Upgrading to a triple

Discussion in 'Bikes and Buying Advice - What Bike?' started by karan733, 26 Apr 2010.

  1. karan733

    karan733 New Member

    Im really struggling to get up hills on my roadie at the moment, so was thinking of switching to a triple so I have a granny gear while getting used to hills. I have a 7spd cassette, and I think my left STI can handle a triple, but what else do I have to take into consideration? And what would be the best way to go about this - fit different chainrings, or replace the whole chainset? I've read that I would need a long arm rear mech - how do I tell if I already have one fitted?

    thanks again!
    Karan
     
  2. Tynan

    Tynan Veteran

    Location:
    e4
    what and where are the hills and how long have you been trying them?

    7sp? this is a rather old bike I'm assuming, you'll need to wait for someone technical but there's going to be a lot of new stuff at the front, and shifters will need to pul enough cable to handle a triple

    far far cheaper to change the cassette to give you options, what's your lowest gear at present? smallest chainring and biggest cog, obviously
     
  3. OP
    OP
    karan733

    karan733 New Member

    Ive been at the hills for over a month, I could get up them on the mtb (in the granny rings though). On the roadie, I actually cant get very far at all. Im very unfit, so I know I'll get better, but walking up hills isnt going to make me able to get up them the next day :evil:

    The bike is a carrera valour (halfords I believe?) from around 2003-2004. I was hoping to upgrade the parts, because I havent got the funds to be able to buy a £700 bike outright. I was thinking I might get the whole Sora crankset front to back from wiggle for around £230, but again, if I can buy second hand off ebay thatd be great :troll:

    how do I tell you my lowest gear? Im really just starting out with bikes, so everything is a learning experience!
     
  4. ianrauk

    ianrauk Tattooed Beat Messiah

    Location:
    Atop a Ti
    you would also need to upgrade the shifters and front (triple specific) & rear dérailleur (long cage). A month is not a long time in the scheme of things. You are too keen imo. Keep at it and you will soon get up the hills. No pain, no gain as they say.
     
  5. OP
    OP
    karan733

    karan733 New Member

  6. alecstilleyedye

    alecstilleyedye nothing in moderation Moderator

    your chainrings are likely to be 52-42 with a 12-25 cassette. my carrera virtuoso of the same era came with that and i had the exact dilemma as you, having joined the local cycling cub and found that the local hills were far too much for the high gearing of the bike.

    i went triple, which involved replacing the whole groupset (it was cheaper to do that) and i went from 8 speed to 9 in the process.

    the good news is that a carrera frame from that era will be a merida one (if it says 6061 heat treated on the seat tube) which is better than the cheaper frames on carreras these days, which means that upgrading the bike is a perfectly reasonable option.

    the cheapest way to change the gearing would be to put a 38 chainring on the front coupled with a 12-27 cassette at the back, as you won't need to change anything else.

    edit: the advice from ianrauk is quite correct. the original gearing from my carrera went on another bike and i can get up some of the hills on it that i couldn't before.
     
  7. OP
    OP
    karan733

    karan733 New Member

    Thats really helpful! It does have the "Light Weight 6061 Heat Treated Aluminium" sticker on it, and its the blue and white liveried frame.

    When you say put a 38 chainring on, is this in addition to the 52/42? And would I need a longer chain given the extra ring?
     
  8. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Location:
    Stevenage
    No - take the 42 off and stick the 38 on instead. The chainring is held on with 5 bolts.
    The original chain *might* be OK - depends on how worn it is.
    If the chain is shot, you'll need a new one and possibly a new cassette as well.

    While I would normally bow to Alex-and-all-the-rest-of-it expert opinion, I'd suggest going the whole hog, if you're going to replace the cassette. One of these, and one of these.

    Your lowest gear will go from 45.4" to 32.1". That's a massive drop, and should make all the difference. It'll work perfectly with your Sora mechs, and it's even lower than the gear that got me up most of Mont Ventoux.
     
  9. alecstilleyedye

    alecstilleyedye nothing in moderation Moderator

    sorry, i meant replace the 42 with a 38. there are limits to how small a chainring you can put on the existing chainset; 38 is about the smallest for a standard double (which is what you have).

    your chain length would be unaffected, as the 52 would still determine how long it needs to be.
     
  10. OP
    OP
    karan733

    karan733 New Member

    Could you elaborate on the 45.4'' and 32.1'' please? What do these numbers mean/relate to?

    Still learning all the time :tongue:
     
  11. RecordAceFromNew

    RecordAceFromNew Swinging Member

    Location:
    West London
    I agree with others' suggestions above, but would like to add a couple of comments:
    1) the critical measurements for an informed decision at this point are the number of teeth on the small chain ring at the front, and the number of teeth at the large sprocket at the back. You might want to count them and confirm to ensure no misunderstanding/mistake.
    2) you are likely to have to change the chain too if the size of the large sprocket at the back is increased.

    The number of inches, what they meant and what they relate to, are here and here.

    The correct length chain you need eventually can be estimated by this for comparing with what you have.
     
  12. PpPete

    PpPete Guru

    Location:
    Chandler's Ford
    gear inches .... one of those historical quirks, don't worry about how it's worked out, it's just a number. Your "top" gear will be around 100 or more.
    Road bike lowest will be around mid 30s, MTB lowest in the mid 20s
     
  13. OP
    OP
    karan733

    karan733 New Member

  14. Chrisc

    Chrisc Über Member

    Location:
    Huddersfield
    Have a look here to see how to work out gear inches using this calculator. Gear inches relate to the diameter of a penny farthing wheel I think. Smaller =easier.

    Spending money on bike stuff should give you a :eek: not a :biggrin: !
     
  15. e-rider

    e-rider crappy member

    Location:
    South West
    A few points to make:

    1. changing from double to triple is going to be expensive especially if you factor in the cost of paying a bike shop to fit everything (I'm assuming you will not do it yourself). You'll need several new parts that will cost quite a lot £££s

    2. that is not really a hill!

    3. you can't just add a 3rd chainring to your existing double chainset (a whole new one is needed)

    4. better to just change your smallest chainring to an even smaller one (38T is the smallest that will fit a 5arm 130BCD; although 34T will fit if you have 110BCD)

    5. you could change the 7 speed cassette to one that has a larger big cog.

    I'd buy a cheap compact chainset (34/48T)and fit that - shouldn't cost more than £40 (just make sure it has the same BB fitting to your current chainset; and that the crank lengths are the same as your current one)
     
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