offset

[darren paget]

I too am interested in the offset discussion. I am going to a center
line wheel. No offset either way. It puts the front wheels in direct
track with the rear wheels. I am making an adapter plate so the wheel
will still be hub centered. I think this is important.
If the wheel has a 5" inside offset or a 5" outside offset it loads the
front axle the same. The difference being it changes the direction of
its pull. On the stock config it bottom loads the inner bearing and top
loads the outer bearing. If you turned the wheel around it would top
load the inner and bottom load the outer. My question is, does the
bearing care whether it is top or bottom loaded? If I use a center line
wheel I am still loading the bearings as the stock config. just moving
some weight around. I do not believe that the bearings care, as long as
you keep them serviced. I have found a wheel that has the look of the
Alcoa Classic but runs center line. It also has brothers which match and
are offset for the rears. I will still have a matching set and save a
few dollars too. Only my thoughts here. Darren

fuel to the fire?

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[travism]

> If the wheel has a 5" inside offset or a 5" outside offset it loads the
> front axle the same. The difference being it changes the direction of
> its pull. On the stock config it bottom loads the inner bearing and top
> loads the outer bearing. If you turned the wheel around it would top
> load the inner and bottom load the outer. My question is, does the
> bearing care whether it is top or bottom loaded? If I use a center line
> wheel I am still loading the bearings as the stock config. just moving
> some weight around. I do not believe that the bearings care, as long as
> you keep them serviced.

Darren, I'd want to see this drawn to be sure, but I think that you are
mistaken in your assumption. As I recall the construction, the present
offset places the centerline of the wheel in approximately the same plane as
the center of the hub. Thus the vectors cancel.

Changing this plane will, I think, change the loading, particularly on the
outer bearing, significantly.

Travis

 

[darren paget]

That may be correct, but the wheel weight is loaded at the bolts not the hub. It
is a simple lever/fulcrum effect on the bearings, with the fulcrum at the bolt
line. If you offset in 5" or out 5" the weight at the bolts is the same. It is
only the loading, top or bottom of the bearing sets that changes. That is the
angle I am going at it from any way. Darren

> > If the wheel has a 5" inside offset or a 5" outside offset it loads the
> > front axle the same. The difference being it changes the direction of
> > its pull. On the stock config it bottom loads the inner bearing and top
> > loads the outer bearing. If you turned the wheel around it would top
> > load the inner and bottom load the outer. My question is, does the
> > bearing care whether it is top or bottom loaded? If I use a center line
> > wheel I am still loading the bearings as the stock config. just moving
> > some weight around. I do not believe that the bearings care, as long as
> > you keep them serviced.
>
> Darren, I'd want to see this drawn to be sure, but I think that you are
> mistaken in your assumption. As I recall the construction, the present
> offset places the centerline of the wheel in approximately the same plane as
> the center of the hub. Thus the vectors cancel.
>
> Changing this plane will, I think, change the loading, particularly on the
> outer bearing, significantly.
>
> Travis

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[bob mclaughlin]

Darren,
C'mon, don't be so secretive. Who makes the wheels? What are the
specifications? Also, can we talk Paul into getting testimonials from those
3 people who are using them.
Bob McL

- -----Original Message-----
From: owner-gmcmotorhome
[mailtowner-gmcmotorhome]On Behalf Of Darren Paget
Sent: Saturday, February 12, 2000 11:57 AM
To: gmcmotorhome
Subject: GMC: offset

I too am interested in the offset discussion. I am going to a center
line wheel. No offset either way. It puts the front wheels in direct
track with the rear wheels. I am making an adapter plate so the wheel
will still be hub centered. I think this is important.
If the wheel has a 5" inside offset or a 5" outside offset it loads the
front axle the same. The difference being it changes the direction of
its pull. On the stock config it bottom loads the inner bearing and top
loads the outer bearing. If you turned the wheel around it would top
load the inner and bottom load the outer. My question is, does the
bearing care whether it is top or bottom loaded? If I use a center line
wheel I am still loading the bearings as the stock config. just moving
some weight around. I do not believe that the bearings care, as long as
you keep them serviced. I have found a wheel that has the look of the
Alcoa Classic but runs center line. It also has brothers which match and
are offset for the rears. I will still have a matching set and save a
few dollars too. Only my thoughts here. Darren

fuel to the fire?

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[darren paget]

I don't remember. I have to check the catalogue. I will get back in the next
couple of days. Can't check till monday. Not being secretive, just can't tell
you yet. I could even get pictures if wanted. The wheels should even be here
by then. Darren

> Darren,
> C'mon, don't be so secretive. Who makes the wheels? What are the
> specifications? Also, can we talk Paul into getting testimonials from those
> 3 people who are using them.
> Bob McL
>
> -----Original Message-----
> From: owner-gmcmotorhome
> [mailtowner-gmcmotorhome]On Behalf Of Darren Paget
> Sent: Saturday, February 12, 2000 11:57 AM
> To: gmcmotorhome
> Subject: GMC: offset
>
> I too am interested in the offset discussion. I am going to a center
> line wheel. No offset either way. It puts the front wheels in direct
> track with the rear wheels. I am making an adapter plate so the wheel
> will still be hub centered. I think this is important.
> If the wheel has a 5" inside offset or a 5" outside offset it loads the
> front axle the same. The difference being it changes the direction of
> its pull. On the stock config it bottom loads the inner bearing and top
> loads the outer bearing. If you turned the wheel around it would top
> load the inner and bottom load the outer. My question is, does the
> bearing care whether it is top or bottom loaded? If I use a center line
> wheel I am still loading the bearings as the stock config. just moving
> some weight around. I do not believe that the bearings care, as long as
> you keep them serviced. I have found a wheel that has the look of the
> Alcoa Classic but runs center line. It also has brothers which match and
> are offset for the rears. I will still have a matching set and save a
> few dollars too. Only my thoughts here. Darren
>
> fuel to the fire?
>
> --
> Darren Paget
> 76 Experimental
> Another Fab Day
> http://www.TZEplus.com

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[travism]

> That may be correct, but the wheel weight is loaded at the bolts not the
hub. It
> is a simple lever/fulcrum effect on the bearings, with the fulcrum at the
bolt
> line. If you offset in 5" or out 5" the weight at the bolts is the same.
It is
> only the loading, top or bottom of the bearing sets that changes. That is
the
> angle I am going at it from any way. Darren

No, it isn't that simple. The stress on the wheel is maximum at the bolt
line, but the load on the bearings is at the centerline of the wheel/tire.

I'm afraid this is going to be like the previous thread on phase; apparently
I don't have the gift for drawing good word pictures.

The location of the wheel/hub interface plane is immaterial. It is outside
of the approximate center of the rim on the GMC simply to provide a way to
get the CV joint in the turning axis...the virtual kingpin if you will. This
is common on front wheel drive cars.

Travis

 

[darren paget]

I agree Travis. This is just ONE of THOSE issues. I was going to keep
quiet on the whole thing till I had some real data to put forth. But
someone asked. I will be a test case for this. I just don't want my
only choice for aftermarket wheels to be Alcoa. I also would really like
to get the front track out. I will keep you posted on how it goes. I
also remember the past posts on this subject and read them all. Some of
the data I agree with and some I think is myth. If you made a drawing of
the forces at work, which I am sure you have, you can probably see where
I am coming from. I am not going radical here. I just think that by
coming outside the OEM wheel by a couple of inches won't change a thing,
except the track. The bearings run straight and whether the loading is
from the top or the sides they are enclosed in a round race. The loads
remain the same, just the direction changes. If bearing sets had an up
and down position, the directional forces would make a difference, but
they don't. I have talked to a couple of people, more knowledgeable than
myself, and they don't see any problems. Like I say, "I don't mind
testing this." My thoughts only. Darren

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[thomas g. warner]

I have read all of the comments on offsetting the front wheels to get a
wider track and think you may be sorry for attempting it. The effect will be
two fold, forst it will change the steering geometry and secondly
significantly increase the loading on the bearings.
There are two forces at play static and dynamic loading. Its not as simple
as you think.

Just my opinion of course.

>In a message dated 02/12/2000 6:54:41 PM Central Standard Time,

>
>> If bearing sets had an up
>> and down position, the directional forces would make a difference, but
>> they don't. I have talked to a couple of people, more knowledgeable than
>> myself, and they don't see any problems. Like I say, "I don't mind
>> testing this." My thoughts only.
>
>Darren
>
>I will throw in a comment here that I made some time ago. When I was
>still teaching and this subject came up I thought of some of my students
>that had the "low rider" cars with the wheels that have sever offset to
>them. I talked to four of them-----none reported any wheel bearing problems.
>One had 87,000 miles on his. I know nothing about this subject but I
>will watch with interest as somebody else goes outside the envelope.
>Good Luck.
>
>Take Care
>Arch
>
>