Co-Motion: Periscope Hammerhead Tandem Bike

Co-Motion's Periscope Hammerhead is possibly the most versatile tandem on the road today. You can take your kid out for a country tour on Saturday, and then one of your teammates out for the local time-trial on Sunday.A telescoping stoker seatpost allows for the tremendous range of captain/stoker heights, which is what my daughter and I have been searching for. I'm 6-foot-2, so only big bikes will work for me.

On a typical tandem, we'd need to wait until she was about 5 feet tall in order to get a good bike. But with the telescoping seatpost, the stoker range is from 3-foot-8 to 6-foot-2.

So this bike will fit both of us for years. At least until my daughter gets taller than I am (and then I can finally be the stoker).It's also easy to adjust the position of the stoker's stem and handlebars. We quickly found a position that was comfortable for her. I often saw her shadow with her arms out like she's flying, or pretending to throw newspapers to the neighbors.A key component to the performance of the Hammerhead is the Gates Carbon Drive. It's a polyurethane belt in lieu of a timing chain, and it provides tremendous power transfer. When my daughter gets out of dream world and actually applies force to the pedals, the difference is incredible.

Speaking of power transfer, getting a tandem frame to be both light and strong isn't easy (and it's certainly not cheap). But Co-Motion pulls it off with its own design of 7005 aluminum. I've had heavier mountain bikes than the Hammerhead. And this bike climbs fabulously. It's strong enough for the captain to get out of the saddle, though your stoker's reaction to that move may be different than mine (high-pitch scream).The options at Co-Motion are practically endless. Different wheel sizes, colors, components, couplers and even custom sizing are available.

The company started building high-end tandems in 1988, and its bikes have ridden across the country, won races, and inspired families to go out for weekend rides ever since.Purchasing a $7,000 tandem, or any bike, requires a high level of commitment. But we're both eager to go out on it, far more so than the heavier loaner we started on.

So even though at that price I could get a Ridley Helium with Campy 11, and she could get a kid's Pinarello with SRAM Rival, we're going to get one of these. Because by myself, I could ride to the next state and back. But on her own, she couldn't ride past the ice cream stand in our town.So together, we ride somewhere in between, and that place is as happy as we've ever been.