If you are towing a trailer or camper, it is critically important to have the right tire pressure for towing. This will ensure that your vehicle is safe to tow and that you do not damage your equipment.
The best tire pressure for towing is between 35 and 65 psi, depending on your vehicle and the weight of your trailer.
Obviously, this is a pretty wide range! Don’t worry, we’ll help you narrow it down.
In this guide, we will discuss the different things you need to consider when choosing the correct tire pressure for your adventure.
We will also provide some tips on how to adjust your pressure depending on the weight of your load for the best results.
The Right Tire Pressure For Towing
As we covered earlier, there’s a broad range (typically between 35 and 65 psi) for the best tire pressure for towing.
That’s a big range, and it comes down to a few different factors that we’ll cover now.
Here’s the secret. It all depends on what type of tire you have, and the max pressure your tire can handle.
Type Of Tire
There are two main types of tires seen on tow vehicles: P-Metric tires and LT tires.
P-Metric tires are passenger vehicle tires, meant for use on cars, minivans, SUVs, or light-duty trucks.
If your tire doesn’t have a letter in front of it on the sidewall, it is a P-Metric tire.
LT tires (short for light truck tires), which are for heavy loads, including off-roading and towing.
They have reinforced sidewalls and treads that protect the tire from damage under heavy loads.
So why does this matter?
Each tire behaves differently and has different idea towing pressure limits, so it’s important to understand which tire you have before we continue.
Before we can figure out the correct tire pressure for towing, we’ll also need to know the max pressure of your tire.
You can find this on the sidewall of your tire, usually indicated as a number in parentheses followed by “psi” or “psi max”.
So for example if we had a tire with a reading of 44 psi max, that tells you the absolute maximum tire pressure it can handle is 44 psi.
Always Use Cold Inflation Pressure Measurements
All specifications from tire and vehicle manufacturers are based off of cold pressure measurement, aka cold psi.
This means the inflation pressure of tires before the car or trailer are driven and the tires are “warmed up”.
Why does this matter?
Well, “hot” or warmed up tire pressures average about 5 psi higher than when checked if cold, throwing everything out of balance.
What’s more, your psi will lower as the tires “cool down”, leaving you with the wrong pressure in your tires for towing.
The Best Tire Pressure For Towing With P Tires
You should always set your tire pressure to the vehicle manufacturer’s specifications when towing with P-tires.
There’s no exception.
Even if your passenger tires show a higher max load, it will not add towing capacity or additional stability when towing.
The vehicle manufacturer’s max psi recommendation is there for a reason: to provide you with a guideline of tire pressure so that your vehicle’s tires can best handle the maximum capacity of your vehicle, including when towing.
Again, the best tire pressure for towing with passenger tires is the vehicle’s manufacturer specifications.
The Best Tire Pressure For Towing With LT Tires
Always set your tire pressure to the max psi rating just above your max load when towing with LT tires, while staying as close as possible to the vehicle manufacturer’s specifications.
Now if you haven’t calculated this before, it can be a little confusing.
Don’t worry! We’ll walk you through it.
How To Calculate Max Load For LT Tires
There’s two ways to do this: the easy way and the hard way (we’ll let you decide which to use).
The Easy Way
The easy way to calculate the max load for LT tires is to refer to the air pressure & load chart for your tire rating.
Take for example this air pressure and load chart for a LT 245 / 70 R17 tire:
Tire Load Limit Chart
|Tire Size||PSI (lbs)||35||40||45||50||55||60||65||70||75||80|
|LT245/70R17||Tire Load Limit (lbs)||1690||1855||2010||2205||2315||2460||2600||2740||2875||3000|
As you can see, the tire pressure of 45 equals a max load limit of 2,010.
Let’s say that you’re hauling a trailer that weighs 8,500 lbs, and the vehicle manufacturer’s specifications calls for 48 psi.
If this is the case, then 45 psi won’t cut it.
At 45 psi, those tires would have a combined load rating of 2,010 x 4, or 8,040 lbs, which isn’t enough.
Additionally, your vehicle requires at least 48 psi, in which case 45 psi isn’t enough either.
You’d then want to increase the tire air pressure for towing to the next psi rating up on the chart, which is 50.
That’d give you a max load rating of 2,205 lbs per tire or a total of 8,820 lbs, putting you in the clear, and just barely above the vehicle manufacturer’s psi specification.
The Hard Way
The hard way is by doing math:
Tire Weight / Tire Pressure = Load Capacity Pounds per PSI
This is reliable, but it requires that you know the weight of your tire.
If you’re going to go to all that trouble, just look up the air pressure and load chart for your tire and save yourself the calculator work!
The Best Trailer Tire Pressure For Towing
Just like with LT tires, trailer tires should always be inflated to the max load psi.
You’ll want to refer to the air pressure & load chart for the trailer tires you have, or do the same math we outlined above for calculating the best tire pressure for towing with LT tires.
The combined load capacity of all the trailer tires must be equal or greater than the Gross Vehicle Weight (GVW) rating of the trailer’s axles.
You can exceed this by about 15-20%.
The main benefit of doing that is that most trail tires run cooler at max tire pressure, reducing wear and the chances of a blowout.
If your trailer tires are wearing in the centers, you can reduce the tire pressure slightly, but never go below the max load psi requirement.
The majority of trailer tire failure incidents are due to too low of psi, or under-inflation.
Frequently Asked Questions
For passenger tires, always use the Vehicle Manufacturer’s psi specification.
For LT tires, you can increase tire pressure when towing to ensure that you are meeting or exceeding the maximum load rating required of your tires while still staying as close to the Vehicle Manufacturer’s psi specification as possible.
Always test your tire pressure “cold” (before driving or towing). This applies to both the tow vehicle’s tires and the trailer tires.
Check them throughout your trip as necessary, keeping an eye on the tire pressure and making sure it’s within the proper range.