At the time, we decided it was important to be able to fit it into the trunk of our car. Most newer tandem trailers have some kind of folding feature which makes this possible, but I passed on a chance to by an older Trail-a-Bike because it lacked this feature. In the end, we chose the WeeRide Co-Pilot, which typically sells for less than half the price of the Trail-a-Bike.
Here is a closeup of the hinge in the middle that allows it to be folded over for transportation.
The rear 90% of the bike is solidly built and I have no complaints about it, especially for the price. The part that has turned out to be huge problem is the front part. Here is a closeup.
The hitch mechanism attaches to the seat post of the adult bike. It's not a particularly elegant design, but it works. Behind the hitch are two joints, designed to allow the trailer to move both horizontally and vertically with respect to the bike. The first problem with the joints is that the weld connecting them to the rest of the trailer is not straight. When the hitch is held perfectly level, the trailer bike leans a couple of degrees to one side.
This is not a one-time anomaly. While this trailer has generally received positive reviews on Amazon, there are a number of 1-star reviewers (full disclosure: I am one of them) who have described this same problem. I don't know how common this is, but there are clearly some quality control problems.
The second problem with the joints is that the bushings get looser over time. After 4 summers of regular 10-20 mile bike rides, there is now enough play in the joints that the trailer can flop back and forth several degrees. This is particularly challenging for the adult rider trying to keep the whole rig upright. A few weeks ago this finally resulted in a crash, and we have decided that it's time to retire the Co-Pilot and find a better solution for family cycling. WeeRide's web site says they now have a new hitch design, so it's possible they are aware of this problem.
The lesson learned from all of this was that if you want to buy a tandem trailer, you really need to spend the money on one of the more expensive models. A year after buying the Co-Pilot, I acquired a true tandem, and we have been using both for the last two years. After using both, I've concluded that the only real advantage of a tandem trailer is cost, and that anyone serious enough about riding to make the investment in a tandem is better off skipping the tandem trailer entirely and going straight from a trailer to the back of a tandem. The advantages of this are:
- Better handling and balancing characteristics than a standard bike pulling a tandem trailer.
- The child can actually help pedal no matter what gear you're in. Above a certain speed, a child on a one-speed tandem trailer can't pedal fast enough to actually contribute, so they end up just coasting and (in my experience) goofing off in ways that can make it a challenge to keep the bike upright.
- A tandem can grow with the child past the age where they might be too big for the trailer.