Date: Fri, 21 Aug 2015 16:05:28 -0700
Reply-To: Mark Hersh <cmwolfsburg@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Hersh <cmwolfsburg@GMAIL.COM>
Subject: Re: Proper Tire valve stems?
In-Reply-To: <BAY405-EAS2995055D656631BA8694AA1A0650@phx.gbl>
Content-Type: text/plain; charset=UTF-8
Thanks! This is helpful and is in line with Mark's earlier (also helpful)
comment. I see now that my "adjusted" inflations are higher than needed,
at least for load capacity reasons.
Drove it yesterday over the OR coast range and was happy with ride and
performance, so I'm not going to make drastic deflationary adjustments.
BTW, Nokian customer service is referring my request to the tech dept in
Finland.... I'll be interested in what they say.
Mark
On Friday, August 21, 2015, Dennis Haynes <d23haynes57@hotmail.com> wrote:
> Here again is a link for the Tire replacement manual.
>
> http://www.tiresafety.com/images/Tire%20Replacement%20Manual.pdf
>
>
>
> This should have the load inflation tables for your tires. You will find
> that load-inflation is not a linear factor and you type of tire reaches
> full carrying capacity at 42 psi. Anything above that is for handling and
> rolling resistance tuning.
>
>
>
> It is a bit of a miss conception that stiffer sidewalls allow a tire to
> carry more weight at highway speeds. A “stronger” tire only gets the
> ability to carry more weight due to the ability to operate at a higher
> pressure. The reality is if that you have the same size tire at a given
> pressure with the only difference being the stiffness of the sidewall or
> tread, the stiffer tire will generate more heat and if that heat becomes
> too great will cause it fail earlier than the more flexible tire. How much
> the tire flexes while it rolls is determined by the shape, design factors,
> speed, load and air pressure. Think this way. When the tire is off the
> ground there is a given radius. When loaded the radius is reduced. This
> reduction is taken up in the sidewalls and tread. For a given size-designed
> tire at a given pressure this reduction will be same regardless of sidewall
> stiffness unless it is so stiff it can be self-supporting. Remember those
> non-pneumatic tires on your first tricycle?
>
>
>
> Dennis
>
>
>
> *From:* Mark Hersh [mailto:cmwolfsburg@gmail.com
> <javascript:_e(%7B%7D,'cvml','cmwolfsburg@gmail.com');>]
> *Sent:* Friday, August 21, 2015 3:31 PM
> *To:* Dennis Haynes <d23haynes57@hotmail.com
> <javascript:_e(%7B%7D,'cvml','d23haynes57@hotmail.com');>>
> *Cc:* Vanagon listserv <vanagon@gerry.vanagon.com
> <javascript:_e(%7B%7D,'cvml','vanagon@gerry.vanagon.com');>>
> *Subject:* Re: Proper Tire valve stems?
>
>
>
> I ran across this paper on the interweb
>
>
>
> http://www.dawsengineering.com/linked_files/tirepressureatreducedloads.pdf
>
>
>
> that says that a conservative estimate of load supported by
> less-than-maximum inflation is a simple proportion. A more accurate
> estimate would take into account the stiffness of the sidewall. More
> conservative is fine with me.
>
>
>
> Example, with the Nokian eNTYREs I just put on Monty:
>
>
>
> First, I reduced the max load by 10% per some official body's guideline
> when running an XL tire on a van/truck. So the 1764 lbs max (100T rating)
> on the tire is 1587 at 51 psi.
>
>
>
> The Gross Vehicle Weight Rating on the plate on Monty's door jamb is
> front, 2646 lbs, rear 2866 lbs, so I need 1323 lbs supported per tire on
> the front and 1433 on each rear tire.
>
>
>
> Those particular weights could be supported by 46 psi in the rear and 42
> in the front. So I'm thinking that's the MAX I will ever have to inflate
> these tires.
>
>
>
> I did not get much help from Nokian when I asked for a load-inflation
> table. They asked me what psi's I was interested in, so I told them 36 to
> 51 and they have not yet responded.
>
>
>
> Mark
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Thu, Aug 20, 2015 at 3:36 PM, Dennis Haynes <d23haynes57@hotmail.com
> <javascript:_e(%7B%7D,'cvml','d23haynes57@hotmail.com');>> wrote:
>
> Proper valve stem length is really a function of wheel covers or the lack
> of. If not using any wheel covers you normally want the shortest stems
> available especially for driving in snow or any off road adventure. The
> longer the stem the easier it is to break off. With covers you want the
> valve long enough so it can be serviced with the wheel cover in place.
>
> In the real truck world metal valves are usually used.
> The 65 psi is the max inflation pressure for the tire. You want to follow
> the door jamb specifications or get the load-inflation table for the tire
> you are using and use the maximum axle weights to determine proper
> pressures.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com
> <javascript:_e(%7B%7D,'cvml','vanagon@gerry.vanagon.com');>] On Behalf Of
> T Collins
> Sent: Thursday, August 20, 2015 12:37 PM
> To: vanagon@GERRY.VANAGON.COM
> <javascript:_e(%7B%7D,'cvml','vanagon@GERRY.VANAGON.COM');>
> Subject: Proper Tire valve stems?
>
> Hello List,
>
> I'm about to get all new tires mounted. I know these are LT tires and are
> rated @65psi. When replacing the valve stems is there any that "NEED" to be
> used because of the higher PSI.
>
> I dont want a leaky tire with these. I have the 14" steel wheels. Also I
> think the current stems are too short. Should they be 2" valve stems?
>
> What says you?
>
> Thanks,
> T.
>
>
>
>
>
> --
>
> 86 Campmobile Six-Seater "Monty"
>
> Black dogs are euthanized at a greater rate than other-colored dogs,
> regardless of temperament. Learn about Black Dog Syndrome at
> http://www.blackpearldogs.com/ Learn about black dogs in a Vanagon at
> http://www.pbase.com/mhersh/image/108220533
>
--
86 Campmobile Six-Seater "Monty"
Black dogs are euthanized at a greater rate than other-colored dogs,
regardless of temperament. Learn about Black Dog Syndrome at
http://www.blackpearldogs.com/ Learn about black dogs in a Vanagon at
http://www.pbase.com/mhersh/image/108220533
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