Tire Question...12R22.5

[smquandt]

315/80/22.5 is what my Kumho Dealer recommended, have two new ones on my
steering. He said it is a more common size than the 12R's.



Steve Quandt

1993-PT40

Iron Mountain, MI



_____

From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of Joe Hagan
Sent: Thursday, October 12, 2006 1:17 PM
To: WanderlodgeForum@yahoogroups.com
Subject: [WanderlodgeForum] Re: Tire Question...12R22.5



As a matter of interest, many - if not most - OTR bus operators that
employ MCI, Prevost, Setra and Van Hool coaches use the 315/80/22.5
tires (Michelin and Goodyear). Weights typically run 52,000-56,000 lbs
on 47-53 passenger coaches (40'-45'. Tire pressure on-average run
S100, D110, T95.

Joe (Pappy) Hagan
St. George, UT
Wannabe

--- In WanderlodgeForum@
yahoogroups.com, "Neil & Pat"
wrote:
>
> Hi Bill, thanks for the reply. I generally do not recommend that we
> reengineer our vehicles, I would rather keep it as designed until it
was no
> longer possible to do so. Note, that I also use the 12R and have had
no
> problem getting them if I plan ahead just a tad. However, to respond
to
> your question please consider the following:
>
> The 315/80R22.5 LRH is very close match for the specs of a 12R LRH, in
> addition, its available in a LRJ as well giving it a major increase in
> capacity. The comparable specs are as follows:
>
> Spec 12R 315/80R
> Wheel 9:00 9:00
> section width 11.80 12.28
> Max dia grown 43.61 43.15
> Overall width 12.74 12.91
> Tire spacing 13.5 13.82
> LRH max load 7390/6780(120psi) 7610/6940(110psi)
> LRJ max load na
8270/7610(120psi)
>
> These are the critical numbers; you need to ascertain if the larger
tire
> will fit the wheel, coach and carry the load. It looks good for
everything
> except for wheel spacing and this is a critical area that I do not
like to
> see pushed (it true that some people consider this less critical for
MHs
> because the are used on highways only). With the correct wheels and
> adequate room on the coach the 315/80 looks like an excellent choice,
which
> will operate at reduced air pressure to enhance the ride; our old
coaches do
> not have computers so the diameter differences appear to be
negligible. I
> don't know how tight the FC coaches are (turning clearance is
generally most
> critical), you will have to check that out. I also do not know how
common
> the 315/80 tires are in the marketplace but at least you could use
either
> the LRH or LRJ at the appropriate pressure.
>
> Regards,
>
> Neil LeKander
> Author "The RVer's Ultimate Survival Guide"
> author@...
>
>
>
>
> Hi Neil,
>
> Is there a higher weight rated, larger tire that is more available.
> that you would recommend???
>
> The 12R's are not available at many tire stores, usually ordered in
> the area that I live, And finding a 12R on the side of the road
> with a flat could be a problem. It would really be hard to find a
> single matching tire replacement.
>
> Bill 88 FC Michigan
>
> --- In WanderlodgeForum@
yahoogroups.com
> , "Neil & Pat" undoone@
> wrote:
> >
> > Hi John, you have already received several answers to your
> inquiry; however,
> > I thought that I would add a few additional thoughts. I believe
> that what
> > you are thinking of doing would not only be ill advised but may be
> downright
> > dangerous. From my years as a tire engineer and with A' Weigh We
> Go
> > weighing coaches including many Bluebirds (my own PT-36 included)
> I have
> > knowledge that most all late 90s Birds are very close to their
> maximum GVWR
> > or GAWR as delivered and many are over that critical (and legally
> > enforceable) limit when operated.
> >
> > For that reason based on the lessor ability to carry a load the
> 11R tires
> > are in no way suitable for use on your 98 LX. The actual load
> capability
> > for the 12R and 11R are #6610/7390 & #6780/6005 (single/dual)
> respectively,
> > thus, you can see that there is a major reduction in the tires
> carrying
> > capacity, probably less that your coach requires. On the slim
> chance that
> > your specific coach might be unusually light where the 11R could
> carry the
> > weight it will require an increase in tire pressure to do so,
> something that
> > most RVers hate to do because of the ride quality reduction that
> accompanies
> > higher tire pressures. In addition there is a approximately
> a .75" radius
> > reduction (affecting your computers and dash readouts) along with
> a .80"
> > reduction in tread width with a corresponding reduction in tire
> footprint
> > area (which will increase wear, decrease steering power and
> decrease
> > stopping power); finally while your current rims will probably be
> OK to use
> > they are not optimal for the 11R (9:00 vs. 8:25) a fact which will
> also
> > compromise somewhat the total tire performance
> >
> > Do not listen to those who are not unbiased experts in just what
> tires are
> > required for RV usage. Remember also that RV are the only vehicle
> on the
> > road that "operates at 100% of its capability 100% of the tire."
> Tires are
> > no place to compromise; there are some very important people on
> board your
> > coach. Do the right thing and have your coach weighed properly,
> > wheel-by-wheel as is done by the RVSEF, only then will you be able
> to make
> > sound judgments re: tires, pressures, etc. If you have any other
> questions
> > or if I have misread your original question please do not hesitate
> to ask
> > additional questions.
> >
> > Regards,
> >
> > Neil LeKander
> > Author "The RVer's Ultimate Survival Guide"
> > author@
> >
> > -----Original Message-----
> > From: WanderlodgeForum@
yahoogroups.com
>
> > [mailto: WanderlodgeForum@
yahoogroups.com
> ]On Behalf Of John
> > Sent: Wednesday, October 11, 2006 6:44 PM
> > To: WanderlodgeForum@
yahoogroups.com
>
> > Subject: [WanderlodgeForum] Tire Question...12R22.5
> >
> > I have started looking for new tires for our coach as it has the
> > origional tires on it. While they are showing no cracking at all,
> I am
> > still concerned about their age and would like to start swapping
> them
> > out before I have to do it from the side of the road. The current
> > tires are 12R22.5 which seems to be a lot more uncommon than
> > 11R22.5s(which I run on my dump truck). From talking to a couple
> tire
> > people they say the 11R22.5 are a little smaller(shorter). Has
> anyone
> > switched from the 12s to the 11s? Any recomendations on a
> particular
> > brand?
> >
> > Thanks,
> > John Cassel
> > 98 Wanderlodge LX
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
> [Non-text portions of this message have been removed]
>





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