I originally wrote this in June 2006, but at the time Brian insisted I pull it off the site. His signature bike is now available, and he’s leaving GT, so I guess it’s OK to put this back up.
Lately I’ve received questions about sizing for dirt jump/4X bikes. Brian Lopes left his prototype GT Lopes signature model in my garage for a day, and while he was gone I made some measurements.
BL is of course a racer, so that’s what his bike is optimized for. But he’ll throw the occasional 360 or backflip on the same bike.
Key sizing specs
Lopes: 5 feet, 9 inches of restless fury
Top tube: 22″
Chain stays: 16.5″
Head tube angle: 69 degrees
Seat tube angle: 71 degrees
Stem length: 65mm. “Same on all my bikes”
Handlebar width: 27 inches. “I used to ride 26 inches, then I used a bar that was 27 inches, and I liked that better.” All of his bikes are the same.
On hindsight: I wish I would have measured the horizontal and vertical distances between his bottom bracket and handlebars. I’m beginning to think that’s the key to the kingdom.
Other specs of note
Fork: Prototype Marzocchi Bomber with a coil spring set to 85mm. “These forks are so plush.” When Brian raced for FOX he experimented with an external clip that holds the fork down for gate starts; the fork opens up when you hit the first bump. He says the lockdown really helps his starts, but the clip used to break. His Bomber has this function inside the fork — controlled by a lever on the right leg. Slick.
Crankset: Shimano Saint
Chain guide: MRP
Derailleur: XTR. But old-style, where the finger trigger shifts to a smaller cog. This is way better for grabbing taller gears in a race.
Shifter: Customized Shimano trigger. The index-finger trigger has been shortened so he can keep all his fingers on the bar and make the shift with his knuckle. Key in his line of work.
Rims: Sun Singletracks (I think — they’re finished in gray camo). I’ve seen his rims bare, and he usually has big holes drilled into the inner surface.
Tires: Kenda Small Block Eight. They roll fast and seem to rail on hardpack.
This bike feels very tight, light and quick. I think I could be a world champ on this rig. Maybe world champ of my back yard …