DaveinOlyWA
Posts: 13230
Joined: Sat Apr 24, 2010 7:43 pm
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Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Tire Pressure

Tue Feb 22, 2011 4:45 pm

mogur wrote:And you read this where? And by that, I mean from an actual tire manufacturer or other respected authority.

This is from the DOT's website:

Maximum Permissible Inflation Pressure:
This number is the greatest amount of air pressure that should ever be put in the tire under normal driving conditions.


DaveinOlyWA wrote:the max pressure on the sidewall is for ultimate safety margins. u can, under "normal" circumstances, easily exceed the rating by 50% with minimal compromise to your safety.


a true and reasonable max tire pressure cannot be advertised due to inaccuracies measuring the pressure coupled with the limited common sense of the person filling the tire so therefore the max rating has a VERY comfortable margin of safety built in
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 11,987 miles, 485 GIDs, 37.6 kwh 110.89 Ahr , SOH 96.00, Hx 115.22
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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TomT
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Joined: Sun Aug 08, 2010 12:09 pm
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Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: Tire Pressure

Tue Feb 22, 2011 5:16 pm

Again, where is this written? I am an engineer; I know about designing with safety margins and worst possible case scenarios. I also know that that number was not taken from thin air (no pun intended) and is based on sound engineering and science. Exceeding it is like prodding the tiger and if your tolerances happen to line up in the wrong direction - and you will have no way to know that in advance - you are risking a possibly catastrophic failure. I'm sorry, but in my eyes it is a fool's errand and I have to strongly recommend against it.


DaveinOlyWA wrote:
mogur wrote:And you read this where? And by that, I mean from an actual tire manufacturer or other respected authority.

This is from the DOT's website:

Maximum Permissible Inflation Pressure:
This number is the greatest amount of air pressure that should ever be put in the tire under normal driving conditions.


DaveinOlyWA wrote:the max pressure on the sidewall is for ultimate safety margins. u can, under "normal" circumstances, easily exceed the rating by 50% with minimal compromise to your safety.


a true and reasonable max tire pressure cannot be advertised due to inaccuracies measuring the pressure coupled with the limited common sense of the person filling the tire so therefore the max rating has a VERY comfortable margin of safety built in
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2016 Volt Premier.

DaveinOlyWA
Posts: 13230
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Tire Pressure

Tue Feb 22, 2011 5:49 pm

mogur wrote: I'm sorry, but in my eyes it is a fool's errand and I have to strongly recommend against it.




so do i
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 11,987 miles, 485 GIDs, 37.6 kwh 110.89 Ahr , SOH 96.00, Hx 115.22
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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DeaneG
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Leaf Number: 594
Location: Cupertino, CA

Re: Tire Pressure

Tue Feb 22, 2011 5:59 pm

If you grossly overinflate your tires to try to save a few kWh, you might also want to try slamming on the brakes to assess the tradeoff you're making in stopping distance.
White SL w/L3, 3kWDC Solar PV

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LakeLeaf
Posts: 1424
Joined: Mon Jun 07, 2010 4:15 pm
Delivery Date: 04 Aug 2018
Location: South Lake Tahoe, California

Re: Tire Pressure

Tue Feb 22, 2011 6:03 pm

I also run my Prius tires a bit on the high side - but always got the impression that the return of better mileage for high tire pressure strongly diminished as the tire pressure hit the 40-42 psi range. Over that I never noticed a reasonable enough increase in the mileage to warrant any higher pressures.

Are your experiences similar to that?

(Seems like the kind of experiment that Bob Wilson would have run - with lots of charts and graphs to go along with it)

DaveinOlyWA
Posts: 13230
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Tire Pressure

Tue Feb 22, 2011 6:22 pm

i guess we missed the part when i said i set mine to 42 PSI. hypermilers set their Priuses to 60 PSI and have been doing it for years.

i am not suggesting that anyone here do the same and i question the benefit of going much over 44 PSI on modern tires anyway.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 11,987 miles, 485 GIDs, 37.6 kwh 110.89 Ahr , SOH 96.00, Hx 115.22
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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evnow
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Leaf Number: 303
Location: Seattle, WA

Re: Tire Pressure

Tue Feb 22, 2011 6:33 pm

DeaneG wrote:If you grossly overinflate your tires to try to save a few kWh, you might also want to try slamming on the brakes to assess the tradeoff you're making in stopping distance.

Yes - risk is in breaking, as much as in a blow out.

BTW, with regen - does it still matter ?
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

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LakeLeaf
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Joined: Mon Jun 07, 2010 4:15 pm
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Location: South Lake Tahoe, California

Re: Tire Pressure

Tue Feb 22, 2011 9:11 pm

evnow wrote:Yes - risk is in breaking, as much as in a blow out.


Aren't they the same thing? :mrgreen:

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Nubo
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Location: Vallejo, CA

Re: Tire Pressure

Wed Feb 23, 2011 10:34 am

evnow wrote:
DeaneG wrote:If you grossly overinflate your tires to try to save a few kWh, you might also want to try slamming on the brakes to assess the tradeoff you're making in stopping distance.

Yes - risk is in breaking, as much as in a blow out.


Add to that uneven and premature tire wear.


Not too economical.

Image
I noticed you're still working with polymers.

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