| Rear end Ride Height [message #139320] |
Mon, 15 August 2011 17:26  |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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I have done every thing that I can afford to get max caster and I still would like a wee bit more.
As you lower the rear end the caster gets better. Please share your thoughts on running with the rear end lower then stock. The front end is at the stock height. What are the limiting factors on how low can you go.
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: [GMCnet] Rear end Ride Height [message #140133 is a reply to message #139320] |
Fri, 19 August 2011 22:14  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Wayne,
That's really not a viable option. You've got something like 4" you can
lower the rear before you run out of suspension travel and start destroying
the shocks and everything else that's subject to impact and vibration
damage. For that, figuring about 0.3* caster per inch of rear movement,
you'll get maybe 1.2* increase in caster -- until something breaks.
The next question would be, "how about raising the front?" Just as bad:
The CV joints work at an angle -- but don't really like it, so if you raise
(or lower) the front, the axles will force the CV joints to run at an angle
continuously. That's if there's even enough adjustment on the torsion bar
adjusting screws to let you move an appreciable distance.
There are several other factors to consider too, all of them detrimental to
the idea, but the danger of having no "jounce" space in the rear is probably
the worst.
Save up for a set (or two) of Moog offset bushings for the upper control
arms.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Mon, Aug 15, 2011 at 6:26 PM, Wayne Lawrence <wayne4@ca.rr.com> wrote:
>
>
> I have done every thing that I can afford to get max caster and I still
> would like a wee bit more.
>
> As you lower the rear end the caster gets better. Please share your
> thoughts on running with the rear end lower then stock. The front end is at
> the stock height. What are the limiting factors on how low can you go.
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Rear end Ride Height [message #140152 is a reply to message #140133] |
Sat, 20 August 2011 01:21 |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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Senior Member |
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Hi Ken,
Thank you for your input.
I just bought a 2nd set. Just as I was about to start the installation that little nagging voice in my head said recheck everything before you start.
I made drawings to make sure what I would accomplish. It seems (I called Dave and he confirmed my thoughts) like I can't help anything with the extra bushing. The rear upper arm is as close to the frame as the offset bushing will allow. The front upper arm started out as far away from the frame as possible thus giving the max caster. I had to bring the front upper arm in to get O camber. I am left with max caster with proper camber. The front offset bushing will not help as I have plenty of adjustment to move the front a arm away from or closer to the frame. If I am correct most upper front offset bushings are not needed and are a waste of time and money.
If I am missing something PLEASE let me know.
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: [GMCnet] Rear end Ride Height [message #140182 is a reply to message #140158] |
Sat, 20 August 2011 10:05 |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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Senior Member |
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Hi Rob,
Yes, the upper rear arm (rear leg)is set up as Bob Drewes recommended. The camber is O and the tow is o. I don't know what the caster is. I don't have the correct tools to measure it and as everyone says to the alignment shop all the caster you can get I set it to max.
To get max caster you must move the upper ball joint towards the rear of the vehicle. To do this you move the rear of the upper a arm closer to the frame OR move the front of the upper a arm away from the frame. As I have the rear leg of the upper a arm as close to the frame as it will go the only adjustment I have is the front. I had to move the front in to get O camber. The front still has adjustment in either direction so installing another offset in the front will not change anything.
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: [GMCnet] Rear end Ride Height [message #140186 is a reply to message #140182] |
Sat, 20 August 2011 10:23 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Wayne,
From what you've noted below the only way you're going to get more caster is
to install a pair of Dave Lenzi's offset upper control arms.
The max Tom Hampton at Grandview Motorhomes could get on Double Trouble with
offset bushings in the rear legs of the upper control arms was 1.9° caster
at 0° camber.
After John Sharpe and I installed a pair of Dave's upper control arms I got:
Left
Camber: 0.1 degrees
Caster: 5.2 degrees
Toe: 0.0 inches
Right
Camber: -0.2 degrees
Caster: 4.8 degrees
Toe: 0.0 inches
Regards,
Rob M.
Sydney, Australia
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Wayne Lawrence
Sent: Sunday, 21 August 2011 1:06 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Rear end Ride Height
Hi Rob,
Yes, the upper rear arm (rear leg)is set up as Bob Drewes recommended. The
camber is O and the tow is o. I don't know what the caster is. I don't have
the correct tools to measure it and as everyone says to the alignment shop
all the caster you can get I set it to max.
To get max caster you must move the upper ball joint towards the rear of
the vehicle. To do this you move the rear of the upper a arm closer to the
frame OR move the front of the upper a arm away from the frame. As I have
the rear leg of the upper a arm as close to the frame as it will go the only
adjustment I have is the front. I had to move the front in to get O camber.
The front still has adjustment in either direction so installing another
offset in the front will not change anything.
--
Wayne Lawrence
76 Birchaven
Bellflower CA
wayne4@ca.rr.com
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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
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