Cold tire pressure question
 

Should my just bought '96 24' FunLite take 50 lbs per 13" tire? It had 40 to 45 in each tire when I bought. Should I go to 50 lbs cold?

Jerry

Jerry:

The answer is....."well, it depends".

Google is your friend.

Check your tire manufacturer's website. As an authority on that kind of question, they're hard to beat. You might also check the age of the tires while you're looking at them.

Look at the sidewall of the tire and it will tell you what the max tire press should be. The max press will vary depending on the load rating of the tire. There is a code number also on the sidewall that will tell you the date of manufacture of the tire. Go to the website of the manufacture of your tire and you can find where the code number is located and how to convert the code to the date your tire was made. Any tire 7 years old or older should be replaced. Do not go by how good the tread might look.

Jim, thanks. Tire max is 80, so maybe I'll be OK at 50. As you said, Jim, my tires are prob more than 7 years old and should be replaced. Tread is good. I'll only be towing 20 miles to and from FL State Park, so maybe these will be OK for awhile. Spare is brand new, but I'll need jack and tool to remove wheel nuts.

Jerry

Actually, Jerry and Jim - I'm pretty sure the trailer webpages generally advise replacing trailer tires after 5 years. Reading about the damage that can happen if one blows out, I would not want to have that happen.

Jerry, if your tire's max pressure is 80, you'll be fine at 50 and you should inflate to that pressure. The tire's rated load drops with decreased pressure, so you don't want it to be low. And, at lower pressures, the tire runs hotter, which can lead to failure too.

- Jack

Almost all trailer tires recommend running at max cold. So put them at 80psi cold. They will last the longest, build the lease amount of heat, get the best fuel economy, and carry the most load. Remember that's 80 cold, on a got day running down the freeway they may go well over 80 psi, again that's fine, all part of the design.

a little confused
 

I have Load Range D tires and there is a warning about "BEAD SETTING PRESSURE". Not 100% sure, but I think it's 80PSI. Load Range D tires are 65PSI cold. Not sure what load range tires you have miranda, but unless they are some special tires, :confused: I think 80 PSI might be the max bead setting pressure. :eek: For your safety, please double check that max cold pressure amount.
Tree
PS: Hook up with CUGrad soon as you can, he's super! :)

Hersbird and Tree, my cold tire max is 80 (printed on tire), but should I air up to 80 cold? Seems someone said that Hi-Lo recommended pressure for my 13" tires should be 50 and not 80, so I am really confused on this. And, my tires are old and mismatched. Would you still recommend 80 psi cold?

BTW I know I will need 4 new tires but can't afford right now, so.....I gotta wait awhile. Know what I mean guys?

Jerry

Jerry, I suspect the tires you have that show 80 PSI max are Load Range E tires. You should be able to find the load range rating on the sidewall, along with the other information such as date of manufacture. Load Range D tires normally have a max pressure of 65 PSI. Load Range C is 50, and that's what was OEM on your trailer, most likely. That's why HiLo's inflation recommendation is 50 PSI.

Your trailer tires have their "rated" load carrying capacity at the 80 PSI setting. At 50 PSI, they essentially act like Load Range C tires. At 65 PSI, they have the load carrying capacity of Load Range D and so on. So, you'd be best to inflate to 80 PSI cold, regardless of their age. Just make sure, since you say they are "mismatched" that ALL of them are rated to 80 PSI. If not, I'd go with whatever tire has the lowest max pressure.

I don't really care for the fact that you have mismatched tires and think that should be corrected. Also, you DO need to check the dates on them. If they are older than 5 years, you should do whatever you need to do to replace them. A tire blowout while towing is no fun at all.

- Jack

Jack, do you know how I might read the tire code to determine age of each tire?

Jerry

You'll see the marking "DOT" followed by a stamped 4 digit number, such as "4714".
The 47 denotes the 47th week. And the "14" denotes the last two digits of the year. Thus 4714 would be approx last week in November in 2014. Hope this helps. When buying tires, try and get the same dates if possible, the fresher the better. I'd also go with a higher LOAD RANGE. Normally Hi Los came with load range "C". "Ds" allow a higher weight per tire and a bit higher speed. (most states around the south east only allow 65 mph with a trailer--good luck with that!) I've seen 85+, must really want to get there.
Tree

Tree beat me to the punch, Jerry. His advice about the date code is absolutely correct. Interestingly, everything I've read on trailer tire life says it doesn't matter if the tire is stored out of contact with sunlight or not. The rubber degrades due to TIME, period. So, try to get the "freshest" tires you can, when you get new ones.

I will take exception with one thing Tree posted though. I've never seen a trailer tire rated higher than 65 mph, regardless of its load rating. I don't think the speed depends on the state, I think it's built in to the tire. For that reason, I am very careful to keep my speed when towing to no more than 65 mph, no matter where I tow. And, when you think about it, your stopping distance is higher, your maneuverability is lower, and the potential for damage and injury due to the higher total moving mass is greater, so a lower speed seems prudent.

Anyway, those are my thoughts, and I recommend the highest Load Rating you can get with your size too. My trailer tires are Load Range D, and I inflate them to 65 PSI.

- Jack

Jack, stamped into my rims is "50 lbs max psi" , so, with "C" rated, I don't think I will exceed 50 lbs psi. What say You?

Jerry

PS--I only want to travel 20 miles to State Park, camp a couple of nights, and then return home. Am I OK with 50 cold lbs per tire?

I think yes to the trip length and pressure, and I responded in more detail in your other post.

- Jack

My new 2017 camper has "75 mph max" stamped onto the tires I can't remember the brand right now.

The 50 psi rims are a concern, but old or new I would run the tires at max. I have heard of lots of tire failures but never a rim failure and old or new, the tire failure is almost always do to low pressure and heat. I have never heard of a tire bursting from high pressure and some people will run even a 44psi tire well over that. I don't think going over is a good idea, but 80 psi is good if thats what the tire was designed for. Also the higher the load range the better. The factory goes as cheaply as they can and put the tires right on the ragged edge. They don't care if they only last you a few seasons.

After researching the rim max pressure a bit, it looks like their way of giving a load rating to the rim. That would be they are rated for a 50 psi "C" range tire. No way 80 psi is going to hurt the rim in some way unless you run the "E" tires and also load the camper to the point of being at max load of an "E" tire which is going to be way over your axles, frame, tounge, etc anyway. Running the "E" tires is still better IMO as they are much tougher then the "C" you are not trying to gain weight rating, just make the tires more reliable and last longer. That will only happen at 80 psi. At 50 psi they actually wear faster and carry less load then a "C " tire at 50 psi.