Triple to Double

wilkij1975
wilkij1975 Posts: 532
edited January 2011 in Workshop
Hi All

I have just got a good deal on a Cannondale CAAD 8 Sora. Its got a basic FSA triple on it at the moment which I know i'll want to change to a compact. What I want to know is will I have to buy a new front mech and shifter for a double or can I use the current ones?

Cheers

Comments

  • John.T
    John.T Posts: 3,698
    Your current ones should work OK. With 8sp you may be better staying with the triple. You can avoid having such big jumps between gears by using a closer ratio cassette. I use a compact on both 9sp and 10sp with 12/27 cassettes. I miss the 16 sprocket on the 9sp and would rather like a 18 on the 10 (to make it 11 :wink: ).
  • Cheers John. It is a 9 speed and as I live in the flat part of the world I shouldn't need the small front ring. I did give road cycling a try the other year with an Allez 18 with a compact and it was perfect for me. I assume that when setting up at the front, i'd just set the stop screws so it can't over / under shift?
  • John.T
    John.T Posts: 3,698
    You will need to re-set the cable as well as you are using the 'granny to middle' click to move the chain middle to big (almost). The geometry of the triple mech is slightly different to a double one so it may not be perfect. Double mechs are pretty cheap if you find you need one.
  • brin
    brin Posts: 1,122
    I had to change my front mech when swapping over from triple to a compact, previous post is correct they only cost £20 or so
  • Cheers lads.

    I'm not bothered about getting a new front mech because, as you say, they are cheap. I just don't really want to spend big on some new shifters right away.

    I'm coming at it from an MTB point of view as thats what I know and people are going to doubles more and using the same mech and shifters that ran their triples.
  • John.T
    John.T Posts: 3,698
    The shifters will definately be OK. The mech probably so try it first.
  • Chris James
    Chris James Posts: 1,040
    Is it worth the bother?

    If anything I would have thought the two larger rings on the triple would be more suitable for cycling on the flat than a compact chainset.

    The inner ring weighs next to nowt and you don't have to use it.
  • It may not be worth the bother. I'm going to give it a go first but was just thinking ahead. It is also a square taper BB and i'm used to the external type now so not sure how it will feel. I think i'm just the sort of person who can't leave things alone. I'm always doing stuff to the MTB and want to with the road bike before i've even ridden it :)
  • sungod
    sungod Posts: 16,885
    if it's the fsa vero chainset then certainly worth considering changing it

    last year i bought a marin that had a vero triple, after a few months the middle ring buckled while going hard uphill (wasn't changing gear at the time), took it off and found it easy to bend with fingers

    didn't fancy a repetition, so i replaced it with an old 105 double (5500 series), stiffer, bb was smoother, better shifting too
    my bike - faster than god's and twice as shiny
  • Good to know sun (it is a Vero). I'm quite hefty at around 16st and do stand on the pedals quite hard. Thats why i'm thinking a stiffer external BB might be in order.
  • I made the change last year from 9spd Sora triple to a full 10 speed Ultegra compact groupset.

    Got away just changing the chainset for a while, then gradually replaced the front mech, rear mech (which works fine in 9 or 10spd) and eventually the shifters. As long as you don't change the cassette until you change the shifters you can pretty much take your time with the whole thing, Worked out well for me because I got really good deals on each component from various sales and put the whole groupset together for about £350 instead of the £550 it retails at..

    Definitely go for an external BB if you're a heavier rider though. I always had problems with creaky and dying BB's from too much stomping, and I'm only 14 stone. Never had a single problem on road or mountain bike with hollowtech :)
  • Cheers Rich. How did the long cage mech work with a compact (if you had a long cage one)?
  • I think (can't remember for sure) that I had a long cage on originally but then changed to a medium cage when upgrading, didn't notice any problems at all with it
  • John.T
    John.T Posts: 3,698
    The long cage mech will work fine. It just has a longer cage to take up the extra chain on the triple. The rest of the geometry is the same. Most change because a short cage looks better (racier).
  • Thats good to know. At least I can change one bit at a time if I decide to.

    Are there any compatability problems between the different Shimano groups? I assume you can't use Shimano / Campag / Sram mix?
  • Chris James
    Chris James Posts: 1,040
    Richa1181 wrote:
    Definitely go for an external BB if you're a heavier rider though. I always had problems with creaky and dying BB's from too much stomping, and I'm only 14 stone. Never had a single problem on road or mountain bike with hollowtech :)

    To be fair, square taper brackets have been around for donkeys years and some distance riders are still running them due to them lasting longer than more modern designs. External bottom brackets had a terrible reliability reputation when they were first introduced, but seem to have improved in that regard in recent designs.

    For example, see the Bike Radar review of the UN54 bottom bracket

    http://www.bikeradar.com/gear/category/ ... cket-14172

    Having said that, I don't know the chainset and bottom bracket on the OPs bike, so they may be made of cheese!
  • The chainset is an FSA Vero triple. Not sure what the BB is but probably not the best around. I just like the extra stiffness you get from the external BB's. When I switched on my MTB I couldn't believe the difference.

    All i'd like to do at this point is put a compact chainset on with maybe a new short cage rear mech. Seen 105 for next to nothing on some sites. I've used the Sora STI's before and liked them and not bothered about going 10 speed yet. As long as the 105 rear mech works with the Sora shifters and 9 speed i'll be happy (for now).

    I know it might seem stupid to up-grade straight away, but I got a good deal on the bike and can do these mods and still not have spent the rrp on it.
  • sungod
    sungod Posts: 16,885
    105 rear mech will be ok with sora shifters

    also it should work ok on both 9 and 10 speed, so future proof!

    btw there are two vintages of 105 chainset bb, the 55xx was octalink, the 56xx onwards is hollowtech ii, there were some really cheap deals on the older octalink ones last year, if you are buying now i'd look for a 56xx onwards

    if you hadn't already discovered it, you can get all the shimano instructions here for fitting/servicing... http://techdocs.shimano.com/

    and this chart shows compatibility between the various families/series...

    http://tinyurl.com/24rsl8x
    my bike - faster than god's and twice as shiny
  • Cheers again Sun!

    I imagined that most Shimano groups would be compatible. I did read something about the new 105 shifters (with the under bar gear cable) might not work with older 105 rear mechs.
  • John C.
    John C. Posts: 2,113
    Is it worth the bother?

    If anything I would have thought the two larger rings on the triple would be more suitable for cycling on the flat than a compact chainset.

    The inner ring weighs next to nowt and you don't have to use it.[I'd leave it for the time being then if you do end up doing some hills which just may happen, you have your lower gears]
    http://www.ripon-loiterers.org.uk/

    Fail to prepare, prepare to fail
    Hills are just a matter of pace
  • So, got my Compact the other day, a 105 5600 model. I also have a 105 rear mech 5700 model. I noticed that model isn't on the compatability chart that Sungod put on here and am now a bit worried it won't work with the Sora shifters. Does anyone think it might be a problem as i've read about the slightly different pull ration or something?