Date: Sat, 19 Nov 2016 14:32:02 -0500
Reply-To: Eric Wunrow <VW@ERICWUNROW.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Eric Wunrow <VW@ERICWUNROW.COM>
Subject: Re: Vredestein Comtrac Winter tire
In-Reply-To: <CAFdLW6nSYerru2z6j9JJuyLO577nMrLbfqnMFRe6FZOh=Qw5gA@mail.gmail.com>
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Yes, Dan, you're seeing it now.
But, my overriding point isn't so much about how much pressure does what, it's about pressure balance and how that affects handling — and there's too many variables for blanket rules such as FWD vs. RWD, weight transfer when turning, suspension stiffness, weight balance and cargo load within the vehicle, and many more.
I also have a '96 Jetta, and since we've been on the road for nearly 40 months I honestly can't recall what my pressures were. But believe it or not, even on that FWD, front-engined car I still ran more pressure on the front — but less than five lbs. more if I'm recalling correctly — so I hesitate quoting anything about that.
Saying that less pressure automatically means more bite has limits as well, though in your statement of letting air from the rears for more traction is dead on — but that's only one application in a very limited situation. But certainly not as a blanket rule for all situations, and especially not for all vehicles.
I realize how complex this all sounds — hence my lengthy ramblings — but should again stress it always comes down to how well the vehicle turns, sans excessive oversteer or understeer, and with all four tires being within a normal heat range after a lengthy run at highway speeds. Say you have a really worn front suspension, and a brand-new rear suspension, and are on a windy two-lane, all bets are off because the front tires will have much more stress on them vs. the rears while turning, as the struts and springs fail under load and transfer excess weight on those tires, so pressures will need to consider that.
Thanks for the reply!
Eric
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On Nov 19, 2016, at 2:13 PM, Dan N <dn92610@gmail.com> wrote:
> hi Eric,
>
> I though about this some more and here are my observations...
>
> for the sake of the discussion let's say you inflate your vanagon tires at 50psi all around...
>
> - if you get stuck in the sand/mud/gravel road... you will deflate the rear till it get more traction to get you out... right?
>
> but NOT the front...
>
> - you leave the front alone, you don't want to deflate it because if you do you will increase contact thus resistance...
>
> now... in any car front or rear wheel drive, in any situation you want the most traction on the wheels that have power... right?
>
> so as I think about your finding it make a lot of sense... because on a 2WD vanagon I want the most traction on the Rear and the least resistance on the Front.. -
> so for the vanagon 40psi in the Rear and 50 psi in the front make a lot of sense.
>
> but if I have a front wheel drive car/van I will do the reverse..
>
> it's a bit different on a 4WD car/van because of you get stuck you want the traction on all 4 wheels.
>
> dan
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