[urq] Tire pressure for ice racing ?

[LL - NY]

On tarmac, in autocross on courses about the same as your ice racing
courses, we tend to run the lowest pressure that will yield enough turn-in
response as possible (assuming enough pressure to not roll the tire past the
tread and onto the sidewall).  The reason...increase of contact patch area
will increase the grip at that end.

Thus, to decrease understeer, lower the front pressures (without letting the
tires to roll). As an example, in Solo2 Stock with my 2200 lb wet A2 GTi, I
used to run 36F/42 on period DOT-R's, On my Solo2 Stock 3300lb Saabaru I run
36F/48R on current DOT-Rs (which are much stiffer and stickier). Both cars
naturally understeer in steady state cornering.
I dunno if the same principles apply on ice, but from what I've learned in
the Driving Schools I've attended, they should still apply.
On Fri, Feb 12, 2010 at 9:35 AM, Louis-Alain Richard <laraa at sympatico.ca>wrote:

> Thanks Vittorio,
>
>
>
> So lower pressures are better on ice ? Interesting, since higher pressures
> are the way to go on tarmac… I’ll try that next week for sure.
>
>
>
> Would you try to cure the inherent understeer by dropping the fronts more
> than the rears ?
>
> Or would you unlock the rear diff ?
>
>
>
> About the different tires, the real snow tires are the Pirelli (very open
> tread) and since they are not ice tires, they propose to stud them. Nice,
> the only drawbacks are bad dry-cold tarmac traction, and noise.
>
> But the question is : can a studless expensive tire like the Michelin be
> any good on ice ? Or at least, as good as the Pirelli ? I’m sure this
> Michelin won’t be any good in deep snow, the tread is not enough aggressive,
> but on ice, with its multiple sipes and its very soft rubber, I guess it
> could work. What do you think ?
>
>
>
> Louis-Alain
>
>
>
>
>
>
>
> De : vittorio at mybares.com [mailto:vittorio at mybares.com]
> Envoyé : 12 février 2010 01:02
> À : Louis-Alain Richard
> Cc : urq at audifans.com; quattro at audifans.com
> Objet : RE: Tire pressure for ice racing ?
>
>
>
> On lake ice, I'll start at 26psi, and will typically endup in the low
> 20's...depends on conditions.
>
>
>
> But, yeah, regardless if you're on studs or super snow, drop the pressure
> and you'll get better traction - but there's lots of variables:
>
> -- how deep is the snow
>
> -- how wide are the tires
>
> -- what type of tread block are you running
>
> -- temperature
>
> -- etc...
>
>
>
> -------- Original Message --------
> Subject: Tire pressure for ice racing ?
> From: "Louis-Alain Richard" <laraa at sympatico.ca>
> Date: Thu, February 11, 2010 6:25 pm
> To: <urq at audifans.com>, <quattro at audifans.com>
>
> Since I have at least 2 other outings this winter for some hot (cold ?)
> laps
> on an ice track, I was wondering if I can improve traction by playing with
> tire pressure and tire type.
>
>
>
> From factory, my urQuattro mandates 26 psi all around on 205/60VR15 tires.
>
>
>
> But I'm running 185/65SR15 studded Pirelli Carving, still looking new but 5
> years old. http://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli
> <http://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli <
> http://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli&tireModel=Winter+C>
> &tireModel=Winter+C
> arving> &tireModel=Winter+Carving
>
>
>
> I have also a set of Michelin Pilot Alpin PA2 non-studded, 205/60HR15, also
> not worn at all, but 4 years old.
> http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin
> <http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin <
> http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot%252>
> &tireModel=Pilot%2
> 0Alpin%20PA2> &tireModel=Pilot%20Alpin%20PA2
>
>
>
>
>
> What would it be the best setup (pressure and tire type) for :
>
>
>
> 1 - Deep snow over packed ice, just below freezing point temps ?
>
>
>
> 2- Bare ice, no snow after the very first laps, and -20 Celsius (-4 F) ?
>
>
>
> I have absolutely no clue if I must raise pressure or keep it low, and if a
> rough but studded tire like the Carving is better on ice than a
> sophisticated unstudded tire like the Michelin.
>
>
>
> Louis-Alain
>
> In Montreal, where there was no real snowfall since end of December. Hey
> Washington and New York, I want my snow back !
>
>
>
>
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