Symox

I was doing a road hill ride on my Carbon frame rim brake Specialized Roubaix (2007 Comp Triple). At the end of the road was a dirt trail and said to myself, "I wonder how it will handle it" I have never ridden this bike on anything but tarmac.

To my surprise, it worked out great (it was all dry). Also to my surprise the Gatorskin 28s I had worked fine (although I didn't push it on corners and did run them at lowish psi (65 front/80 rear)). Admittedly i wasn't doing anything really technical but climbing and descending on the trail wasn't an issue. The trail didn't have a lot of ruts/rocks.

The brakes are the only thing that seemed to suffer due to the dust (they weren't as crisp)

My questions are:

1) Am I asking for trouble using a carbon fiber frame meant for tarmac that cannot handle wider tires than possible 30cm? - I'm wondering if small rocks smacking the frame could be a problem

2) Is it normal for gravel/dirt riders to use slick or low tread tires?

I'm going to try a set of Panaracer Gravel Kings on the trail and see what that is like next. However I am concerned about those tires kicking up rocks.

terrymorse 

Mountain bike frames are made of carbon, and they get ridden over rocks.

You may want to install some frame protection, like Bike Armor.

HTupolev

For rocky aggregate? Yeah. On loose materials without fibrous content, there's not really much for knobs to bite into or grab onto. Many people don't go full slick, but it's not an especially weird choice, especially for a mixed-surface bike which is going to be seeing lots of pavement.

Symox

excellent points. I'll look into frame protection

Iride01 

If you get to the point you want to jump ravines, you might need to look at a proper mountain bike. I'd be surprised if the designers of the Roubaix ever expected you want to do that.

blacknbluebikes 

Love my 2005 S-Works Roubaix. Made to win on the cobbles. Gravel, sure, nooo problem. Fabian Cancellara and Tom Boonen rode 'em to win Paris-Roubaix.

caloso

It's fine.

A lot of riders would be surprised how capable a road bike is on dirt roads, especially if it's hard packed and not too rocky.

terrymorse 

Indeed. Before the days of special-purpose off-road bikes, we rode everywhere on our "10-speeds".



Old Haul Road, Santa Cruz Mountains, California, 1977 (Jobst Brandt photo)

caloso

Probably on a 42-26 low gear too.

Koyote

Frame material is not as important as the strength standards...though I suspect that, on your Roubaix, you would destroy the wheels before breaking the fork or frame. Just bear in mind that the bike is not really designed for anything beyond fairly smooth dirt and gravel roads.

Symox

For the first time I took the bike on a real gravel trail on an old quarry that was converted to a park with small lakes. The trail was nothing challenging but had various types of crushed gravel, dirt and small rock. I was impressed with how well the Roubaix did - it was downright comfortable! I was using 28mm (that's the widest I can fit - rim brakes) Gatorskins at lowish pressures and the traction was good enough to enjoy the experience. I'm sure I would have struggled on some of the looser gravel on turns, but it was actually kinda fun challenging myself to see what the setup could do. I may try slapping on some Panaracer Gravelkings to see how more traction affects the ride.

As others have said, many road bikes are surprisingly capable on hardpacked gravel/fire roads.

This was a bit of a milestone for me as my bike (except for the fire road experience from the OP) has only been on tarmac. I'm convinced the carbon frame, geometry and tire pressures all led to this being a fun experience.

Thanks everyone for the encouragement!

aclinjury

keep riding your Roubaix on dirt and all will not end well at some point. All it takes is one big hit or rut and you'll have a nice facial to show the wife.

Seattle Forrest

I ride my Cervelo on dirt roads with 28s and no tread.

Atlas Shrugged

I was planning on staying off the forum due to the constant trolling and ridiculous responses rarely answering the op's question but I checked in after a couple of weeks and I couldn't resist yours. In my world facial and wife are rarely used in the same sentence.

phrantic09

Same on my rim brake R3

PeteHski

Cobbles taken flat out at race speeds are a much harsher bike test than a casual ride along a typical fire road.

Symox

That’s how real men do it

Symox

good point
the Roubaix was literally made for bumpy cobblestones. I’m gonna enjoy riding it on more fire roads