[ale] way OT - used car buying tips - yea or nea - PT 2

Thu Nov 29 09:15:32 EST 2012

I have 2 cars here. 05 Honda Civic LX 1.7L auto. Has trailer hitch
05 Honda accord EX V6 auto. Has a trailer hitch. They are handy to have
around. Best example is Dad one time bought a new door for the house. I
went to uhaul and rented a $15 trailer, vs paying $100 for delivery.
The civic gets about 34mpg. If I clean the engine and go highway at 60mph I
can get 38. The accord gets about 28mpg. The best I have done is 35mpg.
Which isn't bad. I love the V6 though. Has the power to get you out of
stupid situation.

On Thu, Nov 29, 2012 at 7:31 AM, Jim Kinney <jim.kinney at gmail.com> wrote:

> Maybe it's just me but it seems like all of the data about uneven tire
> wear causing premature drive line failure is coming from TIRE SALES.
>
> I seriously doubt that the engineers that designed the Subaru AWD
> system considered "slip" to be a whopping 4 full tire revolution per
> mile incrementally. I would consider, and expect they would too, slip
> to be a sudden change in rotation difference. As the hydraulics
> involved use pressure differential valving, it's pretty clear to me
> that small differences, like those between the inner tire and outer
> tire on a curve (a similar difference as between wear levels) would be
> the normal differential action. It should only be the action of a tire
> suddenly spinning that causes a pressure drop across a circuit that
> allows a pin valve to close off power to that wheel.
>
> I can see if someone put different SIZE tires causing an issue. But
> tire wear is all within the realm of turning differentials.
>
> On Wed, Nov 28, 2012 at 10:55 PM, Ron Frazier (ALE)
> <atllinuxenthinfo at techstarship.com> wrote:
> > I found this link.  I think I'll stop researching the awd for now and
> pick it up again later.
> >
> > http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=18
> >
> > Ron
> >
> >
> > "Ron Frazier (ALE)" <atllinuxenthinfo at techstarship.com> wrote:
> >
> >>Hi Sean,
> >>
> >>I'm not an expert on AWD, just reporting what I've been told.  I'll try
> >>to do some research when I can and post anything I find that looks
> >>useful.  Here's the situation as I understand it.  I think you're right
> >>that most Santa Fe style AWD systems are FWD most of the time.  Many of
> >>the new cars have traction control or stability control.  If the system
> >>detects slippage, the rear wheels are engaged.  If all tires are the
> >>same size and none are slipping, the system is happy.  Let's say you
> >>replace one tire with a used smaller one because an original one was
> >>damaged.  Then, that new tire will be spinning faster.  The system may
> >>think that one is slipping.  Then the viscous couplings, etc. try to
> >>route additional power to the other three wheels and reduce power to
> >>the "slipping" wheel.  Which, of course, they cannot do because the
> >>other three are turning as fast as they can.  So, the traction control
> >>system becomes engaged full time and wears things out.  If you had put
> >>a larger!
> >>tire on to replace the damaged one, then the system might think all
> >>three others are slipping, and try to route power to the one new one,
> >>which would again cause problems.
> >>
> >>This forum post says Subaru has a system which requires no more
> >>variance in tire size than 1/4" in circumference, which is 1.25 / 32"
> >>of tread depth, a goal which is almost impossible to meet.
> >>
> >>http://townhall-talk.edmunds.com/direct/view/.f1b9005/26
> >>
> >>In another forum post, I found out that tirerack.com has a tire shaving
> >>service that they use to equalize the size of a set of tires for
> >>people.
> >>
> >>In the case of the Mazda I almost bought, I was having a pre purchase
> >>inspection done at the dealer, but was not buying the car from them.
> >>The service manager was very emphatic that I could not just replace the
> >>tire with the nail and screw in it.  I don't think he was trying to
> >>defraud me.
> >>
> >>Sincerely,
> >>
> >>Ron
> >>
> >>
> >>Sean Kilpatrick <kilpatms at gmail.com> wrote:
> >>
> >>>I am very suspicious of this.  There are significant differences
> >>>between
> >>>four-wheel drive and "all-wheel drive."  The latter, which most
> >>>light-duty
> >>>SUVs have today, is for temporary use only on slippery surfaces as the
> >>
> >>>drive electronics lock the differentials. That is, the wheels on the
> >>>left
> >>>side are turning in lock step with the ones on the right. When the
> >>>diffs
> >>>are locked, then the left/right tire pairs have to be very close to
> >>the
> >>>
> >>>same circumference or the constant drag/slippage almost certainly will
> >>
> >>>cause problems. On snow, ice, or mud, not really a problem for small
> >>>differences.
> >>>
> >>>The problem, such as it is, is real for vehicles (think older Land
> >>>Rovers)
> >>>that have the ability to lock any of the three diffs independently.
> >>At
> >>>
> >>>that point the tires need to be the same size to avoid problems.
> >>>
> >>>Today almost all "AWD" vehicles are full time front-wheel drive and
> >>>have
> >>>only two diffs: One for the front and one for the center.  When the
> >>>center
> >>>one is "engaged" the back wheels turn as one and the front diff also
> >>is
> >>>
> >>>locked. Significant differences in tire circumference will put stress
> >>>on the
> >>>drive train.
> >>>
> >>>But a thirty-second or two is probably not significant.  The tire on
> >>my
> >>>SUV
> >>>has a current diameter of 28.25 inches (more than 30k miles.)  Suppose
> >>>I
> >>>replaced it with another used tire with an additional 2/32" of tread.
> >>>The
> >>>rolling diameter of the smaller tire would still be 99.78% of the
> >>>larger.
> >>>If this were a real problem, there would be many more drive train
> >>>failures
> >>>caused by installing the spare tire and continuing down the
> >>interstate.
> >>>(And, no, I wasn't willing to haul out the spare tire and measure its
> >>>actual diameter.)
> >>>
> >>>Sean
> >>>
>
> >>>--------------------------------------------------------------------------------------
> >>>
> >>>
> >>>
> >>>On Wednesday, November 28, 2012 05:16:11 pm Ron Frazier (ALE) wrote:
> >>>> Re: awd - All wheel drive can be very handy.  I almost bought an AWD
> >>>> Mazda Tribute.  However, it had an unpatchable screw AND nail in one
> >>>> tire.  They said I had to replace all tires at once to keep them the
> >>>> same circumference.  I did some research and it appears to be
> >>>> true.  You have to keep the tread depth of all tires within 1 or
> >>2/32
> >>>> of an inch or it screws up the drive train and can cause premature
> >>>> failure.  I never knew that before
> >>>
> >>>
> >>>------------------------------------------------------------------------
> >>>
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> >>
> >>
> >>--
> >>
> >>Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9
> >>Mail.
> >>Please excuse my potential brevity.
> >>
> >>(To whom it may concern.  My email address has changed.  Replying to
> >>former
> >>messages prior to 03/31/12 with my personal address will go to the
> >>wrong
> >>address.  Please send all personal correspondence to the new address.)
> >>
> >>(PS - If you email me and don't get a quick response, you might want to
> >>call on the phone.  I get about 300 emails per day from alternate
> >>energy
> >>mailing lists and such.  I don't always see new email messages very
> >>quickly.)
> >>
> >>Ron Frazier
> >>770-205-9422 (O)   Leave a message.
> >>linuxdude AT techstarship.com
> >>
> >>
> >>_______________________________________________
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> >
> >
> > --
> >
> > Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9
> Mail.
> > Please excuse my potential brevity.
> >
> > (To whom it may concern.  My email address has changed.  Replying to
> former
> > messages prior to 03/31/12 with my personal address will go to the wrong
> > address.  Please send all personal correspondence to the new address.)
> >
> > (PS - If you email me and don't get a quick response, you might want to
> > call on the phone.  I get about 300 emails per day from alternate energy
> > mailing lists and such.  I don't always see new email messages very
> quickly.)
> >
> > Ron Frazier
> > 770-205-9422 (O)   Leave a message.
> > linuxdude AT techstarship.com
> >
> >
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>
>
>
> --
> --
> James P. Kinney III
>
> Every time you stop a school, you will have to build a jail. What you
> gain at one end you lose at the other. It's like feeding a dog on his
> own tail. It won't fatten the dog.
> - Speech 11/23/1900 Mark Twain
>
> http://electjimkinney.org
> http://heretothereideas.blogspot.com/
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-- 
SimonTek
912-398-6704
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