Kirklee Lays Up World’s Smallest Carbon Fiber Bike: An $8,000 20″ Triathlon Bike
What’s a kid to do when Dr. Daddy glams the group rides with his $19,000 Cervelo Project California and junior’s stuck rolling along on a $600 BMX whip?
Talk to Kirklee, that’s what.Â They’ve just put together what’s possibly the world’s smallest carbon fiber bike with 20″ wheels.Â Brad Cason of Kirklee says “With building that bike, I learned more than I ever thought possible about BMX parts.
“There are two wheel sizes: 405 and 451, and the tires won’t cross over.Â I built this on a 451, which is what the recumbent guys use, but the 405 is what more traditional BMX bikes run.Â Basically, the difference is the rim width.Â About the bike, it’s a 20” road bike built for a 5-year-old boy that’s into doing triathlons.Â We put independent stays on the back rather than our traditional wishbone rear end…we had to do this because the seat tube is so short and the angle was too much to properly position the brakes.Â There’s a titanium brake bridge embedded into the carbon, the BB shell 6/4 Ti.Â On our regular bikes, we ovalize our top tubes that flares toward the headtube, but with this one the top tube is so short that the kid would have been hitting his knees on the flared part, so I used a smaller diameter round tube.Â Because of that, I used a typical 1-1/8″ headtube with a Chris King headset.
Check out more pics and all the details of the bike after the break…
“We ran the brakes moto style because that’s what the kid’s dad wanted, and we had to swap the cable runs for the derailleur because of the curvature of the downtube.
“For the handlebars, we couldn’t use a drop bar because the kid’s hands are too small for STI shifters, so we put 10-speed index shifters on a FSA K-Force Light flat bar with a 50mm Thomson DH stem.Â The stem really illustrated one of the things we found with spec’ing this bike. The weight of the bike was right at 13lbs.Â We were shooting for 10lbs, but people just don’t make high end, lightweight parts for kids bikes.Â But, he came off a Specialized Hot Rock that weighed about 26lbs, so it’s a massive improvement.
“We used Shimano brake levers, which were the only ones we could find that had enough cable pull and had fully adjustable reach so we could tweak them down for a kid-sized hands.
“It has 390mm chainstays, Dura-Ace 10speed cassette and rear derailleur.Â The cage gets pretty low when it’s on the larger cog, but you can still corner.
“The cranks are 130mm Sinz cranks with square taper titanium bottom bracket with a carbon fiber shell.Â The seatpost is a 31.6 Thomson that we had to cut down to get it into the seat tube.Â The seat is an Odyssey junior racing seat, and it’s not much heavier than an SLR saddle (which they tried, but it was too big for the kid and the bike).Â The fork is a custom one-off from Wound-Up.Â They make a smaller fork for recumbents that use longer travel brake arms, but they had to trim 4mm off the fork legs for this bike.Â Again, illustrating the lack of available high end parts, this was the first of these forks they’ve sold in two years…there just isn’t demand for things like this.
“We’re running 38T elliptical ring from Rotor, and we’re about to put a 40T Rotor ring on there because he needs more gearing.Â We started with a 36T, but he blew through that.
“The wheels are a set of Velocity Uriels because they had the lowest weight and spoke count we could find.Â They’re wrapped with Schwalbe Durano tires, which were the lightest tires we could find.Â They’re 451 x 1.25” in size.
“The paint was done by Darin Wheeler at 2WheelerCustoms.com, which is about the only person I’ll let paint my bikes. Darin is a true professional…he’ll call you back, keep you posted on job status and delivers as promised.
“Performance wise, I’m hearing from the owner that on a flat course the kid can hold 12.45mph average on a test loop, besting his previous 11mph average on his old bike.Â He’s been known to hold 19mph with a tail wind and perfect conditions.
The tab?Â It’s more than your standard Kirklee…it was probably a little over $8k. For that coin, the obvious question is ‘can it grow with him?‘
“Well, the bike is intentionally a little big on him, but he’s growing incredibly fast and we’re already talking about building a 24″ version,” Cason said.Â “Fortunately, he’s got two younger siblings that can use it.”
(Editorial note: I made up the ‘Dr. Daddy’ stuff because we all know some doctor that buys a ridiculous bike then hardly rides it.Â Those are bike shops’ favorite customers.Â While Kirklee doesn’t divulge customer info, Brad did say the parents weren’t doctors and that triathlon is a family passion.)