preferred-google-button
log in
register

46/30 crankset on a Giant Defy 4?

  • Creator
    Topic
  • August 18, 2015 at 6:50 am #24638
    exilegareth

    BTW, please please do flood the thread with posts suggesting I should MTFU and run huge gears that real men can turn while sipping an espresso – I do need a laugh in the morning…

    Anyway, I’ve got my 2014 Giant Defy 4 sitting on the landing, which is going to be used this winter for commuting and social runs out with friends. It still has the bog standard Shimano Claris gears, with FSA crankset. I am heavy, slow and old, and would probably find hills less horrible (although I live in Northumberland, a county that specializes in horrible hills) if I could swap out the 50/34 crankset for 46/30 – but no-one seems to make them and sell them in the UK, because cyclists aren’t supposed to be heavy, slow and old….

    Does anyone know if this setup is possible or doable on a reasonable budget that doesn’t involve getting the dwarves of Ankh-Morpork to hand craft the parts in Unobtainium in return for buckets of gold? Someone did suggest, as an alternative, getting a new rear mech and a cassette with sprockets the size of dinner plates, but the dwarves don’t seem to make these either…

  • Creator
    Topic
Viewing 7 replies - 1 through 7 (of 7 total)
  • Author
    Replies
  • August 18, 2015 at 2:25 pm #857333
    0
    Simon E

    For a triple you would need a
    For a triple you would need a new front derailleur as well as chainset and STI.

    If you put a 32t cassette on the back (your rear derailleur may be fine, otherwise slap on a ‘GS’ medium cage one) for 28″ lowest ratio, which is pretty low with 34t chainring. Dropping a 4 teeth on the front won’t make a huge difference, bottom ratio on 30×32 would be 25″.

    You won’t get much lower gearing without a MTB style chainset, which probably requires a lower clamping point than on your Defy.

    I believe you can run 36t cassette with a MTB rear mech (the 9-speed XT?) but would have to dig through back issues of CTC mag for the details.

    Don’t forget to work on your climbing technique – pedalling, breathing, posture. This will be of far greater benefit than any amount of gearing, lightweight stuff, carbon, drillium etc. GCN videos are good and most road-oriented sites discuss climbing technique regularly. Like anything worth achieving, it takes time and effort, but is very rewarding.

    Edit: just seen your reply to bushman. Hope you get something sorted.

    August 18, 2015 at 10:16 am #857331
    0
    exilegareth

    Hi Bushman,
    Have emailed via
    Hi Bushman,
    Have emailed via your website…. Cassette is 11/32

    August 18, 2015 at 9:54 am #857329
    0
    bushman

    Fellow Northumbrian from
    Fellow Northumbrian from Cycle Art here. We do this kind of conversion all the time so come and see us if you like. It does make more difference changing the sprockets at the back but if you prefer the chainset route we can do that to. You may have chainline issues trying to use an MTB chainset but Im sure we can work something out. What size cassette do you currently have?

    August 18, 2015 at 9:09 am #857327
    0
    exilegareth

    In reverse order
    Hi Kev-s – I
    In reverse order
    Hi Kev-s – I did consider just doing a triple conversion, but that probably demands a new left hand bar lever, (they’re different models on triples and compacts) which costs more than a crankset!
    Hi Joemmo – I started exploring the crankset route because, while lots of people thought a new mech and cassette were possible in theory, no-one seemed to have done it in practice and there seemed to be a lot of fettling involved…
    Hmmm – I may just see if I can ebay some second hand bits, take ’em apart myself and see how it’s going to work….

    August 18, 2015 at 8:37 am #857325
    0
    kev-s

    Depending on what model fsa
    Depending on what model fsa crank you have you could just buy new chainrings in those sizes (or as near as you can)

    http://www.chainreactioncycles.com/chainrings?f=2259,4294966649

    Or buy a triple crank, most have 50.39.30 chainrings

    http://www.chainreactioncycles.com/cranksets/road-cranksets?f=2259

    August 18, 2015 at 8:18 am #857323
    0
    joemmo

    Fellow Northumbrian and anti
    Fellow Northumbrian and anti gear snob here too.

    The cassette and mech option (you’ll also need a new chain) is probably the easiest option but if claris is 8 speed you are limited to 11-32 at least as far as I can see. There are plenty of options for the mech and a long cage 8-9 speed mtb is probably your best bet.

    If you want to go the chainset route then you could get a road triple and run it as a double with the inner 30 ring and an after market 46 in the middle position using single chainring bolts. You might need a different front mech but I suspect it will probably work OK.

    Option B for chainsets is to fit an MTB double but you would likely need spacers at the bottom bracket to correct for the axle width.

    Good luck

    August 18, 2015 at 7:45 am #857321
    0
    Mombee

    There’s no shame in running a
    There’s no shame in running a smaller crankset and Shimano do a CX50, which is designed mainly for cyclocross set-ups, but in principle there’s no reason why it shouldn’t work for you. The black-magic will involve checking whether it’s an easy swap with the existing bottom-bracket, which again in principle it should be as they’re both Shimano, but I’d suggest getting help from a local bike shop if you’re unsure.
    The other option might be to whack a bigger (dare I say it, mountain bike) cassette on the back, but that may need a longer-cage derailleur as well and unfortunately Shimano mountain bike derailleurs aren’t as compatible as they’re road brethren, so agin the LBS might be needed.
    Just for the record, I’m running two cyclocross bikes – a Kinesis with a standard compact chain set, it’s fast, but can be hard to ride in the steep rough stuff – and a Cannondale CAADX with a 46/36 chainset that’s clearly happier on harder terrain, but has equally done sterling service piling on the road miles during the winter, so a cyclocross chain set isn’t as daft as some might think.

  • Author
    Replies
Viewing 7 replies - 1 through 7 (of 7 total)
  • You must be logged in to reply to this topic.