<VV> Tire Pressure (Corvair content)

[Sethracer at aol.com]

In a message dated 4/15/2006 12:03:59 PM Pacific Standard Time,  
kc_eck at sbcglobal.net writes:

I know  on a vair the front should have
less pressure than the back but how much is  enough, if
say all 4 tires have a maximum of 44 PSI?  On a new
car  if I beef up the tires what do i do to detemine
the correct  pressure?



People set tire pressures to whatever pleases them. You are correct in your  
assumption of a front/rear pressure differential. It is actually easy to  
determine the best pressures if you are racing a Corvair, it is equally easy to  
determine the best pressures for an economy run. For daily driving, however, 
you  will have to make compromises. The front end of the Corvair is lightly 
loaded -  in regular status - compared to the rear. Remember that the Corvair was  
introduced and sold with non-radial tires, with some possible 
dealer-installed  radials in a tiny number of cases. Also, until recently, all Corvair race 
tires  (non-DOT) were bias ply tires as well. You will likely be running radial 
tires  on your Corvair. Radials are much less sensitive to pressures than 
bias tires -  in my experience. With older tires, and to some extent, with 
radials, raising  the pressures on the front tires can lift much of the tread off 
the ground as  the pressure rounds out the tire. When it isn't touching, it 
isn't working. But  radials don't ballon out as much under higher pressures, 
because of the steel  belts, I suppose. You probably recognize this on the road, 
when someone driving  a current passenger car has a tire looking as if it is low 
on pressure, you are  usually seeing 10 PSI or less inside the tire. It is 
easy to tell the difference  between that and 20 PSI. But it is harder to tell 
the difference between 20 and  30 (or even 40) by the eyeball method. For most 
radial tires on near-stock  wheels, say up to 7" width, you can stay with the 
24-34 (10-PSI) spread. But  when you do that, look carefully at the front tire 
where the tread is in  contact. If the whole horizontal portion of the tread 
is not in contact  with the pavement, consider dropping the pressure in the 
fronts by 1 or 2 lbs.  If the steering because difficult, or the sides of the 
front treads see to be  wearing, raise them up a couple of PSI. I do know people 
who run 30 PSI all  around on their Corvairs and are as happy as clams. I 
don't recommend it myself,  but some folks are happy with it. I cannot think of 
any instance where you would  need that full 44 PSI on the sidewalls of the 
tires you were looking at. I have  run pressures that high on the front tires of 
cars with heavy front engine  designs. Whan I autocrossed a Lola Super Vee on 
race tires, I headed out with 10  PSI in the wide front racing tires. The soft 
compound worked great at that  pressure with the low weight on that corner of 
the light car.  - Seth  Emerson