Thread: Tire Pressure
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  #19  
Old May 3rd 05, 11:04 AM
Tim Rogers
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"Jim Adney" > wrote in message
...
>
> The sticker is correct. You could add a couple of pounds to each,
> especially if the car is heavily loaded, but don't inflate it the same
> as your Chevy. The reason the front tires get so little pressure is
> that they have so little weight on them.
>
>


....................Correct! And if the front tires are larger than the std.
165's, they should have less pressure, not more. My '77 has 185/65-15's on
the front and I've been running 16 psi for about 10,000 miles now. These
tires are wearing evenly and handle superbly even when cornering and braking
hard. With no front bumper, There is only about 425 lbs. load on each front
tire which is way way below the load rating of these tires. A tire's
cross-section shape is determined by the load and the pressure working to
counteract the other and less load always requires less pressure to maintain
the optimal shape that maximises the contact patch on the pavement while not
sacrificing the structural integrity of the tire. Formula 1 racing cars use
less than 25 psi on the front tires I read somewhere because they have large
profiles and only 200 lbs. load per front tire at rest and still only about
800 lbs. load per tire from the downforce generated by the wings & spoilers
that are used to increase traction at 200 mph! The worst aspect of this
'theory' that the front tires on a bug should be inflated to the twenty or
thirty psi range is that the tread's grip during braking and cornering goes
way down. I've done a lot of 'seat of the pants' experimenting with this
question over the years and I drive like a maniac sometimes. This goes
beyond everyone's right to their own opinion for me because I've seen
through direct experience that overinflated front tires on a bug are a
direct cause for loss of control at high speeds when cornering and braking.
When the road is wet, this loss of tire grip from overinflated tires is even
worse.


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