Today I used a trailer and towed my daughters in our first bike ride together. We were about five miles out when my rear tire went completely flat. I used the bike a few days prior without the trailer and all was fine. Could having the additional weight (approximately 70 pounds) on the rear tire caused it to go flat?

the trailer is attached with a coupling to the rear hub. I am just trying to figure out if I had the wrong pressure in my tire for pulling the trailer with my girls in it. Can putting additional weight behind the bike cause a flat with the rear tire? I had recently replaced the tube and didn’t feel anything sharp on the rim.

If my tube should be inflated to max of 85 psi, what should I use while towing my two girls? I am so disappointed this happened. I really want to be able to ride my bike with my girls!

  • 4
    Hi, welcome to bicycles. Are you talking about a bike seat? A trailer should have its own wheels that carry most of the weight, rather than loading the rear wheel.
    – DavidW
    Commented Feb 28 at 3:18
  • 5
    It is a good idea to state/link/show what kind of trailer you are using, so people don't answer based on possibly false assumptions.
    – WornChain
    Commented Feb 28 at 13:54
  • Not sure if a comment on the question is the place to share this, but: I accept that there won't be much extra weight on the wheel from the trailer. But I do wonder if the pressure needs to be adjusted for the lateral forces: longitudinal in braking (and to a lesser extent acceleration), and transverse in cornering.
    – pateksan
    Commented Feb 28 at 15:14
  • By the pressure, I guess your bike is a road bike, did you find what part of the tire was the pinch? Probably your rim is damaged Commented Feb 28 at 21:43

3 Answers 3


The fact that you were towing a trailer should not have had any influence on your tire going flat. Quite surely it was either some sharp or pointy object that the tire picked up on the road or something that got into the tire as you changed the inner tube. It is merely only an unhappy coincidence that the flat just happened on your first ride with a trailer.

Concerning tire pressure and the extra weight: when towing a trailer there should be no need to adjust the tire pressure since the trailer has its own wheels which carry almost all of the additional weight of the kids in there. It would be somewhat different with a child seat which is mounted to the rear end of the bike behind the saddle, but for a trailer the tire pressure you run normally should be fine.


The nose weight of the trailer should be no more than a couple of moderate panniers or a fairly heavy backpack. Not worth extra pressure but worth making sure your tyres aren't really soft to start with.

Note that there has to be some nose weight otherwise the trailer is trying to lift the back wheel and that isn't good for handling. Yes you can try to get it to zero, but kids and loads move, and slops change the centre of gravity, so trailers (bike or car) always run with nose weight.


Haven't seen the punctured tire, I cannot exclude the possibility of bad luck, however, there is a fairly good possibility that the puncture was a pinch flat which typically occurs on bikes running lower pressures. When the bike hits a rock or a pothole, the tire flexes out of the rim slightly "nibbling" the tube. Probably the trailer attachment was rocking up and down slightly with road roughness and the kids squirming causing the tire to hit harder and flexing the tire. Slightly higher pressure on the bike would help. Slightly lower pressure on the trailer would reduce its tendency to bounce. Also, look at the trailer and see if you can adjust the connection of the trailer to the bike reduce the bounce. Your worse case scenario is a trailer that is nearly balanced causing it to easily rock causing the attachment point at the end of the shaft to bounce.

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