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Specific gear ratio question and advice for upgrade.

CoalTheCatCoalTheCat Posts: 91
edited May 2016 in The workshop
I currently have a Hoy flatbar hybrid (Shizuoka 001) that despite a few teething issues I actually love it.
My ride to work scheme is up in October and I intend to spank the full £1000 plus another £5/600 for a “proper” road bike. (Ignore this for now.)

The problem…

I have started to extend my commute, I am lucky in that where I live peak meets plain. I have the peak district to one side and the Cheshire plain to the other side. The bike is perfect for my commute, but when I do extend my commute, I am struggling in the big climbs ( I realise this will improve as my fitness does) and also as soon as I am going downhill or even a flat with a tail wind my legs are spinning to fast.

I need to do something now. I am thinking about either buying something second hand and roadie or upgrading the drive train on my current Hoy.

My currently has a 38T chain ring with 8 cogs 11-32T cassette.

Upgrade - I like the look of the SRAM drivetrain used on the Boardman CX team bike. Which is a 44T chain ring with an 11 cog 10-42 cassette. I think I like the simplicity of a single cassette. I don’t know why I think that though.

The question is (and I have looked on a few sites that help work out ratios, but I’m not the brightest spark and still can’t make head nor tail of it) with this broaden my current gearing to make climbs easier and be faster on the flat?

With a few other upgrades the budget for this would be about £4/500.

Or do I spend the £4/500 on something second hand now?

Any thoughts advice would be appreciated.

Nick.

Posts

  • drlodgedrlodge Posts: 4,824
    I like to think of gear ratios in "gear inches" hence for a 27 inch wheel, a 1:1 ratio is 27, a pretty low gear. 100 gear inches is a typical top gear for a road bike.

    Currently you have 38/32 as a bottom gear, that's 32 gear-inches. The new setup would be 44/42 which is 28.2 gear-inches, a lower gear by about 12%.

    Top gear moves from 38/11 (93GI) to 44/10 (118 GI) so a much wider gear range, a lower low gear ad a higher top gear.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
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  • CoalTheCatCoalTheCat Posts: 91
    Perfect (I think). Thank you drlodge.
  • keef66keef66 Posts: 13,286
    To make climbing hills easier you want a smaller front chainring and / or a larger rear sprocket. For faster downhill you need the reverse.

    To achieve both at the same time on a bike like yours with a single chainring is nearly impossible, and you already have cassette with a 32 tooth sprocket which is as big as they come without resorting to MTB kit.

    You also have 8 gears so fitting an 11 speed cassette wouldn't work without the corresponding 11 speed shifters.

    If you really want to climb easier and descend faster you need a road bike with a double chainring, say 36 / 50, and say a 12-30 cassette
  • CoalTheCatCoalTheCat Posts: 91
    keef66 wrote:
    To make climbing hills easier you want a smaller front chainring and / or a larger rear sprocket. For faster downhill you need the reverse.

    To achieve both at the same time on a bike like yours with a single chainring is nearly impossible, and you already have cassette with a 32 tooth sprocket which is as big as they come without resorting to MTB kit.

    You also have 8 gears so fitting an 11 speed cassette wouldn't work without the corresponding 11 speed shifters.

    If you really want to climb easier and descend faster you need a road bike with a double chainring, say 36 / 50, and say a 12-30 cassette

    Thanks, I get that’s the conventional wisdom. The “proper” road bike is in the pipeline for October. I wanted to keep this bike fairly simple as it will continue to be my commuter. I prefer the flatbar position for rush hour traffic and I cart round a heavy laptop rucksack when commuting.

    SRAM have a flatbar shifter that’s compatible and within the upgrade plans.

    I want to get to the point I can climb the hills on my commuter so when I do get my road bike I can smash them. I feel like I am one cog short from making the steepest climbs at the moment.

    Do you think the money would be better spent on a second hand road bike with conventional gearing?

    Thanks again,

    Nick.
  • Mad_MalxMad_Malx Posts: 4,031
    keef66 wrote:
    If you really want to climb easier and descend faster you need a road bike with a double chainring, say 36 / 50, and say a 12-30 cassette

    But OP says he is struggling on hills with his current 38/32, your suggestion gives him almost the same bottom gear of 36/30, and a 34/30 wouldn't be much better. To get a real difference he will need at least a 32 cog on the back, with a bit smaller on the front.
  • The RookieThe Rookie Posts: 27,747
    You could go to a Suntour MX3 cassette (11-40t or 11-42T), if you have a Shimano derailleur you can keep that and use a Shimano ROAD flat bar shifter (10 speed) such as a Tiagra (NOT MTB). You'll also need a ten speed chain.

    Then increase the chainwheel size to get the balance between better climbing (using the lower lowest gear) and downhill (where you have the same highest gear on the cassette). A narrow wide chainring will help prevent chain derailments.
  • CoalTheCatCoalTheCat Posts: 91
    The Rookie wrote:
    You could go to a Suntour MX3 cassette (11-40t or 11-42T), if you have a Shimano derailleur you can keep that and use a Shimano ROAD flat bar shifter (10 speed) such as a Tiagra (NOT MTB). You'll also need a ten speed chain.

    Then increase the chainwheel size to get the balance between better climbing (using the lower lowest gear) and downhill (where you have the same highest gear on the cassette). A narrow wide chainring will help prevent chain derailments.

    Thanks man, will look at this option too.
  • imatfaalimatfaal Posts: 2,716
    On my hybrid I run all sram - and all picked up second hand from the bay. Apex 50 / 34 with cheap replacement rings at the front with an Apex FD and 11/36 at the back with an X9 long cage RD - all controlled with XX shifters (works fine wiht the old x5 shifters too).* When as a real newbie I was doing a spate of charity bike rides in Yorkshire/Lancashire /Derbyshire (Sutton Bank Holme Moss et al) I installed a real dinner plate at the back - either a 40 or a 42; and you can get up everything with that - the hardest bit is staying up right when your cadence is high and you are hardly making any forward progress.

    x5/7/9/0/x shifters will control Apex/Force/Rival rear and front derailleurs - but unless you are overly concerned with weight you might as well stick to mtb rear derailleur (easy to get long cage/huge cassette range)

    * I trashed the entire drivetrain the bike came with by poor maintenance (although now I would probably fix/salvage it rather than start again)
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