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Changing to a compact

mr_pollmr_poll Posts: 1,612
edited November 2010 in Road beginners
Hi got a second hand bike early this year with Sora - double chainset, the plan was to get something nice after 12 months once I got into the sport - however finances are looking tight for the next 6 months so that plan is going to go on hold.

I fancy doing some more challenging rides, especially in the hills but some of the tougher gradients take their toll so I was thinking about changing to a compact. Is this as simple as gettting a compact crank and swapping the 2 over? Or more complicated than that?

Or should I just man-up and train harder?

Posts

  • Nope thats all you need to do. The only adjustment you'll need to make is to lower the front mech a tad. Don't be fooled into thinking a compact will be a massive improvement, the engine is still your legs, so yes change and yes man up and train harder.
    The dissenter is every human being at those moments of his life when he resigns
    momentarily from the herd and thinks for himself.
  • andrew_sandrew_s Posts: 2,511
    Yes, it is pretty much as simple.
    You will want to move the front mech about 6mm lower, assuming you are changing from 53/39 to 50/34, so if it's a braze on mech check before spending money.
    Make sure you pick a chainset that matches your existing bottom bracket.
  • ChiggyChiggy Posts: 261
    mr_poll wrote:
    Hi got a second hand bike early this year with Sora - double chainset, the plan was to get something nice after 12 months once I got into the sport - however finances are looking tight for the next 6 months so that plan is going to go on hold.

    I fancy doing some more challenging rides, especially in the hills but some of the tougher gradients take their toll so I was thinking about changing to a compact. Is this as simple as gettting a compact crank and swapping the 2 over? Or more complicated than that?

    Or should I just man-up and train harder?

    For hills. Mini sub compact.

    P1021_26-11-10.jpg
  • mr_poll wrote:
    Hi got a second hand bike early this year with Sora - double chainset, the plan was to get something nice after 12 months once I got into the sport - however finances are looking tight for the next 6 months so that plan is going to go on hold.

    I fancy doing some more challenging rides, especially in the hills but some of the tougher gradients take their toll so I was thinking about changing to a compact. Is this as simple as gettting a compact crank and swapping the 2 over? Or more complicated than that?

    Or should I just man-up and train harder?

    Is it a Sora chainset? I thought they were only available as a compact or triple.
  • nochekmatenochekmate Posts: 3,460
    Nope thats all you need to do. The only adjustment you'll need to make is to lower the front mech a tad. Don't be fooled into thinking a compact will be a massive improvement, the engine is still your legs, so yes change and yes man up and train harder.

    Is it not also true that he will need to shorten the chain length a tad from that being run on his traditional 53/39 set up?
  • Mark AlexanderMark Alexander Posts: 2,277
    edited November 2010
    I'd say with a bit of tounge in cheek, man up, 39 x 25 is enough for all but the most evil of hills. just practice practice, practice. The engine will improve over time changing to a compact will cost a lot and be a waste of money over time.
    http://twitter.com/mgalex
    www.ogmorevalleywheelers.co.uk

    10TT 24:36 25TT: 57:59 50TT: 2:08:11, 100TT: 4:30:05 12hr 204.... unfinished business
  • nochekmate wrote:
    Nope thats all you need to do. The only adjustment you'll need to make is to lower the front mech a tad. Don't be fooled into thinking a compact will be a massive improvement, the engine is still your legs, so yes change and yes man up and train harder.

    Is it not also true that he will need to shorten the chain length a tad from that being run on his traditional 53/39 set up?

    yep. good point
    The dissenter is every human being at those moments of his life when he resigns
    momentarily from the herd and thinks for himself.
  • simon_esimon_e Posts: 1,676
    I'd say with a bit of tounge in cheek, man up, 39 x 25 is enough for all but the most evil of hills.
    That's easy for you to say.

    @mr_poll normal people can only MU so much (and it takes time), so if you're into riding (or live) in hilly terrain I'd get the compact crankset. No-one will thank you for being knackered half way through a long, hilly ride because you went up the first few climbs in too high a gear while the others twiddled happily in 34x25.

    The current chainset may be the older 8-speed Sora kit that was produced in 52/39. Any current Sora or Tiagra compact chainset should be fine, but check whether it's square taper, Octalink or Hollowtech... or just replace your BB at the same time, it's an inexpensive component.
    Aspire not to have more, but to be more.
  • ChiggyChiggy Posts: 261
    Go to Decathlon and get a Shimano Alivio 42/32/22 chainset in a bubble pack with a B/B included for £29.99.

    Whip off the 42 ring and replace it with washers so the bolts can tighten.

    With a 11 - 25 cassette, top will be 77", which is good for 25 mph at 110 rpm ( 380ish Watts on the flat ). I consistantly ride along in 70" ( 32 x 12 ) at 18 mph spinning in mid eighties rpm. About 170 W on that Dawes.

    Lowest will be 23". Lower than most touring bikes.

    You'll have 6 ratios on the 32 ring and 6 on the 22 ring.
  • pbamfpbamf Posts: 69
    Why do shimano do rear mechs short medium and long? Do you not have to swap those aswell. Just thought i'd ask. Sorry but don't know if same applies for campag or sram.
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