Date: Thu, 9 Nov 2006 17:48:19 -0700
Reply-To: Jon Kanas <kanas@QADAS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jon Kanas <kanas@QADAS.COM>
Subject: AWD and Tires
Content-Type: text/plain; charset=us-ascii; format=flowed
Good Evening Lee,
AWD vehicles have either mechanical (viscous coupling like a Syncro) or
electronic sensors which effectively measure wheel slip between wheels
and lock the differential between the front and rear when there is a
difference in speed. For a Vanagon, I believe that a 6% difference in
speed of rotation is the specification to induce lockup. I looked at
Elements when I was looking for a new car last year (ended up with an
Outback XT). I believe that the Honda system is electronic. The wheel
sensors for the ABS send signals to the traction control computer, which
engages the front/rear differential when a difference is detected.
The short and long of this is that there is a significant probability of
driveline damage on any AWD vehicle if tire wear is sufficient that the
AWD fully engages while you are on dry pavement. Furthermore, you run
the risk of Honda declining to honor the warranty on your Element if the
tires are not essentially identical on all four corners, and you have
any driveline problems. I strongly recommend replacing all 4 tires,
then selling the two "OK" leftovers on Craigslist to recover some of
your expense. You'll also avoid the "tire recycling" fee for those two
tires, if you have such in your state. The Element has a front-drive
bias, meaning under no-slip conditions the front wheels propel the car,
hence greater wear on the front tires. You are probably a candidate for
rotating the tires front to rear on a frequent basis to equalize this
wear pattern.
I have, unfortunately, encountered the situation where an odd-size tire
(compact spare) made our 1995 Outback essentially undrivable after a
flat tire as the AWD would engage unexpectedly when turning, making the
car very unmanageable during one very exciting freeway exit adventure.
To make matters worse, the puncture we had was on the sidewall, and we
ended up giving up three perfectly good tires in order to replace one.
AWD systems are very sensitive and well engineered, and also incredibly
expensive if you break them.
--
Best Regards,
Jon B Kanas
Longmont, Colorado; Cultural Center of the Universe
Email: kanas@qadas.com <mailto:kanas@qadas.com>
Website: http://www.qadas.com/~kanas <http://www.qadas.com/%7Ekanas>
AOL Instant Messenger ID: KanasColo
Whenever morality is based on theology,
whenever right is made dependent on divine authority,
the most immoral, unjust, infamous things can be justified and
established. -Ludwig Feuerbach, philosopher (1804-1872)
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Date: Wed, 8 Nov 2006 22:54:56 -0800
From: Lee Kouns <LeeKouns@WEBTV.NET>
Subject: NVC Question on AWD and tire tread depth
Are there any all-wheel-drive experts out there who can enlighten me on
something? Here's my situation:
1) The front two tires on my AWD Honda Element need to be replaced.
2) The rear tires seem barely worn.
3) I'm thinking of replacing the front tires only, with the exact same
tire that is currently on the rear.
4) I've been told by a tire dealer that if there is too much wear on
the rear tires that I risk damaging the drive train. (The transmission
is manual--if that matters)
Is there truth to what the tire dealer is telling me? If so, how much
wear on the back tires is too much? I'm wondering if the dealer just
wants to sell me 4 tires instead of 2?
As always, any comments on the matter will be greatly appreciated.
Lee Kouns
'88 Westy
'04 Honda Element
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