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Roof mounting carbon bikes - downtube or forks

craigus89craigus89 Posts: 887
edited November 2018 in Road buying advice
I'm looking at options for carrying our bikes on the roof of the car, I'm reading a lot of mixed opinions about whether carbon bikes should be mounted with the more traditional downtube clamp or the clamped at the forks.

My question really is: has anyone actually seen a bike that has been damaged (beyond cosmetically) from using a downtube mounting roof rack?

I think it would be more practical and easy to use a downtube mounting rack, as we have a growing fleet of different bikes and it seems like it would be easier than removing wheels on some occasions, so that is my preferred option, I just wanted to check to see if it is the usual internet bluster about it being 'dangerous' for carbon bikes.

I must say that some bikes wobbling on the motorway do make me nervous, and the fork mounts look more secure...

Posts

  • oxomanoxoman Posts: 10,452
    Fork mounts are sturdier, however I use a Thule one that has a clutch mechanism built into the clamp to stop overtightening combined with a wrap to take shock loading and stop surface damage I assume. Never had a problem even at motorway speeds.
    https://www.halfords.com/camping-leisur ... ke%20Racks
    https://www.tredz.co.uk/.Thule-Carbon-F ... 1400114067
    Too many bikes according to Mrs O.
  • I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings
  • imposter2.0imposter2.0 Posts: 11,729
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..
  • stueysstueys Posts: 1,332
    Fork mount would be more secure, tow bar mount even better if that’s an option.
  • navrig2navrig2 Posts: 1,703
    I have both and have no problems with either.

    The Thule 591
    https://www.sandicliffe.co.uk/shop/thul ... 4kQAvD_BwE

    has a turn knob to tighten the clamp. I doubt I could tighten that enough to damage any downtube. All bikes are firmly held though.
  • cougiecougie Posts: 22,512
    Put some padding in and be sensible. You just want to take up the slack on the clamp.
  • svettysvetty Posts: 1,904
    Imposter wrote:
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..
    This is called 'brinelling' IIRC
    FFS! Harden up and grow a pair :D
  • Imposter wrote:
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..

    Well you say that but I bet it wouldn't have happened with a bike rack that supported the bike with both wheels, or a back door rack that supported the frame so it is still related.
  • craigus89craigus89 Posts: 887
    Thanks for the responses. It obviously depends on how many people have seen this thread, but no one has given me any horror stories about the normal frame mounting roof racks. I'll probably pick up some of the Thule ones linked above.

    Ta.
  • svettysvetty Posts: 1,904
    OnTheRopes wrote:
    Well you say that but I bet it wouldn't have happened with a bike rack that supported the bike with both wheels, or a back door rack that supported the frame so it is still related.

    I'd love to be your bookie :lol::lol:
    FFS! Harden up and grow a pair :D
  • -Dash-Dash Posts: 179
    I've seen a MTB fall through a Thule 591 downtube clamp. The newer 598 has more closure around the downtube and would have prevented it. Still, fortunately the fall happened at low speed turn into a side road and the wheel straps held the bike on the roof. No visible damage to bike or car. Lucky.
  • imposter2.0imposter2.0 Posts: 11,729
    OnTheRopes wrote:
    Imposter wrote:
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..

    Well you say that but I bet it wouldn't have happened with a bike rack that supported the bike with both wheels, or a back door rack that supported the frame so it is still related.

    I think you’re missing the point. ‘Indexing’ is common on old or worn headsets and is nothing to do with how they are mounted on a roof carrier. I’ve had bikes in years gone by which have developed that trait without ever going near a car roof.
  • Svetty wrote:
    Imposter wrote:
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..
    This is called 'brinelling' IIRC
    How would this be caused by a roof rack? Did you keep talking it though a car wash or something?
  • Imposter wrote:
    OnTheRopes wrote:
    Imposter wrote:
    OnTheRopes wrote:
    I can't speak for modern bikes, the last bike I travelled extensively with on the roof was a steel bike with traditional "open" bearings in the headset. After many miles using a fork mount the bearing made small impressions and made the steering kind of indexed. It shouldn't be a problem with sealed bearings

    That would be an issue with the headset, not the fork-mount carrier. Headsets tend to do that as they wear..

    Well you say that but I bet it wouldn't have happened with a bike rack that supported the bike with both wheels, or a back door rack that supported the frame so it is still related.

    I think you’re missing the point. ‘Indexing’ is common on old or worn headsets and is nothing to do with how they are mounted on a roof carrier. I’ve had bikes in years gone by which have developed that trait without ever going near a car roof.
    I've developed quite a lot of wear and tear and I never travel on a roof rack.
  • trek_dantrek_dan Posts: 1,366
    Yakima - both wheels mount which means you don't have to worry about buying bikes with different axle standard. clamps scratching downtubes or removing front wheels.
  • No problem for me clamping carbon downtube with Thule 591. I put clamp close to crankset with chain in big ring. This gave best grip for my canyon frame.

    **Until I drove into carpark with bike on roof. This wrecks carbon frames but probably would with either type of roof rack!
    Summer: Canyon Ultimate CF SL 2019
    Winter/Commuter: Planet X RT-58 6700
    Dead: Specialized Allez Elite 2009
  • I think I'm settled on the Thule 598. I'm sure it will be fine.

    Thanks for the feedback all.
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