Miata Mailing List: August 1999, Message #16

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Hey Fletch,
welcome home! I was looking at Gary Morrisons new NZ web site yesterday,
very impressive. http://homepages.paradise.net.nz/~gm/miatanet/index.htm , I
really love people that come to the list, ask a question then piss on the
reply. My answer to him was based on the opinion of the professional
instructors at the Advanced Driver training courses and those of Bob Hall,
not to mention several senior Mazda personnel in Oz. If I'm wrong I've
wasted the last few years with the Club especially the long hours at the
track during our competition events!

Jeff Gehrig
MX5 Club NSW #169
'99 Grace Green
Oz TeamVoodoo
Team Grandpa
http://mx5.com.au/nsw


----- Original Message -----
From: Fletcher Blades <fletch@powerlink.co.nz>
To: Multiple recipients of list <miata@list.miata.net>
Sent: Sunday, August 01, 1999 9:04 PM
Subject: Re: tyre pressures, safe maximums


Chad,

Tyre pressures are an entirely personal thing, and If you're happy with 26,
thats cool, but before you dismiss Jeff's 38 (for the track) as being
outside the manufactures allowed limit, go and read those side-walls again.

My previous set of tyres (Falken Ziex) said maximum safe pressure was 38
psi for 500kg of car weight. My current Toyo T1's say 44 psi for 475 kg.

The miata weighs only 1000kg (or maybe 1150 for later, high optioned
models), so thats half the rated weight for that pressure.... (there are
four wheels, each holding close to 1/4 the total weight). I expect your
tyres will be similar...

The "safe" pressure of your "35 psi max" is probably way higher than you
think...

Fletch.




>From: Chad A Blatchley <chadmd72@ix.netcom.com>
>>To: Jeff Gehrig <miata@bigpond.com>
>Cc: Multiple recipients of list <miata@realbig.com>
>Sent: Sunday, August 01, 1999 10:29 AM
>Subject: Re: DAILY digest of "soft-shell" mailing list (part 1 of 1)
>
>
>I appreciate your input Jeff. I guess we will have to agree to disagree. I
>have
>heard of higher pressures for autocross etc. but for everyday vibration
free
>driving I think that mazda hit it right with 26psi. The maximum pressure
>stated
>for the Yokohama AVID H4's is 35psi, 3 pounds lower than your stated
38psi.
>Running  33psi as the shop had left it, my car shimmied and shaked at
>highway
>speeds, the tires would cut loose way to soon, and the ride was very hard.
>This
>is my fourth miata since they were introduced and I have had a total of 10
>combined years of ownership. I  have experimented with many different
>pressures
>and always have gone back to the 26psi range. Once again I respectfully
>thank
>you for your input. Chad...: )
>
>Jeff Gehrig wrote:
>
>> It is the general opinion of most here on the list, that 26 is way too
>low.
>> When I did the free driver education course (Twice) with my two Miatas
the
>> instructors insisted that the pressures be at least 38 and they checked
>> while we were in class, 38 is possibly a little high for normal road use
>and
>> most here run around 32 for everyday driving. I know that 26 is the
>pressure
>> recommended on the door plate but it's a compromise for comfort,
>> manufacturers being a little scared that people won't buy their product
if
>> the ride seems too firm. Your tyre dealer was a little more switched on
>that
>> you give him credit for.
>>
>> Jeff Gehrig
>> '99 Grace Green
>> Oz TeamVoodoo
>> Team Grandpa