12' trailer tires

JDEM

Well-known Member
I have several small trailers with 12" tires. Either 4.80-12" or 5.30-12", both in 6 ply ratings. Last few sets of tires were made in China and started to dry rot in two years. Name-brand, but still very poor quality. I suspect because they are not car or truck tires they can get away with making them low quality.

So I am wondering - where can I find something I know will be better? How about using automotive radial tires like 155/80-12"? The car tires cost more but the size and weight rating is correct and I am thinking the quality might be better? I need these for a camper-trailer that will see quite a bit of 75 MPH driving.

I have heard all the doom-and-gloom warnings how trailers should get trailer-tires only. I am not sure I believe it.
 
You are correct about car/truck tires being more dependiable than trailer rated. When I want the best service possible from a trailer that is equipped with small tires,here's how I handle it. Check clearance to see what is the largest tire size that will clear. Buy hubs and rims in desired size from wrecking yard. Take original inner and outer trailer bearing along with hub races from replacement hub to bearing distributer. They give me bearing sets to mount replacement hubs on trailer axle. I stick with 5 lug on 4.5 circle so that spares interchange in a pinch.
 
Remember that 12" tire will be turning at a rate of about 150 MPH when your truck is traveling at 75 MPH and you will never find a car or trailer tire that is speed rated for those speeds.
 
In many cases you can change over to 13" tires and get regular radial tires which are generally better than anything you can get in 12". Make sure you check diameter and clearance first. You should be able to get either 4 or 5 bolt rims easily to match your hubs. You can also change out the hubs if you want.
 
(quoted from post at 19:13:46 06/20/17) Remember that 12" tire will be turning at a rate of about 150 MPH when your truck is traveling at 75 MPH and you will never find a car or trailer tire that is speed rated for those speeds.

If the truck is going 75mph every tire on the road is going 75 mph. Yes the rpm of the smaller tire is higher, but any 12" DOT car tire would have to be capable of 75mph, the rpm has to be taken into account by the manufacturer. The lowest speed rating allowed is L and thats light truck/mud tires rated at 75 mph, basic S rated car tires for family cars and sedans are rated for 112mph
 
How would the tire being going any faster on a trailer.....let's say you have a Geo metro with 12" tires, you buy 6 matching tires, 4 on the car and two on your trailer, they all spin the same speed, and if they don't you got bigger problems than tires eh!
 
His 12" tires will have a diameter of about half of what the truck he will be pulling it with so with that half diameter that means the circumfronce is way smaller than his truck tire so for the tread to travel as far it will have to spin twice what his larger tires do so therefore spinning twice as fast equals 150 MPH equivolent when he is traveling at truck speedometer reading of 75 MPH. The tread on pavement is what makes your speeds. Did you pass math in school?
 
According to this http://www.tyresizecalculator.com/tyre-wheel-calculators/tire-size-calculator-tire-dimensions there is less than 10 inches difference between a 13 inch tire and a 16 inch tire every thing else being equal which would blow your twice as fast theory away as well
 
"I have heard all the doom-and-gloom warnings how trailers should get trailer-tires only. I am not sure I believe it."

Internet lore, plain and simple. Having tried ST type tires in the past I go along with your theory that they are garbage that couldn't pass for car or truck tires, at least the current crop of china tires. Car and truck tires work just fine on a trailer, just use them and dont tell anyone on here and you wont have to put up with the nay say, As for the dry rot that seems to be a fact of life with Chinese rubber products. Parking the trailers on boards helps, especially over the winter and parking them out of the sun helps also.
 

At one time I owned a Ford Fiesta with P155-80-R12 tires. It would eat up a full set of tires every year. Just plain wore them out. All tires were name brand. Even had 1 set of Michelins. Made no difference. 12" tires are just to small for anything other than a lawnmower.
 
Moms Fiesta was so bad about eating tires, she bought a set of 13" rims and tires for hers. Problem solved. In fact, she sold it
about 5 years later for almost twice what she paid for it.
 
I had the same problems on a 1990 Subaru Justy 4WD. 12" tires and last car sold in the USA to have a carb. Now that I think
of it - it likely weighed twice what my camper weighs but had four tires instead of two. So maybe car tires for my trailer is
not such a great idea.
 
Discussions like this prove some people give advice, on stuff they are clueless about themselves. Look at the load rating on a 12" tire then a 13",14"and 15",now read what some people said in this thread. Who should we believe,people that built tire or people on YT?
 
Actually the rubber that contacts the road on a 12" tire turns the same speed as the rubber on a 24" tire. It just makes contact with the road more often and wears out faster. I assume runs hotter too.
 
(quoted from post at 21:07:41 06/20/17) His 12" tires will have a diameter of about half of what the truck he will be pulling it with so with that half diameter that means the circumfronce is way smaller than his truck tire so for the tread to travel as far it will have to spin twice what his larger tires do so therefore spinning twice as fast equals 150 MPH equivolent when he is traveling at truck speedometer reading of 75 MPH. The tread on pavement is what makes your speeds. Did you pass math in school?

Math class. Miles per hour is a measurement of distance over time. 75 mph means the vehicle will cover 75 miles in one hour. All the tires on the truck and trailer will therefore cover 75 miles in one hour. Their rolling circumference determines their revolutions per minute not their speed in mph. It is physically impossible for them to run at different mph but is possible and true they turn at different rpms. All taken into account by the tire manufacturers speed ratings
 
A ST (Special Trailer) tire has a stiffer side wall to reduce trailer sway.
Most if not all ST tires are rated at 65 mph max.
So if you want to keep the still side wall to stop trailer sway and pull it 75 mph you should be using light truck (LT) tires.

The thing to watch out for when pulling a trailer with small tires at fast highway speeds is the bearings.
Due to the small size of the bearing combined with the revolutions a small tire has to make in a mile you can over speed and burn up the bearings. Have seen it several times with people pulling trailers with 8 inch tires at highway speeds.
 
JDEM,
I use two local tire stores. I'm a big fan of the Tire Barn. The store manager has been there since the store opened. He takes care of me. Recently he got me a good set of radial tires for my 10k dump trailer. They had a heavier rating than the OEM tires and they are radials.

Not sure why, but the store manager sold me the tires cheaper than I could have bought cheap tires off the internet. They balanced the tires too.

Find yourself a good local tire store that will also sell you road hazard. Most trailer tires have an out of site warranty. Warranty is good until you are out of site of the store.

I also have a good local tire store for Tractor tires.

A good tire store will sell you tires they think will meet your needs. Mine has.
geo
 

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