Carbon bikes on trunk racks... a myth?
 

I really want to be able to transport my bike on my car. Won't fit. And I don't want to get a new car just to be able to transport my bike (inside it or with a hitch).

Ive always been told you should not put a carbon frame on a trunk rack... but is that really true?

I haven't been able to find a hard recommendation against it from bike manufactures. Trek says they recommend against it.

Thoughts? Experience with this?

What kind of car do you have? What type of bike? Experienced members may be able to offer some suggestions for transporting your bike inside the car. I have transported 2 road bikes and a week's worth of luggage for 2 people inside a 2003 Volkswagen Passat

What's the myth? The only caution that I've heard of is that you should be aware of your wheel/tire placement with regard to the exhaust, particularly with carbon rims.

Scaremongers have said many things over the last 25 plus years about carbon bikes. I've found none of it true for bikes made today. Perhaps some early carbon bikes did have some issues, but then again so did steel, aluminum and titanium.

Just use some common sense for things that might rub or bump it. Just like steel and other bike, you don't want that finish marred. Don't be imagining it's going to mysteriously morph in to something broken that you can't ride.

I carried my specialized roubaix on my trunk rack countless times without any problems. It was a Hyundai Sonata and the rack was a Yakima something Joe 2 bike rack. It had straps for the top tube and a sway strap for the seat tube that kept it cradled nicely in the cups. Never had an issue.

You’d probably want to make sure you don’t scrape your paint because of any grit or whatnot when you tighten the straps down - and maybe it’s be a little harder for a snug fit in the cradles of the rack because of the shape of frames these days, but that’s all I can think of.

The argument against is basically the same argument against clamping a carbon top tube in a workstand clamp.

Why not install a hitch on your car or get a roof rack?

+1 I understood this was primary concern with carbon on a trunk rack, leading to potential high heat exhaust exposure. IOW, if your setup doesn't put your bike near your exhaust, there shouldn't be a concern.

I understand it's the concern of clamping a top tube, but a lot of common sense applies. My rack (haven't used it in decades, I should sell, Grabber maybe ?) uses a rubber foot and rubber straps. I'm pretty certain that would not damage the top tube and I would have no qualms using this rack with my carbon bike. Other racks is a case by case and dependent as to how it clamps.

not a problem

Thanks to all for the reply.
- Is an Audi A5.
- Trek Domane SLR and specializes sirrus carbon frame.
- Inside the car would only fit one and not the Domane without taking off the handlebars
- Installing a hitch would be tough based on how the car is designed. The add on hitches you see are installed poorly and end up damaging some part (also, they get almost always rusted in the midwest).
- Roof rack is maybe a more feasible option. I think the trunk rack is more convenient, so that's why I asked.

The issue is that while carbon fiber tubing is strong and stiff, it is not very resistant to impacts along the side of the tube. Thus, while you can be careful clamping the tube, if the bike is bounced on the mount the impact to the side of the top tube can damage it.

Take an Emonda SLR frame, for example. The top tube has sections that are very thin and you can compress the sides to some degree just with your hands in some places. They are still very strong, stiff, and sufficient for the stresses the bike has while riding. I'd be leery of hanging it by the top tube while driving due to the constant bouncing and impact between the top tube and the rack contact points.

Personally, I'd go for a roof rack using Audi's legs and cross bars: Audi A5 Sportback Base Carrier Bars - 8W8071126 | Audi Dominion, San Antonio TX

For a hitch, these are pretty nice and not really visible from the rear of the car: Audi A5 & S5 Hitch | The Hitch Made to be Hidden | Stealth Hitches. There is very little trimming of the bumper cover required, and it is in a location that is not visible unless you get under the car (A5).

Trunk mount racks also run the risk of damaging the paint on the car where the rack contacts the paint, and the risk of the bikes scratching the paint.

My 2 cents.

And bottom line is these are multiple thousand dollar bikes. Why take a chance for damage clamping and hanging. Roof rack is best option. I use a Yakima Front Loader mount that grabs the front wheel. It's a very nice design.

If you don’t already have crossbars, I’d highly recommend a seasucker rack

Tell that to the people that have driven into their garage with a roof-mounted bike.

There isn't a perfect, risk-free option - it's up to the individual to assess the best option for their situation.

Yep, I came about 2" away from smashing our bikes into a steel pole once while backing up with them on a hitch rack.

With a roof rack you need some kind of system..............that tells you there are bikes on top of your car. With all of the electronics and sensors installed on modern cars, there should be something you can use via app or car's central system.

Eyeballs work ...

About as many folks get rear ended with bikes totalled. This is an old and tiring argument, there are negatives and positives for both.

Yet you hailed it as the unqualified best option. I guess we're on the same page, now. Kudos.

I have a high tech solution I use on my car with two carbon bikes on the roof rack (Yakima Front Loaders)
It's called an index card, with the word "BIKES" printed in bold lettering.
I stuff it behind the clip that holds the garage door opener to my visor.

I've carried two bikes in a 1986 Honda Civic, considerably smaller than an Audi A5. Wheels had to come off, but that's all. Lay a blanket over the back seat, stand one up in the footwell and another on top of the seat.

I have seen trunk-mounted racks that work more or less like roof racks, with the bike mounted longitudinally on rails. I had one such rack (the Rhode Gear Euro Shuttle), but it hasn't been made in ages. And I'm pretty sure some people have just mounted roof racks on their trunks.

Having owned a 5 series Audi, I can tell you that getting anything into the backseat is very difficult. When my seat was in driving position, there was about 2" of room between the front and back seats. I wouldn't even try shoving a bike back there. The pass through from the trunk does not provide much relief. Maybe a front wheel in the backseat.

You should have bought the A5 Sportback instead of the A5 Coupe; in early 2020 I almost bought one because the liftback made it the perfect car to transport a road bike, but instead I bought my wife an A6.

But I still manage in my A3, which is even smaller; why don't you just take off the front wheel and turn the handlebar 90 degrees?

This ^^^

You are misinterpreting my post and forgetting that the OP indicated the hitch option was a poor choice for his vehicle. With trunk mount or roof rack the alternatives, roof then being the better option was what I was referring to.