The D7 is unassuming in looks. It’s a comfortable commute bike, and it was inexpensive and came with fenders and a rack. There’s nothing fancy about this bike, but I’ve enjoyed long rides (50+ miles) on it. The bike is easy to maintain and has been dependable for about 10 years. It is also easy to lock the seat, making it a good urban bike.

The Speed TT is the bike I got in order to take to California when I was working on the San Mateo County Bike Map. At 23 lbs, skinny tires, 27 speeds, a shock absorbing hub, and time trial style handlebars, it has been a pleasure to ride. I got clipless pedals to use with it. The 2008 model that I have has handlebars that are a little narrow. The bike feels pretty quick. I’ve added fenders and a rack to it. If I were going on an 80 mile bike ride, I’d probably take this bike.

When I bought the TT, what I really needed was the TR. The TR is 10 pounds heavier and has fatter, lower pressure tires. The handebars are about 5″ wider. I bought the 2008 version and replaced the rear rack with the traveller touring rack that comes on the 2009 model. There’s a front rack for panniers as well, and a air pump built into the seat post. The TR has 24 speeds (a wider ratio than the 27 speed TT), and the front hub is a generator hub that will power the front lights or my iphone. This is the bike I can use to carry groceries without my heal hitting the rear grocery bag pannier. It’s also, if I have time, the bike I can go overnight camping with. It seems very durable.

I find all the Dahons comfortable, and they are simple enough that I can maintain them. They are also one-size-fits all, so I can loan a bike to a friend for a ride.

My other “folding” bike is a Bike Friday Family Tandem, which I find essential as a parent. This bike actually comes apart rather than folds. I’ve added a special crank attachment that essentially shortens the crank to better fit a kid. I attach a trailer-bike to it in order to travel with both of my kids.

Each of these bikes has functions best depending on the context. To sum it up:

D7 – Urban trips (to Center City, or keep in the trunk of my car).
TR – Suburban Shopping, Overnight Touring (bringing it on Amtrak, SEPTA or a bus).
TT – On-road rides of longer distances that aren’t touring. Likely involves a train ride.
Family Tandem – Daily trips with kids.