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Should carbon frames go on a trunk rack?

86K views 49 replies 42 participants last post by  martinrjensen  
#1 ·
Hey everyone!

So, I've got a cheap bike rack for my car. Got it back when I had a trunk and now I have a hatchback (rack still fits ok). I've been putting my carbon bike on the rack for a while (even used it when I moved cross country from UT to WI a few years ago). A bunch of people at the LBS just told me you shouldn't ever put a carbon bike on a trunk rack (I guess you're also not supposed to put all your weight on the top tube, either, according to the same people). Is that true?

I'm just wondering if it's a myth, or if the tight ties on the rack paired with road bumps somehow damage the frame. I did notice a tiny indentation in my top tube the other day and wondered if that's how it got there. I've been putting the bike inside the car since I heard this, but want to know if there's actually any science behind the claim. If so, I hope I haven't caused any actual damage...
 
#5 ·
I'm somewhat concerned about having my carbon bike with other bikes all stacked up on a bike rack. They tend to move around during transit, and the frames or pedals often bump together. So the carbon bike goes inside the car (safest option) or on the roof-mount (which brings its own complications), while the random collection of aluminum bikes go on the back.
 
#7 ·
I'm somewhat concerned about having my carbon bike with other bikes all stacked up on a bike rack...
Me too so I don't put my carbon bike on a rack with other bikes either. But if it's the only bike on rack that supports it under the top tube (hitch rack in my case) then I'm not worried. IMO trunk racks tend to have the bike lean in towards the car more and represent a "whole 'nuther" list of complications to both the car and bike finishes.
 
#8 ·
I have a pair of cylindrical foam packing implements (have no idea what to call them) that come when bicycles are shipped from the factory. I put them around my top tube and then attach the bike to the trunk rack so that the foam is between the straps and the top tube. (Is that described clearly?) It prevents any scratching but holds the bike firmly enough that I don't have to worry. It also makes me worry less about any kind of structural damage that my bike may experience when traveling due to bumps etc. because it basically float in the squishy foam. You might try that. I've been carrying it for some time that way and have never had an issue.
 
#11 ·
All that UV radiation will melt your frame. Use sunbolck on the frame, if you ride outside. Rain will also make the frame soggy. Bird droppings will burn right through a crabon frame.

Watch out.......
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#14 ·
Fair enough - but any self-respecting bike could be put on a trunk rack.

You should (or shouldn't) put a carbon bike on a trunk rack for the exact set of reasons that you should (or shouldn't) trust life and limb to it while riding. If you are comfortable with one, you should be comfortable with the other. If not...
 
#17 ·
I just got a trunk rack (Saris Bones) for my "other" car that won't work with any other kid of rack. I originally intended to use one of those adapter bars designed for women's bikes that goes between the stem and seat tube and hang it from that, but there wasn't enough clearance between the top tube and the bar at the front to get it on the rack, and the bike would probably hang too low. Short of doing Dukes of Hazard type jumps, I can't imagine the load on the top tube would be a problem given how light the bike it. It won't be my primary bike rack (have a fork secured roof rack on the "regular" car), but I'm not worrying about using it when I need it.
 
#18 ·
I'd like to know if anyone making the following statements has actual experience or is just relating "what the guy said", urban legend sort of stuff:

Don't hang a carbon fiber bike from a trunk rack

Don't sit on a carbon fiber bike top tube.

The reason I ask is that so much of this stuff is just urban legend. Does anyone have actual first hand knowledge of either of those things damaging a bike? Can anyone point to manufacturer's directions not to do either?

I'm not claiming I know, because I don't. It's just that I see guys - the duffers I ride with as well as photos of real racers - sitting on top tubes all the time. It's very common as far as I can tell.

In addition, guys I ride with carry their bikes in normal dangling type trunk and hitch racks all the time. I personally don't but I wouldn't even put my crappy old steel mountain bikes on there because one of the reasons every old bike in my family is beat up is because we used to carry them on those dangling type of racks. It's not the top tube I'd worry about, it's getting beat up by the wheels, bars and cranks of the other bikes. We've converted to hitch and roof mount upright tray type carriers, or slide the bike individually inside the Subaru.

Finally, to complete my rant: Is it really reasonable for any reputable bike manufacturer to design a bike that will not withstand two entirely predictable and normal uses? I'm saying that carrying a bike that way and sitting on the top tube is common, predictable, and I would consider normal use for a bike - therefore any bike that can't withstand that use is defective.
 
#21 ·
<snip>

Don't sit on a carbon fiber bike top tube.

The reason I ask is that so much of this stuff is just urban legend. Does anyone have actual first hand knowledge of either of those things damaging a bike? Can anyone point to manufacturer's directions not to do either?

<snip>
I have first hand knowledge of an Orbea top tube failing when sat upon at a stop light. To be fair, the rider weighed in at 190 or so (it wasn't me), Orbea would not warranty it. Since then, I won't sit on my TT!
 
#19 ·
I have an '05 focus hatch. Trunk rack, mainly because I don't feel like drilling the roof for a roof rack.

It is more the vibrations on the top tube that is the major concern. If the bike does not jump or vibrate loosely on the rack, then you have nothing to worry about. I would not suggest driving across the Western Hemisphere with it attached.

I ride a super6. So carbon to carbon.
 
#42 · (Edited)
Oh c'mon! Top tube vibrating is going to cause damage? What happens when you ride? Ever take your CF bike on a chip & seal road? Do you ever go over bumps? Ever ride on rough roads? What do you thing happens then? And those examples include your body weight on the bike, not the 15-20# the bike weighs. :rolleyes:

I also have a Focus hatch back I the bike goes inside because it's easier & faster for me to load & unload the bike, not because it might damage the CF. My CF bike also gets carried on a trunk rack.

Carbon fiber on bicycles isn't that fragile. You have to be very careful when clamping it, e.g.. the seat post. Also it may be damaged if it gets whacked hard. Aside from that...what?

Again-borrowing from another poster on these forums, ":It ain't a tea cup that the queen gave you." Ride it & carry it on a trunk rack if you want. As I said earlier, when I carry mine on a trunk rack I wrap the tubes where it's going to contact the rack with a rag, and the only reason I do that is to protect the paint.
 
#25 ·
I own a convertible and treat my vinyl top with 303 Aerospace protectant which aids in protection and prevention of UV damage. It has kept my vinyl top looking brand new.

303 Products, Inc.: 303 Aerospace Protectant

I started using this on my carbon bike. I spray a little bit on a microfiber cloth and trace the entire frame. I let it soak in the 303 for about 10-15 minutes then I wipe it completely dry. It really gives my bike frame a silky surface after treatment. It puts me at ease to know that my bike is wearing sunblock on those blistering hot days, and won't melt away like a box of chocolates :D
 
#30 ·
The dealer where I brought my latest bike had a demo where he took a CF tube and whacked it as hard as he could on a desk corner. Not a bit of damage!
All CF tubes are not equal. A carbon steerer is a beefy tube, no doubt. But some areas of the top tube of a high-end carbon frame bike are very thin - to the extent that you can easily push in the tube with finger pressure. If you whack that area on a desk corner it is going to fold or crack. Some Al tubing has the same property by the way.
 
#32 ·
Don't be regretful. Almost all of the "scares" are nothing but a bunch of cow puckie. when I saw the OPs post that said "...A bunch of people at the LBS just told me you shouldn't ever put a carbon bike on a trunk rack. The 1st thing out of mouth would have been, "Who are you & how do you know?" I'm fortunate that I have a hatchback that my bike will easily fit in, but it's been carried many times on a trunk rack. I just put a small rag around the tubes where the rack clamps it & that's only to protect the paint.

What exactly is supposed to be harmful about it? Shouldn't put that much weight on the top tube??? What does the bike weigh-16-20#?
 
#35 ·
Check out the Thule 9003. It has a platform, so your bike rests on its wheels, not hanging from the top tube.

There are clamping arms that hold top tubes, but you are able to set them very gently against the frames so as not to hurt the carbon, then lock them in place so they can't be tighten or loosened.

I have one on my car and I really like it.

Image
 
#37 ·
I have a light weight version of this from a place called hollywoodracks.com. The only problem I've had these last two years is that if the bikes are very similar (i.e. both similar size road bikes) it is very difficult to make the attachment brackets (the ratcheting ones) fit over the frame properly. You have handle bars interfering with saddles on both ends, and the resulting required distance between the bikes not quite within the reach of the hold-downs. It's much easier if the bikes are dissimilar...
 
#38 ·
I opted for the tray-style carrier for our car as well--mine's a KĂĽat. Very sturdy. secure mounting of the bikes with a strap for the rear wheel and tension bar for the fronts. Rack comes with a nice maintenance post/clamp as well.

Some stock pics from the company site:

Image


Image
 
#40 ·
I put my Madone 5.2 on my Saris Bones trunk rack all the time. No dents or scratches. I would love to have a hitch mounted rack but there are no hitches available for my car, and I can't use a roof rack because it's a convertible. In any event I have read several threads here in the past of people driving into their garages with he bike still on the roof. Not one actual story of a frame being damaged by a trunk rack. Trek does say on their website somewhere not to put their carbon bikes on a rack like that but my LBS said it would be ok. I also store the bike by hanging it by the top tube.