Ultegra 6800 calipers

Jon_1976
Jon_1976 Posts: 690
edited February 2014 in Workshop
Does anyone know if it would be ok to run 6800 calipers with 4600 levers? I'm in need of a new caliper and I was intending of upgrading the group to 6800 sometime this year. So was just wondering, instead of getting a 4600 caliper, I could start the upgrading earlier.

Comments

  • Mccaria
    Mccaria Posts: 869
    Assume 4600 is 10 speed Tiagra. In which case it was part of the 5700,6700 generation of products and is compatible with next series 6800. After 6600 Shimano changed the caliper/lever pull ratio for 6700 and have kept it the same for 6800. There can be performance issues mixing 6600 calipers or levers with either 6700 or 6800 but there shouldn't be any for 4600 and 6800.

    See attached chart
    http://www.celebrazio.net/bicycling/shi ... ility.html
  • Bozman
    Bozman Posts: 2,518
    I would have thought that 4600 will have a different pull ratio to 6800 because the 6800 cables are fed under the bar tape while the other are external. Isn't 4600 Tiagra the old gen 5600 105 rebadged.
    They'll still work fine whatever the pull ratio.
  • Mccaria
    Mccaria Posts: 869
    Sorry - double post
  • rolf_f
    rolf_f Posts: 16,015
    Bozman wrote:
    I would have thought that 4600 will have a different pull ratio to 6800 because the 6800 cables are fed under the bar tape while the other are external.

    Why would that make a difference? What determines the amount of cable pulled per unit length of lever movement is the distance between the lever pivot and the cable mount. What happens between there and and the caliper is irrelevant - you could make the cable routing an accurate representation of the Gravelly Hill Interchange and it still wouldn't change the numbers though friction might be an issue! The pull ratio is going to be determined by what people find comfortable and effective.
    Faster than a tent.......
  • Bozman
    Bozman Posts: 2,518
    Rolf F wrote:
    Bozman wrote:
    I would have thought that 4600 will have a different pull ratio to 6800 because the 6800 cables are fed under the bar tape while the other are external.

    Why would that make a difference? What determines the amount of cable pulled per unit length of lever movement is the distance between the lever pivot and the cable mount. What happens between there and and the caliper is irrelevant - you could make the cable routing an accurate representation of the Gravelly Hill Interchange and it still wouldn't change the numbers though friction might be an issue! The pull ratio is going to be determined by what people find comfortable and effective.

    That's when they changed the pull ratio, relevant or irrelevant.
  • Mccaria
    Mccaria Posts: 869
    Tiagra 4600 10speed was only launched in 2011 - well after the launch of 5700, 6700 and 7900. My understanding is that the 4600 was made to be consistent with those groupsets I.e after they had changed the pull ratio. As such it should also be compatible with 6800 as confirmed by the Shimano compatibility charts
  • mister p
    mister p Posts: 405
    1c4e5774-1b0a-4285-8b0e-911173d02895_zps9f96617e.jpg

    The 2014 Shimano book says yes, this combination is fine.
  • majormantra
    majormantra Posts: 2,094
    What's bizarre about that is that Shimano no longer make a 'compatible' STI/long reach brake combination unless you use the crappy 7 speed ST-A070.

    Of course there are plenty of people ignoring those guidelines without apparent issue.
  • mister p
    mister p Posts: 405
    I have used R451 long drop callipers with both ST6700 and ST6800 with no problems. Shimano really do err on the side of caution with their compatibility charts.
  • Jon_1976
    Jon_1976 Posts: 690
    Thanks for the help everyone :)

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