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05-04-2009, 12:23 PM | #37 |
Drives: 2008 Yaris 5 speed HB Join Date: Oct 2008
Location: NH
Posts: 171
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Just an observation:
The TPWS in the Yaris seems to trigger somewhere down around 25 psi, and there doesn't seem to be any upper limit. (purely a limit warning system and not an active monitoring) Thus for myself, I am more concerned about letting them get too low, than running a few psi high. |
05-04-2009, 12:55 PM | #38 |
Drives: 2013 Chevy Spark 1LT 5-speed Join Date: Oct 2008
Location: Oklahoma
Posts: 1,185
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I set it the way Toyota likes it; the way I like it
I think I'd rather be warned after losing 6 or 7 lbs vs losing 36 or 37 lbs (running 32psi instead of 60psi)
__________________
1997 Lincoln Town Car - SOLD 2008 Scion xD (w/ automatic) - SOLD 2008 Yaris HB - SOLD Last edited by 1stToyota; 05-04-2009 at 02:26 PM. |
05-04-2009, 12:59 PM | #39 | |
Drives: . Join Date: Feb 2007
Location: .
Posts: 1,931
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Quote:
I keep mine at 36 cold to increase sidewall stiffness (for cornering), and decrease wind movement. If you corner harder, the outer edges will wear the same as the centre. Each to his or her own, however. I set my car the way I like it, and fully hope everyone else does the same (i.e. how THEY like it, not how their friends tell them it should be) |
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05-04-2009, 03:22 PM | #40 | |
50 MPG or BUST!
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Quote:
Spoken like a true Rhode Islander! I doubt that any of the belligerents here will ever agree on this issue, or more importantly convince the other side. I recognize that both sides only want what is best for us fellow yaris drivers and want to share their info and educated opinions on the topic. But at the point where it shifts from a positive sharing of information and opinions to a negative, mudslinging argument (from whichever side it may be...) I second the solution of "to each his own." On a side note, I personally keep my OEM tires at or around 44 psi. As weird as it is, I prefer the comfort of 44 as opposed to 32, and that is why I keep it there. I have not noticed any uneven or untimely wear on my tires, although as someone mentioned previously, I am not measuring the wear scientifically. I have noticed a significant change/decrease in fuel economy the times my tires have been around 32psi, so I also second Bailout. (And that is my contribution to forming any kind of unscientific consensus.) |
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05-04-2009, 03:57 PM | #41 |
Drives: '14 GT86, '08 Vitz Join Date: Dec 2006
Location: Central Valley, CA
Posts: 9,873
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Seems like the police is on the side of having the tire wall max rating rather than the door jamb rating.
http://cardealerforums.com/alt-autos...rspective.html A good read. |
05-04-2009, 03:58 PM | #42 |
Drives: '14 GT86, '08 Vitz Join Date: Dec 2006
Location: Central Valley, CA
Posts: 9,873
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For those who are lazy to click on the link ()
Maximum Tire pressure (a police perspective) We've talked here before about max cold tire inflation pressure. Here's a fascinating article from Officer.com . Some police officers drive with maximum air pressure in their tires as shown on the tire sidewall, not the door sill or the owner's manual. Here's a link to the article for some great photographs: http://www.officer.com/article/artic...on=19&id=27281 and here's the text in case the page is deleted in the future: Driving Under Pressure Proper Tire Pressure Could Save Your Life Posted: Wednesday, December 21, 2005 SGT. DAVE STORTON EVOC Contributor Officer.com How many officers check the tire pressure on their patrol car on a regular basis? We all seem to be great at checking that the lights and siren work, because the time to find out they don't work is not when you get a Code 3 call. Likewise, the time to find out your tire pressure is too low is not when you are in a pursuit and trying to take a corner at high speed. What is proper pressure? The proper tire pressure for the Police Crown Victoria is 44 psi. If you look on the sidewall of the tire, you will see that it lists 44 psi max pressure. Regardless of what vehicle you have, use the maximum pressure listed on the sidewall. Higher pressure results in better performance, decreased tire wear, and it lessens your chance of hydroplaning at a given speed. This number on the sidewall lists the maximum amount of pressure you should ever put in the tire under normal driving conditions. Pursuits and Code 3 responses are not normal driving conditions. Many agencies maintain tire pressure at 35 psi since this is what is listed in the owner's manual and on the door placard. The reason the owner's manual lists 35 psi is because we get the same manual as the civilian version of the Crown Victoria. The police version, however, is fully loaded with communications equipment, a cage, and your gear. You are not looking for a soft and cushy ride, you want performance. Myths about pressure Let^�s put to rest some common misconceptions. The tires will not balloon out creating a peak in the center portion of the tread when tire pressure is above 35 psi. There is a steel belt that prevents this from happening. Also, you are not overstressing the tire with higher pressure, and the tire will not be forced off the rim with higher pressure. The picture above is Bobby Ore of Bobby Ore Motorsports driving a Ford Ranger on two wheels. The tires on the left side have 100 psi in them, and they happen to be tires and rims from a 1999 Crown Victoria! This is a dramatic example of how pressure holds the tire in shape, and how much stress a tire can handle. Performance If you were able to watch a tire as it travels across the ground at high speed, you would see that it deflects to one side during cornering. The faster you are going through a corner, the more tire deflection you get. As the tire deflects over onto the sidewall, you get less traction and more of a tendency to understeer or oversteer. This could spell disaster when negotiating a corner at high speed during a pursuit or a Code 3 run. Higher pressure keeps the tire from deflecting onto the sidewall as much, which keeps more of the treaded portion on the road. A good demonstration for EVOC instructors is to have students drive a high-speed course in a vehicle with 32 to 35 psi. Then have them run the same course with 44 to 50 psi in the tires. The student will experience a marked difference in performance. Having officers experience this difference in vehicle performance is much more effective than just telling them to check their tire pressure. Hydroplaning When a tire rolls across a road covered with water, the tire tread channels water away so the rubber remains in contact with the road. The factors that affect hydroplaning are speed, and water depth. Conventional wisdom says that vehicles will hydroplane in as little as 1/16th of an inch of water. Not so coincidentally, legal tread depth is 1/16th of an inch. Tire manufactures and the Association of Law Enforcement Emergency Response Trainers International (ALERT) have shown that tires have more of a tendency to hydroplane when pressure is low. This happens because the tire footprint (the portion of the tire actually in contact with the road) is larger. For those of you who water ski, think of which is easier to get up on: a fat ski or a skinny ski. More tire surface in contact with the water makes it easier to hydroplane, just as it is easier to water ski on a fat ski. Also, a soft tire can be pushed in more by the pressure of the water on the center portion of the tread. This results in less rubber in contact with the road. Tire wear Much better tire wear results from maintaining proper pressure. Tires with lower pressure will wear off the outside of the tread faster from the deflection of the tire during cornering, and the tires will heat up more from increased road friction. This is one of the factors that caused the failure of a certain brand of tires on Ford Explorers some years ago. In 1999 the San Jose Police Department realized a significant cost savings by increasing the pressure in the training fleet to 50 psi. They soon followed up by increasing the pressure in the patrol fleet to 44 psi. For liability reasons, most agencies are reluctant to exceed the maximum pressure listed on the tire for actual patrol vehicles, but they reap the cost saving when going to 50 psi on training vehicles. Next time you inspect your vehicle, make sure you check your tire pressure since your ability to performance drive is significantly affected by it. You are not driving to the store to get a loaf of bread! You may be called upon to chase a dangerous criminal or respond to assist another officer in trouble. You don't wonder whether or not your gun is loaded before you hit the street; don't wonder whether your tire pressure is correct once the pursuit starts. Check your tires routinely, just as you do with all other critical equipment. -- Sgt. Dave Storton is the Director of the San Jose Police Academy, and he holds a Master's Degree in Adult Education. He is the lead instructor for the Emergency Vehicle Operations Course (EVOC) at the San Jose Police Academy, and is a lead instructor for the local regional academy. He teaches EVOC instructor courses, advanced EVOC instructor courses, off road EVOC, counter-terrorist / dignitary protection driving, and motion picture stunt driving. Dave has trained over 3,500 drivers. Photo courtesy of Bobby Ore Motorsports |
05-04-2009, 04:44 PM | #43 |
Drives: '08 Yaris LB 5M Join Date: Nov 2008
Location: MN
Posts: 31
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Overall it seems that those who actually run with high tire pressures on their Yaris note that it works rather well while some who have no actual experience in the matter (haven't even tried it) are convinced it is wrong/false/dangerous/blahblahblah.
How can we expect to enhance our technical knowledge it we poison every thread that begins to challenge our existing understanding? Isn't just laying out facts and observations without including our "unconfirmed beliefs" and then letting the readers piece it together a more productive way? Who is going to come back here to "talk tech" when all they'll get for their trouble is a ration of shit?? |
05-04-2009, 04:46 PM | #44 |
Drives: '08 Yaris Join Date: Oct 2008
Location: Dover, Ohio
Posts: 7,606
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I ran 45+ PSI in my tires for gas mileage reasons.
I personally believe it led to less grip, which led to this: Bottom line, I run 32 PSI now. |
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