28mm tyres on new zondas/giant defy composite?

johngti
johngti Posts: 2,508
edited February 2017 in Road buying advice
What do we think? 2014 defy comp, the new c17 zondas. Or just stick with 25mm? Planning on continental gp4000sii tyres.

My concern would whether there's enough clearance for 28mm. It'd be good to know if anyone is running that size.

Comments

  • shortfall
    shortfall Posts: 3,288
    I tried 25mm gp4000s on the old Zondas and the tyres actually fouled on the underside of the fork crown (3T Rigida Pro) to the point that the tyre wouldn't rotate! Guess these tires have quite a tall profile as I've had no problems with 24mm Rubino Pro Radiales or 25mm Rubino G+ .
  • flasher
    flasher Posts: 1,734
    I have no idea, but GP4000's size up quite a bit my 23mm come in at virtually 25mm and 25mm at a smidge over 27mm, therefore it wouldn't surprise me if 28mm come in at over 30mm.
  • johngti
    johngti Posts: 2,508
    Flasher wrote:
    I have no idea, but GP4000's size up quite a bit my 23mm come in at virtually 25mm and 25mm at a smidge over 27mm, therefore it wouldn't surprise me if 28mm come in at over 30mm.

    Now that's interesting to know. I have an old pair of 25mm Michelin pro 4 sc tyres lying around. I believe they come up a bit big. Might fit them tomorrow and have a look.
  • zefs
    zefs Posts: 484
    I use the 28c gp's and they measure 30mm. The overall improvement in comfort is very noticeable when compared to 25c (which are 25mm) of the same tyre. No penalty in rolling resistance atleast in my observation.
  • johngti
    johngti Posts: 2,508
    zefs wrote:
    I use the 28c gp's and they measure 30mm. The overall improvement in comfort is very noticeable when compared to 25c (which are 25mm) of the same tyre. No penalty in rolling resistance atleast in my observation.

    What bike are they fitted to? Still slightly concerned about clearance
  • zefs
    zefs Posts: 484
    Defy advanced 3 2016 model.
    Also here's the test for rolling resistance, you can basically run them 20psi lower than 25c without loosing watts: http://www.bicyclerollingresistance.com ... i-23-25-28
  • johngti
    johngti Posts: 2,508
    zefs wrote:
    Defy advanced 3 2016 model.
    Also here's the test for rolling resistance, you can basically run them 20psi lower than 25c without loosing watts: http://www.bicyclerollingresistance.com ... i-23-25-28

    Seems like a no brainer if they'll clear the brakes then.
  • gimpl
    gimpl Posts: 269
    johngti wrote:
    zefs wrote:
    Defy advanced 3 2016 model.
    Also here's the test for rolling resistance, you can basically run them 20psi lower than 25c without loosing watts: http://www.bicyclerollingresistance.com ... i-23-25-28

    Seems like a no brainer if they'll clear the brakes then.

    Except I'm pretty sure that the 2016 Defy Advanced is disk brake and yours (and mine) isn't.

    I'm interested in the answer though as might be able to fit 28 mm on mine too.
  • johngti
    johngti Posts: 2,508
    Yeah I spotted that. I'll have a look tomorrow; may have to stick with 25mm.
  • johngti
    johngti Posts: 2,508
    This is a 2016 TCR. Doesn't give me much hope that the rim brakes defy will work...

    https://youtu.be/wyEc5N-B-ew
  • letap73
    letap73 Posts: 1,608
    If it is any consolation the 25mm GP4000s make for a very confortable ride.
    Saying that, I am running 28 mm Schwalbe ones on an admittedly wider rim (Archetypes) than the Zondas - with plenty of clearance on my advanced defy.
  • johngti
    johngti Posts: 2,508
    Rim brakes or discs? I had a brief flirtation with 25mm gp4000sii on the older zondas I've just sold in the classifieds last summer before getting tubeless wheels and tyres. Now I've bought the wider zondas I'm back to clinchers (thought I was getting two way fit wheels to carry on the tubeless theme - eBay purchase off a private seller so not really worth messing about with). I don't remember the 25s to have been uncomfortable to be honest.
  • letap73
    letap73 Posts: 1,608
    Older advanced Defy - rim brakes.
  • dj58
    dj58 Posts: 2,223
    John, I don't know what brake calipers you have on your Defy, but 105 5800 brake calipers have clearance for up to 28c tyres, which may help if the only issue is clearance on the existing calipers.
  • johngti
    johngti Posts: 2,508
    Ultegra. I know there's no clearance for mudguards with 25mm tyres. No idea how that would compare to wider tyres though
  • johngti
    johngti Posts: 2,508
    Had a look. Bike currently has the original 25mm tyres on Giant c15 rims. I can just squeeze a 5mm Allen wrench in between the tyre and the bottom of the fork. This leads me to think that Conti 28mm tyres would probably be too close fitting for comfort so I'll stick with 25s

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