[Healeys] tire pressure

Len and/or Marge Hartnett thehartnetts at earthlink.net
Mon Oct 24 16:55:27 MDT 2016

Likewise, you can use a tire depth gauge.  This will take more time but over 
time it can indicate problems other than tire pressure.  Measure the depth 
at the inner edge of the tire, the center of the tire, and the outer edge of 
the tire.  If checked every six or so months, even wear over the width of 
the tread would indicate a pressure that is providing full tread contact 
(9-9-9).  If wear is greater at the edges, tire pressure is too low (7-9-7). 
If wear is greater in the center, pressure it too high (9-7-9).  If one edge 
is wearing more than the other, wheel alignment could be a problem (7-9-9 or 

If you need an excuse to  go out and drive the car hard periodically, the 
chalk method will be your first and best choice.  The depth gauge method 
will make you check your tire pressure and wear close-up more often so I 
recommend you do that, also.

While you are down there, check the date on the tires and the condition of 
the sidewalls.  If you are getting depth readings at or below the threes or 
they are over 7 - 10 years old, you are overdue for new ones.

(The Other) Len
Fairfield, CA, USA
1967 AH 3000 MkIII, HBJ8L39031

----- Original Message ----- 
From: "Richard J. Hockert" <rjhco at att.net>
To: "Mike" <phoenix722 at comcast.net>
Cc: "Healey List" <healeys at autox.team.net>
Sent: Monday, October 24, 2016 6:04 AM
Subject: [Healeys] tire pressure

> The correct tire pressure will vary widely from car to car, depending on 
> tire type and static weight distribution.
> The correct method for determining proper tire pressure is as follows:
> 1. Use a soft white chalk to mark several vertical stripes across the 
> tread and sidewall of each tire;
> 2. Drive the car hard, including tight turns;
> 3. Check the chalk marks. The marks should end at the knuckle where the 
> tread and sidewall meet. Some tires have small triangles or arrows to mark 
> the knuckle.
> 4. If the chalk remains on the tread, the pressure is too high. You are 
> not using all of the tire.
> Chalk ends below knuckle, tire pressure is too low. The tire is rolling 
> over too much.
> Best regards,
> Jim

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