LX570 - stock 285/50/20 tire pressure on sand?

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Dan Lee

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No 4WD experience. This is my first SUV. I took it out to some sandy area recently and noticed that in some deeper sandy spots, I started to lose traction. I never got stuck, even when driving slow. But I did notice some wheel spin at times.

Question: if I get into a spot where it really is too loose and deep and I start to get stuck, I know that deflating the tires a bit can help. But I think this is usually when the tires are 60 or 70 profile. To what pressure can I safely operate the stock 285/50/20 tires? And will that pressure actually help? I'm still trying to make the 20s work for me given my relatively easy usages. I just don't know if I can lower the tire pressure enough for these conditions so that it'll provide any benefit.
 
Thanks. So, 15+ psi on 20"/21" sounds okay (the article referenced 21" wheels?). Ideally, for those conditions, sounds like 18"/19" is still preferred but operating down to 15 psi is okay....

But is there a practical benefit you've observed? The article seems to indicate that they didn't test with full pressure - the lowered the pressure as soon as they left the tarmac. So, I'm not sure if if lower the pressure was beneficial or not.

That being said, sounds like it's okay to operate down to 15 psi which is about where one would lower 18" (285/65/18) as well. So, at least the operating pressure can be the same. I'd guess that the 18" would result in a larger tread patch still.
 
With the side wall being very short on a 20" tire the results are not as noticeable as a 18". If you have access to air and your aren't out carving bowls you should be fine as Ryan mentioned at about 15-20 lbs.

If you are stuck (or could be shortly) i would drop down to 12-15 lbs. Just know that you need to refill before you spend any time on the blacktop. I have had my 275/60/20 down at 12 lbs while on some reasonable tough trails and have not lost a bead (yet). After running 10-12 lbs on my 40 so long I really don't think much of it anymore.
 
Thanks. Okay, I'll consider 15psi good to go, at least for straight. Do I need to exercise more caution (for losing the bead) when turning and/or going over small rocks/bumps in the 'road?' Or 15psi is fine as long as I keep the speed down (air up if I start to pick up speed)?

I'll be getting a 12v compressor soon (considering the 88p).
 
your biggest concern will be off camber sections that put extra load on the outside bead of the tire. If you are turning quickly, or running sideways on steep inclines. The bumps really shouldn't cause you any problems at all, it will just be much smoother ride.

Yo are exactly right when you get back to the road. The tire is building up much more heat since its flexing so much.
 
Great. Thanks for the info. I scared myself a few times my first time off pavement. I think I just need to build up confidence in the machine and learn these kinds of things so that I can safely better utilize the car's capabilities.
 
I haven't gone to 12 lb

Our LX sees a lot of sand south of the border as well and it hasn't gotten stuck yet

However good to know you have had luck going down to 12psi as well
Back 40 said:
With the side wall being very short on a 20" tire the results are not as noticeable as a 18". If you have access to air and your aren't out carving bowls you should be fine as Ryan mentioned at about 15-20 lbs.

If you are stuck (or could be shortly) i would drop down to 12-15 lbs. Just know that you need to refill before you spend any time on the blacktop. I have had my 275/60/20 down at 12 lbs while on some reasonable tough trails and have not lost a bead (yet). After running 10-12 lbs on my 40 so long I really don't think much of it anymore.
Click to expand...
 
Dan Lee said:
Great. Thanks for the info. I scared myself a few times my first time off pavement. I think I just need to build up confidence in the machine and learn these kinds of things so that I can safely better utilize the car's capabilities.
Click to expand...
Both the LX and LC (we have had both in our garage at the same time -his and hers - since the lx450 came out)

They are both extremely capable machines even in OEM spec

I know if you read this section too long, one gets convinced that you need $25,000 parts for your 200 series to make it a non mall crawler

Have confidence in the Oem spec of the machine. Go out there and try it out within your own abilities

If you run to the end of the oem capabilities, upgrade according to your needs


Have fun and be safe
 
I'm with @ryanCA that these trucks are extremely capable as OEM in sand (and off road generally). Expect some wheel spin in sand and experiment with the controls like the center diff lock, etc. You'll slow down as the tires bog down in deep sand, but you'll keep going even at regular tire pressure in all but the loosest sand. In extreme conditions like sand dunes, I've found 20 psi a happy compromise between good flotation in the deep stuff and safe travel on pavement for a few miles until I can get to a place to air up. I would also note that with many 12V compressors, you could order take-out and have dinner in the time it takes to air up four big tires from 15 to 35 psi. So look carefully at the specs like cfm at various pressures and at duty cycle. Anyway, with some more experience with how things feel off-road you'll gain confidence and likely not have to air down until you realiy start to push limits. So get out there!
 
You big sissies!! Hahahah!

Too much time in my unrefined 40. ;) I might be too comfortable in dropping down on air pressure. To each his own, but the biggest thing is to stay out there and keep wheeling like Sandroad said. You will begin to feel more at home in the dirt and make your own rules. Who knows, some day you might even go down to 11 lbs. lol
 
I wouldn't bother the hassle of changing tire pressure until you get stuck. The only benefit I see a slightly softer ride on bumps. To get the LX/LC stuck it will take some effort and most likely crawl control will help you get out. Never got stuck in in 4runner/GX/LC. The only vehicle that gave me problems ever on the beach was Acura MDX.
 
Thanks guys. I'll get out and test more. Is the Viair 88p good for this vehicle (seems like it's the model appropriate for the stock tires)? Any recommendations for something different? Since the car has both 12V (lighter) and 120AC outlets, does that open up additional choices? I also will have the Battery Tender ring quick disconnect cord attached to the battery - something I could use with that to make inflation quick?
 
Dan Lee said:
Thanks guys. I'll get out and test more. Is the Viair 88p good for this vehicle (seems like it's the model appropriate for the stock tires)? Any recommendations for something different? Since the car has both 12V (lighter) and 120AC outlets, does that open up additional choices? I also will have the Battery Tender ring quick disconnect cord attached to the battery - something I could use with that to make inflation quick?
Click to expand...
You can't run a good pump off 120VAC since the outlet is for light use only. My 200 outlet is just 100 watts. ;(

You could connect a pump to the battery tender plug but again, that cable is for only a few amps at best, you need _heavy_ gauge cable for a high output air pump. A 75 amp winch QD connector with appropriate cables for the load would be dandy.

The first time you inflate four tires you will understand why you need a high CFM and a long duty cycle. That 88P is very marginal. As these little pumps get hot the output decreases and the inflation time increases. Buy a MUCH bigger pump than you think you will need, then you will be happy every time you use it, instead of swearing and praying it doesn't burn up before your tires are at street pressure..

For ocassional use this pump would be fine, but you need to change the stupid hose fittings to standard sized ones. It fills tires very quickly. The airflow is strong enough that you can actually use a small air nozzle for blowing dust off stuff.

https://www.amazon.com/Smittybilt-2781-5-65-Universal-Compressor/dp/B004K25GMG

John Davies
Spokane WA
 
Last edited:
Ah, thanks! So, these little pumps require higher power / current than the AC outlet and BT cables can provide. So, I'm guessing that I'm looking for a high CFM pump that can attach directly to the battery (while the car is on) using low gauge (thicker), high current cables.

Thanks for the recommendation. I'll keep that in the cart and keep searching for options along these lines.
 
Here are some pics of that Smittybilt pump. I cut off the stupid weird fittings at the black hose coming off the pump. I installed standard QR air hose fittings everywhere. The hose coming off the pump requires a 1/4 inch barbed to 1/4 MPT adapter at the far end. The pump end remains untouched.

The coiled yellow hose is a replacement with MPT fittings, the blue hose is a 1/4 inch x 25 ft extension. I made a swiveling air chuck. All except the blue hose are from Harbor freight for about $20... I can't recall the source for that.

IMG_3126.webp
IMG_3128.webp
IMG_3129.webp


With the engine running, the pump inflated a stock 200 tire from 22 to 34 psi in about 1 minute 20 seconds.

You do not need an inline gauge, just time the pump - it raises the pressure about 10 psi every minute. Over-inflate each tire and then drop the pressure to the correct amount using a good digital gauge.

Keep some spares in case you need to repair a hose in the field. Everything shown except the gauge fits in the supplied soft case.

John Davies
Spokane WA
 
Last edited:
Nice. I'll try to figure out the QR hose and fittings needed as I build a hose. May come back w/ questions.
 
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