Shimano Mixture Query

jpower
jpower Posts: 554
edited August 2019 in Road buying advice
Hi,

Few parts needed changing on the bike, thought I'd try upgrading but I am unsure about crank compatibility.

So the bike came with 105 5800 groups (hydraulic disc brakes)

So far have bought Ultegra 6800 front and rear derailleur

Now I want to change my 50/34 to 52/36 question I have is can I use 105 R7000 crank? Prefer not to have to change BB.

Thanks.

Comments

  • keef66
    keef66 Posts: 13,123
    Should be a straight swap leaving the existing BB in there.

    Out of curiosity, any reason you went for 6800 rather than R8000?
  • jpower
    jpower Posts: 554
    keef66 wrote:
    Should be a straight swap leaving the existing BB in there.

    Out of curiosity, any reason you went for 6800 rather than R8000?

    So this is for the +1 bike on which I try and keep costs down. I thought I read you can't go 5800 to 7000/8000 derailleur hence the 6800 plus they were nearly new buys from eBay so reasonable price.

    However I am now tempted to just go with front and rear R7000 plus the crank - I assume that would work?
  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,063
    I think I read somewhere that R7000 cranksets don't work quite so well with 5800 front derailleur, no idea if that applies to 6800 too, IIRC it was to do with chain rub.

    BB should be fine.
    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • jpower
    jpower Posts: 554
    so maybe going 7000's on those 3 parts maybe better
  • keef66
    keef66 Posts: 13,123
    NitrousOxide wrote:
    I think I read somewhere that R7000 cranksets don't work quite so well with 5800 front derailleur, no idea if that applies to 6800 too, IIRC it was to do with chain rub.

    BB should be fine.

    According to Shimano R7000 chainset is OK if it's a 5801 front derailleur, so maybe the 5800 FD is an issue
  • philbar72
    philbar72 Posts: 2,229
    NitrousOxide wrote:
    I think I read somewhere that R7000 cranksets don't work quite so well with 5800 front derailleur, no idea if that applies to 6800 too, IIRC it was to do with chain rub.

    BB should be fine.

    the newer cranksets are very slightly different in terms of spacing. its a minor adjustment on a front mech to sort out.

    they definitely work!
  • joe_totale-2
    joe_totale-2 Posts: 1,333
    May be worth keeping an eye on eBay for something like this:

    https://www.ebay.co.uk/itm/Shimano-Ulte ... Sw~epdRf~w
  • jpower
    jpower Posts: 554
    Joe Totale wrote:
    May be worth keeping an eye on eBay for something like this:

    https://www.ebay.co.uk/itm/Shimano-Ulte ... Sw~epdRf~w

    Will do. Gone with R7000 front and rear will keep an eye on the cranks but I do like the slightly chunkier R7000/8000 crank.

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