Date: Sun, 29 Aug 2010 22:52:00 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: Tire question: Sorry, but ...
In-Reply-To: <AANLkTikQ-Wn8GBJ2tcDO8q05eOG2NZPEh=bGCQOa2D-W@mail.gmail.com>
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Hey well just for the fun of it...I am going to use my tire temperature
probe from the racetrack. Left over in my tool box from my racing days
where I use that to tune suspension, etc.
I learned a LOT about tires when I raced, but not much about street
tires. I did learn about heat generated by tire pressures.
One wide-spread practice in racetires is to inflate them with nitrogen to
minimize heat-generated pressure increase. As a tire comes up to racing
temp with atmosphere inflated inside, they can gain up to 7psi but with
nitrogen, they will only gain a few lbs....So when you filled the tires with
nitrogen, you could start a race with almost the correct pressures, rather
than running a lap or so underinflated while the temperature caused the
pressure to increase.
When you are running about 20psi in a 12.5" wide slick racing tire...7lbs
is huge. You couldn't really start at 13psi and depend on the tire staying
on with the forces generated by high cornering G-forces and big HP.
I started these Hakkas out at 44r and 39f..then after my test drive, I
upped the fronts to 43 and the rear to 46...I will take some tread temp
readings...see what temps I get...I bet cold, compared to a race tire
Don Hanson
On Sun, Aug 29, 2010 at 10:00 PM, Loren Busch <starwagen@gmail.com> wrote:
> On Sun, Aug 29, 2010 at 9:03 PM, Scott Daniel - Turbovans <
> scottdaniel@turbovans.com> wrote:
>
> >
> >
> > interestingly, on the same vehicle...
> > for the 185 R 14 C 6 PR they say 39 front, 48 rear.
> >
>
> Not totally true Scott. Some years back, just for kicks, I did a survey
> (on
> vehicles I could walk up to at a WetWesties gathering and also asked people
> online for info and several in a local bone yard) and VW increased the
> recommended pressure over the years. From about '88 on, on a Westy, for
> the
> 185R14 they say 43 front, 53 rear. What prompted my mini survey was a
> discussion just like this.
> And my (very subjective) testing of various inflations on my rig, first
> with
> Michelin Agilis and now with Hakka CS I've found the 43-45 front 53-55 rear
> gives me the best feel/handling. But this is a truly YMMV situation.
>
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