Airing Up/Down stock tires

[Timmyjoe]

In sandy or soft mud conditions, does it make much difference airing down the stock Sport S tires on my 2-Door JL? They're Goodyear Wrangler AT Adventure Kevlar tires in 245/75R17 size. I've heard that if the sidewalls are too stiff, airing down makes no difference. Not sure if the sidewalls on these tires would rate as "too stiff"?

Also, does anyone have a recommendation for an inflator to carry in the Jeep? I've looked at a number of different ones, but they seem very light duty, or very low output, something that would take a very long time to inflate a Jeep tire.

Thanks for the info.

Best,
-Tim

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[MtCamper]

OH yeah. Big difference. Also makes a much smoother ride on crappy roads, I go to 16# most of the time but have gone as low as 8 for real soft stuff. Vair makes a good compressor with stock sizes. If you get into 35 and above ARB twin works better. You can get by with HF for a while but they fail when you need them.

 

[jeepoch]

In sandy or soft mud conditions, does it make much difference airing down the stock Sport S tires on my 2-Door JL? They're Goodyear Wrangler AT tires in 245/75R17 size. I've heard that if the sidewalls are too stiff, airing down makes no difference. Not sure if the sidewalls on these tires would rate as "too stiff"?

Also, does anyone have a recommendation for an inflator to carry in the Jeep? I've looked at a number of different ones, but they seem very light duty, or very low output, something that would take a very long time to inflate a Jeep tire.

Thanks for the info.

Best,
-Tim

Tim,

There are quite a lot of options for airing up tires. Anything from permanently mounted on-board compressors to CO2 Air tanks and a boatload of options in-between. The on-board compressors are great for convenience and the CO2 tanks are the quickest and as always each have their pros and cons.

For the on-board compressor there is the installation and fittings for the tanks the re-fill is the drawback.

I went with the portable Viair 400P. I connect it up to the battery as needed. The coiled hose is long enough to get to all four corners easily.

However, I have the Goodyear Duratrac Wrangler All-Terrains in the larger 35x12.5x17 size. It takes the 400P between 3 to 6 minutes per tire, depending on how low I've aired down. I typically air all the way back up to 38 psi for on-road. This is the tire pressure that runs the chalk test best for even tread-wear on my 2-door Sport. Most people typically don't go that high in pressure favoring a better overall ride.

So I would imagine for your tire size, with the smaller volume of air required you could probably expect half my time to fill yours back up.

Also, the Viair unit I purchased is rather rugged, has never yet shut down due to overheating and is pretty lightweight. I'm certain there are other better but more expensive compressors available, you'll have to do your own homework. I'm just providing feedback not an all out recommendation.

And yes, airing down dramatically improves off-road traction in almost all conditions. My low point however is typically about 15 psi for the severe stuff and 18 psi for the milder trails. Going too low you run the risk of blowing a bead. I'm pretty sure you don't have beadlock wheels on stock (or nearly stock) tires. So be aware of that.

Otherwise, with a 12v Compressor (or Tank) either on-board or portable you'll have everything you need to experiment and find your own 'sweet spot' for tire pressures in any driving condition.

I also routinely air down to 30 psi for the more than occasional deep snow we get here in Northern Colorado. So for me, my air compressor gets used quite a bit.

Hope this helps.
Jay

 

[MauiSteve]

I got the ARB single, sort of an in between selection. The ARB dual of course is the alpha unit. The vair is also good.
Airing down makes a lot of difference.

 

[calemasters]

In sandy or soft mud conditions, does it make much difference airing down the stock Sport S tires on my 2-Door JL? They're Goodyear Wrangler AT Adventure Kevlar tires in 245/75R17 size. I've heard that if the sidewalls are too stiff, airing down makes no difference. Not sure if the sidewalls on these tires would rate as "too stiff"?

Also, does anyone have a recommendation for an inflator to carry in the Jeep? I've looked at a number of different ones, but they seem very light duty, or very low output, something that would take a very long time to inflate a Jeep tire.

Thanks for the info.

Best,
-Tim

Your side walls are not that stiff. Airing down makes a big difference. I bought a cheap air compressor from PEP Boys, but ended up giving it away. So now I have the ARB (CKMP12) 12V High Performance Portable Air Compressor. I am very pleased with it. Very good quality. Cost more than the PEP Boys cheap compressor, but guess what, it works. And works well.

 

[Timmyjoe]

Thanks for everyone's input. Really helpful. Glad to know that airing down my stock tires will help in certain conditions.

All the air compressor suggestions are better quality/higher rated than what I have been looking at. Quick question. I see two options with some of the compressors listed above, one is set up to plug into a cigarette lighter/power socket, and one is for clipping straight to the Jeep battery. Are the power sockets on the Jeep rated for higher than 15 amps? And alternatively, are there any issues with clipping to the battery, with all this second battery/ESS equipment under the hood?

Thanks.

Best,
-Tim

 

[calemasters]

Thanks for everyone's input. Really helpful. Glad to know that airing down my stock tires will help in certain conditions.

All the air compressor suggestions are better quality/higher rated than what I have been looking at. Quick question. I see two options with some of the compressors listed above, one is set up to plug into a cigarette lighter/power socket, and one is for clipping straight to the Jeep battery. Are the power sockets on the Jeep rated for higher than 15 amps? And alternatively, are there any issues with clipping to the battery, with all this second battery/ESS equipment under the hood?

Thanks.

Best,
-Tim

I think the +12v power outlet has a 20A fuse. But if you have a good air compressor, it may require more that 20 amps (240 watts) so it is better to connect across the main battery terminals. My ARB (CKMP12) requires a 40A fuse, so I do not use the +12v power outlet. Also, as I found out the hard way, when using the compressor, make sure your engine is idling. Ask me how I know.

 

[neil]

Thanks for everyone's input. Really helpful. Glad to know that airing down my stock tires will help in certain conditions.

All the air compressor suggestions are better quality/higher rated than what I have been looking at. Quick question. I see two options with some of the compressors listed above, one is set up to plug into a cigarette lighter/power socket, and one is for clipping straight to the Jeep battery. Are the power sockets on the Jeep rated for higher than 15 amps? And alternatively, are there any issues with clipping to the battery, with all this second battery/ESS equipment under the hood?

Thanks.

Best,
-Tim

I have a small one gallon compressor that is older and says 15a, and it has always tripped 15a circuits when on it.

I vote for the single arb w stock tires, double w 35s or more. Mount it in the back. There are a million options from 25 bucks to mount. If you don't like it because your a moron, then sell it on the forum....they are loved, someone will buy it.

 

[Some Random Guy]

If you have the trailer group, consider this. The 400/400p run on 30A. You can do this so you don’t have to pop the hood to air up. It is a 30A line to the 7 pin connector.

30A in the 7 pin trailer connector, if you have it. Best of both worlds unless you buy a 40A plus compressor. My 400p automatic hasn’t tripped either fuse yet (fusebox or in-line).

 

[jeepoch]

Tim,

I concur with all the above. The battery connected compressor seems the best for me.
However the 7-pin Tow Connector may have some merit if you are more comfortable with a plug-in solution.

As far as the ESS functionality is concerned, there is an impact. My ESS generally indicates "Battery Protection Mode" everytime I come off trail even before I start airing up. Even though I always disable ESS when on-trail.

I air up while idling then drive home as normal. "Battery Protection Mode" stays on until I drive about a half-hour or so and make a stop with an Engine Off, like a fuel fill-up. Only after that engine restart does ESS seem to start working again.

I've checked everything out, letting the dealership load test both batteries and validating voltages (with a voltmeter) without disconnecting any cabling. Nothing ever shows up as trouble, but to make me happy (shut me up) the dealership replaced the Intelligent Battery Sensor (IBS).

Unfortunately they did this last November after my last off-road excursion of the year. I have not gone out yet this season. ESS has properly worked with no issues since.

I'm convinced that low RPM (low speed) wheeling is not enough to keep the AUX Battery happy. So I'm going to continue to air up and ignore ESS, keeping it disabled until my first stop after normal on-road driving.

This ESS design certainly SUCKS! But I'm not going to let it ruin my Jeeping experience. For now, I'm going to live with it. If I ever go out wheeling on my own (highly unlikely) I'll have to carry a Main spare. Having a 2019 I know that if the AUX dies and as long as the Main is good, the Jeep will still start on the second attempt.

But that's another story...

Jay

 

[SlowPoke21]

I have this one. Works good enough for 33” tire. I should prolly get a little bit bigger one. Dunno. Does what I need it to do.

I have used it on everything besides the Jeep. Does well for 32psi. And does it fairly quick

 

[melendez69]

In sandy or soft mud conditions, does it make much difference airing down the stock Sport S tires on my 2-Door JL? They're Goodyear Wrangler AT Adventure Kevlar tires in 245/75R17 size. I've heard that if the sidewalls are too stiff, airing down makes no difference. Not sure if the sidewalls on these tires would rate as "too stiff"?

Also, does anyone have a recommendation for an inflator to carry in the Jeep? I've looked at a number of different ones, but they seem very light duty, or very low output, something that would take a very long time to inflate a Jeep tire.

Thanks for the info.

Best,
-Tim

I carry this guy around... I don't break it out often enough for popping the hood to be an inconvenience. For the times I needed it coming off trails, it hasn't let me down.

 

[SlowPoke21]

^^way nicer one than I have. And I agree. You don’t break it out much. So raising the hood and hooking it up isn’t that bad.

 

[MauiSteve]

Connect to the battery as the better connection will reduce the chance of under volting the motor which will hasten overheating. Have engine running.

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