Trailer Tires VS car Tires


#1

Hey Gang, quick question. I have a tow dolly (a small trailer that you drive the front tires of a car onto so you can tow the car). It currently has trailer tires on it, but they are cracked and dry rotted to the point I dont want to use them much longer. Today I was junking a car with brand new tires on it. The tires are the same size as my tow dolly, and the rims MAY even be the same bolt pattern as my trailer. In any event, being that this trailer does not see heavy dutey. Is there any real risk to using the car tires on my dolly?? Free VS $100+ per tire is a big factor here.



If this was a real trailer, one that could easyly be over loaded I would probably stick with the trailer tires. However this trailer just cant be over loaded, because all that will ever be on it are cars that it is rated to tow, and the car tires are rated to suport those cars.



Also should I over inflate the tires to 50psi as that is what the trailer tires are rated at…



Thanks


#2

I’ve never towed trailor dolley but have towed lots otherwise…don’t mess. I would err on side of caution and find the appropriate tire for that dolley. There is a reason it’s not a car tire to begin with.


#3

I was told to never put car tires on a dual axle trailer because when you back & fill you put high loads on the sidewalls. Trailer tires are typically bias ply. In your application (single axle, lightly loaded) I would think car tires should be okay. I would inflate them to the pressure listed on the sidewall. Just my opinion, however.


#4

Take a look at the tires on the tow doly. They will say something like Max Load XXXX at 50 psi (based on what you said in your post.

Now take a look at the car tires. They will say something like Max Load YYYY Max pressure ZZ psi.

Note that both max load XXXX is much higher than YYYY and the pressure ZZ is lower than 50 psi.

This means you can not achieve the load carrying capacity that the trailer tires have with the passenger car tires. And that means that if you try to use the passenger car tires, the tires will likely suffer an overload type failure (there are several kinds) and damage the tow dolly and the vehicle on it.

Never replace “ST” (Special Trailer) or “LT” (Light Truck) tires with “P” (passenger car) tires. Please note: The Europeans and the Asian tire manufacturers don’t use the letter “P”, and don’t use those either.


#5

It’s not just a question of weight carrying capability. Trailers have a tendency to sway. This builds heat in the tire sidewall. The stiffer sidewall of the ST tires helps to control sway and they’re made to handle the load/heat better. Next time you tow, feel the tire sidewalls and compare that to your car’s tires.


#6

No, you should get the trailer tires that should go on there. You don’t have to replace them every year, so you shouldn’t think of the hundred dollars as an immediate expense. You should figure the true cost per year and try to be happy with that.