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Home » Public Forums » GMCnet » Wheel alignment specs (Wondering what alignment setting people are using.)
Wheel alignment specs [message #106632] Wed, 24 November 2010 17:53 Go to next message
tze73 is currently offline  tze73   Canada
Messages: 13
Registered: August 2010
Location: Montreal, Quebec
Karma: 0
Junior Member
Hi, I've been trying to fine tune the handling of our coach before a long trip. I have completly rebuilt the complete front and rear suspension.

I have tried similar to factory settings ie: slight positive camber in the rear and front with 1/8 toe out. Today I tried ~1/4 degree of negative camber in the front with the maximum caster angle. Seems to go better.

Also, after I aligned the rear wheels to factory spec after doing the rear bushings, which had a lot of negative camber initially, it seemed that the handling was degraded.

I'm getting the impression that the best alignment settings for good directional stability are probably in the range of 1/2 to 1 degree of negative camber all the way around.

As a side note a friend of mine with a vw type 2 that had 2 degrees of negative camber in the rear wheels aligned them to 1 degree and found that the directional stability was negatively affected.

Also, handling in cars is improved with negative caster.

Any thoughts?
Re: [GMCnet] Wheel alignment specs [message #106638 is a reply to message #106632] Wed, 24 November 2010 18:28 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
You will have tire wear pattern if you go 1degree. keep it at 1/2
degree negative .
Check the height, if you go by the book it can be incorrect as tire
diameter varies, so do as Ken Frey suggests and set the rear
boggiepins at same height as the center of the rear tires.

On Wed, Nov 24, 2010 at 3:54 PM, kp <kpattington@yahoo.ca> wrote:
>
>
> Hi, I've been trying to fine tune the handling of our coach before a long trip. I have completly rebuilt the complete front and rear suspension.
>
> I have tried similar to factory settings ie: slight positive camber in the rear and front with 1/8 toe out. Today I tried ~1/4 degree of negative camber in the front with the maximum caster angle. Seems to go better.
>
> Also, after I aligned the rear wheels to factory spec after doing the rear bushings, which had a lot of negative camber initially, it seemed that the handling was degraded.
>
> I'm getting the impression that the best alignment settings for good directional stability are probably in the range of 1/2 to 1 degree of negative camber all the way around.
>
> As a side note a friend of mine with a vw type 2 that had 2 degrees of negative camber in the rear wheels aligned them to 1 degree and found that the directional stability was negatively affected.
>
> Also, handling in cars is improved with negative caster.
>
> Any thoughts?
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Wheel alignment specs [message #106648 is a reply to message #106638] Wed, 24 November 2010 19:27 Go to previous messageGo to next message
tze73 is currently offline  tze73   Canada
Messages: 13
Registered: August 2010
Location: Montreal, Quebec
Karma: 0
Junior Member
My ride height is about 3/4 inch lower than factory in the front and rear.

Does negative camber in the rear generally improve stability?
Re: [GMCnet] Wheel alignment specs [message #106655 is a reply to message #106632] Wed, 24 November 2010 20:13 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
KP,

If you are running radial tires Dave Lenzi (alignment guru) recommends:

Caster: as much as you can get up to 5 degrees
Camber: 0 degrees
Toe In/Out: 0

Regards,
Rob M.
USAussie

-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of kp
Sent: Wednesday, November 24, 2010 5:54 PM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Wheel alignment specs



Hi, I've been trying to fine tune the handling of our coach before a long
trip. I have completly rebuilt the complete front and rear suspension.

I have tried similar to factory settings ie: slight positive camber in the
rear and front with 1/8 toe out. Today I tried ~1/4 degree of negative
camber in the front with the maximum caster angle. Seems to go better.

Also, after I aligned the rear wheels to factory spec after doing the rear
bushings, which had a lot of negative camber initially, it seemed that the
handling was degraded.

I'm getting the impression that the best alignment settings for good
directional stability are probably in the range of 1/2 to 1 degree of
negative camber all the way around.

As a side note a friend of mine with a vw type 2 that had 2 degrees of
negative camber in the rear wheels aligned them to 1 degree and found that
the directional stability was negatively affected.

Also, handling in cars is improved with negative caster.

Any thoughts?
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http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

_______________________________________________
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List Information and Subscription Options:
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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426
Re: [GMCnet] Wheel alignment specs [message #106659 is a reply to message #106648] Wed, 24 November 2010 20:21 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
Messages: 6806
Registered: May 2010
Karma: -62
Senior Member
In my personal experience with race cars, which includes drag racing comp
coupes & sedans, slingshot front engine dragsters, midget racers with
straight front axles that only turned left and steered mostly with the
throttle, sprint cars, go carts, & very limited sports cars that turned both
ways, most of them with adjustable suspension, one thing stands out in my
mind. Weight. Less is better and the more of it between the wheels on circle
cars the better they handle. If you want a GMC to handle, steer, stop,
accelerate better, put her on a diet. Fuel mileage is improved as a
secondary benefit. Next would come decreasing the drag if you exceed 70 mph,
otherwise not so much. Go with the specs that Jim K has for the rear and it
won't try to steer the front end. Keep ride height close to the same side to
side. The front end OEM specs are pretty close. If you run a great deal on
secondary roads, some people prefer to have the ditch side a little
different than the driver side. Just what I have learned over the years.
Jim Hupy
Salem, Or
78 Royale 403

On Wed, Nov 24, 2010 at 5:27 PM, kp <kpattington@yahoo.ca> wrote:

>
>
> My ride height is about 3/4 inch lower than factory in the front and rear.
>
> Does negative camber in the rear generally improve stability?
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] Wheel alignment specs [message #106677 is a reply to message #106659] Wed, 24 November 2010 22:04 Go to previous messageGo to next message
tze73 is currently offline  tze73   Canada
Messages: 13
Registered: August 2010
Location: Montreal, Quebec
Karma: 0
Junior Member
Our TZE is already pretty light being a 73, no AC at all, no onan, etc.

Looked around, can't seem to find Jim K's specs for the rear. Do you have a link.
Re: [GMCnet] Wheel alignment specs [message #106684 is a reply to message #106655] Wed, 24 November 2010 23:20 Go to previous message
George Beckman is currently offline  George Beckman   United States
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Registered: October 2008
Location: Colfax, CA
Karma: 11
Senior Member
Robert Mueller wrote on Wed, 24 November 2010 18:13

KP,

If you are running radial tires Dave Lenzi (alignment guru) recommends:

Caster: as much as you can get up to 5 degrees
Camber: 0 degrees
Toe In/Out: 0

Regards,
Rob M.
USAussie




In the front, I go with Dave Lenzi, too, but could not get that much Caster. ( I don't have his re engineered A-arms.) Just to be clear, that is Positive (like a motor cycle) Caster. Which makes sense, because the wheels are pulling the coach.

A shopping cart has negative caster when you push it, because the front wheels are trailing. They flip around naturally when they trail. Our front wheels don't trail, they pull. We don't want our wheels "trying" to flip around when they pull.

I have a new bicycle with almost no positive caster. Pain in the neck... I cannot ride with no hands. Can't push it by the seat. Squirrelly as all get out.


'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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