RE: Tire Sizes and how to calculate

[Jeff Adams <ledman_70@xxxxxxxxxxx>]

I can go one better than the Dakota story. I went to get tires for my 83 
Mazda pickup and picked out a set that was on sale. The counter guy told 
me he couldn't do it when I asked him to turn the whitewalls in. I said 
why not? He said they would be facing the wrong direction and that would 
void the warranty. I told him that made no sense because they weren't 
directional tires, but it made no difference. So I let them mount the 
tires whitewall out and then I tire blacked them when I got home. Now, 
THAT guy was an idiot!
Layne Grissman wrote:
> 
> Wow, Good post.   And I will agree, too many of the "Car and Tire"
> Shops out there depend too much on the computer...
> As for the 3.91's, well, we got the car with the 3.91's in her,
> however it was not original, as the person we bought the car from many
> years ago made some very significant changes to the car.  This one had
> a 413 in it from a '63 Imperial, so we built it up...It was a Max
> Wedge Block casting...We bored it over .030, and added dual fours to
> her, new cam, new Edelbrock Performer RPM heads and Doug's Headers to
> her, so she will be a performer to an extent...., it was originally a
> 318....as well as the 489 case and 3.91 gears, which from what we know
> were originally 3.23's....non sure grip....
> 
> This car is not stock and we are not worried about the originality of
> it.  Things would have been easier if we only went with original.  We
> are not tubbing it out, we are not making body changes, and we are
> keeping it as close to stock as the day we got it, if that makes any
> sense.   We're just trying to work with what we have, hence the reason
> I asked the question.
> 
> We were thinking about going with 29" tall to try and compensate a
> little but I wanted to be sure and get a little more specific on
> exactly what we needed...
> 
> This is why we are trying to figure the proper size.
> 
> Hope that all makes sense...
> 
> Layne
> 
> On Wed, Jun 10, 2009 at 11:32 AM, Herb<zephyr9900@xxxxxxxxxxx> wrote:
> >
> >
> > When your replacing tires on your car you need to get tires the same 
> > heig=
> ht
> > as were installed from the factory such as a 27 inch tall tire was the
> > average for our B body's. =C2=A0Rim diameter dosen't matter or the width 
> > =
> of the
> > tire other than rubbing on the inner or outer fenders. =C2=A0If the 
> > 3:91s=
>  were
> > stock and you change your tires to a taller tire you will throw your
> > speedometer off and on new cars with a computer a Lot More. =C2=A0If the 
> > =
> 3:91s
> > were not stock and you installed them you are completely defeating the
> > purpose of installing 3:91s and your wasting all the money you spent on 
> > t=
> hem
> > going with a bigger tire! =C2=A0 You should have thought about RPMs & 
> > MPH=
>  before
> > the gear change and not in your tire choice!! =C2=A0If the tire shop 
> > your=
>  dealing
> > with cant help you with a 27 inch tall tire in any width or rim size 
> > they
> > are idiots that you need to run away from them ASAP!! =C2=A0Their are 
> > sev=
> eral out
> > their that haven't got a clue as to how to properly fit a tire to a car
> > other than what the book/computer says. =C2=A0Was looking for tires for 
> > m=
> y
> > Durango last week and was told by a tire shop that I had to buy new rims 
> > =
> &
> > tires for it because no one makes tires for that size rim on Durango's
> > anymore. =C2=A0Stunned I asked if they don't make 285/50 R20s anymore? =
> =C2=A0They said
> > yes but not for a Durango! =C2=A0They need to close their doors and go 
> > aw=
> ay in
> > embarrassment. =C2=A0Now if you are trying to get better gas mileage the 
> > =
> best
> > thing to do is change your 3:91s to something more streetable such as a 
> > 3=
> :23
> > or 2:73s but that is not always affordable & don't forget your tranny 
> > gea=
> r.
> > The other problem other than your spedo is if you go to too tall of a 
> > tir=
> e
> > to make a difference in offsetting the 3:91s, your going to have to 
> > inves=
> t
> > in air shocks to keep things from rubbing and remember the taller the 
> > tir=
> e
> > the narrower it will have to be to keep from rubbing the outer fender 
> > wel=
> l
> > making your Polara look goofy driving down the road. =C2=A0What area do 
> > y=
> ou live
> > in I have a 3:23 & a 2:73 sure grip that we can work out a trade for 
> > your
> > 3:91 or something. =C2=A0Sorry for such a long winded reply but their is 
> > =
> a point
> > that form over function dictates the avenue followed but, it is your 
> > car!=
> !
> >
> > =EF=BB=BF =EF=BB=BF =EF=BB=BF =EF=BB=BF =EF=BB=BF =EF=BB=BF =EF=BB=BF 
> > =EF=
> =BB=BF =EF=BB=BF
> > =C2=A0Herb
> >
> > 1956 Plymouth Belvedere 361
> > 1959 Coronet 326 Poly
> > 1963 Fury 2D/HT 6.1
> > 1963 Sport Fury Convertible 361
> > 1970 Challenger RT 440
> > 1999 Durango SLT 5.9
> > 2006 300-C Heritage 5.7
> > 2008 SRT-8 Magnum 6.1
> > St. Louis, MO.
> >
> > http://1962to1965mopar.ornocar.com/mmo42009.html
> >
> >
> >
> >
> > -------Original Message-------
> >
> > From: Layne Grissman
> > Date: 6/9/2009 10:58:41 PM
> > To: 1962to1965mopars@xxxxxxxxxx
> > Subject: Tire Sizes and how to calculate
> >
> > Does anyone know how to calculate final tire size when trying to keep
> > the RPM's down? =C2=A0What is the typical RPM range I should try to keep 
> > =
> it
> > in and at what speeds? =C2=A0I was figuring about 2800 RPM at about 
> > 60-65
> > mph.....We have a 3.91 Sure Grip rear...Want to get the right tires
> > the first time.... =C2=A0:) =C2=A0Is there a formula?
> >
> > Also was the typical final gear on the A727 1.00??
> >
> > Thanks all!
> >
> > Layne
> > '64 Polara 500
> > '08 Charger
> > '08 Ram (yeah it's got a Hemi)
> > [Non-text portions of this message have been removed]
> >
> >
> > ----
> > Please address private mail -- mail of interest to only one person -- 
> > dir=
> ectly to that person. =C2=A0I.e., send parts/car transactions and 
> negotiati=
> ons as well as other personal messages only to the intended recipient, 
> not =
> to the Clubhouse public address. This practice will protect your 
> privacy, r=
> educe the total volume of mail and fine tune the content signal to Mopar 
> to=
> pic. =C2=A0Thanks!
> >
> > '62 to '65 Mopar Clubhouse Discussion Guidelines:
> > http://www.1962to1965mopar.ornocar.org/mletiq.html.
> >
> >
> >



Jeff Adams
64 Polara


----
Please address private mail -- mail of interest to only one person -- directly to that person.  I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic.  Thanks!

'62 to '65 Mopar Clubhouse Discussion Guidelines:
http://www.1962to1965mopar.ornocar.org/mletiq.html.