Worth Paying for one more rotation?

The OEM tires on my '07 Accord EX-L V6 Sedan (Michelin Pilot MXM4,
215/50-17) show even tread wear but three of them are between 5/32 and
6/32 tread depth while the RF has 7/32. They've got about about 33,000
miles on them.

I'm due for an A-1 service (oil change, tire rotation) and wondering if
it's worth paying for the rotation seeing as how they'll probably need
to replaced sooner rather than later.

 

How much are they charging for the rotation itself?

 

$20

 

For a measly $20, I'd get it done.

Surely you'll get that back in slightly longer tire life, maybe even $20
more life.

 

i'll take the longer survival life of the driver thanks. rotation ruins
traction and braking control because it reduces the amount of actual
rubber contacting the pavement.

 

You have some pretty odd ideas, sir.

 

one of the things you learn early on in materials science is that the
micro determines the macro. [this is an observation principle many
never learn, and even some who have been taught, never fully
appreciate.] thus, if you methodically observe the "micro" of the
tire's behavior, you will understand the "macro" of its performance.

i've repeated the description of this easy-to-do-for-yourself experiment
on this forum many times - chalk up some hdfb, lay it on some flat road
and with your "has been in this position for a few thousand miles now"
tires still in those positions, drive across it. take a pic of the
rubber blocks on the tire, and what percentage of each is chalked. then
rotate the tires, and repeat [taking the trouble to drive around the
block to de-chalk from last time of course]. you will see a dramatic
reduction in the contact area on each single block, particularly the
ones at the edges of the tire.

this is the reason why the "sport" car manufacturer segment recommends
/against/ tire rotation - this reduced contact area. and they're making
sense because some clown jumping into their m5 [bmw is one such
manufacturer that recommends against rotation] and trying to take an
on-ramp at the same speed they always do will quickly come to grief
because of it.

"good riddance to that guy" you may say, but the same applies to your
wife driving the kiddies to school - her emergency braking distance will
be increased in proportion to the reduced rubber contact area after a
rotation. i'm sure you don't want that, and now you can do your chalk
experiment, you can prove what i've said for yourself.

reality is, perpetuation of the tire rotation mantra is both ill
informed and anachronistic for today's radial tires. some people say it
because either their cars are crap and can't track a tire straight under
any circumstances, they don't know how the tire actually behaves, or
because they think it's some kind of legal cya. all are ridiculous imo.

 

You have some pretty odd ideas, sir.[/QUOTE]

....ideas which BMW put into writing and practice some time ago, for the
same reasons jim outlines.

There is no tire rotation for BMW vehicles.

 

...ideas which BMW put into writing and practice some time ago, for the
same reasons jim outlines.

There is no tire rotation for BMW vehicles.[/QUOTE]



jim says that the reason you shouldn't rotate tires is because of
temporarily-reduced contact patch when the tires change positions. And this
is perfectly true.

It's also true that if you never rotate your tires, you will maintain
maximal contact patch through out the tires' life. For race cars, or road-
going performance-cars such as BMWs, this is important when approaching the
limits of the cars' capabilities.

Unfortunately, maintaining maximal contact-patch has a tradeoff: shorter
usable tire life. Without rotation, the portions of the tread that wear
most will reach their wear-limit more quickly than if the tires had been
subject to different wear-patterns regularly.

Does the temporarily-reduced contact-patch make any real difference to the
handling and safety of daily-driver Hondas that are driven the way most
people drive them? I don't think so. I think most people appreciate getting
the longest life they can out of their Honda's tires, and are unlikely to
drive their Hondas the way race cars are driven.

 

Man....ask a simple question! Hey, thanks for the advice.

I'd post a longer reply but I'm out here on the interstate commuting to
work. I don't want to take the risk of raising the sun-tinted Polaroid
visor on my racing helmet so I can see the cell phone screen more
clearly-- nor taking off my fireproof nomex racing gloves to get my
fingers on the tiny little keyboard better.

Shoot, there's the dreaded yellow flag-- backing it down past 150 mph
now. Good damn thing my tires are so grippy...only the inside two are
contacting the pavement as I make this tight turn...

 

wow, i wish i lived where you live. great wide straight flat roads,
perfect weather all the time, no other doofuses on the road to change
lanes without using their mirrors. and no kids chasing out into the
street either. at least, i hope not...

 

only if you toss the whole set when one axle's tires are done.
"rotation" simply averages the wear rate over all the tires at the same
time. if tires remain in one station, their wear rate for each station
is still exactly the same [higher in fact since individual blocks get
stressed more after a change], they're just not averaged over the set.

 

forgot: this "longer life" mantra is a fundamental misconception. wear
rate is the same, it's merely averaged over more tires. that is /not/
"longer life".

 

And if you haven't rotated your tires, you're enjoying maximum contact
patch on those two! Good for a few more MPH, for sure.

 

Some of which use different tire sizes and profiles front and rear.

 

why do people trivialize this? traction is a safety thing much more
than a "racing" thing. doesn't anyone want to /not/ rear-end the car
that can stop faster than you?

 

I think you're overreacting just a little bit.

 

I'm guessing BMW is expecting its owners to take their cars to 10/10ths
regularly. Few daily-driver Honda owners would do that unless they're young
and/or ricers. And when you're that close to the limit, inexperience and
incompetence is more likely to result in crashes than some small and
temporary reduction in contact-patch.

 

I'm with you, I'll rotate the tires.

"Tegger" wrote in message

I'm guessing BMW is expecting its owners to take their cars to 10/10ths
regularly. Few daily-driver Honda owners would do that unless they're young
and/or ricers. And when you're that close to the limit, inexperience and
incompetence is more likely to result in crashes than some small and
temporary reduction in contact-patch.

 

b.s. bmw's break if you actually /do/ drive them hard. ask my buddy
with the m3 and three new subframes.

the factor common to all drivers, irrespective of "inexperience" or
"incompetence" is emergency braking. and with abs control, driver
competence is simply not a factor.