Trailer tires

[Gene Masse]

I think this subject has been covered but I need some quick response. I found a 98 17' Casita that I am getting. Intend to pick it up tomorrow, Tuesday. The guy got new tires for it. The think is he didn't get ST tires. As far as I know he got regular radial.
He said it rides better too. I'm looking for opinions here. Should I change them anyway?

[Jared J]

I'm sure others will say differently, but on a single axle trailer, if they're LT tires, and the trailer rides fine, I wouldn't think twice about leaving them.

[Bob Miller]

As mentioned, be sure that there is plenty of reserve load capacity. If the tires are load rated at 36 PSI they may be passenger car tires and might be marginal for load carrying capacity.

[Jack L]

All tires have a maxium load weight rating on the sidewall. Find out how much weight these tires will carry and find out the actual weight of the trailer when it is loaded. If the trailer weight is more than the tire rating, new tires are required. Passenger and light truck tires usually will not carry the weight of a trailer. Just my opinion but new tires would be a good idea..

[Steve L.]

Whether the tires are adequate depends on how much risk you are prepared to accept. A key factor is the actual trailer weight. Best if it were weighed. Second would be to look at Trailer Weights in the Real World thread on the forum for a range of likely weights of other trailers in your size. Its up to you whether you choose the average weight or max. weight. Dividing the weight in half would approximate the tire load.

The maximum tire load and inflation are molded on the sidewall. You can also look up the tire capacity at different pressures in any of the commonly available tables on the web. Pay attention to the tire size branded on the sidewall. It may have no prefix, P, LT or ST.

If you care to operate to industry standards tires prefixed with P must have their load capacity reduced by 10% when used on a trailer rather than a car. LT and ST tires don’t have that requirement. (For cars the cushion is less. By law the car manufacturers must build the vehicle with tires that provide a 6% cushion with P tires.) Manufacturers are allowed to label their P tires at higher than 32/36 psi so max inflation can be misleading as to their intended usage.

Look at the last 4 digits of the DOT serial number (lots of web sites describe the DOT code). The last two digits are the year the tire was made (the first two of the last four are the week of manufacture. Many manufactures recommend replacing the tires every 5-6 years regardless of mileage (mostly due to sidewall and rubber deterioration).

[Bob Miller]

Hmmmmm....Either the tires are adequate or they are not adequate. There is no one on this site, or any other for that mater, that can accept any "risk" when it comes to safety on the road.

It could be anyone's children or grandchildren along side when someone's risk becomes collateral damage when a failure occurs.

The are no "Fifty Shades of Gray" when it comes to safety, either it's safe or it's not.....

[J Mac]

There are a lot of big American cars that are front wheel drive. Older Cadillac, Lincolns etc used to tour endlessly with full passenger loads and often travel trailers without incident and they were front wheel drive. I doubt they had trailer tires on them. Does anyone know if semi trailers use trailer tires?

[Steve Outlaw]

Like Jared said, IF they are LT's with a high enough load rating, I would not hesitate to leave them, if fact I'd rather have them. We are having sixteen inch Michelin LT RIB tires installed on our new Oliver. I'll let you know how that works out.

[Bob Miller]

ST or Special Trailer tires cannot be used on a driving or a steering wheel. This means they can't be used on 2 or 4 wd vehicles. Technically they could be used on the back of a front wheel drive vehicle, but not on the front.

Over the road trucks use tires designed for the specific mount, be it driving, steering or trailer. I believe they can be cited and ordered off the road if the wrong tires are caught at an inspection station.

And yes, we did some pretty silly things back in the day, it's a wonder that this many of us survived those vehicles and our ignorance.

I.E. I pulled a 25' Airstream over 25,000 miles with a 1972 Blazer in 1977 without a thought to tongue weight, towing limits, etc. Although my new bride did learn, that if the trailer brakes aren't set correctly, that it is possible to swap ends at 55 MPH.

[Steve L.]

Originally Posted by Bob Miller

Hmmmmm....Either the tires are adequate or they are not adequate. There is no one on this site, or any other for that mater, that can accept any "risk" when it comes to safety on the road.

It could be anyone's children or grandchildren along side when someone's risk becomes collateral damage when a failure occurs.

The are no "Fifty Shades of Gray" when it comes to safety, either it's safe or it's not.....

I pretty much agree with you. Some on the forum tow overloaded (over vehicle specifications) or use P-metric tires where not advised and advocate such actions. In their eyes the rest of us are fear mongerers. They seem uneffected by the possible outsome of their actions. Perhaps I erred by leaving wiggle room in my comments to avoid being "pecked to death by ducks."