| [GMCnet] Interesting comparison. 1 ton to original suspension. [message #251092] |
Sat, 31 May 2014 11:01  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
|
Senior Member |
|
|
One note of caution WRT caster. The greater the caster the easier it is for your coach to go straight down the road. Also, the greater the caster the harder it is for the coach to turn putting greater stress and strain on all the steering components. So, like everything else it is a compromise. You want enough caster to keep the coach going straight without over stressing things. That seems to be around 3 to 4 degrees for most of our coaches now that we are running radial ply tires where the contact patch does not move rearward with speed. With the bias ply tires our coaches came with, the designers started out specing 3 degrees static caster (which would produce around 4 to 5 degrees at speed with the movement of the contact patch). In 1974 they changed that to a spec of 2 degrees static which would produce around 3 to 4 degrees at speed. That 2 degree spec remained for the rest of the production run. My surmise is they found the 3 degrees static to put too much str
ain on the steering components. If that is true, then perhaps going up to 5 to 6 degrees static caster with radial ply tires could be too much for long term durability even though it really does make the coaches go straight no matter what the road surface.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
,,,,,,,,,
Message: 3
Date: Sat, 31 May 2014 17:37:34 +1000
From: "Robert Mueller"
Subject: Re: [GMCnet] Interesting comparison. 1 ton to original
suspension.
To:
Message-ID:
Content-Type: text/plain; charset="iso-8859-1"
Larry,
I have offset upper control arms built by Dave Lenzi and I Double Trouble has 4.9? caster on one side and 5? on the other and it
goes straight!
Here?s what they look like:
http://www.gmcmhphotos.com/photos/g5861-dave-lenzi-s-offset-upper-control-arms.html
Regards,
Rob M.
-----Original Message-----
From: Larry Davick
I wonder what improvement the Curtis adjustable A-Frame offers
The description (not shouting) is:
THIS CUSTOM UPPER A FRAME WILL ALLOW 4.5 TO 6 DEGREES CASTER TO ALLOW COACH TO TRACK DOWN THE ROAD CONSIDERABLE BETTER WITH RADIAL
TIRE. THE STOCK UNIT IS NOT ALWAYS CAPABLE OF REACHING 4.5 TO 6 DEGREES CASTER EVEN WITH SPECIAL OFFSET BUSHINGS YOU'LL ATTAIN ONLY
2.5 TO 3.5 DEGREE CASTER
Larry
,,,,,,,,,,,,,,,
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jerry & Sharon Work
78 Royale
Kerby, OR
|
|
|
|
| Re: [GMCnet] Interesting comparison. 1 ton to original suspension. [message #251098 is a reply to message #251092] |
Sat, 31 May 2014 13:26  |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
""One note of caution WRT caster. The greater the caster the easier it is for your coach to go straight down the road. Also, the greater the caster the harder it is for the coach to turn putting greater stress and strain on all the steering components. So, like everything else it is a compromise. You want enough caster to keep the coach going straight without over stressing things. That seems to be around 3 to 4 degrees for most of our coaches now that we are running radial ply tires where the contact patch does not move rearward with speed. With the bias ply tires our coaches came with, the designers started out specing 3 degrees static caster (which would produce around 4 to 5 degrees at speed with the movement of the contact patch). In 1974 they changed that to a spec of 2 degrees static which would produce around 3 to 4 degrees at speed. That 2 degree spec remained for the rest of the production run. My surmise is they found the 3 degrees static to put too much str
ain on the steering components. If that is true, then perhaps going up to 5 to 6 degrees static caster with radial ply tires could be too much for long term durability even though it really does make the coaches go straight no matter what the road surface.
Jerry
Jerry Work""
I've mentioned several times that the quest for more caster has a downside. The stress on the steering gear, pitman arm, and tie rods goes up dramatically with increased caster. When GM first went to 5 degrees on the 1973 Monte Carlo, we had serious issues with broken pitman arms and steering wheel lickback.
Bob de Kruyff
78 Eleganza
Chandler, AZ
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
