Carbon fibre engineer's advice sort after,,,
I have a technical question regarding my PX pro carbon.
I'm using it for an unsupported JoGLE trip (b&b, not camping) so am wanting a rack for it.
I understand all the arguments that this is an unsuitable bike etc, but I have ONE bike.
It's this one.
It is not a steel or Ti audax'er/tourer.
I can't get another one. So I have to make do.
I love my bike. I don't find the front end 'flexy' as others do. I want to do this ride on MY BIKE, not a hire bike.
It is a carbon frame, with alloy rear mech dropout and an ally seat post.
I am 64kg and plan to carry around 10kg (max) of kit in panniers.
So total weight is not a problem as I see it, when guys of +85kg ride the same bike.
Plus I will be using a 32 spoke Open Pro on a shimano hub on the rear wheel, so I am pretty sure I could carry an elephant from a weight perspective with the wheelset,,,,,
I asked a question of Planet X if a rack that attaches to the quick release skewer and a seat clamp would be ok.
(Such as the Bontrager Backrack Lightweight http://www.evanscycles.com/products/bontrager/back-rack-lightweight-bike... or Axiom Streamliner Road DLX etc...attaching to an M:part seat clamp http://www.ukbikestore.co.uk/product/407/spt102/mparts-seat-clamp-mount-... )...
According to a response from Planet X, any rack is UNsuitable, however it attaches.
But a seat post 'beam rack' would be ok. (Such as the Topeak MTX etc,,,,)
Can someone please explain to me why this would be the case?
I understand that you wouldn't want to 'compress' a carbon seat stay with 'p-clips', but with adapters that attach the rack to the QR skewer and either a seat post clamp or the actual aluminium seat post itself, there is surely no alternate stresses applied to the carbon fibre bits of the frame than in normal riding?
As far as my tiny mind can see, the weight that is on the rack, is being born by the wheel, hub and skewer, with minimal torsional forces applied to the aluminium seat post.
In any case, these forces would surely be greater on a rack that ONLY attached to the seat post, as with the beam rack?
If someone with more idea on carbon fibre frame construction than me can help understand why the beam rack is ok, but the QR and seat post rack is a 'NO-GO,' I would be most appreciative.
I had a look using the 'search' function, and also, Google, but I didn't find anything other than folks saying nothing should attach to a carbon bike etc,,,,
Anyway, if you have made it this far through my question, well done.
Thanks for reading/listening/helping,
Kind regards and happy cycling,