Michelin XPS Rib Tires

D

dave1

New member
Jul 23, 1998
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All this talk of tires.
I guess its time to jump in.

When I got my 73 Sequoia it had load range D tires on the original rims. I
discovered that there was a problem with using radial tires on the original
rims after one of them failed. Fortunately it was just a small crack that
caused a slow leak. Because I didn't ignore it I probably saved myself a
lot of grief. Fortunately I was able to find a good set of used radial
wheels.

I still did not know about the load range D recall so I just remounted my D
tires on the new wheels. A couple years ago I noticed that the belts where
separating on two of them. So it was time for new tires. After making a few
phone calls (I didn't know about this list at that time), the consensus was
to use Michelin XPS Rib Tires. They where not easy to find and where very
costly but they look indestructible. I run them at 70psi (cold) and the
ride is only slightly harsher than my load range D tires at 65psi.

What I am wondering is; are these good tires for the GMC? Is there anyone
else out there using them and have you experienced any problems?

I have seen some problems with Michelin's mentioned on the list but I am
wondering if any of them where the Michelin XPS Rib tires? My understanding
is that the XPS Rib tires have a stronger sidewall so as to be able to
withstand the higher side loads and flexing they experience on the GMC.

Dave
73 Sequoia
 
Dave I have friends that use only Michelin tires on their Ford E350
Econoline van and regularly get 100,000 miles on them. I am always amazed
when they take them off that there is still a lot of tread on them. they
religiously change them all out every 3 years. that made me a believer.

I just purchased (still ashamed at the deal) a complete set of Michelin
LT22575R16 E rated tires. they are indeed impressive and very rugged. they
do cost a little more but what is peace of mind worth?

>All this talk of tires.
>I guess its time to jump in.
>
>When I got my 73 Sequoia it had load range D tires on the original rims. I
>discovered that there was a problem with using radial tires on the original
>rims after one of them failed. Fortunately it was just a small crack that
>caused a slow leak. Because I didn't ignore it I probably saved myself a
>lot of grief. Fortunately I was able to find a good set of used radial
>wheels.
>
>I still did not know about the load range D recall so I just remounted my D
>tires on the new wheels. A couple years ago I noticed that the belts where
>separating on two of them. So it was time for new tires. After making a few
>phone calls (I didn't know about this list at that time), the consensus was
>to use Michelin XPS Rib Tires. They where not easy to find and where very
>costly but they look indestructible. I run them at 70psi (cold) and the
>ride is only slightly harsher than my load range D tires at 65psi.
>
>What I am wondering is; are these good tires for the GMC? Is there anyone
>else out there using them and have you experienced any problems?
>
>I have seen some problems with Michelin's mentioned on the list but I am
>wondering if any of them where the Michelin XPS Rib tires? My understanding
>is that the XPS Rib tires have a stronger sidewall so as to be able to
>withstand the higher side loads and flexing they experience on the GMC.
>
>Dave
>73 Sequoia
>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Dave:

In the summer of 1997, I went from 16.5" Michelin XPS Rib to 16" Bridgestone
R 265 tires and noticed what for me was a night and day difference. I
noticed right off the bat that the Michelin tires felt like I was riding on
what I characterize as square wheels.

The XPS have steel side walls and the R 265 does not. When another
individual asked Michelin what the advantage of steel sidewalls meant, he
was told nothing but increased load carrying capacity.

You say "a stronger sidewall so as to be able to withstand the higher side
loads and flexing they experience on the GMC". How does a GMC differ from
any other vehicle in that respect???

Paul Bartz

From: Dave [mailto:DGMDGM]
Sent: Monday, April 12, 1999 11:29 AM
Subject: GMC: Michelin XPS Rib Tires

All this talk of tires.
I guess its time to jump in.
When I got my 73 Sequoia it had load range D tires on the original rims. I
discovered that there was a problem with using radial tires on the original
rims after one of them failed. Fortunately it was just a small crack that
caused a slow leak. Because I didn't ignore it I probably saved myself a lot
of grief. Fortunately I was able to find a good set of used radial wheels.
I still did not know about the load range D recall so I just remounted my D
tires on the new wheels. A couple years ago I noticed that the belts where
separating on two of them. So it was time for new tires. After making a few
phone calls (I didn't know about this list at that time), the consensus was
to use Michelin XPS Rib Tires. They where not easy to find and where very
costly but they look indestructible. I run them at 70psi (cold) and the ride
is only slightly harsher than my load range D tires at 65psi.
What I am wondering is; are these good tires for the GMC? Is there anyone
else out there using them and have you experienced any problems?
I have seen some problems with Michelin's mentioned on the list but I am
wondering if any of them where the Michelin XPS Rib tires? My understanding
is that the XPS Rib tires have a stronger sidewall so as to be able to
withstand the higher side loads and flexing they experience on the GMC.
 
Emery:

I hear ya'. However when I asked the question below, I knew the dynamics of
sidewall flex in the context of our coach operation. What I don't see is
any difference in tire effect on the GMC vs. other vehicle's (e. g. truck
trailers and other tandem axle type motorhomes, etc.). Further, the
majority of our normal driving is in a straight line mode. Therefore, what
concern is there about tire sidewall flex????

I agree with your comments on constant sidewall flexing leading to
additional heat buildup. However, do you feel that is of any concern in our
case.

Paul

From: EMERYSTORA [mailto:EMERYSTORA]
Sent: Monday, April 12, 1999 2:50 PM
Subject: Re: GMC: RE: Michelin XPS Rib Tires

>

Paul - on the rear of your GMC there are four wheels that are fixed in
relation to each other with regard to a side to side movement. When you
turn
the GMC, for example changing lanes on the highway or going around a corner,

the sidewalls flex to allow the turn without scuffing off too much tread
from
the tires. For example, if you are turning left, imagine the two left tires

rotating around a pivot point about halfway between the two tires (this is
not meant to be exact as to where that pivot point is). The sidewall of
the
front bogie tire is going to flex toward the left and the sidewall of the
rear bogie tire is going to flex to the right.

Think of it as if you were pulling a child's wagon on your driveway and
could
not turn the front wheels. The only way you can get it to turn is to scuff
the tires on the pavement. Since the sidewalls of the GMC flex it will
allow
some rotation of the tire into an arc which allows you to turn. Have you
ever made a sharp turn in a parking lot or a service station only to have
someone tell you that there is something wrong with your rear wheels? One
tire will be flexed in and the other tire flexed out.

This is not going to occur with your automobile because you have one tire on

the rear and it should pivot at the center of the tread.

The constant flexing can cause additional heat buildup in the sidewalls and
can lead to premature failure of the tires. I'll bet that if we had a
survey
of people that have had blowouts, that almost all of them have been on rear
tires. I've had two rear tires Load Range D, less than 3 years old, with
plenty of tread blow about 3000 miles apart. Since getting my Load Range E
I've driven about 20,000 with no problems.

Emery Stora
77 Kingsley
Santa Fe, NM
 
In the case of the GMC it is not entirely load carrying capability that is
important. The GMC has two problems (abnormal stresses on the tires) that
other motorhomes do not have. The steering wheels are powered (tremendous
load on the sidewalls in turns), and the rear bogies move as they track, ie;
follow a GMC as it turns into a gas station etc and watch the attitude of
the wheels. sometimes the mid and rear bogies camber go in different
directions.

I have sent a note to Wes Cauglan and will be interested in his response.

>Dave:
>
>In the summer of 1997, I went from 16.5" Michelin XPS Rib to 16" Bridgestone
>R 265 tires and noticed what for me was a night and day difference. I
>noticed right off the bat that the Michelin tires felt like I was riding on
>what I characterize as square wheels.
>
>The XPS have steel side walls and the R 265 does not. When another
>individual asked Michelin what the advantage of steel sidewalls meant, he
>was told nothing but increased load carrying capacity.
>
>You say "a stronger sidewall so as to be able to withstand the higher side
>loads and flexing they experience on the GMC". How does a GMC differ from
>any other vehicle in that respect???
>
> Paul Bartz
>
>From: Dave [mailto:DGMDGM]
>Sent: Monday, April 12, 1999 11:29 AM
>Subject: GMC: Michelin XPS Rib Tires
>
>All this talk of tires.
>I guess its time to jump in.
>When I got my 73 Sequoia it had load range D tires on the original rims. I
>discovered that there was a problem with using radial tires on the original
>rims after one of them failed. Fortunately it was just a small crack that
>caused a slow leak. Because I didn't ignore it I probably saved myself a lot
>of grief. Fortunately I was able to find a good set of used radial wheels.
>I still did not know about the load range D recall so I just remounted my D
>tires on the new wheels. A couple years ago I noticed that the belts where
>separating on two of them. So it was time for new tires. After making a few
>phone calls (I didn't know about this list at that time), the consensus was
>to use Michelin XPS Rib Tires. They where not easy to find and where very
>costly but they look indestructible. I run them at 70psi (cold) and the ride
>is only slightly harsher than my load range D tires at 65psi.
>What I am wondering is; are these good tires for the GMC? Is there anyone
>else out there using them and have you experienced any problems?
>I have seen some problems with Michelin's mentioned on the list but I am
>wondering if any of them where the Michelin XPS Rib tires? My understanding
>is that the XPS Rib tires have a stronger sidewall so as to be able to
>withstand the higher side loads and flexing they experience on the GMC.
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Emery...

I ask the following not knowing the answer but strongly feeling that most
of the flexing going on in this application is the result of vertical
forces on the tire. That is to say, I don't disagree with what you said,
but note there may be a far greater amount of flexing of the sidewall due
to vertical up and down force on the tire than the turning/scuffing. No?

>This is not going to occur with your automobile because you have one
>tire on the rear and it should pivot at the center of the tread.

>The constant flexing can cause additional heat buildup in the sidewalls
>and can lead to premature failure of the tires.

John
 
As I understand the 4 bag system, it among other things, effectively
makes each of the rear wheels more independent. By that I mean with the
2 bag suspension, if the right leading boggie hits a bump it flexes its
sidewall, and transfers a downward force on the trailing boggie causing
flexing. Milliseconds later the process is repeated as the trailing
boggie hits the same bump, and the leading boggie gets the reflection.

It would be interesting to see how many failures of Ds occurr with 4
baggers. How long have you had your four baggers and Ds, Heinz and
others?

John
74 Glacier
 
>
>In a message dated 4/12/1999 11:20:31 AM, s9d3452
>writes:
>
>from
>any other vehicle in that respect???
>
> Paul Bartz >>
>
>Paul - on the rear of your GMC there are four wheels that are fixed in
>
>relation to each other with regard to a side to side movement. When
>you turn
>the GMC, for example changing lanes on the highway or going around a
>corner,
>the sidewalls flex to allow the turn without scuffing off too much
>tread from
>the tires. For example, if you are turning left, imagine the two left
>tires
>r
Snip........

This why some of the advanced chassis design for the Prevosts, et al, use
a tandem axle that lifts up for low speed turns. The side or lateral
stress is so mean that radial tires on bias wheels will cause the wheels
to break, usually at the leading rear bogie.

David Lee Greenberg
GMC Motorhome Registry
200 MacFarlane Drive
Delray Beach, FL 33483-6829
 
>One other thing -- I have never seen another vehicle that distorts the
>tires so much when turning. I will be very interested in Wes Caughlan
>answer to Tom Warner questions.

It really bothers me when I see that happen and I always say, I hope I
never do that... My feeling is that happens so rarely (I hope) that it
can't be what caused the D failures. I hope we do get some feedback from
Wes on this.

The only thing that I have seen that comes close is those dump trucks
with 8 wheels toward the back end and then three or feet forward is
another set of 2 wheels that can be cranked down to touch the ground.
I'm not sure one could turn at all with those forward wheels down.

- --
"I do whatever my Rice Krispies tell me to..." John said.
 
John:

Guess you're not familiar with all the 32 wheeler trailers that operate
every day throughout Michigan, which allows a GVW of 160,000 lbs???

Paul Bartz

From: jdolan [mailto:jdolan]
Sent: Tuesday, April 13, 1999 1:58 AM
Subject: Re: GMC: RE: Michelin XPS Rib Tires

One other thing-I have never seen another vehicle that distorts the
tires so much when turning. I will be very interested in Wes Caughlan
answer to Tom Warner questions.

It really bothers me when I see that happen and I always say, I hope I never
do that... My feeling is that happens so rarely (I hope) that it can't be
what caused the D failures. I hope we do get some feedback from Wes on
this.
The only thing that I have seen that comes close is those dump trucks with 8
wheels toward the back end and then three or feet forward is another set of
2 wheels that can be cranked down to touch the ground. I'm not sure one
could turn at all with those forward wheels down.
 
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