What pressure should 19" tyres on new defender 110 be when offroad (corrugations)
Thanks
Bob

 

It depends on what terrain you intend to off road. I usually take the pressure down -5 psi if running on sand.

 

Thanks for your reply. Do you drop the tyre pressure on your defender on rough dirt roads with lots of sharp crushed rocks.

 

I do, absolutely. On an actual off-road trail, where speeds are under 25 or usually even under 20 miles an hour, and it’s lots of small rocks, I’ll run 23 to 25 pounds. Strictly for comfort, not extra traction.

 

I go low now. 20" 5098 wheels with 33" K02's. I started off wussy footing it not going below 30 on mine because of what I'd read here... but traction wasn't good. Here's where I've landed with good results.

22 on rocks, ruts, and trails with a lot of obstacles. Slow speeds. Never had an issue
25 on mud. Some wheel spin so keep the pressure up a bit more. Never had an issue
18-22 on snow. Never had an issue but get stuck alot still. Because - snow.
Been as low as 12 on sand. Debeaded 2 tires hooning it and spinning tires. Settled on around 18 on sand.

The guy from LR who posted "we didn't design the traction control systems for aired down tires" seemed knowledgeable but I tried what he suggested and I determined, through my own real world non scientific testing, that the advice was poor. I have found that airing down helps greatly.

 

This is a good video about sand especially.

 

Great post. Thanks for the share.

 

Yes, I normally do if the drive is going to be long on rough roads.

 

The Ronnie Dahl material on tire pressures is most excellent.

The info on contact patch sizes at various psi is especially informative.

Not huge changes between 50 to 40 to 30 but as you get lower, the percentage increase in footprint length per pound of psi dropped becomes very pronounced. This is why when you're on soft sand or deep snow, dropping even an additional 2psi from 18 to lets say 16 or 14 will give you a very marked increase in footprint and traction. I've not gone lower than 14 but I'm sure you can.




Anyone who says that you can run trails on highway pressures clearly doesn't mind having their vehicle and teeth in their head rattled apart. On rough gravel roads with corrugations especially. Dropping down to 20 or so psi is just so much more comfy on driver and gentler on the vehicle. Obviously tailor it to your anticipated speed. When I plan on being in lo-range for quite some time I pretty much start at 18psi and go from there.

I have my Stauns set at 18



Like with most things in life. Having the right set of boots on is paramount.

 

I have trail tires for my Jeep, 37" bias plies. One advantage (the only one) of bi-plies over radials is for some reason they stay on a rim better at super low pressures. I could run these Intercos at 7 # on solid rock in Utah without beadlock wheels and without problems (I've only rolled one off, on a steep off-camber crossing, since 2017). But I usually run them at 10# for a little more margin because reseating is a pain the ***.

It is unimaginable how much traction these tires have -- they never make a sound. No tortured slipping sound as they scrabble for purchase on a steep incline. They roll up like a tracked Bobcat.

That said, they are unusable on highway. Sounds like a C141 landing 50 yards away. I mean, they work -- I leave them on for weeks at a time driving around Utah (slowly) between trails. But it's pretty miserable. At low speeds on the road (under 20mph) you can literally feel every separate tread block as it contacts the highway.




Here you can see the time I rolled one off; the spare:




Re: having your Stauns set at 14: It took so long to bleed these down to 10 pounds or lower that I bought a cool device that pulls a valve core, bleeds the air out really fast, and allows you to instantly close the valve to check pressure, without having to unscrew anything. When you get where you want, just screw the valve core back in. It stays inside the tool's fitting the whole time so you can't lose it. Stauns tend to not work consistently below 10#, and can wind up draining too much air and popping the bead before you realize you're at 3#. But I use them exclusively on the Defender.