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Trailer Cycles: What to Look For

Trailer cycles, also called trail-a-bikes or trainer bikes, are a great option for riding with older kids. A trailer cycle consists of handlebars, a seat, pedals, and a wheel that attaches to the back of a standard adult bike. This allows the kid to get involved in the ride while remaining safely attached to the adult bike.

WeeHoo Trailer
Unlike the stoker (back) seat on a traditional tandem, a kid on a trailer cycle is not required to pedal along with the adult rider in front, so trailer cycles are great for families wanting to go farther than little legs can handle on their own. All in all, trailer cycles are a wonderfully versatile option for kids who have moved beyond the bike trailer or child seat, but who aren’t quite ready to ride solo all the time.

Our Top Trailer Cycle Picks by Type

1. The Child Rider

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Before purchasing a trailer cycle, you’ll want to make sure your child is ready to ride. For starters, s/he will need to be tall enough to reach the pedals. Most trailer bikes are about 18″-20″ from the top of the saddle to the top of the pedals at their lowest position. Kids who fit a 4T pants size are probably about big enough for a trailer cycle.

Unlike a regular bike, it is okay if your child cannot reach the ground while sitting on the seat of a trailer bike. As the adult rider, you’ll provide the balance needed when mounting, starting, stopping, and dismounting.

The child rider is not strapped into the trailer cycle in any way (except for the recumbent style Weehoo trailer), and s/he can dramatically affect the handling of the entire setup by shifts in weight (e.g. by leaning sharply to one side). So you’ll want to make sure your child is mature enough to sit stably on a bike seat, without making sudden movements or attempting to dismount abruptly. If you have concerns, consider the Weehoo I-Go or the Adams Trail-a-Bike Back Rest (which is compatible with some other trailer cycles). Both provide a back rest and harness for wigglier kids. Or, stick with a bike trailer or bike seat until your child is able to safely ride a trailer cycle.

2. Adult Bike Requirements

Most trailer cycles attach to the seat post of the adult bike. This means that they are compatible with most adult bikes, as long as you have about 2″ of exposed seat post between your seat tube and your seat. If your seat post is unusually thick or thin, you should check to ensure that the hitch on your trailer cycle of choice will fit it. Non-round seat posts or seat posts made out of materials other than aluminum or steel (e.g. carbon fiber) are generally incompatible. Some trailer cycles attach to a cargo rack on the rear of the adult bike, rather than to the seat post. These racks typically require bike rack eyelet mounts on the frame of your bike. Many commonly used bikes — particularly road bikes and full suspension mountain bikes — don’t have these mounts, so check carefully before buying.

Trailer Cycle Mounts

3. The “Wobble Factor”

The most common issue with trailer cycles is that they tend to be wobbly. This is due in part to the fact that trailer cycle riders tend to be wobbly, but the design of the hitch (the part that connects the trailer cycle to the adult bike) can greatly increase or decrease the “wobble factor.”

Most hitches go around the adult bike seat post and tighten via bolts. Then the hitch attaches to the arm of the trailer cycle via a separate large bolt. The large bolt allows the trailer cycle to pivot freely from side to side. A separate bolt allows for vertical movement, which is needed when going over bumps.

Trailer Cycle 06

It is very important to really tighten down the seat post bolts, or the entire hitch may turn around the seat post, causing the trailer cycle to hang crookedly off the back of the adult bike. It can take some practice figuring out exactly how tight you need to make those bolts, so for your first few rides, it’s not a bad idea to bring along the tools you need to re-tighten those bolts, just in case you discover mid-ride that you didn’t get it quite right.

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The fewer connection points, the less wobble gets introduced and the more stable the ride. On higher-end trailers, such as Trek Mountain Train shown below, the trailer cycle arm connects directly to the hitch, which is then designed to pivot around the seat post. This effectively eliminates two of the three connection points in the standard trailer cycle hitch, resulting in a ride that’s noticeably less wobbly. Rack-mounted trailer cycles provide the most stable ride of all, thanks to their secure attachment that’s perpendicular to the ground.

Trailer Cycle08

4. Quick Release

If you plan to frequently switch between towing the trailer cycle and riding child-free, you’ll want to pay attention to the way that the trailer cycle removes from the adult bike. Seat-post-mounted trailer cycles generally have a quick release, which allows you to quickly install or remove the trailer cycle without any tools, while leaving the hitch attached to the seat post.

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Rack mounted trailer cycles remove easily from the rack. The rack itself requires tools to uninstall, so it’s not something you’ll want to do regularly, but the rack can be used to mount panniers/saddle bags and other gear when you’re riding on your own.

5. Gears

While most trailer cycles are single speed, some do have gears, typically 6 or 7 on a rear derailleur. This gives kids a great opportunity to experiment with shifting gears, while still under the control of an adult bike. Most trailer cycles have grip shifters while others have thumb shifters. Thumb shifters are generally considered to be easier for small hands to operate, but shifters do vary widely in stiffness and ease of operation. If at all possible, have your kids test ride a geared trailer cycle before purchasing to ensure they’re physically able to operate the shifter.

Trailer Cycle Gears

Gears don’t make much of a difference in the ease of pedaling for the adult rider. Trailer cycles with gears are also more expensive than their single-speed equivalents, and require more maintenance due to the rear derailleur. It’s up to you to decide whether the extra practice is worth the extra money and hassle.

5. Folding arm

Many trailer cycles have some sort of quick release connection midway down the arm that allows you to fold the arm under the trailer cycle. This is handy to reduce storage space or for transporting in a car.

Trailer Cycle 16

6. Seat Post

If you have multiple trailer cycle riders of differing heights, look for a model that has a quick release on the seat post. Otherwise, you’ll need to carry an Allen wrench for any mid-trip rider switches (or swap out the stock seat post collar for a quick release version).

Trailer Cycle 17

7. Child comfort and safety

Adjustable handlebars, while not essential, can help dial the fit for riders of different heights.

Trailer Cycle 19

Some trailer cycles include a splash guard on the trailer cycle arm. Riding in rainy Seattle, my kids and I have not noticed a significant difference in the amount of splash with vs. without a splash guard, so I don’t consider it to be an essential feature, either. If your kids are getting sprayed when riding in wet conditions, you can also consider a fender on the adult bike’s back wheel.

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A flag is really important to increase visibility/awareness of your trailer cycle rider. If your trailer cycle didn’t come with one, you can easily buy a generic one on Amazon. There are many options, although this is my favorite, as the reflective strips on the flag make it more visible in low-light conditions.

8. Rear rack compatibility

If you have a rear cargo rack on your bike (or want to install one), you’ll want to ensure it’s compatible with the trailer cycle you choose. I tested a number of different combinations of trailer cycles, adult bikes, and racks, and was generally able to get them all to work together. One rack, an Axiom, is height-adjustable and I had to adjust the rack nearly all the way down to make it low enough for a trailer cycle to fit over it.

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The one rack that gave me consistent problems was a seatpost-mounted rack. (I have a Delta Post Porter). If I mounted it below the trailer cycle, the trailer cycle arm rubbed on it. If I mounted it above, it hit the “bump” in the trailer cycle arm. I also had concerns that the weight of the cargo + kid might be too much for the seat post. You will need panniers or other bags that hang off the sides of your rack. “Rack trunks” that install on top of the rack will interfere with the pivoting of the trailer cycle arm.

9. Transporting other children

If you have a younger child who you want to transport along with your trailer cycle rider, the best option is a front-mounted child seat, as this does not interfere with the trailer cycle in any way. Trailer cycles are generally incompatible with rear-mounted child seats, as the child seat interferes with the trailer cycle arm.

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You may be able to hook up a bicycle trailer to the back of the trailer cycle. The resulting “road train” is quite long and more difficult to maneuver, so you’ll need to ride very cautiously. You may want to stick to bike trails and other spots with less traffic and less required maneuvering. Be sure to double check your trailer cycle’s manual first, as some explicitly state that they should not be used with bike trailers. If you want to transport two older children on a trailer cycle, consider a two-seater trailer cycle, such as the Weehoo iGo Pro 2.

What trailer is best for you?

Now that you know what to look for, check our Trailers Comparison Charts for help finding the best trailer cycle for you.


By: Lisa

Last Updated: January 21, 2017