We are planning a trip with a bike rack attached to our trailer hitch. What is the best way to lock the bikes while the vehicle is unattended? I see some racks have locks on the knobs but they don't seem very strong.

What do you suggest?

  • Actually, the locks on the knobs are probably fairly secure, since the average bike thief would not have the tools at hand to break them. In any event, you can only slow down the determined thief, making him look elsewhere for an easier target. May 6, 2015 at 11:34

3 Answers 3


Don't rely on the racks locks alone to keep you bikes safe. They willat very best, slow the thief down (shows the point). A hitch rack provides a good lever that can be effectively used to snap the rack (or the hitch) off to take the bikes, and if the bikes are damaged in the process, the thief just walks away leaving a mess.

Strong cable lock though a closed loop on the car (the cars tie down loop / eye) around the bikes, threaded to limit the range of twisting and lever motions, meaning the racks locking mechanisms cannot be push further than they can cope with.

For any length of time, take the bikes off the rack and store safely inside, or out of site locked to a secure rack. Cheap bikes also help.

  • 2
    Also for multiple bikes, locking them together with a D-lock helps. It means a third would have to remove both/all bikes at once (which isn't something they'd want to be seen doing) and also makes access to the clamps holding the inner bike(s) much harder slowing them down.
    – Chris H
    May 6, 2015 at 8:31
  • 5
    +1 Never rely on locks to secure bikes for any length of time. A lock is a deterrent and nothing more; even the toughest of bike locks will only slow a well-equipped thief for a matter of minutes. And when the anchor is your car, you also risk the thief damaging the car in his/her attempts to remove the bikes. Jun 5, 2015 at 7:50
  • Really a hitch design to tow a trailer and you can just snap it off? Even a class one hitch will tow 2000 lbs and you think a human is just going to snap the hitch. A trailer is a longer lever than any bike rack.
    – paparazzo
    Jul 28, 2015 at 2:02

If you anticipate stopping in places with a real potential for bike thievery, I would lock the bikes up the same way I normally would while leaving them unattended in the city, with u-locks. No sense losing the bikes mid-trip.

On trips with little to no chance of such potential for theft, I'll be in proximity to the car the entire time, or I'll just be at remote campgrounds near other vacation-going folks like me, etc, a simple cable lock will suffice.

If you are going to be in any densely populated areas, I can't stress enough about the inadequacy of a cable lock. Some $15 branch loppers will go through them like butter.

Side note: make sure your hitch-mounted rack is locked to your hitch, otherwise your bike lock will be rendered useless when a thief walks away with your entire rack.

  • 2
    The rack attachment to the car is a very weak link in terms of bike security - its not a "Side note:"
    – mattnz
    May 6, 2015 at 4:37

I would start by considering avoiding the use of a trailer hitch for any other purpose than that for which it has been designed: hitching a trailer. Hitches are constructed to support lateral, longitudinal and vertical forces applied at low heights, the latter up to about 50kg - think a maximum of two bikes and the rack itself. However, they are not built to withstand torque applied either side-to-side or front-to-back. The other vehicle attachment points will have to stand that - but these points are usually on the tailgate which is also not built for that particular purpose.

The safest way I know of transporting bikes on a (perhaps long) trip is inside a rather non-descript van, with no windows potential thiefs can see through and doors that lock. Perhaps you could consider renting such a vehicle? I am sure you can get quite good prices by shopping around and choosing a time frame in which businesses typically do not need to rent many vehicles, e.g. in summer.


  • 2
    The colloquial term for such vehicles is "creeper van." No thanks!
    – RoboKaren
    Jun 5, 2015 at 12:22
  • 1
    Any trailer hitch that can only support 50 kg of vertical force is going to snap off the moment you hit a bump while pulling a real trailer at highway speeds. they are not built to withstand torque applied either side-to-side or front-to-back Huh? No side-to-side torque? How can you turn while pulling an actual trailer then? Apr 17, 2023 at 19:21

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