Check your bike's rear axle before you buy a dog trailer
Look at the center of your back wheel. A lever means quick release, which most trailer hitches fit. A nut on each side means a nutted axle, and a thick axle that screws into the frame means a thru-axle. Both of those usually need an adapter, so check before you buy.
Most dog bike trailers hitch to your bike's rear axle. If the hitch doesn't fit that axle, the trailer can't go on the bike, and you won't know until it arrives. Two minutes with the back wheel tells you what you have.
Look at the back wheel
Find the center of the rear wheel, where it bolts to the frame. You'll see one of three things. This follows Burley's hitch guide.
| What you see | Axle type | Common on |
|---|---|---|
| A lever on one side and a small rounded nut on the other | Quick release | Burley calls it the most common type |
| A six-sided nut on each side, tightened with a wrench | Nutted (bolt-on) | E-bikes with a motor in the back wheel, single-speed and cruiser bikes |
| A thick, hollow axle that screws into the frame, with a lever or a hex-key socket on one end | Thru-axle | Newer bikes with disc brakes, including many mountain, gravel and e-bikes |
What each one means for a trailer
Quick release: the easy one. Burley says its included steel hitch attaches directly to a quick-release axle.
Nutted: you'll usually need an adapter sized to your axle's thread. Burley sells a Hitch Adapter ($24.95 on burley.com, checked October 20, 2026) in sizes such as M10x1.0, M12x1.25 and M14x1.5. The numbers are the axle's diameter and thread pitch, which your bike's maker can give you. Schwinn's trailer manuals say their coupler fits a hub nut or a quick-release lever.
Thru-axle: you'll need a replacement axle with a hitch mount. Burley's Thru Axle ($64.95, checked October 20, 2026) comes in seven versions, set by thread pitch and hub length, so check Burley's fit guide or ask a bike shop before you order.
If the trailer says "universal coupler"
Many budget trailers include a "universal" coupler but don't say which axle types it fits. Of the trailers we compare, only Burley names adapters for thru-axle and nutted bikes. If your bike has a thru-axle, ask the seller before you buy.
E-bikes
Burley says most e-bikes use thru-axles or nutted axles, and that riders should keep to about 10 to 15 mph when towing and 5 mph when turning (Burley's e-bike trailer guide). Other makers are stricter: VEVOR says to stay under 8 mph on an e-bike with its 100 lb PTS22SJ and doesn't recommend e-bikes with two other models, and Schwinn's manuals say never to tow with a motorized vehicle. Follow the trailer maker's rule, not the bike's.
Before your dog's first ride
Let your dog get in and out at home first, with the trailer's brake on. Use a harness, not a collar, if the trailer has a leash clip. If your dog has balance, heart or breathing problems, ask your vet before you start.
Questions people ask
Do dog bike trailers fit thru-axle bikes?
Some do with an adapter. Burley sells a Thru Axle in seven versions set by thread pitch and hub length. Many budget trailers with a universal coupler don't say whether they fit thru-axles, so ask the seller first.
How do I find my axle's thread size?
Ask your bike's maker or a bike shop. Nutted adapters are named by diameter and thread pitch, such as M12x1.25, and Burley's hitch guide lists the sizes it sells.