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| nugat Elite Veteran Date registered: Jan 2007 Location: Warsaw, Poland Vehicle(s): 280GE, 290GD, c303 Posts: 876  | Low pressure tires and tubed--why not? I heard it is not advisable to run tires on low pressure and with tubes? Does anybody know why? Even with beadlocks? The reason I ask is I have a set of military tubed tires (non-radial, biased 4 ply 280/85/16 from volvo c303) that I'd like to try on my G and run it below 10 psi. Doable? | ||
| #65813 |
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| 4x4abc Date registered: Apr 2006 Location: La Paz, Baja California, Mexico Vehicle(s): 02 G500  | RE: Low pressure tires and tubed--why not? Not doable. Main reason for not running tubes in tires at low psi is that the tube will constantly rub against the tire - the tube will destroy itself. Only high psi will ensure that the tube sits so tight against the tire that there is no movement and no rubbing. Besides, bias ply tires have such stiff sidewall that they do not give you a significant wider footprint when aired down. So, either run you mil spec tires at 50 psi with tubes or get decent radial tires that you can air down to 10 psi and get results from it. By the way, bias ply tires are dinosaur technology. They should rest in peace somewhere. | ||
| #65815 - in reply to #65813 |
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| nugat Elite Veteran Date registered: Jan 2007 Location: Warsaw, Poland Vehicle(s): 280GE, 290GD, c303 Posts: 876 | RE: Low pressure tires and tubed--why not? Thank Harald, that's clear to me now. Bias ply is still used by the Swedish military though. On my c303 I have a set of trelleborgs cross country 153 at specified 23-25 psi--excllent tire (the spare set on before was Good Years Studded SureGrip- Made in Sweden!). The side sturdiness is apparently superior against punctures and in some other situations (which ?). Even those new trelleborgs are (bias ply) tubed. Again, some advantages supposedly, but what kind? Out of curiosity, what tires Humvees use? Now on my G, I have BFG 33/10.5/15 MT. How low with pressure can I go without beadlocks? How low with beadlocks? What is the best tire for low psi in up to 35 inch range? But most of all--deflate, or not to deflate? | ||
| #65849 - in reply to #65813 |
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| 4x4abc Date registered: Apr 2006 Location: La Paz, Baja California, Mexico Vehicle(s): 02 G500 | Re: Low pressure tires and tubed--why not? nugat, yes, bias ply tires are very strong (the sidewall is as thick as the tread) and can carry very heavy loads (maybe that's why some military guys still like them). But handling is very bad on-road. They simply do not run straight, make a lot of noise and are very uncomfortable (sidewall does not flex) - but those things are not on any military's list. However, for most of us save comfortable on-road handling is mandatory. Since the invention of radial tires by Michelin the world has gotten safer and more comfortable. By now radials carry as much weight as those old bias (all trucks run on radials now) and sidewall strength has improved to the point that they have left the bias ply behind. All Hummers use radial tires. Usually Goodyear MT or MTR in 37" All off-road racers use radial tires. How low can you go in tire pressure? Depends on the weight of your vehicle, the volume of your tires, the strength of your tires when aired down (not all tires like it - BFG published a chart some years ago how their tires behave at different psi), the purpose of your driving, your style of driving. My guess in your case: 25 psi general off-road (anything beyond pavement), 15 psi for mud, snow and sand. 10 psi in very deep and soft sand (avoid any sharp turns - they will pop the bead for sure, besides, sharp turns in sand will get you stuck). Once upgraded to wider tires (higher volume of air) you can expand you driving range and go to lower psi (20,12,8) http://4x4abc.com/jeep101/soft-sand-deflate.html I don't know the best tire for low psi. Haven't tested that specifically. Best tire for off-road in my eyes is BFG. Deflate or not deflate? Depends on what for. Sand, mud, deep snow - yes yes yes! General off-road - yes of course. Rock crawling - could not be done without it. Rallye and off-road racing - probably not a good idea. Beadlocks. They have been invented by off-road racers to keep the tires from popping off the rim after a high impact jump and in turns driven at 100 mph. They clamp the tire at both sidewalls against the rim. Works great for them Now, there are many bad and or aggressive off-road drivers out there. They always had problems at low tire psi with sidewalls popping off the rim as well - until they discovered beadlocks. Immediately beadlocks were heavily peddled in magzines (reason #1 magazines make money by selling product, reason #2 beadlocks are very fotogenic). And now everyone thinking about venturing into the wild for the first time with their 4x4 think (well, its in the magazines) they have to have beadlocks. Like many think they need a roof rack, a shovel, a winch, extra lights and K&N filters. Not so. If you are a thoughtful driver (should be anyway when leaving pavement) you will not need beadlocks. You should always be aware of the interaction between, torque, traction, surface, obstacles and steering angle - and then breaking the bead will only happen by (rare) accident. Now what about those accidents. Well, military and racers don't have time to deal with accidents. They need to be avoided - at any cost. So, for them it is no discussion to shell out around $5,000 for a set of beadlock wheels. Aftermarket versions are about $2,500. And then there the fake ones if you want to look loke a pro. For you and me its more prudent to get a good compressor (around $700) to bring the popped off tire back on the bead after that rare accident - you'll need a compressor anyway when you are serious abot off-road. I go 4wheeling for a living and do it a lot more than most. I myself or one of my clients have a bead come off about once a year. Takes about 5 minutes to reset. Jack up tire, connect hose to compressor, pfffffffffft, pop, more pfft, check with gauge - done. | ||
| #65862 - in reply to #65813 |
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| nugat Elite Veteran Date registered: Jan 2007 Location: Warsaw, Poland Vehicle(s): 280GE, 290GD, c303 Posts: 876 | RE: Low pressure tires and tubed--why not? Thanks Harald, That was the most comprehensive asnwer one could expect. One final thought. Any use of inner tubes in the radial world? | ||
| #65881 - in reply to #65813 |
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| DUTCH Administrator Doppelgänger Date registered: Apr 2006 Location: US, GA, Atlanta Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter Posts: 9963 | RE: Low pressure tires and tubed--why not? nugat - 3/4/2007 3:26 PM Thanks Harald, That was the most comprehensive asnwer one could expect. One final thought. Any use of inner tubes in the radial world? The tires that came on my 1984 280GE from the factory were 6 ply rated 215R16 Michelin M + S radials. They were tubed. | ||
| #65885 - in reply to #65881 |
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| 4x4abc Date registered: Apr 2006 Location: La Paz, Baja California, Mexico Vehicle(s): 02 G500 | RE: Low pressure tires and tubed--why not? Here is the law in California: Inner Tubes 27455. (a) On and after January 1, 1975, no person shall sell or offer for sale an inner tube for use in a radial tire unless, at the time of manufacture, the tube valve stem is colored red or is distinctly marked in accordance with rules and regulations adopted by the department, taking into consideration the recommendations of manufacturers of inner tubes. (b) No person shall install an inner tube in a radial tire unless the inner tube is designed for use in a radial tire. So yes, tubes can be used in radial tires - however they have to be very much different than tubes for bias ply tires. The constant flexing of the radials require a different rubber compound for the tubes. Also, not all radials are of "tubeless" design (they can't lock onto the humps inside the rim) and actually need a tube. Tubes in tubeless tires is kinda silly. However, it makes sense to carry a tube or two for tires that can't be repaired and no replacement can't be found (like in Siberia) - then I would stick the tube in. A word of caution though, check the thickness of the tube's valve stem before you go on that trip. Wheels designed for tubeless tires have a smaller hole for the valve stem than wheels for tubes. | ||
| #65889 - in reply to #65885 |
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| DUTCH Administrator Doppelgänger Date registered: Apr 2006 Location: US, GA, Atlanta Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter Posts: 9963 | RE: Low pressure tires and tubed--why not? 4x4abc - 3/4/2007 5:59 PM A word of caution though, check the thickness of the tube's valve stem before you go on that trip. Wheels designed for tubeless tires have a smaller hole for the valve stem than wheels for tubes. When the factory tubed radials wore out, I replaced them with tubeless radials. No problems with the valve stem holes; but of course the 1984 G was not made to be sold in Kalifornia anyway. | ||
| #65892 - in reply to #65889 |
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