Offroad tyre pressures and consumption
Submitted: Monday, Dec 09, 2002 at 01:00
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Savvas
Hi all,
I just read a claim on the Staun website (
http://www.staunproducts.com/benefits.php) that states -
"Fuel usage increases when tyres are at higher pressures because more revs and greater acceleration is required to take the vehicle over the off-road surfaces."
It's generally accepted that higher pressures aid economy on road, but it's the first time I've heard that fuel consumption is increased by having high pressures off road.
Any thoughts or comments?
Reply By: Moggs - Monday, Dec 09, 2002 at 01:00
Monday, Dec 09, 2002 at 01:00
Savvas,
I too read this claim on the Staun website. On further enquiry to Staun I was unable to ascertain from them any basis other than "its logical, isn't it??" As far as I am concerned the whole claim is purely a lame marketing ploy designed to make the tyre deflators more attractive to those people who need more justification to purchase other than a desire not to get the tyre gauge out or bend their legs.
I suppose gimmick products do not tend sell themselves and need a bit of fluff to move out the door.
I would not take too much notice of this claim - in fact, such a claim in my eyes cheapens the image of what is, by all accounts, a quality product.
Question, why is it that people go to extremes of physical and mental effort to get away in their 4wd, yet balk at bending the knees and using a tyre guage - don't you need a gauge anyway when you put the pressures back up?? - don't you bend the knees then anyway? Save your money and leave the deflators out of the kit.
Rgds,
Moggs
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Follow Up By: Gpa - Monday, Dec 09, 2002 at 01:00
Monday, Dec 09, 2002 at 01:00
Dodgy marketing hype aside, the Staun tyre deflators are great. I have no problem 'bending the knees', or using a tyre guage, but using the deflators is quicker as all 4 tyres deflate at the same time - and there is no risk of the kids letting one of them down too much before I get around with the tyre guage...
I have a mate who is equally impatient as I am - and he likes to take the valve out to hurry things up - problem is when he lets it down too far and has to get the compressor out - meanwhile I'm done and am surveying the track/route...
As for using the guage when pumping them back up - I've timed how long it takes (my compressor) to get from 18psi - 34psi, I just use the timer on my watch - might
check the last one with a guage depending on how far the drive is to the servo.
For what it's worth.
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Reply By: MikeyS - Monday, Dec 09, 2002 at 01:00
Monday, Dec 09, 2002 at 01:00
I think their last few of their reasons for lowering tyre pressures are getting a bit "desperate". Irrespective of whether you need their product or not, if they haven't convinced buyers of the merits of reducing tyre pressures before the "improved fuel economy" claim then I don't think going into spurious claims will make any difference. Why dilute a good reason by adding dodgy reasons? MikeyS
AnswerID:
9472
Reply By: Eric - Monday, Dec 09, 2002 at 01:00
Monday, Dec 09, 2002 at 01:00
savvas.
When
Dunlop took out his patent on the pheumatic tyre one of the claimed benifits was the reduced effort of pedaling a bycle with his tyres compared to a solid rubber tyre. It is true that on a rough surface you use less fuel with lower tyre pressures. try pushing a wheel barow of concrete with a solid wheel compared to a tyre. the reason is that the energy to accelerate the barow full of concrete verticaly when you hit a change in the level of the ground comes from the mug pushing the thing, so if you reduce the vertical acceleration you reduce the effort. the best fuel economy on a 4x4 on rough ground is acheaved at the lowest pressure possible without damaging the side walls. You are probably thinking that the heat generated by the side walls flexing is wasting fuel, it is but the heat disipated by the shockers and the energy to accelerate the
suspension verticaly is reduced by a greater amount. No I don't sell deflators. Eric.
AnswerID:
9484
Reply By: Member - Mal - Tuesday, Dec 10, 2002 at 01:00
Tuesday, Dec 10, 2002 at 01:00
That claim is true in soft sand. Mal T.
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9503