[DeTomaso] Snoped!- Firestone recomendation is ludicrous! Speed secrets busted!

Matt matt at nwpantera.com
Thu Apr 1 22:06:38 EDT 2010


Jack,
I dearly appreciate the time you took to reply to my post and it was very informative. Thank you my man.
However, it is apparent that you are so good at enjoying life after work that looking at the calendar is not at the top of your daily to do list ;-)
This is not a bad thing at all. Rather to be congratulated in fact :-)))
Why do I feel like the little boy who cried wolf?

bad me,
Matt
ps-should have an update on a front pillar aero test after this weekend ,weather permitting, as I was out of town last week. Special order for Jack!

----- Original Message ----- 
From: JDeRyke at aol.com To: matt at nwpantera.com ; detomaso at realbig.com 
  Sent: Thursday, April 01, 2010 11:26 AM
  Subject: Re: [DeTomaso] Firestone recomendation

  This is the most ludicrous collection of 'speed secrets' I've yet seen for street cars. First, the air inside a tire isn't "dirty". It may have some water vapor in it, which can lead to deterioration of the rubber and possibly the metal wheel- over decades of time. Water vapor also expands under heat and contracts when cool which is important if you're a sensitive enough driver to feel the traction changes from 2-lb variations in tire pressures. The odor of old air from inside a tire comes from rubber plasticizers- important to keep the rubber supple and non-hardening.
  To get rid of the water vapor and resulting small pressure variations, real-racers use nitrogen which is dry. Air from a compressor that is run thru a commercial refrigeration-drier also works. Helium is a 'leaky' gas and won't last long. It also costs far more than nitrogen.
  No one removes the schrader valves from tire stems "for lightness"; a schrader valve weighs less than 1 gram (1/454th of a pound!) Instead, one uses angled valve stems that point the stem at an severe angle to the rim so centrifugal force cannot pull the valve stem open above 250 mph. This is important at Bonneville but not at other places. There is no 'torque value' on a valve-stem cap. Most have no hex for a wrench- a definite clue that 'finger-tight' is fine.  All thats necessary is to seat the soft rubber gasket inside a metal cap- with fingers. A metal hex-cap if overtightened will strip the soft brass threads of a valve stem. We snug the shiny chromed-brass logo-caps up to keep children from stealing them for their bicycles.
  I also recommend metal valve stems- not as a 'speed secret' but to prevent ozone & sulfur from attacking the rubber and cracking it. A cracked rubber valve stem can catastrophically fail from such atmospheric damage- as well as being easily knocked off by road debris. This has happened to Panteras on road trips at near-legal speeds. FWIW- J DeRyke 

  original message-
  Hello helpful forum members,
  I took my car to the Firestone shop this morning.They rotated the tires
  for me(left to right of course).The mechanic suggested I remove the old
  "dirty" air in the tires and replace it with helium.He said the benefits
  are many including less upsprung weight and total weight reduction of the
  car. I called my wife and she said it made sense to her so for $42.00 per
  axle I now have helium in my tires! I'm the man! He then needed to know
  what the factory torque specs were for the valve stem caps.
  He said this is critical because to further reduce weight he removed the
  innards of the valve stem. An old racing trick he said.I didn't have that
  info handy so he used a hi-tech calculation method on his computer
  database. That was only $19.95 and it seemed important so I said go for
  it.
  Better safe than sorry.
  It's rare to find a shop that really cares so much about safety and
  performance with our "exotic supercars",as they put it.
  I would sincerly recommend Firestone to anyone seeking help with the new
  up to date methods of increasing performance on your Pantera.

  Matt
  3584



More information about the DeTomaso mailing list