Quote:
Originally Posted by ACEV
Higher tire pressure will be obtained by driving faster. The tire heats up more and the pressure will increase. I am not dealing with more than US highway speed limits here. Driving on the Autobahn is counterproductive to increased fuel savings, overall.
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The difference is that this higher pressure is due to heat and deformation. And that's bad. Using higher pressure in the first place prevents heat build up. That's good. Which is why manufacturers recommend higher pressures for high speed use. Which is the entire point of the article you yourself cited.
Quote:
Originally Posted by ACEV
Extreme vibration causes much more damage than a few bolts and bushings. It can actually break welds and cause stress fractures. Besides, the average driver never checks for loose bolts.
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Bolt tightening is something you do after a few hundred thousand (insert distance units here). Most people don't keep their cars as long as I do.
And vibration itself, as pointed out, does not happen with all tires, and is a separate item from damage directly due to hard tires.
Quote:
Originally Posted by ACEV
The point, as I understand it from my research, for stiffer unibody construction techniques was to create a lighter automobile and to be able to compensate for less metal in the design. I doubt very much that the utilization of unibody was to use stiffer tires.
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Who said that stiffer
unibodies were to compensate for stiffer tires? Manufacturers tune the
suspension to compensate for stiffer tires. Better bushings, rubber isolation for the subframes, firmer shocks, shock and spring settings tuned for the tire inflation pressures used.
Quote:
Originally Posted by ACEV
Hydroplaing effects increase at higher pressure.
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citation required
Because absolutely everybody else (and personal experience) says you're completely and utterly
wrong:
NPRM on TIRE PRESSURE MONITORING SYSTEM FMVSS No. 138
http://www.tirerack.com/tires/tirete...e.jsp?techid=3
The smaller the tire footprint, the less it hydroplanes. If you can actually overinflate a tire to the point that you lift the edge of the tread, you can decrease hydroplaning even further.
Quote:
Originally Posted by ACEV
Actually, the universal tire rating is the door sticker.
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I have two cars that use nearly the same size of tires and weigh approximately the same. One suggests 26 psi (cold) up front and the other suggests 35. Sounds pretty universal to me.
I've been in this biz for a while, and I've seen door pressure stickers creep up over time. The door pressure sticker is determined by a number of things... the need for the manufacturer to provide a "comfortable" ride (just ask Ford how that went with the Explorer and them Firestones, eh?), the need to meet performance requirements and the need to meet economy requirements.
As the last requirement becomes more important, door sticker pressures have started to creep up. Not because the "universal" pressure has started to creep up, but because the need to meet CAFE/CO2/whatever comes first. To restore ride comfort, manufacturers retune (again) the suspension to compensate.
Quote:
Originally Posted by ACEV
Most people are doing their own calculations, but failing to calculate damage to the vehicle. And that is the problem.
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The damage isn't in the vibration... which can be pretty bad if you're underinflated on the highway... but in the harshness over bumps. Then again, again... it depends on how high you're going.
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Not that I'm an advocate of ultra-high "10-20 psi over max. sidewall" pressures... but let's put things in perspective, here.