BajaNomad - Downside To Airing Down Tires?

Downside To Airing Down Tires?

AlanDow - 1-17-2018 at 03:30 PM

I am spending the winter in Bahia Asuncion and I drive a rear wheel drive Toyota Tacoma and have generally had good luck following the advice often repeated on this forum, to air down tires when driving off pavement - until I experienced a sidewall blowout. I had just checked the pressure the morning of my mishap and all four tires were 22 lbs. I was a few miles south of BA on a good section of the road to La Bocana going about 30 mph, and had not encountered any road hazards when I heard /felt the blowout - essentially a 3 inch split along a radius of the sidewall (from near the rim to near the tread) on what was a nearly new tire.

Now wondering if it is likely the lower air pressure caused this, indicating there may be a significant downside to this practice, or maybe a defective tire, or what? So thought I would ask if this has happened to others following this practice?

Also I have a smaller class C motor home and was thinking of taking it back on hwy 5 and wondering what pressure I should air down as the normal pressure on it's tires is 65lb, so was thinking maybe airing down to 40 lb on the unpaved section of hwy 5 - now after this mishap wondering if I should do so at all? Appreciate any input from those with more experience on this topic. Thanks

JZ - 1-17-2018 at 03:40 PM

We go from 60-65 to 30-35 on E load tires. Makes a world of difference in comfort, night and day difference level. Woudn't think of not doing it.

[Edited on 1-17-2018 by JZ]

Bob and Susan - 1-17-2018 at 03:45 PM

look at the date code on YOUR tires...
if over 3 years old you are at risk for a FLAT

https://www.youtube.com/watch?v=S_VYhD49fjk

David K - 1-17-2018 at 03:46 PM

Good questions!

When you are deflated, you are indeed risking the sidewall to damage. You just may have grazed a pointy rock just right or there could have been a metal plate of some kind or just a tire fail.
Most tires are made to run on paved roads at the recommended pressure in your door jam.

I have a 4-door Tacoma and run the brand of tires I use at 34 psi on the highway. If I deflate, it is to 22-24 psi for dirt roads and to 16-18 psi for sand. Other types of tires or very loose sand (or those shell beaches south of Asuncion) will dictate different or much lower pressure numbers.

I have not had a sidewall failure, but have had holes punched through right where the tread and sidewall come together. In Mexico, they will put a patch in. Back home, they replace the tire. This borderline puncture at 24 psi was admittedly driving a bit too fast on a rocky, graded road (north of San Borja). It may have just as easily happened at full pressure. I tend to feel that deflating the tires to the low 20s resists sharp rock punctures as the rubber gives more going over a pointy rock.

I used to never deflate for dirt roads (only for sand) and I got a lot of flats on my previous Tacomas! I think deflating for any lengthy drive on dirt is a good practice, especially if you want to drive at a fair speed. The ride is smoother too.

TMW - 1-17-2018 at 04:31 PM

On my Tacoma I air down to at least 25 and sometimes I forgot or just didn't bother to air up when I would go home and I never had a problem with BFG TA/KO tires. I'm a little more careful now that I'm running a P version of the Toyo tires instead of the LT version. With the BFG tires you could hardly tell the difference between 35 and 25 lbs just looking at them. I've never had a sidewall failure, always thru the tread. Now I will knock on wood.

4x4abc - 1-17-2018 at 04:40 PM

the damage described is either the result of a previous traumatic impact at higher pressure or a manufacturing fault.
What brand tires are they?

Tire damages related to low tire pressure look very different than what you describe.
Most prominent are the "half moon cuts" - if you hit a good size rock with deflated tires and the rock compresses the tire to the edge of the rim, you'll get two distinct half moon shaped cuts.
The other distinct damage related to low tire pressure is a puncture in the transition zone between tread and sidewall. It is the first 1/3 of side wall that is at risk due to bulging out.
The better off-road tires (BFG and some Goodyear) have that area reinforced. Most other LT rated tires do not have that feature.

However, you are more likely to have tire damage (usually tread punctures) at full pressure and speeds above 30mph on dirt roads than with deflated tires. At 20 psi that risk goes down to zero.

A common mistake in airing down is that one does not air down enough for the environment. David's pressures are a good example. They are too high. He wanted to do something good but was afraid to go too far. By doing so, he did not go far enough. For his tire size and truck, 20 psi is the right number for dirt roads. 10 psi is the right number for the beach.

[Edited on 1-18-2018 by 4x4abc]

4x4abc - 1-17-2018 at 04:44 PM

Quote: Originally posted by TMW

On my Tacoma I air down to at least 25 and sometimes I forgot or just didn't bother to air up when I would go home and I never had a problem with BFG TA/KO tires. I'm a little more careful now that I'm running a P version of the Toyo tires instead of the LT version. With the BFG tires you could hardly tell the difference between 35 and 25 lbs just looking at them. I've never had a sidewall failure, always thru the tread. Now I will knock on wood.

P rated tires are like dancing shoes for a rough hike. Would you use tennis for Mt. Everest?
Tread punctures indicate that your tire pressure was too high.

David K - 1-17-2018 at 11:09 PM

20 psi sounds fine Harald (I run just a tad more is all 22-24), I don't argue that pressure for good tires, but 10 psi is far lower than needed for sand floatation.... with the 'cheaper' tires I use.

10 psi is indeed the place to be for your BFG All Terrains, I agree on that! I ran 10 psi on my 3-ply Cooper Discoverer STT tires just for normal sand driving that worked well at 15 psi on other tires.
Stiff sidewall or mud-terrain type tires need much more air removed than street or most all-terrain tires.

4x4abc is the expert on off-roading... He wrote the book and has the website: http://4x4abc.com/

chippy - 1-17-2018 at 11:15 PM

Quote: Originally posted by David K

20 psi sounds fine Harald (I run just a tad more is all 22-24), I don't argue that pressure for good tires, but 10 psi is far lower than needed for sand floatation.... with the 'cheaper' tires I use.

10 psi is indeed the place to be for your BFG All Terrains, I agree on that! I ran 10 psi on my 3-ply Cooper Discoverer STT tires just for normal sand driving that worked well at 15 psi on other tires.
Stiff sidewall or mud-terrain type tires need much more air removed than street or most all-terrain tires.

4x4abc is the expert on off-roading... He wrote the book and has the website: http://4x4abc.com/

How did you get to Jan 18? :?:

chippy - 1-17-2018 at 11:19 PM

Both our dates are 1/18/18 :?:

David K - 1-17-2018 at 11:26 PM

Edit: Yes, the Nomad clock is off by 6 hrs and 12 minutes...

***However, I just noticed it is 6 hours off! LOL It is not 10 pm here. I will check mine too.***

OK, I sent Doug an alert.

[Edited on 1-18-2018 by David K]

chippy - 1-17-2018 at 11:38 PM

I´m still set at central time :?:

[Edited on 1-18-2018 by chippy]

basautter - 1-18-2018 at 12:14 AM

I air down to the mid 20s for long stretches of gravel road and upper teens for sand. With lower pressure, the tires flatten out a bit exposing the sidewall more. This has resulted in a damaged tire or two for me, but better then beating the #$@& out of my body, gear and truck! I am diligent about airing back up on pavement. The heat from flexing can also shorten the life of a tire.

Bajazly - 1-18-2018 at 12:36 AM

It's funny when I lived in Australia 30 years ago we did some back country travel and the first thing any one would say when you said you were going off road is, make sure your tires are good and aired up, don't want those side walls running over the rocks in the road.

Different strokes I guess.

bajatrailrider - 1-18-2018 at 01:04 AM

Could not even think to air up tires off road nuts. My Toyota off road truck 18psi / Nissan Diesel 18 psi/ Bronco 18 psi/ Heavy Dodge diesel 20 psi. Motos 6 front /6psi rear/ KXF700 ATV 2 psi. Sidewall problems zero off road time every week for over 40 years. Nissan has p rated tires was aired down pulling Wils heavy bronco in deep sand Pole line trip. Zero problems.

JZ - 1-18-2018 at 01:27 AM

Quote: Originally posted by bajatrailrider

Could not even think to air up tires off road nuts. My Toyota off road truck 18psi / Nissan Diesel 18 psi/ Bronco 18 psi/ Heavy Dodge diesel 20 psi. Motos 6 front /6psi rear/ KXF700 ATV 2 psi. Sidewall problems zero off road time every week for over 40 years. Nissan has p rated tires was aired down pulling Wils heavy bronco in deep sand Pole line trip. Zero problems.

Still can't believe you run the bikes at 6 psi.

Is the Dodge a 3/4 ton? What's it's recommended payment psi?

motoged - 1-18-2018 at 02:14 AM

Quote: Originally posted by JZ

Quote: Originally posted by bajatrailrider

..... Motos 6 front /6psi rear/

Still can't believe you run the bikes at 6 psi....

No pinch flats ???? Maybe just for sand with no rocks or sharp edges....

BajaNomad - 1-18-2018 at 06:30 AM

Quote: Originally posted by David K

Yes, the Nomad clock is off by 6 hrs and 12 minutes...

***However, I just noticed it is 6 hours off! LOL It is not 10 pm here. I will check mine too.***

OK, I sent Doug an alert.

Still working on this....

PaulW - 1-18-2018 at 07:32 AM

Heavy Jeep 35" BFG KM2 tires. 14-15psi on the dirt 28 Highway. For Moab on the hard trails I use 12 psi.
Flats - once in 12 years and the damage was a cut sidewall on a tire ready for replacement. Goodyear 35" MTR

AlanDow - 1-18-2018 at 07:53 AM

Harold the brand of tire is Douglas which happened to be the all season tire that was on sale when I purchased this set. I mostly drive on payment and have always bought low cost all season tires and have not had any prior issue with airing down for occasional dirt or sand drives. As far as age, I bought them less than six months ago and they have a 2017 mfg date, so age was not the issue. Thanks for the replies

4x4abc - 1-18-2018 at 09:30 AM

Alan,
a radial split sounds very much like a manufacturing glitch.
Time for a new tire

Bob and Susan - 1-18-2018 at 09:33 AM

"douglas tire" name is owned by Walmart

so you bought Walmart tires

sometimes they are made by goodyear and sometimes they are not

sometimes its better to get a better tire especially if you are going to use them in the dirt

good tires are cheap insurance

David K - 1-18-2018 at 09:53 AM

A 'name brand' tire, but cheaper than the BIG BOYS, I have really liked the performance of the Hankook DynaPro ATM. It is quiet on the highway, superior in the sand, yet still great in mud and snow. They are very popular with others on Tacoma World forums and are now the stock tire used by Nissan on the Xterra and Frontier trucks, I hear.

bajatrailrider - 1-18-2018 at 09:57 AM

Quote: Originally posted by JZ

Quote: Originally posted by bajatrailrider

Still can't believe you run the bikes at 6 psi.

Is the Dodge a 3/4 ton? What's it's recommended payment psi?

Yes Dodge is 3/4 4x4 stick shift diesel It has BFGs max psi on tire is 50. I don't run these rigs on long pavement runs with low psi. On my dirt bikes we use Ultra H.D tubes 4mil thick. I have run as little as 4 psi. Why would I do this its better then pushing the bike up the foot trails we ride. Also running 10/12psi beats you to death. Where not racing the bikes with low psi. Just riding normal having fun not looking to get hurt. As far as the KFX700 at 5 psi its all over the place on dirt road. With 2psi just right.

bkbend - 1-18-2018 at 10:01 AM

http://douglas-tires-reviews.measuredup.com/3962

4x4abc - 1-18-2018 at 11:54 AM

if you run the "max load xyz lb at xyz psi" pressure printed on your tire you are hurting the tires if your load per tire is less than xyz
and you are hurting your spine and brain by shaking them to pieces

but hey, science is not for everyone

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=...

4x4abc - 1-18-2018 at 12:08 PM

example
my truck has a GVWR of 7,000 lbs.
my tires (LT295/75R16) have max load of 3,970lbs. @ 80 psi (per tire mind you)
3,970 lbs. time 4 is 15,880 lbs.

if I would run the tires at the max rating, the center of the tread would wear out first - not good
the truck would run like a wheelbarrow - bad for my aging body

using the chalk method I found that the best everyday pressure for the tires is 29psi
40 psi for long fast highway runs
20 psi for dirt roads
10 psi for beaches
5 psi for the quicksand at Malarrimo

haven't had a flat tire in 20 years
have never lost a bead

I drive where few dare to go
I have never been stuck

however, you are all free to believe whatever is good for you

believing is religion - knowing is science

StuckSucks - 1-18-2018 at 12:08 PM

A dozen years ago, I worked and lived in San Felipe for about four months. I quickly figured out to run around town with my tires aired down to mid teens - made for a better ride on the SF "paved" roads, plus easy to spontaneously run in the desert.

del mar - 1-18-2018 at 12:16 PM

Quote: Originally posted by 4x4abc

example
my truck has a GVWR of 7,000 lbs.
my tires (LT295/75R16) have max load of 3,970lbs. @ 80 psi (per tire mind you)
3,970 lbs. time 4 is 15,880 lbs.

if I would run the tires at the max rating, the center of the tread would wear out first - not good
the truck would run like a wheelbarrow - bad for my aging body

using the chalk method I found that the best everyday pressure for the tires is 29psi
40 psi for long fast highway runs
20 psi for dirt roads
10 psi for beaches
5 psi for the quicksand at Malarrimo

haven't had a flat tire in 20 years
have never lost a bead

I drive where few dare to go
I have never been stuck

however, you are all free to believe whatever is good for you

believing is religion - knowing is science

Harald, what would you suggest be the the proper (or safest) tire pressure for navigating the pot hole fields of Catavina?

4x4abc - 1-18-2018 at 12:26 PM

what are the pot hole fields of Catavina?

Bob and Susan - 1-18-2018 at 12:29 PM

Quote: Originally posted by 4x4abc

example
my truck has a GVWR of 7,000 lbs.
my tires (LT295/75R16) have max load of 3,970lbs. @ 80 psi (per tire mind you)
3,970 lbs. time 4 is 15,880 lbs....

i'm pretty sure this isn't a correct calculation
and this 15880 lbs is wrong

i'll have to do some research now...damn

del mar - 1-18-2018 at 12:32 PM

Quote: Originally posted by 4x4abc

what are the pot hole fields of Catavina?

highway 1 with deep sharp edged potholes, impossible to avoid em all. pump em up hard?

TMW - 1-18-2018 at 12:40 PM

Avoid that section of hwy and take the coastal route by the sea.

bajatrailrider - 1-18-2018 at 01:35 PM

JAAAA your right TMW only Mexico could have a dirt road better then paved.

David K - 1-18-2018 at 03:26 PM

Quote: Originally posted by bajatrailrider

JAAAA your right TMW only Mexico could have a dirt road better then paved.

Where is the LIKE button?

4x4abc - 1-18-2018 at 04:03 PM

Quote: Originally posted by Bob and Susan

i'm pretty sure this isn't a correct calculation
and this 15880 lbs is wrong

i'll have to do some research now...damn

go to tirerack.com
select tires by size
select 295/75R16
https://www.tirerack.com/tires/TireSearchResults.jsp?zip-cod...

first tire that shows up is a BFG
https://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich...

click on specs

it shows you 3,970 lbs. at 80 psi

if one tire can carry 3,970 lbs. - 4 tires can carry 15,880 lbs.
my truck will max out at 7,000 lbs.
so, 15,880 @ 80 is way too much
pressure needs to be reduced

John Harper - 1-18-2018 at 04:40 PM

Quote: Originally posted by 4x4abc

Using the chalk method I found that the best everyday pressure for the tires is 29psi
40 psi for long fast highway runs
20 psi for dirt roads
10 psi for beaches
5 psi for the quicksand at Malarrimo

haven't had a flat tire in 20 years
have never lost a bead

I drive where few dare to go
I have never been stuck

Knowing is science

One question, do you measure these pressures on cold tires?

I set my deflators at 24 (and checked it) on the way to Mike's last year. Next morning at Mike's, the tires read 20 (your recommended pressure). Obviously since I got off Hwy 3 the tires were warm and pressures up. I realized I should have checked overall pressure first (cold inflation was 34) to see the difference when warm. It seems my setting of 24 becomes 20 on cold tires, so maybe I should stay at the 24 setting when on warm tires?

I will check this in April when I return to Mike's. I appreciate your input and experience. I will use your advice.

John

4x4abc - 1-18-2018 at 05:39 PM

if 20 psi is the pressure you desire today for today's driving conditions - you set them to 20 psi
you may have to adjust the tire pressure tomorrow when the conditions have changed
temperature is one of those factors
another factor is elevation

the pressure we check in our tires is a relative pressure
relative to the outside air pressure
as you drive up in elevation, outside pressure goes down - your tire pressure goes up
the change is about 4.5 psi for every 10.000 ft
so, driving up to the San Pedro Martir observatory your tire pressure will increase by around 4 psi
since 4 psi won't affect any of us much this point is academic - but it needed to be mentioned for completeness

I was part of an expedition some years back in Iceland.
the rigs were running 44" tires with 2 psi
a change in temperature or elevation would make a significant difference when you aim for a 2 psi optimum
we had to adjust tire pressure every 2 hours

how did they keep the tires on the rims at 2 psi?
super glue
not kidding

back to the temperature related drop or rise in psi
every 10 degree increase will rise your pressure by 1 psi
so, John's drop of 4 psi at Mike's indicates a temperature drop of 40F

TMW - 1-18-2018 at 09:02 PM

What would be the proper pressure for driving in snow and ice? I was in the mountains driving to our transmitter site when I came upon an ice patch. All 4 wheels would just spin, no traction. I didn't have chains on so I aired down to I think about 20 lbs and away I went up the hill.

4x4abc - 1-18-2018 at 10:57 PM

always think of tanks and caterpillars - they have huge "tire footprints"
the more you air down, the closer you get to a caterpillar

on some trips I have changed tire pressure 4 or 5 times.
sometimes just for 10 minutes to climb a nasty hill

that means, a serious 4x4 needs a serious air compressor

smart move, by the way, Tom!

State of California wanted to hire me some years back to teach maintenance crews for remote radio sites in 4x4 recovery. I talked them into teaching not to get stuck. Tire pressure plays a big role in it. We added a few hours of recovery anyway, because it never hurts - but the main thinking has to be "how can I avoid getting stuck", not "how do I use my winch"

[Edited on 1-19-2018 by 4x4abc]

John Harper - 1-19-2018 at 06:28 AM

Quote: Originally posted by 4x4abc

every 10 degree increase will rise your pressure by 1 psi
so, John's drop of 4 psi at Mike's indicates a temperature drop of 40F

That's what I'm looking for. Since my tires were a bit warm to the touch at the turnoff to Mike's, it would roughly correspond to 100-110*, about 40* above a nominal 70* starting temp. I like your POV on "not getting stuck" as a priority.

John

[Edited on 1-19-2018 by John Harper]

4x4abc - 1-19-2018 at 06:42 AM

Quote: Originally posted by del mar

Harald, what would you suggest be the the proper (or safest) tire pressure for navigating the pot hole fields of Catavina?

I would use the lowest speed possible
tire pressure around 50 psi

as you remember, I had already recommended a +10 psi pressure for highway driving

del mar - 1-19-2018 at 10:38 AM

Quote: Originally posted by 4x4abc

always think of tanks and caterpillars - they have huge "tire footprints"
the more you air down, the closer you get to a caterpillar

on some trips I have changed tire pressure 4 or 5 times.
sometimes just for 10 minutes to climb a nasty hill

that means, a serious 4x4 needs a serious air compressor

smart move, by the way, Tom!

State of California wanted to hire me some years back to teach maintenance crews for remote radio sites in 4x4 recovery. I talked them into teaching not to get stuck. Tire pressure plays a big role in it. We added a few hours of recovery anyway, because it never hurts - but the main thinking has to be "how can I avoid getting stuck", not "how do I use my winch"

[Edited on 1-19-2018 by 4x4abc]

sounds like a two-way tire pressure system would be convenient
anyone use em?
https://www.wildboaroffroad.com/2WayAir-Tire-Pressure-System...

David K - 1-19-2018 at 11:33 AM

Thanks for sharing that link, Del Mar.

Harald probably has answers for this...

Question: If one tire gets a flat, what stops the air from draining out of all four?

Reading the website: Taking 6 minutes to let the air out for off-roading seems long?

Looks like a kit for Jeeps only?

4x4abc - 1-19-2018 at 11:45 AM

unless you have portal axles, there is no reliable central air system on the market
the one shown has the lines hanging outside the tires at all times
guess the vendor has never been off-road