need a little more storage than a seat bag can offer. I want to mount a rear rack to my 2008 Roubaix pro are no eyelets on the Roubaix. I don't intend to carry any more than 5 Lbs on the rack. Should I be concerned about attaching a rack on Carbon Fiber seatstays ?
Please help !

Full carbon bike with Zertz insert? I wouldn't chance it if it was my bike. I got a CR1 carbon frame bike and I can feel some flex when I hit bumps. I'm no expert but I think having anything clamped to a carbon Seat stay is not to good of an idea if there will be some flex on your frame. Beside that, you may need to use p-clips which also be stress on the seat stay when you tighten those around the carbon along with the weight of the load and the rack.

What are you trying to carry? Small item can be fitted in extra pack such as a frame pack on the triangle of the frame. If you need more, than perhaps a Topeak Dyna Pack which clamps on to the seat post will be ok. Just beware of the torque needed to tighten the clamp around the carbon post. If you are carrying books and such, I would go with a messenger bag or backpack. In another thread, someone suggested an Old Man Mountain rack for my FS MTB. I've never tried the product myself but it might work. It used the skewer as part of the rack mounting. Something like that may be better than clamping to the seat stay since most of the load will be on the wheel instead of the seat stay, I think........

If it it's not CF, I say go for it using P-clips. CF is too what's the word.... sissy when it comes to such use.

Look into the Axiom Streamliner Road DLX rear rack. It's made specifically for road bikes that don't have braze-ons or eyelets for rack mounting. The bottom of the rack connects to a bracket that mounts on on the skewer of the wheel and the top mounts using the bolt for the rear caliper. My desciption might not sound so hot but it's a pretty decent rack for what it's for. The top is slimmer so as to bring your panniers closer to the cent of gravity. Because of the slimmer rack top, it's definitely a pannier rack. Give it a look as I can't think of anything else that will work without modification.

I'm not too keen on CF bikes but you'd need P-clamps to maount most ay other rack and as others have mentions, it'll probably do some damage to CF seat-stays.

Links for the Axiom Road racks:
https://www.axiomgear.com/products/ge...iner-road-dlx/
https://www.axiomgear.com/products/ge...eamliner-road/

The DLX is the narrower of the two. The key features are the single top mount that goes to the bike's brake bridge and the extended lower mounts that use the skewer and, just as importantly, hold the rack farther back to help avoid heelstrike against panniers. Touring bikes have longer chainstays partly to help avoid heelstrike.

I think your bike needs some modifications bro

this is one of the reasons I'm going for the Secteur instead of the Roubaix

I was looking at the Axiom streamliner racks for my bike in the event that I wanted larger panniers than what I use now. They can be had for under $30 if you look around and are just about ideal for what you're after.

There are other racks that mount on the axle/QR skewer but these seemed to be priced the most moderately.

Why? There's at least one moderately priced quality rack that'll work with his bike. If he wants to spend more he's got more options.

Ahhh... yes. This will do nicely.

I've got the secteur. Makes an awesome commuter. I've got full fenders and a real rack on it.

If it's a carbon fiber Roubaix, you're making a huge mistake by attaching a rack to the seat stays with anytype of "retro fitting." I would recommend that you use a Seatpost Quick Release system made by carradice available at peterwhitecycles.com. However, I would not recommend that for a carbon fiber seatpost. The Roubaix is a racebike (or performance road bike) and if you need to carry 25+ lbs of gear then it's probably not an appropriate commuter unless you are willing to carry it on your back in a backpack. The beauty of the SQR is that you can remove the bag in about 15 seconds and use the bike for it's intended use - road rides.

Similar to the aforementioned Topeak Dynapack, maybe one of these Hi-Tails from Detours will work. Or go with a different take on the frame bag. Or why not just get a handlebar bag?

I know this a few weeks old but I have an 09 roubaix and I am about to mount the srq on it for my carradice pendle bag. I don't know why everyone is so scared of a carbon seatpost. That seatpost is strong as hell. I'm 99kg and it holds me fine (it held me at 110), if I was worried about a 7 to 10lb bag attached to the strongest part of the tube breaking I'd never ride the bike. A 5lb load on a 400gram seatpost rack is not going to break your bike. But I would choose one with a nice wide clamping area and that wont scratch the post all up.
A lot of distance riders ride carbon bikes and use saddlebags/handlebar bags and I can only guess that some of those guys have to install little seatpost racks to hold the bags.

Carbon fiber holds weight as well as any other material used for bikes, but it's a little more delicate when it comes to something being clamped onto it. You could theoretically crush any seatpost - steel, aluminum, titanium, etc if you clamped down a seatpost to much. In practice, this wasn't a problem as you either needed power tools or a enormous lever to do so by hand.

But you sometimes can crush carbon fiber with a strong arm and hand tools. If you look at a bike with a carbon seatpost, it will often specify how many foot-pounds (torque) should be applied to tighten it correctly, often requiring a torque wrench to get it precisely right.

There's also something about carbon fiber where it's only strong in the direction it's designed to hold weight, but I don't know that much about that topic.

I think if anything is clampable, it's the seatpost - you gotta clamp it down to secure it anyways. Just don't wrench on it as hard as you possible can and it should be fine. I'm not so sure about some of the other parts of the bike - those rear seat stays are usually unbelievably thin, and they're not designed to be clamped down onto.

The Axiom rack mentioned above, and most other racks, simply attach at the bike in locations designed to bear weight. Usually it's the rear wheel skewer (which is designed to hold much of your body weight) and right where the brakes are attached (which needs to withstand the forces of bringing your 200 pound body weight to a screeching halt from 30mph or more).

I totally agree in general with what you're saying - what's another 5 pounds on a bike designed to hold a 300 pound rider? It's just a matter of not crushing something that wasn't designed to be squeezed, and putting the weight on a bike in a location that's designed to handle it.

I wouldn't hesitate to put a rack on a Roubaix (the right kind of rack). With it's more stable handling, it would be fine. Putting a rack on some of the twitchier bikes brings up issues of handling with the added weight (depending on how much weight, etc, be seriously - some of them can be really squirrelly).

I have a carbon Roubaix that I occasionally use for commuting---when I communte with it, I use an aluminum seatpost and the clamp-on Topeak beam rack. I only carry a minimum amount of stuff in the rack bag on those days. The clamp-on rack can apparently tend to swing from side to side unless you screw it down really tight to the seatpost. I was afraid to do that on the carbon seatpost that comes with the Roubaix. You can get a decent aluminum seatpost for a modest amount.

FWIW, I can't really tell any difference in the ride between my cheap aluminum seatpost and the "zertz" carbon seatpost that comes with the Roubaix.

Most Tubus Rack can be used with their QR Adapter set to mount to the skewer. The Fly and Luna would then mount to the brake bridge to complete the set up.

This would be the best bet. If you have a carbon post, the same issues apply as to clamping stuff to the frame.

Or, perhaps, it's time for another bike that will do the duty that you want it to do. Keep the Robaix for those light and fast rides but get something else for the epic rides and plodding to work.

Some of the same issues, but not all of them. While rear seat stays are tiny, often irregularly shaped, and not designed to be clamped onto, a carbon seatpost by is larger, uniformly shaped (so when you clamp something on it fits), and is actually designed to have the seatpost clamp tightened onto it. You don't want to just clamp a rack on there - if you overtighten it you could break the seatpost. But the seatpost comes with a torque rating - I've always wondered if you replace the hand tightened bolt with a regular bolt, and used a torque wrench, if you could still connect the rack.

To be fair, if it's only 5 pounds getting an oversized underseat bag sounds a lot easier, though.

I wouldn't consider putting anything heavier than a blinky light on carbon seat stays. I think the safest rack for your bike would be one that mounts to the Quick release of the rear wheel. Old Man Mountain and Tubus racks have this option.