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Air Compressor Filling up Camper Tires
By: Amber S.
Read time: 4 minutes
Updated: 1/19/2024

Safety check: how to check & adjust your trailer tire pressure

You’ve almost certainly seen a trailer, RV, or camper stranded on the side of the road (hopefully you haven’t been the stranded one), and chances are it was due to a tire blowout. Blown trailer tires are unfortunately common, at least in part due to a general lack of diligence when it comes to keeping them properly inflated. But that’s why you’re here, right? To learn how to avoid getting stranded—because you're prepared like that. So let’s get into it.

How Often Should You Check Your RV/Trailer Tire Pressure?

In a perfect world, you should check your tires prior to every trip. Personally, I’ve been on trips where a pre-departure tire check saved us from a potentially disastrous situation, so I can’t recommend this enough. However, I also know this is the real world, and some people are simply not going to make the effort every time. At the very least, you should check your tires before your first trip of the year, if the temperature suddenly changes (dropping temps wreak havoc on tire pressure), or if your steering ever feels wonky. Another option that I highly recommend is a Tire Pressure Monitoring System. These systems actually warn you in real time if your tires need attention, much like the systems in many cars these days.
TireMinder TPMS on tire valve stem
TireMinder TPMS attached to valve stem

What Should Your Tire Pressure (PSI) Be?

You always want your trailer tires to be aired up according to manufacturer specifications. Going too high or too low increases your chance of a dangerous blowout—not to mention lower fuel efficiency, damaged rims, and uneven tire wear.Your tire's required PSI should be listed on its sidewall.
Tire requiring 90 PSI
Max Tire Pressure: 90 PSI

How to Check Your Tire Pressure

All you need is a tire pressure gauge (and your tire, of course). I recommend purchasing a gauge to keep in your vehicle or trailer, but some gas stations have them built into air pumps as well.
Valve stem on trailer tire
Step 1: Locate the valve stem on your tire and remove the valve stem cap.
TireMinder Tire Pressure Gauge on Tire
Step 2: Press your gauge onto the stem. You'll hear a hiss – that's the sound of your gauge getting the pressure reading.
Tire pressure reading on gauge
Step 3: Check the number on the gauge and compare it to the recommended pressure listed on your trailer tire’s sidewall. (We'll cover adjusting tire pressure in the next section.)

How to Adjust Tire Pressure

If your tires are low, you’ll need an air compressor to fill them up. Many gas stations offer free use of air compressors, but in the event of an emergency, it’s also nice to have one of your own. You can purchase an onboard or portable tire inflator designed for your RV or trailer.
Viair air compressor attached to valve stem
Step 1: Connect the Compressor to Your TireAttach the compressor to your tire’s valve stem. If your compressor comes with multiple attachments, choose the one that fits your valve stem.
Viair Portable RV Compressor Hooked to Car Battery
Step 2: Connect the Compressor to a Power Source (If Needed)Attach your compressor to a power source. Your compressor might run off your car's battery, a portable power pack, or rechargeable batteries, depending on the model.
Checking Viair Portable Compressor Gauge
Step 3: Adjust the Pressure As NeededTurn your air compressor on and fill your tire. If you have a "smart" compressor with automatic shutoff, it should shut off when you reach the specified PSI. Otherwise, you'll need to stop and recheck your tire regularly with your pressure gauge to monitor its progress. Stop when you reach the PSI indicated on your tire's sidewall.
Pro tip: You should try to inflate tires when they're cool when possible. However, if you're stranded on the side of the road due to a flat, sometimes you've got to do what you've got to do. If you're adjusting tire pressure after a long drive when the tires are hot, add a couple of PSI to compensate for the cooling effect.
Boat trailer tire
Step 4: Disconnect and Repeat for all Low/Flat Tires Once you've hit the sweet spot, disconnect the compressor from the valve stem and replace the valve cap. Repeat these steps for each tire as needed.

Portable Air Compressors

Tire Gauges

Conclusion

Remember, proper tire pressure isn't just about preventing a flat – it's also about improving fuel efficiency, handling, and overall road safety. So, toss that tire gauge in your glove compartment, and don't neglect your tires!
Amber S.
About Amber S.As a content writer for etrailer, I might spend my morning loading and unloading a bike on five different bike racks to figure out which is easiest to use. I might be in the parking lot, taking pictures of an impressive RV battery setup our techs came across in the shop and discussing the benefits of the setup with the owner. I might spend an afternoon in a manufacturer training classes for some hands-on experience with new products, and then sit down to assemble all this information into a coherent article.At etrailer, one of our core values is that we are always learning, and I learn something new every day. I start each morning with the goal in mind of taking all of this information and figuring out the best way to answer the questions people ask us (and the ones they don’t know to ask yet), and helping people get the solutions they need to make their lives easier, safer, and more fun. I’m a DIYer at heart, so it brings me great joy to help a fellow DIYer find what they’re looking for, whether that’s a product, an answer, or a community.
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Ty C.

4/22/2024

The max pressure is NOT the manufacturers recommended pressure. You must check with the manufacturer and base the pressure on the load weight. For example, I run Goodyear Endurance Special Trailer (ST225/75R15) tires. This is the load/inflations information from Goodyear: https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf My trailer is 7,600 pounds loaded on dual axles. So 7,600 divided by 4 is 1,900 pounds. The recommended pressure from the manufacturer is 45 PSI, NOT the max pressure of 80 PSI. There are several disadvantages to running at the max pressure if the recommended pressure is lower. The ride will be rough, since over-inflated tires will bounce more. For a travel trailer, this can result in damage to the trailer and contents being bounced around while in transit. More importantly, it reduces the tire traction because there is less contact with the road, which can affect handling and braking, especially in rain. It also increases the risk of blowouts, since the tires don't have as much "give" when you hit potholes and other road hazards. Under-inflating is also bad and can result in overheating, bad wear, poor handling and braking, and blowouts. Find the proper inflation from the manufacturer, weigh your trailer, and inflate to the recommended PSI. Another thing many people don't consider is that trailer tires have specific lifespans, usually 3 to 6 years, regardless of tread depth. There is a DOT code on the side of the tire that indicates the week and year it was manufactured. Rubber breaks down with exposure to oxygen and ozone and most people don't put enough miles on a trailer to wear out the tread before the tire ages out. And while you're checking pressure, also visually inspect the tire for cracks, bulging, etc. Many trailers are stored outside and sunlight can be harsh on tires. Combine aged tires running at max pressure with a pothole and the results are not pretty.

Etrailer Expert

Mike L.

5/15/2024

@TyC Goodyear is the exception, because they list the tire's capacity at various pressures. Most trailer tire manufacturers don't do that. The listed weight capacity is at full inflation. This is why we recommend that folks keep their tires fully inflated because if the pressure is reduced, the weight capacity is unknown which can lead to an overloaded tire, heat build up and ultimately, tire failure. I 100% agree with everything else you stated!

Chris

4/19/2024

Your web site provides a better answer than the one in the article. Why not say what you have already said? Trailer tires, which will have an ST in front of the size, should always be inflated to the maximum psi indicated on the tire. Trailer tires usually do not have a recommended and maximum psi indication so I am curious if the tries on the camper are ST tires or regular passenger vehicle tires. On a regular trailer tire you would inflate it to the max psi indicated on the tire because trailer tires are built with a thicker sidewall to handle more vertical load.

Art W.

4/19/2024

Thank you, better safe than sorry. Max pressure is better than low pressure.

Rob D.

4/19/2024

I disagree with your statement that the max tire pressure given on the sidewall should be used to fill your tires. This assumes the vehicle is loaded enough for each tire to be be at its maximum design weight. Highly unlikely. Every modern vehicle or trailer has the recommended COLD tire pressure given, usually ion the left front door frame for cars and trucks, and assume use of the factory delivered tires. This brings me to my question. I tow a light 2300 lb '97 Chevy Tracker 4WD, with over-size BF Goodrich All Terrain TA K02 tires. The door post sticker shows original P205/75/R15 pressure to be 23 psi. Can you tell me an authoritative source, such as BFG, what pressure should be run in the new tires? I commonly deflate to about 12 psi while four wheeling for less washboard bounce and more traction. I measure no difference in tread depth wear between the outer and inner treads.

Etrailer Expert

Jameson C.

5/14/2024

@RobD Trailer tires are a different animal than vehicle tires. Go with what BFG recommends for tire pressure in your application. We actually don't offer any vehicle tires which is why we only really talk about trailer tire pressure.

Robs

5/14/2024

@JamesonC my question remains: where can I find BFG's authoritative data on what initial tire pressure should be used when the given tire is loaded with 550 lbs of vehicle, or trailer, weight?
Etrailer Expert

Jameson C.

5/15/2024

@Robs You would have to ask BFG for that. We don't have a relationship with them so I don't have a contact or anything I could give you.

Chris

4/19/2024

Your good article states that trailer tires should be inflated to their recommended pressure. However, the tire shows "max pressure" and your article seems to conflate the two. Is "recommended" the same as "max pressure"?

William

4/19/2024

The pressure on the sidewall is the maximum the tire can safely be inflated too. The load your tire carries will determine the pressure you should have. If you have excessive tread wear in the middle of the tire then you have overinflated the tire. Conversely if the outer edges are wearing excessively it is under inflated. My tire sidewall says 50 psi. I run at 40 psi and enjoy good tire life and good handling.
Etrailer Expert

Jameson C.

5/14/2024

@Chris Yes it is the same. On trailer tires inflate to the "max pressure rating".


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