CRAWFORD, Texas — The most powerful man in the world is also a heck of a mountain bike rider.

And that has nothing to do with the fact that he's followed on his rides by a military attache with the secret codes for unleashing nuclear Armageddon.

George Bush invited me and a few other reporters for a mountain bike ride on his 1,600-acre ranch Saturday. His escapades on the bike have been well-documented: an over-the-handlebars crash here at the ranch and a wet-pavement wipeout in Scotland that hurt a pedestrian policeman.

But the truth about this 59-year-old mountain biker is that the man can really ride. Over the course of a two-hour Tour de Crawford, Bush humbled every rider in Peloton One with a strong and steady pace over hot paved roads, muddy creek crossings, energy-sapping tall grass and steep climbs on loose and crumbling rock.

"This is not a race," he insisted at the start of the ride. "This is a chance for me to show you a little slice of heaven, as far as I'm concerned. You know, some guys go on their ranch and ride horses — I like to ride my ranch on a mountain bike."

But there is one rule: don't pass the president.

No problem. Keeping up with Bush — whose fitness level was recently rated in his annual physical as being in the top 1 percent of men 55 to 59 — was as difficult as any race I've entered.

I started out riding next to him at the beginning of the ride, but when we left the dirt trails and hit the rolling asphalt the pace accelerated to more than 20 mph, which is pretty good for road bikes but absolutely blazing for heavier, knobby-tired mountain bikes. And did I mention that the only factor mitigating the mid-80s temperatures was a very strong headwind?

"I like speed," says Bush, who wore a red-white-and blue helmet and a Western-style bike jersey, complete with pearl snap buttons. His loose-fitting black shorts bore small rips from his crash in Scotland. "There's something exhilarating about heading down a hill at 35 mph on a mountain bike — or trying to grind up a hill at 9 mph."

The president does prefer the speed zones to the technically difficult traverses up and over loose limestone and mud, but his abilities in that area are increasing rapidly.

He began riding just two years ago when a knee injury ended his running routine, but his skills already are quite advanced.

"I love the outdoors," he says, straddling his $3,000 Trek Fuel bike. "If I'm not exercising here, I'll be fishing over there. If I'm not fishing, I'll be working with the chainsaw. I really enjoy being outside, and mountain biking is a way for me to spend a fair amount of time — four or five days a week — outdoors.