What is the best tire pressure and why? - Toyota Sienna Forum - siennachat.com
 
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post #1 of 15 (permalink) Old 05-10-2009, 02:08 PM Thread Starter
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What is the best tire pressure and why?

I remember the old site had this discussion, which was very technical and very, very informative. I changed (increased) the tire pressure on my Sienna as a result of that discussion. It is not clear whether the old discussion can be brought in, but some new stuff has already been posted on our site, which I am going to copy here. Stand by!

'06 Sienna CE 7 pass FWD
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post #2 of 15 (permalink) Old 05-10-2009, 02:09 PM Thread Starter
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by kolkh
Quote:
Originally Posted by SiennaOwner
...

Pressures are good, alignment is good, tires are rotated at 5k miles. Why does my van eat tires?
Since you ARE from SiennaClub, you probably remember that recommended tire pressure (as per the Manual) was criticized as being too low and, therefore, being a contributing factor to "tire-eating".

In this context, may I ask what tire pressures are?


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post #3 of 15 (permalink) Old 05-10-2009, 02:12 PM Thread Starter
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by tonystewart
06 Limited

Yokohama TRZ 225/60/17

45 psi front
40 psi rear unless heavily loaded then 45 psi rear
------------------
Quote:
Originally Posted by kolkh
Quote:
Originally Posted by tonystewart
06 Limited

Yokohama TRZ 225/60/17

45 psi front
40 psi rear unless heavily loaded then 45 psi rear
45 psi ? WOW!
As far as I remember, the "old site textbook" came up with 40 psi...
What is your source for 45 psi?

...I would not be surprised if the Greatest Sienna Modifier (aka tonystewart) performed his own experiments...
-----------------------

Quote:
Originally Posted by tonystewart
I took a long trip to Atlanta. 8+ hours of high speed driving (85-95) with a big load. Brought along my digital tire pyrometer to get a feel for tire temperature and contact patch. Checked tires at every stop, potty breaks, food breaks, fuel stops etc.

Max psi on a Yokohama TRZ 225/60/17 is 51 psi.

I started at 40 psi and went up in one psi increments throughout the trip. Settled on 45 psi front and rear with big load. Fuel economy improved. Tire temperatures were even across the tire and lower in temperature at 45 psi. Handling improved, a little. Crosswind handling improved a little. The rear spring airbags were set at 15 psi loaded and 10 psi unloaded for the empty trip home.

I lowered the rears to 40 psi with no load and noted little change with tire temperatures.

I think it depends on the tire, the weight of the van, the speed you drive and the roads.

Too many variables to give anyone a base line.

My two cents...
-------------

Quote:
Originally Posted by brian_bp
Quote:
Originally Posted by tonystewart
I took a long trip to Atlanta. 8+ hours of high speed driving (85-95) with a big load. Brought along my digital tire pyrometer to get a feel for tire temperature and contact patch. Checked tires at every stop, potty breaks, food breaks, fuel stops etc.

Max psi on a Yokohama TRZ 225/60/17 is 51 psi.

I started at 40 psi and went up in one psi increments throughout the trip. Settled on 45 psi front and rear with big load. Fuel economy improved. Tire temperatures were even across the tire and lower in temperature at 45 psi. Handling improved, a little. Crosswind handling improved a little. The rear spring airbags were set at 15 psi loaded and 10 psi unloaded for the empty trip home.

I lowered the rears to 40 psi with no load and noted little change with tire temperatures.

I think it depends on the tire, the weight of the van, the speed you drive and the roads.

Too many variables to give anyone a base line.

My two cents...
Worth a lot more than two cents, in my book! Thanks for the systematic examination and the description.

For anyone interested in using the numbers, I'll note that different sizes, and even to some extent different tire construction in the same size, could lead to different ideal pressures even under the same driving condition.

I haven't run pressures that high (45 psi) yet, but my original winter tires and my current tires both have a 51 psi maximum inflation pressure.

'06 Sienna CE 7 pass FWD
'07 Camry LE I4 5AT
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post #4 of 15 (permalink) Old 05-10-2009, 07:11 PM
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Re: What is the best tire pressure and why?

[Old Crows] reminded me of the old-school "chalk" test at the old site.

You inflate the tires to whatever specified/experimental pressure (within the safe range as specified for the tire). Rub chalk across the full width of the tire tread. Drive a short distance. Stop and inspect the wear pattern of the chalk. Adjust inflation until the chalk wears evenly across the tread. Verify again "later" with the tires cold just to be more accurate.

After much trial & error, he settled on 40psi front & rear as optimal for the contact patch of the tread....meaning even wear across the width of the tire tread. Of course, this will vary depending upon load, alignment, and maybe tire design.

I used 40psi front/rear based upon his findings and had no issues. Worked fine for me.

YMMV.
Good Luck!! 8)

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post #5 of 15 (permalink) Old 05-10-2009, 07:42 PM Thread Starter
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Re: What is the best tire pressure and why?

Thanks to topspy and Old Crows for that reminder! Now, it is time to remind (as was done during the old discussion) that one of OEM tire models has maximum allowable cold tire pressure of 41 psi.

That is, watch the tire specs!

'06 Sienna CE 7 pass FWD
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post #6 of 15 (permalink) Old 05-18-2009, 11:08 PM
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Re: What is the best tire pressure and why?

Use the tire pressure that will give you even wear. I think 35 psi is too low.
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post #7 of 15 (permalink) Old 05-20-2009, 09:56 PM
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by kolkh
Thanks to topspy and Old Crows for that reminder! Now, it is time to remind (as was done during the old discussion) that one of OEM tire models has maximum allowable cold tire pressure of 41 psi.

That is, watch the tire specs!
Good point... and note that the OEM tires on my Sienna have a maximum allowable cold tire pressure of only 35 psi... which I believe is a reason for the factory recommended inflation pressure being only 35 psi.

Quote:
Originally Posted by Rhino
Use the tire pressure that will give you even wear. I think 35 psi is too low.
Yes, it is probably lower than optimal by some criteria... but see my first comment!
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post #8 of 15 (permalink) Old 02-14-2010, 12:02 AM
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Re: What is the best tire pressure and why?

I changed the pressure in my '04 FWD CE to 40 per recommendations on this board, and wow! It's like a new car. Judging by how it feels behind the wheel, I would say there is less rolling resistance and quicker response to the steering wheel. I haven't measured yet but I know I'm also going to get better gas mileage, since the engine is not working as hard to propel the car. As a corollary to that, it accelerates more quickly and smoothly.

My only concern is, since there is less rolling resistance and quicker steering response, doesn't that mean it is not gripping the road as hard as before? Is that anything I should worry about? Just wondered if anyone else had tried 40 psi and had any safety issues, such as losing grip in the rain, etc.

However so far I am loving it. It just seems like the car is a lot happier now, like this is the way it was meant to run. Thanks to everyone who investigated tire pressure and took the time to share with the community!
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post #9 of 15 (permalink) Old 02-14-2010, 03:29 AM
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Re: What is the best tire pressure and why?

Excessive tire pressure certainly will reduce traction, but it seems unlikely to me that 40 psi is excessive for a Sienna. Compared to most cars, it is relatively heavy for its tire size, so reltively high pressure is required.
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post #10 of 15 (permalink) Old 02-14-2010, 04:04 AM
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by Filius
I changed the pressure in my '04 FWD CE to 40 per recommendations on this board, and wow!
~snip!~
Just be sure that you do not exceed the MAX cold air pressure imprinted on the sidewall of YOUR tire(s). IIRC, some of the tires available for the 16inch wheels on our Siennas cannot accommodate 40psi per tire manufacturer specs.

YMMV.
Good Luck!! 8)

2004 XLE Ltd FWD Phantom Grey Pearl/Stone // 140K miles
. Pod-Style Running Boards
. OEM Hood Deflector (wimpy-version)
. 'kmead/SeanY' Rear-Wiper Salute
. 'mungpat' DIY Cabin Air Filter $$$-Saver
. Michelin HydroEdge (ex-Yokohama TRZ) ... looking for replacements
. Costco/Kirkland #9 battery
. Longer front wipers
. Britax Frontier 90

20131028
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post #11 of 15 (permalink) Old 02-14-2010, 12:46 PM
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Re: What is the best tire pressure and why?

True, some OEM tires - including mine - have a maximum inflation pressure of 35 psi, and it should not be exceeded as a cold inflation pressure.. I believe that the Sienna's recommended inflation pressure of only 35 psi is determined by these tires, rather than the best choice for performance, but that's only my guess.
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post #12 of 15 (permalink) Old 02-18-2010, 09:38 AM
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by topspy
[Old Crows] reminded me of the old-school "chalk" test at the old site.

You inflate the tires to whatever specified/experimental pressure (within the safe range as specified for the tire). Rub chalk across the full width of the tire tread. Drive a short distance. Stop and inspect the wear pattern of the chalk. Adjust inflation until the chalk wears evenly across the tread. Verify again "later" with the tires cold just to be more accurate.

After much trial & error, he settled on 40psi front & rear as optimal for the contact patch of the tread....meaning even wear across the width of the tire tread. Of course, this will vary depending upon load, alignment, and maybe tire design.

I used 40psi front/rear based upon his findings and had no issues. Worked fine for me.

YMMV.
Good Luck!! 8)
It STILL works!!!

I've not taken the time to 'chalk test' the GY ComfyTreds I put on the Sienna about three years ago!!! I run them about 40/39 psi based on my experience with the OEMs ... slightly less than the B'stones, and it seems to be just about a perfect inflation for the GY skins. The wear across F & R tires is even and not excessive IMHO.

The GYs are wearing very well... they have slightly more than 50% of the tread remaining. Maybe they are wearing too well ... as I'm getting the urge to go browsing for new donuts.

I've only two minor complaints on the ComfyTreds. I think they are a little more sticky than the OEM B'stone Turanza EL-42s and the mpg has been about 1 or 2 miles less since installing them. Still, they have been a good choice and would be hard to beat for all around performance. Also, when inflated above 40psi they seem to have a 'squirrely' or 'wormy' feel on some road surfaces... Sort of like the Sienna is on tip toes. (Odd image that... like a pig doing ballet?)

Cheers!




Hill Country, Texas
'04 Sienna LXE
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post #13 of 15 (permalink) Old 02-19-2010, 09:10 PM
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Re: What is the best tire pressure and why?

My 2006 handled best with around 37 PSI in the stock tires, but they were kinda noisy. I switched before they were worn out to Goodyear Comfortreads.

The tire store inflated the Comfortreads to 35 PSI front and rear as suggested on the door sticker. They were slighly quieter and gave a softer ride than the stockers. Unfortunately, the poor Sienna wallowed like a garbage scow.

I experimented with various tire pressures, settling on about 41 for the front and 38 rear. Handling was OK, although wet traction was poor. Unfortunately, the soft and relatively quiet ride was gone.

The Comfortreads are about half worn out now and I hate them. They have gotten noisier as they have worn and I can't even listen to the radio any more. I'm gradually lowering the pressure but it doesn't seem to help.

I really enjoyed having the snow tires on for a couple of months, it felt and sounded like I was driving a luxury car! No snow here now, so I had to go back to the noisytreads. Ugh!

Mike Brown
Vancouver, WA
2006 Sienna

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post #14 of 15 (permalink) Old 02-20-2010, 04:43 PM
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Re: What is the best tire pressure and why?

Quote:
Originally Posted by brownmichael
My 2006 handled best with around 37 PSI in the stock tires, but they were kinda noisy. I switched before they were worn out to Goodyear Comfortreads.

The tire store inflated the Comfortreads to 35 PSI front and rear as suggested on the door sticker. They were slighly quieter and gave a softer ride than the stockers. Unfortunately, the poor Sienna wallowed like a garbage scow.

I experimented with various tire pressures, settling on about 41 for the front and 38 rear. Handling was OK, although wet traction was poor. Unfortunately, the soft and relatively quiet ride was gone.

The Comfortreads are about half worn out now and I hate them. They have gotten noisier as they have worn and I can't even listen to the radio any more. I'm gradually lowering the pressure but it doesn't seem to help.

I really enjoyed having the snow tires on for a couple of months, it felt and sounded like I was driving a luxury car! No snow here now, so I had to go back to the noisytreads. Ugh!

Mike Brown
Vancouver, WA
2006 Sienna
Mike, that's been my experience. These tires have been pretty quiet for the most part. We have coarse textured roads here and there are some that really make these treads growl. I'm not sure The B'stone OEMs were much better .... time has a way of making you forget these kinds of things.. and three years is a long time.


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post #15 of 15 (permalink) Old 03-01-2013, 08:41 PM
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Re: What is the best tire pressure and why?

Rotate 90 degrees to the right. Lf to rf. rf to rr. Rr to lr. Lr to lf. Eliminates tread noise and extends tire life.
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