DI or DII?
- Thread starter 03DISCOII
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Please tell me you're joking.p m said:
The longer footprint achieved with low tire pressure helps the tire conform to rocks and obstacles. Take a watermelon sized rock, for example. With 40psi a tire will not grip on that rock because the tire pressure is too high to allow the tire to deform from a perfectly round shape. Think of a guy with a huge beer gut trying to spoon his wife, not going to happen. With 15psi the tire will deform and tread will actually wrap around and over the rock providing traction.
Really, in all your wheeling you haven't noticed any advantage to airing down? Do you think people run beadlocks just to look cool?
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Lots of smart Jeepers I wheel with then as the values and benefits of airing down are astounding at least in the dry, rocky, ledgy, sandy, gravely terrain of the Four Corners area I live in. On the wet rocks and ledges of our mountains as well or even in our drier winter snow than back East or in the Pacific ranges. We don't deal with much deep mud or swampy or long pools of water out here very much. I have wheeled a lot at highway tire poundage cause I often get flat out lazy about airing down when by myself but airing down allows for so much better traction plus the comfort of a much softer/comfortable, less tiring ride offroad especially on a daylong excursion on rocks and ledges. I have never ever heard a Jeeper say anything about airing down making your contact patch wider, never though it does a tiny bit plus allowing your side MT knobs to grip a bit more as you float over stuff. Even on the easy terrain out here we in my local 4x4 club ( my one Rover and mostly Jeeps and a few other models) air down strictly for the much increased comfortable ride on our mostly aging bodies. All of us run MT or good AT tires. Nobody is running on anything less so we all have tough tires and not weak-walled street tires. Airing down out here in the Four Corners area has tremendous proven value and benefits.p m said:
Ok, think of a guy with a huge beer gut trying to spoon Chapman.Tugela said:
Now go relieve yourself.
Tugela said:
Plenty off road mate, particularly GQ and early GU's. Interestingly though, you see more LR on the Beach Islands doing camping trips than there should be given how few are on the tarmac compared to Toyo. LR are over-represented off road here, but the advertising campaigns over the years by Toyota and the outback dealership network has ensured that Toyo outsell LR quite heavily.
Cheers
My apologies to the OP for derailing the thread.
I used a term "wider" in terms of increased contact patch, regardless of whether it is along or across the vehicle's path.
Now that you decided to get into the nitty-gritty, how does a _longer_ footprint help to get over a rock ledge? People use beadlocks because it allows them to air down to single-digit pressure, AND thus make the contact patch wider because the sidewalls come into contact with the rock.
If you care to reread the article you quoted, going down from 40 to 15 psi only increases your tire's contact patch by 40% or so. It may improve your chance of getting over that particular rock, and will also increase your chance to grab the same or other rock with your diff or axletube. But that's not all there's to it.
3 perfectly good tires were ruined in my years of airing down (I am only counting my own tires!), every one of them for no other reason than bulging sidewalls catching on manzanita branches or rocks. My faith in airing down was seriously shaken after having to use my Disco spare at 12kft in Roverrocks' backyard near Ouray, and it vanished after having to hoist a 35x12.5 full of mud on the roof rack of my jeep. Several tires remained intact, but I became proficient in reseating the beads.
At about the same time, I started listening to KVT's ramblings on technical matters. That was the guy running the trails with forklift'esque 65psi in his tires.
The main reason I moderately air down now (from highway 40-45 to 25-28 psi) is to increase comfort level on washboard rocks. Of course, half of the people who take airing down seriously don't bother with high-flow air pumps, so I have to lend mine and kick the dust for half an hour after the trail ride. If that statement offends you, keep the tally of times you lend your tools against borrowing them.
Is that right?fishEH said:
I used a term "wider" in terms of increased contact patch, regardless of whether it is along or across the vehicle's path.
Now that you decided to get into the nitty-gritty, how does a _longer_ footprint help to get over a rock ledge? People use beadlocks because it allows them to air down to single-digit pressure, AND thus make the contact patch wider because the sidewalls come into contact with the rock.
If you care to reread the article you quoted, going down from 40 to 15 psi only increases your tire's contact patch by 40% or so. It may improve your chance of getting over that particular rock, and will also increase your chance to grab the same or other rock with your diff or axletube. But that's not all there's to it.
3 perfectly good tires were ruined in my years of airing down (I am only counting my own tires!), every one of them for no other reason than bulging sidewalls catching on manzanita branches or rocks. My faith in airing down was seriously shaken after having to use my Disco spare at 12kft in Roverrocks' backyard near Ouray, and it vanished after having to hoist a 35x12.5 full of mud on the roof rack of my jeep. Several tires remained intact, but I became proficient in reseating the beads.
At about the same time, I started listening to KVT's ramblings on technical matters. That was the guy running the trails with forklift'esque 65psi in his tires.
The main reason I moderately air down now (from highway 40-45 to 25-28 psi) is to increase comfort level on washboard rocks. Of course, half of the people who take airing down seriously don't bother with high-flow air pumps, so I have to lend mine and kick the dust for half an hour after the trail ride. If that statement offends you, keep the tally of times you lend your tools against borrowing them.
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????p m said:
Glad I'm not the only one confused here.Roverrocks said:
When I say "tire width" what comes to mind? The sidewall to sidewall(or outside tread edge to inside tread edge) measurement of course. So how PM can mistake increased contact patch for increased tread width is beyond me. I think PM had better go back and read the article because going from 40 to 15 psi increases your contact area by nearly 74%, and none of that has to do with any change in tread with. In fact the tread width stayed the same in every single test.
Why does that guy have 20 PSI in his tires with bead locks? they should have done a 3 psi comparison as well. The rock would be gone.
OK, I stand corrected on the contact patch area. I was looking at the reduction in tire pressure.
Speaking of tire pressure and beadlocks - my tires rotated on the rims at 25 psi after a trip to Wheeler Lake - which is not by any means hardcore. Granted, those are narrow 265/75 on stock rims - wider tires stay better put on narrow rims.
Edit - fishEh, you're getting into hair-splitting details on width. I could simply agree with you and say the tire contact patch gets longer but not wider, or quote you an equally-impressive piece of work -
Enjoy this as well.
The difference between Roverrocks and me is that I like four-wheeling in his neck of the woods, but it is a thousand miles away from me. So I'd take a little hit in rock-climbing prowess in exchange for not having to buy a new set of tires after every trip.
Speaking of tire pressure and beadlocks - my tires rotated on the rims at 25 psi after a trip to Wheeler Lake - which is not by any means hardcore. Granted, those are narrow 265/75 on stock rims - wider tires stay better put on narrow rims.
Edit - fishEh, you're getting into hair-splitting details on width. I could simply agree with you and say the tire contact patch gets longer but not wider, or quote you an equally-impressive piece of work -
Enjoy this as well.
The difference between Roverrocks and me is that I like four-wheeling in his neck of the woods, but it is a thousand miles away from me. So I'd take a little hit in rock-climbing prowess in exchange for not having to buy a new set of tires after every trip.
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p m said:
On rover rims or steel rims? Rover rims have a massive lip that works kinda like a bead lock. Only reason I wish I could use them vs steel rims
On Rover aluminum rims.
FWIW, my Wagoneer runs on 245/75R16 Michelin LTX M/S on steel Series rims (5.5" wide), inflated to 22psi. Had tires of the same size on 7" wide steel wheels on the Disco, and they started to creep along the rims at 25 psi even under very moderate off-roading.
FWIW, my Wagoneer runs on 245/75R16 Michelin LTX M/S on steel Series rims (5.5" wide), inflated to 22psi. Had tires of the same size on 7" wide steel wheels on the Disco, and they started to creep along the rims at 25 psi even under very moderate off-roading.
I don't buy new tires until they are nearly bald and run consistently offroad at 18-20 PSI and have no beadlocks but rather the standard wheels that the Disco came with out of the factory and had when I bought it used years ago. My tire size is 265/75/16 and I have not had a problem with tire movement on the rims that includes Wheeler Lake and many others in Moab and w. Colorado. I have run as low as 14 psi occasionally but lose more clearance than I want to. I have trashed 3 MT's over the years when aired down and that includes one BFG MT that took out a sidewall on an easy gravel road near Moab. I walked up and down the gravel road and never could figure out what ate my tire. It was on a 2w drive road portion. I had one time when I lost my bead at 18 psi when I had broken down in Utah and was being pulled out by a Jeep and ran into a ledge sideways that caused me to lose my bead. We aired it up to pop the bead again and the tire was fine with no damage. All the jeepers I run with have very, very few tire problems when aired down often lower than I do. I believe wholeheartedly in airing down for comfort and traction. I'm sorry your experiences have led you in a different direction. It is mind-boggling to me that you know of somebody offroading at 65 psi. That's like hiking in 6 inch high heels. Ouch.p m said:OK, I stand corrected on the contact patch area. I was looking at the reduction in tire pressure.
Speaking of tire pressure and beadlocks - my tires rotated on the rims at 25 psi after a trip to Wheeler Lake - which is not by any means hardcore. Granted, those are narrow 265/75 on stock rims - wider tires stay better put on narrow rims.
Edit - fishEh, you're getting into hair-splitting details on width. I could simply agree with you and say the tire contact patch gets longer but not wider, or quote you an equally-impressive piece of work -
Enjoy this as well.
The difference between Roverrocks and me is that I like four-wheeling in his neck of the woods, but it is a thousand miles away from me. So I'd take a little hit in rock-climbing prowess in exchange for not having to buy a new set of tires after every trip.
p m said:Edit - fishEh, you're getting into hair-splitting details on width. I could simply agree with you and say the tire contact patch gets longer but not wider, or quote you an equally-impressive piece of work -
Enjoy this as well.
The difference between Roverrocks and me is that I like four-wheeling in his neck of the woods, but it is a thousand miles away from me. So I'd take a little hit in rock-climbing prowess in exchange for not having to buy a new set of tires after every trip.
You might have well just agreed with me because what you linked to and posted supports airing down.
Plain and simple: Airing down gives you more traction. More traction allows you to go slower and pick your lines better. Going slower and picking better lines is SAFER than hot dogging it and bouncing off rocks at 65psi.
Much as I hate saying things like this, but I don't give a shit if I agree with you or not. Nothing personal, that applies to a majority opinion as well as long as I think I know what I deal with.fishEH said:
I know exactly what airing down does, and I prefer to keep as much air in my tires as I can.
I can live with that.p m said:
No hard feelings I hope, just a little spirited debate.Oh, and to the OP. Get a D1!