Organizers of the Red Bull Road Rage in Southern California hope that Saturday’s bike race answers this lingering question:

Who is the fastest descender on the road?

To find out, they’ve assembled some of the world’s best mountain bikers and road bike riders to test their grit and fear factor on a steep and technical section of pavement through Malibu’s Tuna Canyon – and, claim some bragging rights in the process.

Who better to include on the invitation-only list of top professional roadie and knobby-tire riders at the inaugural race than Bend’s Carl Decker – who has proven he can win at both cycling disciplines.

According to a Red Bull Road Rage news release, the screaming, downhill course features 2,000 feet of elevation loss over a snaking two-mile route. Racers’ bike-handling skills will also be tested as they navigate 120-degree hairpin corners around cliff-hanging berms.

Riders are expected to reach speeds up to 60 miles per hour and finish in about four minutes.

In addition to Decker – who was crowned the 2005 elite men’s national road champion this past summer – two dozen other riders are scheduled to vie for the title of best descender, including Discovery Channel team member Tony Cruz, Olympic gold-medalist Marty Nothstein and world mountain bike champion Brian Lopes.

”It’s kind of an old question of who is the best downhiller on the road,” Decker, 30, said Tuesday in Bend. ”There’s never been anything like this that I’m aware of. Looking at the list, it’s really hard to figure out who is going to win.”

In addition to Decker’s accolades on the road bike this year, the professional mountain biker for Giant Bicycles also finished eighth in the cross-country race at the U.S. National Mountain Bike Championships in September and has placed in the top 10 at the first four U.S. Grand Prix of Cyclocross races this fall.

Decker made the decision to tackle the Road Rage about two months ago. At the same time, he began to design – with the help of Ashland’s Desalvo Custom Cycles – a custom road bike built for speed.

”The profile (of the course) is really steep,” said Decker. ”It’s roughly twice as steep as Pilot Butte, and twice as long.”

Decker estimated that the average grade of the Malibu road would be 17 to 18 percent.

The road that summit’s Pilot Butte averages about a 10 percent grade.

Decker’s 30-pound steel bike features a lower bottom bracket to lower the bike’s center of gravity. A 60-tooth front chainring will allow him to pedal at speeds up to 60 mph, he said. (Decker typically road races on a 15-pound bike with a 52-tooth front chainring).

Wider tires – the same as those used by racers in the annual cobblestone-studded spring classic Paris-Roubaix in France – hold 50 percent more volume of air than typical road tires. They provide better traction through corners and more grip on the pavement. Disc brakes, rather than rim brakes, offer better stopping power, while a water bottle filled with pennies (and water) adhered to the downtube add weight and stability, explained Decker.

Other bike modifications include a handlebar lever cabled to Decker’s seat post that, when activated, lowers his seat about three inches. This allows Decker to corner more aggressively by lowering his hips and trunk, and to become more aerodynamic on the bike. But, if he needs some pedal power to accelerate out of a corner, he can raise the seat with the flick of a switch.

Each of Saturday’s racers – including one woman: top female downhill mountain biker Marla Streb – will race in time-trial fashion. The top 16 times will return to race in heats of four.

”That’s something I’m not really used to,” said Decker of the head-to-head race format. ”Racing shoulder to shoulder like that. There are guys (there) that make six figures off of beating you into a corner and not flinching.”

While knocking on wood, Decker said he is confident in his bike-handling skills.

”I’ve raced a couple downhills in my career,” he noted. ”I ride motorcycles a little bit. I’m fairly stable and I don’t tend to crash too often. I’m fairly comfortable with the speed.”

He added, ”I’ll be wide-eyed in the start gate, but by the time I get there (to the time trial) I’ll have done the qualifier (run). I’ll have some ideas on what it will take to win, so it’ll be more exciting than terrifying.”

For the racers’ protection, Road Rage organizers are recommending full-face helmets and downhill mountain-biking gear.

”I’m bringing all that,” said Decker. ”It’s a full suit, basically … pants with knee and shin guards integrated with hip protection – specifically positioned pads for high-impact areas.”

Decker said that part of the allure of competing at Saturday’s Road Rage was the challenge of designing the right bike to race it.

”Part of the reason I did this was trying to guess what a good bike for it would be,” said Decker. ”It’s a clean slate, this sort of race.”

For safety, spectators are not allowed Saturday on the Tuna Canyon course. Photos and results will be posted at www.redbullroadrage.com.

2005 Highlights

* Carl Decker, 30, of Bend

* US Elite National Road Race Champion

* Top 10, USA Mountain Bike National Championship, Cross-Country

* Third place, USA Mountain Bike National Championship, Short Track

* Top 10, first four US Grand Prix of Cyclocross series