Running a higher ride highth then normal.

[Bob Dunahugh]

Got a lot of Dave's parts. But not his upper A arms. Bob Dunahugh 78 Royale

________________________________
From: Bob Dunahugh
Sent: Monday, November 7, 2016 12:30 AM
To: gmclist
Subject: Ruuing a higher ride highth then normal.

I need to run the rear frame height about 1 to 2 inches above the factory spec. I have the quad bag system. This system seems to be more stable. But also a little more course. Over all I'm very please with it's performance. But when you run above stock at the rear. You start to reduce your front negative caster. And we already have very little negative caster to start with. So I need to raise the front to match the rear extra height. So are there others that have done this?

Bob Dunahugh 78 Royale

 

[Jim Hupy]

Anytime you run higher air pressure to achieve increases in ride height,
you are going to have a slightly harsher ride. If you were still running
stock air bags, there are available bag extenders that will achieve a
higher stance at the same air pressure you were running before. If you have
one of the quad bag setups, I don't know any solution except running more
pressure.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

Got a lot of Dave's parts. But not his upper A arms. Bob Dunahugh 78
Royale

________________________________
From: Bob Dunahugh
Sent: Monday, November 7, 2016 12:30 AM
To: gmclist
Subject: Ruuing a higher ride highth then normal.

I need to run the rear frame height about 1 to 2 inches above the factory
spec. I have the quad bag system. This system seems to be more stable.
But also a little more course. Over all I'm very please with it's
performance. But when you run above stock at the rear. You start to reduce
your front negative caster. And we already have very little negative caster
to start with. So I need to raise the front to match the rear extra
height. So are there others that have done this?

Bob Dunahugh 78 Royale
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[Ken H.]

Bob,

The caster change due to rear ride height change that I gave you a while
ago (degrees per 1" = 0.358) was only close (CRS).

Actually, arcsin (1/160)=0.358100953 degrees

Ken H.

> Got a lot of Dave's parts. But not his upper A arms. Bob Dunahugh 78
> Royale
>
> ________________________________
> From: Bob Dunahugh
> Sent: Monday, November 7, 2016 12:30 AM
> To: gmclist
> Subject: Ruuing a higher ride highth then normal.
>
>
> I need to run the rear frame height about 1 to 2 inches above the factory
> spec. I have the quad bag system. This system seems to be more stable.
> But also a little more course. Over all I'm very please with it's
> performance. But when you run above stock at the rear. You start to reduce
> your front negative caster. And we already have very little negative caster
> to start with. So I need to raise the front to match the rear extra
> height. So are there others that have done this?
>

 

[Keith V]

I contend it should be Tan T = o/a since the wheelbase is the adjacent side not the hypotenuse.

That give a completely different angle

arctan(1/160) = 0.35809395932357108773007102845403

________________________________
From: Gmclist on behalf of Ken Henderson
Sent: Monday, November 7, 2016 11:34:04 AM
To: gmclist
Subject: Re: [GMCnet] Running a higher ride highth then normal.

Bob,

The caster change due to rear ride height change that I gave you a while
ago (degrees per 1" = 0.358) was only close (CRS).

Actually, arcsin (1/160)=0.358100953 degrees

Ken H.

> Got a lot of Dave's parts. But not his upper A arms. Bob Dunahugh 78
> Royale
>
> ________________________________
> From: Bob Dunahugh
> Sent: Monday, November 7, 2016 12:30 AM
> To: gmclist
> Subject: Ruuing a higher ride highth then normal.
>
>
> I need to run the rear frame height about 1 to 2 inches above the factory
> spec. I have the quad bag system. This system seems to be more stable.
> But also a little more course. Over all I'm very please with it's
> performance. But when you run above stock at the rear. You start to reduce
> your front negative caster. And we already have very little negative caster
> to start with. So I need to raise the front to match the rear extra
> height. So are there others that have done this?
>
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[Ken H.]

My expression of the extended accuracy was meant only to assure Bob that I
had indeed checked my top-of-the-head number. I have no idea what
orientation of the triangle in question should be for the standard
definition of caster. But I do know that I'm not about to worry about the
0.00000699367* difference between our answers -- the digital level I use
for alignment only reads to 0.1* anyway. All that without even discussing
the true accuracy based on the input integers -- my math degree is over 50
years too old for that!

Ken H.

> I contend it should be Tan T = o/a since the wheelbase is the adjacent
> side not the hypotenuse.
>
> That give a completely different angle
>
>
> arctan(1/160) = 0.35809395932357108773007102845403
>

 

[Hal Kading]

Gee Ken,

You call yourself an Engineer and you are satisfied with a number that is that far off! :roll:

Hal Kading 78 Buskirk Las Cruces NM

 

[Ken H.]

It's sad to witness what happens in old age, isn't it?

Ken H.

> Gee Ken,
>
> You call yourself an Engineer and you are satisfied with a number that is
> that far off! :roll:
>

 

[Bob Dunahugh]

Well that's interesting. Maybe to get the 2 inches at the rear. And then raising the front just 1 inch. Just might be a good starting point. I dumped a pile of money into the convertible front suspension. ( have changed the knuckle to the mouse house. ) And the pure stock mouse house handles better. Not interested in messing that up.

Bob Dunahugh 78 Royale

From: Bob Dunahugh
Sent: Monday, November 7, 2016 12:30 AM
To: gmclist
Subject: Ruuing a higher ride highth then normal.

I need to run the rear frame height about 1 to 2 inches above the factory spec. I have the quad bag system. This system seems to be more stable. But also a little more course. Over all I'm very please with it's performance. But when you run above stock at the rear. You start to reduce your front negative caster. And we already have very little negative caster to start with. So I need to raise the front to match the rear extra height. So are there others that have done this?

Bob Dunahugh 78 Royale

 

[steve southworth]

I set my ride heights a bit differently. Front adjusted to have axels level. Rear ride height adjusted to be the same amount lower than the front
per spec.

I have also forgotten to set suspension to "travel" and drove for some extended times. Didn't notice a difference.
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI

 

[jim kanomata1]

The rear height should be no more than by measuring the pin height and the
rear axle .
People have played with it since 1980 and they all came up with the same
suggestion.
Front can be raised slightly, but not much as the Lower A frame angle can
induce slight driving characteristics.

On Tue, Nov 8, 2016 at 2:52 AM, Steve Southworth
wrote:

> I set my ride heights a bit differently. Front adjusted to have axels
> level. Rear ride height adjusted to be the same amount lower than the front
> per spec.
>
> I have also forgotten to set suspension to "travel" and drove for some
> extended times. Didn't notice a difference.
> --
> Steve Southworth
> 1974 Glacier TZE064V100150 (for workin on)
> 1975 Transmode TZE365V100394 (parts & spares)
> Palmyra WI
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502