Building a Cyclocross Bike PUBLISHED AT WWW.MOUNTAINONLINE.COM

On the cyclocross course, I'm prone

to crashing and taking corners

painfully slow. Neither habit boosts

me to the front of the pack. But at

CrossVegas in mid-September, I

demoed a Specialized CruX carbon

that helped my performance and

made me believe in an elusive cross

victory. It was stable, smooth, and

cornered precisely. I sat down with

Andrew Frasca, the lead bike

engineer, and Ned Overend, a

Mountain Bike Hall of Famer and a

podium finisher at the 1985 cross

national champs, to find out what

separates the CruX from the cross

field.

Ned, you're a legendary endurance athlete. How important is the bike?

In any discipline, the engine is key, but having confidence in your equipment is important whether you're

a beginner or a pro. There is more crashing in cross than road or mountain bike racing. It's just the nature

of the slippery conditions, the skinny tires, and the short races, which make the pace frenetic. Having

confidence in your bike will let you put more focus into going fast.

Ned, why did you want to be involved in designing and producing the bike?

It started with the Tricross model—our re-introduction to cross, which was a bit of a compromise between

a touring bike and a cyclocross bike. After a couple years racing the Tricross, it was obvious we needed a

cyclocross-focused model. Using our own experience and the feedback from the Cal Giant Strawberry

team, our regional CX teams, and Todd Wells, we looked at what we liked about the Tricross and what

we needed to improve on. I've always been passionate about cross and I've been a longtime advocate at

Specialized for developing a great line of cross bikes.

What's the advantage of a bike with cross-specific geometry rather than a road bike with knobby

tires?

Andrew: Cross bikes began as road-oriented bikes, but there are many details that differ. For one, cross is

primarily a fall/winter sport. For many parts of the world that means snow, rain, and mud. Tire size and

clearance is key. Mud builds up in areas where the tire passes closely to the frame—specifically the

chainstays, seatstays, and brake areas. Road bikes don't offer enough clearance. And road bikes use

caliper brakes, which don't offer enough tire or mud clearance to be a solution. Cross bikes are designed

for either cantilever or disc brakes. You want a stable but fast-handling bike for most cross courses, where

tight cornering and quick acceleration bursts require a predictable bike. This means you play with

headtube angles, fork offsets, and bottom bracket heights.

What separates the CruX from other cross bikes on the market?

Ned: First, a relatively low bottom bracket height. I can feel the lower center of gravity in many cornering

situations, but especially when there is a series of "S" turns that require throwing the bike back and forth.

Building a Cyclocross Bike PUBLISHED AT WWW.MOUNTAINONLINE.COM

A lower bottom bracket also requires a little less energy to hop back on, which becomes more obvious the

more tired you become.

Second, the stiffness of the head tube/fork area gives me confidence in the corners. If the front end flexes

during a rough, high-speed, off-camber corner, the bike will tend to drift to the outside. If the front end is

stiff, the bike will hold a more precise line and the steering will be predictable when you need it most.

The stiffness in the bottom bracket area makes the CruX really efficient when you stand up and sprint out

of a turn, which is one of the definitions of cross racing. You want to get back up to speed as fast as

possible coming out of a turn. Also, the bike is light, which is especially helpful when lifting it over

barriers or running up a long flight of steps.

Andrew: The tapered head tube really ties into the size of the joint where the down tube meets the head

tube. With tapered head tubes, you have more material at the head tube/down tube joint and that greatly

improves front-end stiffness. On carbon bikes you can get improved fiber alignment and take more

advantage of larger surface areas. Head angle, fork offset, and the resulting trail—the horizontal distance

measured at the ground between the head angle centerline and a vertical line dropped from the front

axle—all work together to impact handling. There are other aspects of frame geometry that factor in, but

in general, if you have a short trail, you will have pretty quick handling, whereas a longer trail equals

more stability.

You have to find that magic balance between twitchy handling and stability that is appropriate for cross

bikes. We put a lot of time and energy into determining the rider's needs. It's not fluff. One of the first

questions asked in many of our project planning meetings and all the way through the design review

process is, "How will the rider benefit?" We have a pretty established focus here at Specialized. If it's not

an improvement that benefits the rider, why bother? During the development process we test a number of

iterations, we try new ideas, we ask questions and listen to the answers. We focus on ride quality and

performance. The feedback we've been getting on the CruX indicates our efforts have paid off.

What is your take on disc brakes for cross?

Andrew: I am all for disc brakes. Of course, the industry is in transition and when the cross/road-specific

disc brake technology advances to the point that they are as good as mountain bike brakes, there will be

no turning back. I can certainly appreciate the perspective of the purists, and I think the cantilever option

will be around for a long time to come. With that said, the performance benefit of disc brakes on the

horizon cannot be ignored. It's a little short sighted to discount disc brakes based on the brake tech

available today in cross. It is going to improve by huge amounts. —Sydney Fox