Changing components

niki3
niki3 Posts: 3
in Workshop
Looking for advice, I currently have 53/39 chainring with 11/28 cassette. All ultegra 6700. Double crankset ,5 arm 130 BCD, short derailer. 10 speed. 6700 10 rear mech
I now live in a very hilly area and want to change to an easier set up.
My question is can I go to a 50/34 with a 11/30 cassette without changing anything else? Also would I need a new chain and if so, would the 6701 be the one I need.
Thanks in advance

Comments

  • Mad_Malx
    Mad_Malx Posts: 5,183
    the short (SS) derailleur might struggle with a 30T cog, but lots of people get away with it.

    Unless your chain is nearly new it’s a good idea to change the chain if you change the cassette. Use any 10s road chain (the cheaper tiagra ones are fine).
  • MattFalle
    MattFalle Posts: 11,644
    you'll need a new crankset as the compact is a 110BCD and you have a 130 unless you can track down some compact 130s.

    Fibrelyte do these or go on the bay of e.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • dj58
    dj58 Posts: 2,224
    Assuming you are staying with 10sp Ultegra 6700 series, then as above you need to track down a FC-6750 compact 50/34 crankset. The smallest inner you can fit to your 130 BCD double crankset is a 38T.

    Regarding the cassette you have the choice of a CS-6700 11-28T if your RD is the RD-6700 or a CS-6700 12-30T if your RD is the RD-6700-A. You can identify the RD-6700-A by the 30T stamped into the upper outer derailleur pulley cage, adjacent to the upper guide wheel.

    You could also use a Tiagra CS-4600 12-30T if you can find one. There was no CS-6700 11-30T that is an 11sp series cassette.

    Chain, yes Shimano CN-6701, CN-5701 or CN-4601. if you want a chain with a quick link, KMC, SRAM and Connex all do 10sp.
  • MattFalle
    MattFalle Posts: 11,644
    https://forum.bikeradar.com/discussion/13117885/shimano-105-chainset-50-34-and-rotor-q-rings#latest

    buy this and use this. just as good as Ultegra.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    Some people also say that if you use oversized pulley wheels you can use a bigger cassette than normal but i've never tried this so not sure if it works but for a few quid off the 'bay/alibaba its worth a punt.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • First.Aspect
    First.Aspect Posts: 17,397
    MattFalle said:

    Some people also say that if you use oversized pulley wheels you can use a bigger cassette than normal but i've never tried this so not sure if it works but for a few quid off the 'bay/alibaba its worth a punt.

    Surely that would make things worse?

    Shimano are quite conservative with their gear ranges. If it were me I'd try a 30t with existing rear derailleur before buying.
  • MattFalle
    MattFalle Posts: 11,644
    Agree - I've slung a 2 tooth bigger than recommended cassette on a shortcage mech before and it was only small/small where you had an issue, so deffo worth a pop.

    re pulley wheels: dunno. never tried it, never needed to.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • masjer
    masjer Posts: 2,743
    If you wanted to do it on the cheap, you could buy a 9 speed MTB derailleur https://merlincycles.com/shimano-alivio-m3100-rear-derailleur-9-speed-242834.html
    This way you could keep using the existing crankset and get a larger 12-34(36) cassette.
  • MattFalle
    MattFalle Posts: 11,644
    or one of those wolf's tooth thingies
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • lesfirth
    lesfirth Posts: 1,382
    edited February 2022
    First.Aspect said:

    MattFalle said:

    Some people also say that if you use oversized pulley wheels you can use a bigger cassette than normal but i've never tried this so not sure if it works but for a few quid off the 'bay/alibaba its worth a punt.

    Surely that would make things worse?

    Shimano are quite conservative with their gear ranges. If it were me I'd try a 30t with existing rear derailleur before buying.
    I have never tried it but as I see it, bigger jockey wheels will increase chain wrap ( the amount of slack chain that the rear mech can take up ) but will reduce the size of the biggest rear cog you can use. Lack of chain wrap is not a problem. A sagging chain in small front and small rear cog does not matter because you do not need to use that. So the idea ( IMHO) that fitting bigger jockey wheels will help the OP is nonsense.
  • MattFalle
    MattFalle Posts: 11,644
    agree completely. its a daft idea. bigger jockey wheels. tchaaa.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • niki3
    niki3 Posts: 3
    dj58 said:

    Assuming you are staying with 10sp Ultegra 6700 series, then as above you need to track down a FC-6750 compact 50/34 crankset. The smallest inner you can fit to your 130 BCD double crankset is a 38T.

    Regarding the cassette you have the choice of a CS-6700 11-28T if your RD is the RD-6700 or a CS-6700 12-30T if your RD is the RD-6700-A. You can identify the RD-6700-A by the 30T stamped into the upper outer derailleur pulley cage, adjacent to the upper guide wheel.

    You could also use a Tiagra CS-4600 12-30T if you can find one. There was no CS-6700 11-30T that is an 11sp series cassette.

    Chain, yes Shimano CN-6701, CN-5701 or CN-4601. if you want a chain with a quick link, KMC, SRAM and Connex all do 10sp.

    Thank you. Regarding the FC6750, you say compact, mine at the moment is a double, would this make any difference to what you have suggested?
  • dj58
    dj58 Posts: 2,224
    Hello, Your FC-6700 crankset is a standard double, the FC-6750 is a compact double 50/34T as opposed to the FC-6703 which is a triple. There are also super compacts like the GRX 2X 46/30T 48/31T, these would not work with your existing STI and FD-6700, according to the Shimano compatibility chart. My bike uses a FC-6750 50/34T, RD-6700-A and CS-4600 12-30T.
  • niki3
    niki3 Posts: 3
    dj58 said:

    Hello, Your FC-6700 crankset is a standard double, the FC-6750 is a compact double 50/34T as opposed to the FC-6703 which is a triple. There are also super compacts like the GRX 2X 46/30T 48/31T, these would not work with your existing STI and FD-6700, according to the Shimano compatibility chart. My bike uses a FC-6750 50/34T, RD-6700-A and CS-4600 12-30T.

    Brilliant thank you. I dont know anything about compatability. Would I be able to put 105 crankset and cassette on the 6700 groupset. The 6750 seems to be like gold dust. Just to keep my options open if I cannot get the 6750
  • dj58
    dj58 Posts: 2,224
    edited February 2022
    Hello,

    If you cannot locate a good SH 6750 you can use another Shimano HOLLOWTECH II compact double, so yes 10sp105 FC-5750, FC-4650, 4700, also there are people on this forum who have successfully used 11sp double compact cranksets Ultegra FC-6800 and 105 FC-5800 with an otherwise 10sp transmission. Not sure if anyone has used the latest Ultegra FC-R8000 or the 105 FC-R7000 they may also be a possibility.

    There are also Shimano Non Series compact double cranksets FC-R565, FC-RS500, FC-RS510. Yes you can use a 105 CS-5700 cassette.
    Useful documentation in PDF format here https://si.shimano.com/#/
  • webboo
    webboo Posts: 6,087
    A compact chainset is 50 x 34 and is a double like your 53 x 39 chainset.
    Getting rid of drafts.

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