Roof mounted racks - carbon frame
Discussion
seat collors on carbon tubes are about 4.5-5nm so a clamp on a roof rack on the down tube will be way more than that to keep it secure, also on a roof rack pressure is applied to the frame in a position and manner in which it was not designed to withstand. i've seen carbon bikes transported on roof racks and probably without any damage but if it gets windy or you take a tight corner quite speedy you never know what might happen.
A friend of a friend is the UK warranty manager for Trek and he has seen numerous frames fail due to car racks which are not covered by warranty so beware! The only safe option would appear to be those which clamp the forks.
Workstands that clamp the frame are equally troublesome too.
Workstands that clamp the frame are equally troublesome too.
pablo said:
seat collors on carbon tubes are about 4.5-5nm so a clamp on a roof rack on the down tube will be way more than that to keep it secure, also on a roof rack pressure is applied to the frame in a position and manner in which it was not designed to withstand. i've seen carbon bikes transported on roof racks and probably without any damage but if it gets windy or you take a tight corner quite speedy you never know what might happen.
The rack won't be subject to motorway speeds (more 25mph tops 
) so it's more the clamping force that I'm worried about. Looks like a fork clamp is the way forward! Any recommendations as to type?Only one I know of is the Thule 561 but I modified one of the one's that clamp the frame using an old Q/R and some metal so I can now carry a bike either way, clamping down tube or using the fork drop outs. Drove 600 miles from Germany with no problems. Don't use it that much so couldn't justify the cost of the Thule.
If there is flexibility to go for a rear mounted rack, then I can recommend the Saris Gran Fondo. I got one last week and it did a great job with two bikes at the weekend. Quick to set up/remove but also very quick to mount/dismount the bikes. The bikes are held in place by the wheels only and in a way that makes things not only secure and carbon friendly, but also quite aero so less fuel economy hit and a lot lower than if mounted on the roof. The final bonus is that unlike any other rear mounted carrier your number plate and lights are completely visible so no need for a lightboard/electrics.
A guy at the place we were at had one of the fancy Thule Ride on tow bar mounted racks and we had two bike secured and were off before he managed one.
No association with Saris, just an impressed customer. Looking forward to using it to take the bikes to follow the TdF for a few days in July!
A guy at the place we were at had one of the fancy Thule Ride on tow bar mounted racks and we had two bike secured and were off before he managed one.
No association with Saris, just an impressed customer. Looking forward to using it to take the bikes to follow the TdF for a few days in July!
Hackney said:
What!
I can't carry my bike on the car?
Is that an over reaction? How do I carry my carbon bike on the car then?
Was going to get a Saris Bones 2, is that OK?
Chill I can't carry my bike on the car?
Is that an over reaction? How do I carry my carbon bike on the car then?
Was going to get a Saris Bones 2, is that OK?
You can, just don't clamp it on the tube. Hanging on a rear rack is fine, as is clamping by the forks with the front wheel removed on a roof rack 
I've used the Thule carrier that clamps the downtube to transport my Scott CR1 with no problems.
The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
bikemonster said:
I've used the Thule carrier that clamps the downtube to transport my Scott CR1 with no problems.
The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
I think the problem with carbon is that you can't see if you've damaged it or not and I'd rather not risk it.The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
I transport my bikes on the roof of my Cayman using the Thule 561. This clamps the front fork legs. I find it very secure & have confidence that when I get out of the car the bike will still be there. My race bike is a Scott Addict R1, this has carbon dropouts & these are not recommend by Thule to be used with the 561. I've not had any problems though & would say the 561 Outride is the way to go.
I use a Thule 591 with my Cannondale Supersix. The clamping system is not "harsh", and due to the shape of the holder, sort of nestles the down tube. I cannot see, unless you use extreme pressure, how the clamp is more likely to damage a carbon frame, than an aluminium one. An aluminium frame, or a steel, or a ti frame are not designed to have stresses at that point either surely?
AyBee said:
Chill You can, just don't clamp it on the tube. Hanging on a rear rack is fine,
No- hanging anything on a rear rack should be punishable by summary roadside execution, its farm animal stupid. The bikes hang out the sides, block all the lights and number plate and hardly anyone follows the law and fits a repeater plate and the driver forget the extra width and wipe them off all the time (against other peoples cars when they are being particularly stupid) and they totally block rear visibility. You can, just don't clamp it on the tube. Hanging on a rear rack is fine,Buy a proper roof rack or put it inside.
ratbane said:
I use a Thule 591 with my Cannondale Supersix. The clamping system is not "harsh", and due to the shape of the holder, sort of nestles the down tube. I cannot see, unless you use extreme pressure, how the clamp is more likely to damage a carbon frame, than an aluminium one. An aluminium frame, or a steel, or a ti frame are not designed to have stresses at that point either surely?
I use a 591 on my carbon wilier with no probsTo be honest, I do check it regularly, but as said before, it doesn't apply much pressure on the frame as long as you wrap the frame in a piece of cloth (or an old sock in my case)
Have done approx 1500 miles with it on the roof of my (occassionally hastily driven
)RS4 with no probs at allEdited by graeme4130 on Thursday 24th May 17:25
bikemonster said:
I've used the Thule carrier that clamps the downtube to transport my Scott CR1 with no problems.
The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
I have the same, and would think the same as you. There is near enough no force applied to the down tube at all. So long as the outer edges of the clamp are closer together than the width of the down tube, the bike isn't going anywhere, and there's no force being applied to the tube.The Thule carrier uses a v-shaped lower jaw to hold the bike secure, rather than massive clamping force. All you need to do is put some clear stick-on protectors between frame and cables to prevent cables rubbing against the frame.
AyBee said:
I've been looking at roof mounted racks, however, I'm slightly cautious with these due to carbon frames - is it better to get a rack that mounts the front forks (wheel off) rather than clamping the frame? If not, what racks do people recommend please?
Yes, it's better to get one that the forks clamp into. The forks are designed to take the load because it's similar to putting a wheel on, the bike sits lower and has a reduced wind profile and there is no pressure on the down tube. You may also find that your MPG is better.Thule 591's seem the way to go. I have an OEM BMW one, which is based on the same design.
However, I HATE putting my bike on the roof. I'm considering selling my car just to put the bike inside. Fine, people tell you that the carbon is more than capable of taking xxx tonnes of pressure but that pressure is designed to load at very specific points, hence various different modulus carbon fiber on a frame etc. But it's the idea of the bike up there, wind from all over the place, potholes and corners. I drive no faster than 65 mph - it's a real pain.
I really think people are worrying unduly about the Thule clamp rack.
The bike's weight is being supported on the wheels. The down tube clamp just holds it vertical. Stick a rag in the clamp to prevent scratches and I think you'll be fine.
Yes, you might hit potholes, but they'll have far less impact than hitting a pothole on the bike itself.
The bike's weight is being supported on the wheels. The down tube clamp just holds it vertical. Stick a rag in the clamp to prevent scratches and I think you'll be fine.
Yes, you might hit potholes, but they'll have far less impact than hitting a pothole on the bike itself.
I really think people are worrying unduly about the Thule clamp rack.
The bike's weight is being supported on the wheels. The down tube clamp just holds it vertical. Stick a rag in the clamp to prevent scratches and I think you'll be fine.
Yes, you might hit potholes, but they'll have far less impact than hitting a pothole on the bike itself.
The bike's weight is being supported on the wheels. The down tube clamp just holds it vertical. Stick a rag in the clamp to prevent scratches and I think you'll be fine.
Yes, you might hit potholes, but they'll have far less impact than hitting a pothole on the bike itself.
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