratios the way you do cos I can relate to it better myself, but then I’m only riding 26″ wheeled MTB’s mainly (and a road bike very occasionally). For people who ride with different sized wheels more often, gear inches still makes a lot of sense, though perhaps it should be updated?

    I quite like the MPH (or KPH if you’re metric) per ‘X’ crank revolutions system that’s used from time to time. Usually you’d use X = 100, so you know for a given gear (with given wheel and tyre diameters) you will travel at a given speed for a given crank RPM. That’s why I did all the calculations for it on the hub gear ratio calculator spreadsheet I did a few years back (still got it if anyone wants a copy)…

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