I'll try to make this brief. My kayak trailer tires are B load range, and rated at max load of 590#s (ea.) at 60psi. Estimating liberally, the 2 kayaks weigh a max of 120#s and the trailer weighs 175#s for a total weight of 295#s. With a total weight capacity of 1180#s, the load is 25% of the max capacity.

 

With that in mind, running 60 psi would be overinflated relative to the load. I run 40psi as a happy medium. Is my thinking correct? If I ran 60psi my thought is that the trailer would be literally bouncing down the road after it hit some bumps.

 

My truck tires are rated at a max load at 50psi. I run 32psi for maximum tire service life and ride comfort. Wouldn't it be similar with trailer tires?

Yep. PSI is based on the load. Tires usually say something like "max load" at 60 PSI. You could probably run them as low as 35, but 40 to 50 is fine as well, and as you said the closer to 60 you get the rougher the ride.

 

I let my trailer tires get real low one time around 11psi and they were still doing fine. Looked low, but no damage to tire. I try and keep them above 40 now. Drive all over the state with no issues. I think you will be fine as well so long as you have good tires.

 

Load rating is one thing. Speed rating is another. Tires that came with my trailer said max speed 55mph. I changed that out real fast. I needed highway speeds.

Under-inflation can cause lots of problems with tires. @FloridaFishinFool speed rating is hugely important!!!

 

I always run my trailer and 5th wheel tires at max recommended PSI. This is measured when tires are cold. PSI will increase as you drive...that is normal and expected.

 

Another very important issue is tire age. I replace tires after 5 years regardless of miles and tread wear. Last thing you want is a tire doing the grenade thing on the road. Pain in the tail!

 

We picked up a 5th wheel camper back in 2020. Tires looked pretty good...I replaced all four this spring...noticed the tires were nine years old(!). It was a good thing I did replace them...one of the tires had a large bulge that I had not noticed...tire guy said I dodged a major bullet right there. Whew!!

 

 

1 hour ago, DaubsNU1 said:

Under-inflation can cause lots of problems with tires. @FloridaFishinFool speed rating is hugely important!!!

 

I always run my trailer and 5th wheel tires at max recommended PSI. This is measured when tires are cold. PSI will increase as you drive...that is normal and expected.

 

Another very important issue is tire age. I replace tires after 5 years regardless of miles and tread wear. Last thing you want is a tire doing the grenade thing on the road. Pain in the tail!

 

We picked up a 5th wheel camper back in 2020. Tires looked pretty good...I replaced all four this spring...noticed the tires were nine years old(!). It was a good thing I did replace them...one of the tires had a large bulge that I had not noticed...tire guy said I dodged a major bullet right there. Whew!!

 

 

 

X2

What most people don't understand is about tire pressure's effect on heat build up. Running your tires on lower air pressure will soften the ride & the bouncing effect but increases your chance of tire failure from impacts & heat build up. Maximum air pressure as stated on the tires sidewall gives you maximum load carrying capacity the tire is designed to carry. It also gives you maximum protection from impacts breaks like you encounter from chuck holes & also helps protect your wheels or rims from impact damage. Maximum air pressure keeps the tires from building up excessive heat which is the major cause of blowouts. Sidewalls literally tear apart from the shearing action that low air pressure causes. Disclaimer I spent 13 years in the tire business and was on the front line when  a customer had a tire problem. 

So should we run our trailer tires at maximum rated on each tire?

 

I guess I am fortunate to never, not once have a break down issue with my boat trailer in more than 30 years. I always attributed it to regular maintenance. Got lucky I suppose, but I have never run my trailer tires at full 60psi.

 

Am I ok at 40 to 50psi? Or should I keep them at maximum of 60psi?

I check tire pressure before every trip in boat trailer and RV trailer and add air until max PSI.......65 in both trailers.

 

Artificial intelligence says: "Yes, you should inflate your boat trailer tires to the maximum pressure listed on the sidewall, which is often 60 psi, but always double-check the specific tire for its maximum pressure. Boat trailer tires are designed to carry a heavy load and are built with thicker sidewalls compared to regular car tires, and they should be inflated to their maximum pressure for optimal performance and safety."

 

And it further says I should take into account about 5psi for tire heating up, and inflate to around 55psi and I should be good to go.

 

I wasn't far off. Learn something every day.

 

 

 

I'm still not convinced that (in my case) running at max psi is the prudent thing to do. Certainly with a much heavier load will warrant higher pressures. A bias ply tire will crown when inflated to higher pressures relative to load. I really don't think it's so cut and dry as AI suggests.

 

Case in point. Most if not all vehicle manufacturers dictate pressures lower than max load pressure. One key difference to note is the difference between bias ply and radial tires.

23 minutes ago, Crow Horse said:

I'm still not convinced that (in my case) running at max psi is the prudent thing to do. Certainly with a much heavier load will warrant higher pressures. A bias ply tire will crown when inflated to higher pressures relative to load. I really don't think it's so cut and dry as AI suggests.

 

Case in point. Most if not all vehicle manufacturers dictate pressures lower than max load pressure. One key difference to note is the difference between bias ply and radial tires.

 

Vehicle manufacturers have always advocated for lower pressure because it provides a softer ride. None of the auto manufacturers guarantee tires only the tire manufacture. 

6 minutes ago, Dwight Hottle said:

 

Vehicle manufacturers have always advocated for lower pressure because it provides a softer ride. None of the auto manufacturers guarantee tires only the tire manufacture. 

There is the liability factor and I'm sure manufacturers would not risk tire failures by advocating lower than max pressures for the sake of a softer ride. I'm sure there is a sweet spot relative to load where it will provide maximum tire life, ride comfort and safety, not necessarily in that order.

I think we need an engineer to come up with an equation……

for the love of humanity, don’t involve AI in a kayak trailer.

 

pump it up until it doesn’t squish when you stomp it and hammer down. 
 

 

 

How about an equation generated by AI. 👍

1 hour ago, Tennessee Boy said:

How about an equation generated by AI. 👍

Or you can just do it the easy way by adding air up to the max first thing in the morning before you drive on the tires. 

4 minutes ago, Dwight Hottle said:

Or you can just do it the easy way by adding air up to the max first thing in the morning before you drive on the tires. 

Well I just air them up when they look low until they stop adding air when they stop looking low.  I just posted the formula because @TnRiver46 ask for it and he loves AI.  😆

I checked with the manufacturer (Malone) and they recommend 35-40psi with a max of 65psi (although the tires state max. pressure of 60psi). 

 

Speaking of tires, I just ordered some 10" tires for my Malone Ecolight trailer to replace the stock 8" tires. Those 8" tires are only rated for 65mph and the new 10" tires are rated for up to 87mph.

 

I'll have to move or lose the fenders, but that's not a big deal. I'm wondering how it will impact the ride of my trailer or fuel mileage.

1 hour ago, Kayak Koz said:

I'm wondering how it will impact the ride of my trailer or fuel mileage.

I doubt it will have any impact on mileage. The ride of the trailer will improve (or should) but that's difficult to determine while driving.

4 hours ago, Kayak Koz said:

Speaking of tires, I just ordered some 10" tires for my Malone Ecolight trailer to replace the stock 8" tires. Those 8" tires are only rated for 65mph and the new 10" tires are rated for up to 87mph.

 

I'll have to move or lose the fenders, but that's not a big deal. I'm wondering how it will impact the ride of my trailer or fuel mileage.

Kenda tires?

 

On 7/11/2025 at 7:13 PM, Crow Horse said:

Kenda tires?

 

Yes. They were supposed to arrive today but UPS let me down.

 

I can’t wait to get them installed. There should be less friction and their size and compound should provide a smoother ride.

 

I have traveled up to 900 miles at a time to go to tournaments and frequently travel 70+ mph and worry those smaller tires rated for 65 mph may give out. It will nice to travel with peace of mind.

I've always wondered what I should keep my boat trailer tires at for PSI too.

 

My truck tires (factory) indicate a max PSI right on the tire, but on the inside of my door, there is a sticker where the VIN is and it shows the recommended PSI.  That is what I follow.

Obviously the trailer does not have this sticker or information that the truck has, so my default has always been to keep at or near max PSI that is listed on the actual trailer tire.  Now I am second guessing that again.

Some manufacturers have a load/pressure chart for tire pressure. Others state to inflate to the max pressure indicated on the sidewall. I suspect that they take the easy route trying to avoid any liability issues. Max pressure of a tire that is not at max load will bounce down the road and tire wear will most probably be uneven. Overinflated tires tend to crown causing the center of the tire to wear faster than the outsides. This is more prevalent with bias ply tires. Radials tend to be less susceptible to crowning. It gets quite confusing. I would contact the trailer manufacturer and the tire manufacturer to see what they recommend.

I think tire manufactures use the standard of "max cold tire pressure," meaning you set PSI when not driving, or heating up the tire. 

 

Sure, the tire pressure is going to rise when you drive, especially in warm weather. I believe they account for that in the stated MAX PSI when cold rating. 

 

If you wanted, a person could lower PSI after driving for a while...and keep tires at MAX pressure when warm. 

 

And I agree that car manufacturers use recommended tire pressures lower than MAX to improve ride. 

 

My 2500HD states front tires at 60 PSI, rear at 70 PSI. Tires I'm running have max of 80 PSI stated on sidewalls. I run 65 up front, and 70 in back. Most I've seen the tires heat up is around +8 PSI. 

 

I think as long as you are not underinflating tires, you will be good to go. And remember to get new tires every 4-5 years.  

I always buy my tires (truck, car, boat and utility trailer) from the same people who only deal in tires and wheels.  When I go in for my free rotation, they air the tires up to the max pressure listed on the tire.  I’ve never had a problem with that.

I use the following method on my loaded 20cft 10" tire motorcycle tow behind trailer:

 

Using a puddle of water to estimate trailer tire pressure is a technique that can help you visualize the tire's contact patch and adjust the pressure accordingly. 

Here's how to do it

1. Prepare a puddle: Find a flat, level surface and create a shallow puddle of water wide enough for your trailer tires to roll through.
2. Drive through the puddle: Carefully pull your trailer through the puddle.
3. Observe the footprint: Analyze the wet tire marks left on the dry pavement or another surface.
   • If only the center treads are visible: The tire is likely overinflated, meaning there's too much pressure in the tire, causing the center to bulge and reducing the contact patch.
   • If the footprint shows good contact across most of the tread: The pressure is likely closer to the optimal range.
   • If only the outer edges of the tread are visible: The tire is likely underinflated, causing the sidewalls to bulge and the center to lift, resulting in reduced contact and potential overheating.
4. Adjust and repeat:
   • If the tires are overinflated, release small amounts of air and repeat the puddle test until a fuller contact patch is observed.
   • If the tires appear underinflated (showing only the outer edges), add air to them (ensuring you do not exceed the maximum PSI listed on the tire's sidewall) and repeat the puddle test until a fuller contact patch is observed. 

 

I have a Yakima rack and roll, not sure what the mac rating is, maybe 60 but I’m supposed to run them at 36psi as per Yakima