Airing down 19" tires

[hatch]

There's been a fair bit of input from this always helpful community in another general wheel/tire thread, but I was hoping to gather as much feedback on this specific issue (as it is the main driver of my decision on whether to pony up the $$ for 18 wheels). So I thought I'd start a specific thread with a poll to gather responses.

Anyway, here's the question:

I've seen others repeatedly state, firmly, that they would never air down 19" tires due to the weak sidewalls, higher likelihood of contact and thus higher chance of damage to the tire (which of course, could lead to a blow out at highway speeds somewhere down the line ... something none of us want). The idea that 19" should not be aired down seems to be the consensus, but there was at least a dissenting opinion or two. So ...

 

[cperez]

I have aired down 19's when driving in sand and had no ill effects. I think I dropped them to about 20 lbs. My only very minor concern was that I might break a bead and lose pressure completely, but that didn't happen

More recently, I aired down in muddy conditions. This was against my gut feeling but on the advice of the local offroad guide who also owned and was familiar with the course. Yes, I tore a sidewall. I still consider it a fluke as there was no rock crawling involved. I think I grazed a sharp stone or other hazard when squeezing by a muddy bank in one section. On other trails I've been able to scramble through even deeper and slimier mud on fully inflated 19s (Continental TerrainContact A/T tires).

Since my offroading is not super technical, I would lean toward not airing down except for sand. If I got into trouble that clearly called for more contact, I could (almost) always air down as needed on the trail. This is all based on the conditions I'm comfortable driving my truck in.

 

[hatch]

I have aired down 19's when driving in sand and had no ill effects. I think I dropped them to about 20 lbs. My only very minor concern was that I might break a bead and lose pressure completely, but that didn't happen

More recently, I aired down in muddy conditions. This was against my gut feeling but on the advice of the local offroad guide who also owned and was familiar with the course. Yes, I tore a sidewall. I still consider it a fluke as there was no rock crawling involved. I think I grazed a sharp stone or other hazard when squeezing by a muddy bank in one section. On other trails I've been able to scramble through even deeper and slimier mud on fully inflated 19s (Continental TerrainContact A/T tires).

Since my offroading is not super technical, I would lean toward not airing down except for sand. If I got into trouble that clearly called for more contact, I could (almost) always air down as needed on the trail. This is all based on the conditions I'm comfortable driving my truck in.

Thanks for the feedback, hopefully a few others will weigh in.

My truck spends anywhere from 15-25 days a year on the sand, so it's not insignificant. And even though I've aired down my existing tires to 13 lbs or so on sand without any ill effects, it does sound like it's not generally advised w/ the sidewalls on the 19" tires out there. That's what's pushing me to (almost) pull the trigger on some 18" wheels and tires. I don't love the extra expense, but it would be nice to be able to air down without having to constantly worry about breaking a bead or damaging a sidewall.

 

[PaulLR3]

Please add a checkbox for 20 pounds. That is my choice for driving in deep soft sand on 19" wheels. Never had a problem driving about 5 miles to get home with that pressure either. I'm told that OEM wheels have a really tight bead made for airing down.

 

[cperez]

I'm told that OEM wheels have a really tight bead made for airing down.

Super tight. When my indy was mounting some tires for me a while back, he said that the beads popping into place as he inflates them on the tire machine, that sound always startles him even though he is waiting for it. It is pretty loud.

 

[hatch]

And I suppose an important additional question would be: for those that have concerns about airing down 19" tires (with their weaker and shorter sidewalls) -- do all of those concerns go away with the move to 18" tires. Clearly there's a bit taller of a sidewall, and I can then get into an E-rated, thicker sidewall ... but is that enough to set aside most concerns about airing down? Or is going to 18" only a marginal improvement in this (and I suppose other) regards?

 

[PaulLR3]

I have driven on the beach with 20 psi in both 19" and 20" tires. Could not tell any difference so I'd say the comparison between 18" & 19" would be similar.

 

[hatch]

I have driven on the beach with 20 psi in both 19" and 20" tires. Could not tell any difference so I'd say the comparison between 18" & 19" would be similar.

I'd want to be down around 13 lbs or so, but either way I'm not expecting to "feel" much of a difference, I'm just wondering what folks' opinions are on whether going to 18" significantly mitigates the risks of damage many are concerned about when airing down 19" (and 20") tires.

 

[avslash]

I'd want to be down around 13 lbs or so, but either way I'm not expecting to "feel" much of a difference, I'm just wondering what folks' opinions are on whether going to 18" significantly mitigates the risks of damage many are concerned about when airing down 19" (and 20") tires.

Give me a hard enough trail and enough time, and I can destroy whatever tire you want me to destroy.

More sidewall unquestionably reduces the risk of sidewall damage on any particular trail at any PSI.

 

[toddjb122]

I have driven my LR3 and LR4 a LOT on the sand for the past 14 years. I have to air down.
If I go out at 42/36 psi I get stuck in soft sand. If it's really soft, it happens almost immediately. I'm talking soft fine beach sand when it hasn't rained in a while...

...so, now I always air down. If I think the beach is pretty firm I'll go down to the low 22-24. If I just want to be safe side I'll drop them all to 19-20 and not worry about just about anything. If I get stuck, I drop them to 15-16, put it in 4Low and I can drive right out.

When I say "stuck" I can tell when the truck is digging itself down so I stop before I'm resting on my frame. Then I drop the pressure, make sure all 4 wheels have a clear path by removing sand from in front of them, put it in 4Low and ease out. Works every time. In 14 years I have only needed a beach pull out once.

When I first used to drop the air down I would worry about the tire rolling off the rim on the road when I went around turns. I mentioned it to my mechanic and he commented on how hard it is to break a bead on our wheels, and not to worry about it. So, now when I have a beach vacation, and I'm driving every day, I just drop the air down on the first day and leave it there for the week. I don't leave it below 20, and I'm not typically driving over 50mph on pavement, but have never had any issues related to tire wear or anything. I know driving around that low isn't recommended, but it takes a while to air down and air up if you do it every time you get on/off the sand, and I have not had any issues.

Once you have driven the truck on the sand a bit you'll start to get a feel for when it's working hard and when it's driving easy. When I can tell it's working more than it should, I drop the air further and the thing feels like a dune buggy floating along the tops. Very cool. 5,000 lbs on 19" rims. Amazing.

That's my take, anyway.