Carbon fiber bikes and hitch-mounted racks

Quote:

Originally Posted by BNAllen 

I rode in the late 1980's and throughout the 1990's. I sold my Bianchi road bike several years ago.

 

Earlier this spring, my wife decided that she wanted to ride the roads ... as it happens, we both now have nice carbon fiber bikes and we ride as often as we can.

 

Here is my dilemma, is our hitch-mount Allen rack acceptable for our carbon fiber bikes. The bikes do not rub against each other, they do not bounce around, however, the bikes do ride on the top tube ... I worry that resting on the top tube could be a problem (structural integrity, mostly) ... can someone please advise or direct me to a site where I can educate myself on this matter?

I posted this exact question about 4 months ago. The consensus was that while some wouldn't dream of anything touching their carbon fiber bikes, most said there was no problem with the top tube hanging bike racks, I bought one of the Yakima 4 bike racks and have had absolutely no issues at all.
 

For what it's worth I hang my Carbon bike in my garage on a rack by the top tube.  It has been  stored this way since 07 and nothing bad has happened at all.

Kind of reminds me of hanging your bike by the wheels from the ceiling with hooks. Some folks thought this to be a bad idea also.  Did that for years also without any ill effects.

Bikes are made of strong materials that are subjected to all types of mechanical stress while in use. They are not made of fine china so enjoy your rides and dont sweat about the bike hanging in back of your vehicle.

Although I would worry about the brakes on the vehicles following.

I have a Giant TCR carbon road bike and a pretty old Swagman, four bike, top tube clamping hitch rack.  Not a lying on top of the four bike arm with nice rubber overstraps and a padded hanger but a clamp down with large thumbscrews C L A M P.  I was not going to clamp my nice carbon bike in that thing so I bought a Thule 982XT Frame Adapter that goes between the stem and seatpost of the bike giving you a place to hang or clamp the bike to whatever. 

Bought the Thule from my local bike shop though another not quite so chichi adaptor looked better to me but I went with the store recommendation.  I'd used the adaptor with the same rack on the same car for three trips from Albuquerque (Los Q is what I call it) to Los Angeles (LA is what we all call it) and on two of three trips all was well. 

I did not like that the Thule adaptor would always allow the stem to swing and did not lock along its length making the bike never quite solid on the hitch rack but it still kept the nasty clamp away from the carbon fiber. 

Last trip, not quite the worst thing happened but a bad one anyway.  The adaptor bar puts the bike quite a bit lower in relation to the hitch rack than if you were hanging the bike off the rack so the wheels are a lot closer to the ground.  That was obvious from the first time we used the rack and adaptor but on this trip, for whatever reason, we must have hit the Interstate 40 "whoops" a lot faster and the rear wheel ended up trashed on arrival in California.  Hard lesson learned but not quite sure how to solve it (other than not have the teenager drive while the adults both take their sleep shift).

I'd spend a couple hundred on a platform rack for the hitch to insure your very expensive bikes don't get damaged.  They can hang ok in storage, but if you hit a hard bump, all that force is going to go to the rack and transfer right to the frame. 

I use a trunk mounted rack and have no problem putting my Trek 5500 on it. Carbon fiber is lightweight and STRONG! While it isn't impervious to damage, if you take caution and mount the bike securely (in other words, mount it in such a way that it can't move, shift or bounce around while you are driving) it will be just fine. Some people swear by using roof racks, but others, like myself, use trunk-mounted racks with no problems. Just make sure there is sufficient padding anywhere your frame touches the rack. Some foam padding and duct tape will do the job. It may not look pretty, but it will work wonders for protecting your frame.

Indeed, exercising some common sense is key.  There is a big difference between the clamping force neded to hold the bike still and the force required to crush the toip tube.  And this is not a property that is unique to carbon fibre either.