I receive about 300 calls a week. Of those about 20 are from people wanting advice about buying a USED car tow dolly.( It is interesting to me how high the resale value is on used tow dollies. ) So my advice to them is really very simple. There are only a few things to be concerned about. The typical tow dolly on the market has bearings that require regular lubrication and service. These bearings should be serviced about every three thousand to five thousand miles. Very few dollies are this well maintained. So you want to verify that there are no bearing issues to deal with. Any trailer repair center can verify this for you and repack the bearings at the same time for about the same money. Also, have them check and verify that the brakes are functional and the brake pads are not worn out. Interestingly you also should check and make sure the brakes are working and properly engaging. Some dollies have the brake adjusting port blocked by the spindle plate and one cannot adjust these brakes. It may be that the brakes are not working at all if the pads are under adjusted. Also verify that there is no damage to the hub or the drum. Next, and most important of all, is the question about the spindles. The spindles are normally around 1 inch in diameter. The spindle is what interfaces the bearings and the wheels to the dolly. Understand that dollies do not have suspensions out of necessity. ( That is another blog coming soon ) As a result the spindles can be easily damaged. If a user hits a curb with the tow dolly wheel while the dolly is loaded with a car, it is quite possible that the spindle will be damaged, or moved. As an example, our axle and spindles are jig built in a very precise controlled manner. The spindles are attached and welded at exactly one degree of camber. There are actualy 6 axis that have to be precisely measured and verified. These meaurements, or positions, are not even perceptable by the eye. If the spindle is “hit” and moves even an eigth of an inch you will start experincing very fast and uneven tire wear. Unfortunatly this damage is considered permanent and fatal. There is no way to repair this damage. Someone might tell you that they can heat up the spindle  and move it, but they would be guessing about where the spindle should be and it is very unlikely they would ever return it to neutral. Now the “tell tell” for this is ” NEW TIRES ” If you show up to look at a used dolly and it has brand new tires on it you should ask yourself, is this just a selling feature, or a concealment of the tire wear issue. It is always best to see the “old” tires on the dolly. That way you can see the tire wear as it really is. Also remember dolly warranties are only valid to the original buyer. So, I guess if you could save 50 percent buying a used dolly it may be worth it. Given the unrealistic high resale expectations of sellers it is unlikely one would see that much of a savings. If the savings is a mere few hundred dollars  I suspect you would easily pay that in needed maintenace in a short time and still have a dolly with no warranty. So there ya go, now you know what to consider while shopping around.  Remember, Safe Trailers Save Lives. Happy and safe motoring.