Home » Public Forums » GMCnet » [GMCnet] Increased Caster
| Re: [GMCnet] Increased Caster [message #361881 is a reply to message #361879] |
Wed, 20 January 2021 21:38   |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
The eccentric upper control arm bushings, can be used in either forward or
rearward control arms, depending upon the effect desired. In our
application, they are installed to enable the rearward control arm to
travel towards the frame, and in effect, move the upper ball joint towards
the rear of the coach. That has the effect of moving the contact patch of
the front tire towards the front of the coach. Draw a straight line
directly through the centerline of the upper and lower ball joints to
illustrate this effect. It makes the front tire want to travel in a
straight line, rather than turn right or left. Ergo: more hands off
handling rather than less so.
Obviously, many other forces are at work here. Not part of this
subject. Not wanting to get into a big "Hoo-Haw" about this.
Jim Hupy
Salem, Oregon
On Wed, Jan 20, 2021, 7:01 PM Ken Henderson via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Well, I guess I've had my head screwed on backward for quite some time:
> I've been thinking, and discussing, the use of offset bushings in the UPPER
> REAR of the upper A-arm. Tonight, I've been researching offset bushing
> part numbers. LO and BEHOLD: Moog (and everyone else) ONLY mentions
> eccentric (offset) bushings for the upper FRONT! NOT the rear! Holy Moly,
> why hasn't someone called me on that? Or have we GMCers been "doing our
> own thing"?
>
> Here are the ONLY Moog part numbers I've found for '76 Toronado (and by
> extension GMCMH):
>
> Standard Offset(Eccentric)
> Upper Front K7006 K7104
> Upper Rear K6111
> Lower Front K5222
> Lower Rear K6116
>
> Does this mean that the K7104 will ONLY fit the Upper Front, or merely that
> that's where they're recommended (but CAN fit the rear?).
>
> Come on, somebody straighten this mess out.
>
> Ken H.
>
>
> On Wed, Jan 20, 2021 at 9:01 PM Ken Henderson
> wrote:
>
>> I've got another question (or more) for this survey:
>>
>> 1. Is it feasible to use offset bushings in both the rear AND front of
>> the upper A-arms? Seems to me it should be perfectly OK and potentially
>> give about twice as much caster increase as using them only in the rear.
>>
>> 2. Seems to me installing the offset bushing in the rear, to increase
>> caster, would inevitably tend to move camber toward negative. By the
> same
>> rationale, using offset bushings front and rear would have less effect on
>> camber because the front would tend toward positive camber about equal to
>> the rear's negative effect.
>>
>> 3. Has anyone considered or tried the offset upper A-arm shafts? Like
>> this:
>> bit.ly/3obunmp
>> or
>>
>>
> https://www.globalwest.net/billet-steel-stock-upper-control-arm-offset-cross-shaft-camaro-67-68-69-global-west.html
>>
>> I have no idea whether those are available to fit the GMC, but we've got
>> plenty of folks capable of designing and building them. It might be
> easier
>> than modifying A-arms, as Lenzi does. What are the pros & cons?
>>
>> 4. Other options?
>>
>> Rest assured, I'm just trying to learn something here -- I'm happy with
> my
>> 1-ton front end -- and it was installed before Manny decided to increase
>> the caster. (I THINK I did use offset bushings in the rear though --
> tooo
>> long ago for my old memory to be sure.)
>>
>> Thanks for all your inputs/ideas.
>>
>> Ken H.
>>
>>
>> On Thu, Jan 14, 2021 at 11:42 AM Ken Henderson
>> wrote:
>>
>>> Time for a survey of those using Dave Lenzi's upper A-arms modified for
>>> increased caster:
>>>
>>> What's your opinion after using them for a while? Do they significantly
>>> increase the steering stability? Did you try the offset bushings before
>>> going to modified A-arms? How do they compare? Did either affect the
>>> steering effort significantly? Which is the "better buy" -- or is
> either
>>> worth the trouble/cost?
>>>
>>> Thanks for your opinions.
>>>
>>> Ken H.
>>>
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361883 is a reply to message #361881] |
Wed, 20 January 2021 21:55 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Jim,
Sounds like you're confirming my long-held thought that the eccentric
bushings can be installed in either the front or rear of the upper control
arm. However, I'm confused by your reference to "depending upon the effect
desired". I've always thought that the positioning of the bushing's
eccentricity (toward or away from the frame) was what changed the effect.
So, if one placed the center hole of the bushing toward the frame in the
rear, and away from the frame in the front, the maximum possible caster
would be achieved -- without getting into the probable need to adjust one
or both of the adjusting eccentrics a little to set the camber properly.
Am I confused?
Ken H.
On Wed, Jan 20, 2021 at 10:38 PM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> The eccentric upper control arm bushings, can be used in either forward or
> rearward control arms, depending upon the effect desired. In our
> application, they are installed to enable the rearward control arm to
> travel towards the frame, and in effect, move the upper ball joint towards
> the rear of the coach. That has the effect of moving the contact patch of
> the front tire towards the front of the coach. Draw a straight line
> directly through the centerline of the upper and lower ball joints to
> illustrate this effect. It makes the front tire want to travel in a
> straight line, rather than turn right or left. Ergo: more hands off
> handling rather than less so.
> Obviously, many other forces are at work here. Not part of this
> subject. Not wanting to get into a big "Hoo-Haw" about this.
> Jim Hupy
> Salem, Oregon
>
> On Wed, Jan 20, 2021, 7:01 PM Ken Henderson via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Well, I guess I've had my head screwed on backward for quite some time:
>> I've been thinking, and discussing, the use of offset bushings in the
> UPPER
>> REAR of the upper A-arm. Tonight, I've been researching offset bushing
>> part numbers. LO and BEHOLD: Moog (and everyone else) ONLY mentions
>> eccentric (offset) bushings for the upper FRONT! NOT the rear! Holy
> Moly,
>> why hasn't someone called me on that? Or have we GMCers been "doing our
>> own thing"?
>>
>> Here are the ONLY Moog part numbers I've found for '76 Toronado (and by
>> extension GMCMH):
>>
>> Standard Offset(Eccentric)
>> Upper Front K7006 K7104
>> Upper Rear K6111
>> Lower Front K5222
>> Lower Rear K6116
>>
>> Does this mean that the K7104 will ONLY fit the Upper Front, or merely
> that
>> that's where they're recommended (but CAN fit the rear?).
>>
>> Come on, somebody straighten this mess out.
>>
>> Ken H.
>>
>>
>> On Wed, Jan 20, 2021 at 9:01 PM Ken Henderson
>> wrote:
>>
>>> I've got another question (or more) for this survey:
>>>
>>> 1. Is it feasible to use offset bushings in both the rear AND front of
>>> the upper A-arms? Seems to me it should be perfectly OK and
> potentially
>>> give about twice as much caster increase as using them only in the
> rear.
>>>
>>> 2. Seems to me installing the offset bushing in the rear, to increase
>>> caster, would inevitably tend to move camber toward negative. By the
>> same
>>> rationale, using offset bushings front and rear would have less effect
> on
>>> camber because the front would tend toward positive camber about equal
> to
>>> the rear's negative effect.
>>>
>>> 3. Has anyone considered or tried the offset upper A-arm shafts? Like
>>> this:
>>> bit.ly/3obunmp
>>> or
>>>
>>>
>>
> https://www.globalwest.net/billet-steel-stock-upper-control-arm-offset-cross-shaft-camaro-67-68-69-global-west.html
>>>
>>> I have no idea whether those are available to fit the GMC, but we've
> got
>>> plenty of folks capable of designing and building them. It might be
>> easier
>>> than modifying A-arms, as Lenzi does. What are the pros & cons?
>>>
>>> 4. Other options?
>>>
>>> Rest assured, I'm just trying to learn something here -- I'm happy with
>> my
>>> 1-ton front end -- and it was installed before Manny decided to
> increase
>>> the caster. (I THINK I did use offset bushings in the rear though --
>> tooo
>>> long ago for my old memory to be sure.)
>>>
>>> Thanks for all your inputs/ideas.
>>>
>>> Ken H.
>>>
>>>
>>> On Thu, Jan 14, 2021 at 11:42 AM Ken Henderson >
>>> wrote:
>>>
>>>> Time for a survey of those using Dave Lenzi's upper A-arms modified
> for
>>>> increased caster:
>>>>
>>>> What's your opinion after using them for a while? Do they
> significantly
>>>> increase the steering stability? Did you try the offset bushings
> before
>>>> going to modified A-arms? How do they compare? Did either affect the
>>>> steering effort significantly? Which is the "better buy" -- or is
>> either
>>>> worth the trouble/cost?
>>>>
>>>> Thanks for your opinions.
>>>>
>>>> Ken H.
>>>>
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361885 is a reply to message #361883] |
Thu, 21 January 2021 04:56 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
The first thought to enter my mind when I went to bed last night at 11 PM
was, "You dumbkopf!!! What were you thinking? Mentioning an 'upper
control arm shaft' in the same breath with GMC motorhome!"..."There ain't
no such thing!"
So, everyone, please, disregard all my mentions of that non-existant part.
Also, I wish I could say I did it to stimulate thought among all of you,
but I'm afraid the same brain-fart as above also cause the other glaring
error in my last-of-the-night posting: The orientations of the eccentric
bushings which I proposed would have the opposite effect from my
proposition! ...Or would it?... Y'All give it some thought; I won't say
more 'til I'm under the coach. :-)
All-in-all, hopefully not my most outstanding performance! And it's not
even 1 April.
Ken H.
On Wed, Jan 20, 2021 at 10:55 PM Ken Henderson
wrote:
> Jim,
>
> Sounds like you're confirming my long-held thought that the eccentric
> bushings can be installed in either the front or rear of the upper control
> arm. However, I'm confused by your reference to "depending upon the effect
> desired". I've always thought that the positioning of the bushing's
> eccentricity (toward or away from the frame) was what changed the effect.
> So, if one placed the center hole of the bushing toward the frame in the
> rear, and away from the frame in the front, the maximum possible caster
> would be achieved -- without getting into the probable need to adjust one
> or both of the adjusting eccentrics a little to set the camber properly.
>
> Am I confused?
>
> Ken H.
>
>
> On Wed, Jan 20, 2021 at 10:38 PM James Hupy via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> The eccentric upper control arm bushings, can be used in either forward or
>> rearward control arms, depending upon the effect desired. In our
>> application, they are installed to enable the rearward control arm to
>> travel towards the frame, and in effect, move the upper ball joint towards
>> the rear of the coach. That has the effect of moving the contact patch of
>> the front tire towards the front of the coach. Draw a straight line
>> directly through the centerline of the upper and lower ball joints to
>> illustrate this effect. It makes the front tire want to travel in a
>> straight line, rather than turn right or left. Ergo: more hands off
>> handling rather than less so.
>> Obviously, many other forces are at work here. Not part of this
>> subject. Not wanting to get into a big "Hoo-Haw" about this.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Wed, Jan 20, 2021, 7:01 PM Ken Henderson via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> Well, I guess I've had my head screwed on backward for quite some time:
>>> I've been thinking, and discussing, the use of offset bushings in the
>> UPPER
>>> REAR of the upper A-arm. Tonight, I've been researching offset bushing
>>> part numbers. LO and BEHOLD: Moog (and everyone else) ONLY mentions
>>> eccentric (offset) bushings for the upper FRONT! NOT the rear! Holy
>> Moly,
>>> why hasn't someone called me on that? Or have we GMCers been "doing our
>>> own thing"?
>>>
>>> Here are the ONLY Moog part numbers I've found for '76 Toronado (and by
>>> extension GMCMH):
>>>
>>> Standard Offset(Eccentric)
>>> Upper Front K7006 K7104
>>> Upper Rear K6111
>>> Lower Front K5222
>>> Lower Rear K6116
>>>
>>> Does this mean that the K7104 will ONLY fit the Upper Front, or merely
>> that
>>> that's where they're recommended (but CAN fit the rear?).
>>>
>>> Come on, somebody straighten this mess out.
>>>
>>> Ken H.
>>>
>>>
>>> On Wed, Jan 20, 2021 at 9:01 PM Ken Henderson
>>> wrote:
>>>
>>>> I've got another question (or more) for this survey:
>>>>
>>>> 1. Is it feasible to use offset bushings in both the rear AND front
>> of
>>>> the upper A-arms? Seems to me it should be perfectly OK and
>> potentially
>>>> give about twice as much caster increase as using them only in the
>> rear.
>>>>
>>>> 2. Seems to me installing the offset bushing in the rear, to increase
>>>> caster, would inevitably tend to move camber toward negative. By the
>>> same
>>>> rationale, using offset bushings front and rear would have less
>> effect on
>>>> camber because the front would tend toward positive camber about
>> equal to
>>>> the rear's negative effect.
>>>>
>>>> 3. Has anyone considered or tried the offset upper A-arm shafts?
>> Like
>>>> this:
>>>> bit.ly/3obunmp
>>>> or
>>>>
>>>>
>>>
>> https://www.globalwest.net/billet-steel-stock-upper-control-arm-offset-cross-shaft-camaro-67-68-69-global-west.html
>>>>
>>>> I have no idea whether those are available to fit the GMC, but we've
>> got
>>>> plenty of folks capable of designing and building them. It might be
>>> easier
>>>> than modifying A-arms, as Lenzi does. What are the pros & cons?
>>>>
>>>> 4. Other options?
>>>>
>>>> Rest assured, I'm just trying to learn something here -- I'm happy
>> with
>>> my
>>>> 1-ton front end -- and it was installed before Manny decided to
>> increase
>>>> the caster. (I THINK I did use offset bushings in the rear though --
>>> tooo
>>>> long ago for my old memory to be sure.)
>>>>
>>>> Thanks for all your inputs/ideas.
>>>>
>>>> Ken H.
>>>>
>>>>
>>>> On Thu, Jan 14, 2021 at 11:42 AM Ken Henderson > hend4800@bellsouth.net>
>>>> wrote:
>>>>
>>>> > Time for a survey of those using Dave Lenzi's upper A-arms modified
>> for
>>>> > increased caster:
>>>> >
>>>> > What's your opinion after using them for a while? Do they
>> significantly
>>>> > increase the steering stability? Did you try the offset bushings
>> before
>>>> > going to modified A-arms? How do they compare? Did either affect
>> the
>>>> > steering effort significantly? Which is the "better buy" -- or is
>>> either
>>>> > worth the trouble/cost?
>>>> >
>>>> > Thanks for your opinions.
>>>> >
>>>> > Ken H.
>>>> >
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361887 is a reply to message #361748] |
Thu, 21 January 2021 10:58 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Adding only a rear offset correctly would:
Increase positive caster
Increase negative camber
Adding only a front correctly would:
Increase positive caster
Increase positive camber.
In theory adding a front and rear would:
Markedly increase caster
Minimally change camber.
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361888 is a reply to message #361886] |
Thu, 21 January 2021 10:55 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
Dave Lenze told us that he tried both ways of using the offset bushing and
he did not gain any as that effect the camber, so in order to get the max
CASTER he informed us to just use the Offset bushings in the rear.
We automatically supply just one offset on each when we sell the bushings..
Also reuse the original Cam Plate as the ones supplied by Moog is not
correct and they will not correct it as we do not acquire enough to make
the change.
On Thu, Jan 21, 2021 at 5:08 AM Bruce Hislop via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Ken,
> I agree with your idea that an offset bushing in the front and the back of
> the upper control arm (UCA) could (should) give you more caster. Pulling
> the back of the UCA towards the frame and pushing out the front will move
> the UCA ball joint further back. However you need to be able to have your
> camber adjusted to zero by the same adjustments.
>
> On my one-ton I have the standard bushings and the rear of my UCA is set
> to max inward. Looking at the clearance to the fame (in my mind's eye)
> there
> isn't much more room to go any further inward without hitting the frame. I
> have a set of offset bushings, but never installed them because of this. I
> then adjusted the front UCA for zero camber.
>
> My one-ton is an early JimK kit installed in 2011 I believe. I'm not sure
> if the lower ball joint was moved forward on my arms.
>
> For fun several years ago I tried measuring my caster with a laser by
> measure the exact offset of the upper and lower ball joints and calculated
> 4 &
> 4.5 degrees. check it out here:
> http://www.gmcmhphotos.com/photos/g6974-measuring-caster-with-a-laser.html
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361895 is a reply to message #361887] |
Thu, 21 January 2021 12:02 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
IF the eccentric bushings fit both front and rear, as I suspect, then I
agree with John. I think I know someone who's about ready to try that
arrangement so maybe we'll have some good empirical data soon.
Ken H.
On Thu, Jan 21, 2021 at 11:59 AM John R. Lebetski via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Adding only a rear offset correctly would:
> Increase positive caster
> Increase negative camber
>
> Adding only a front correctly would:
> Increase positive caster
> Increase positive camber.
>
> In theory adding a front and rear would:
> Markedly increase caster
> Minimally change camber.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361896 is a reply to message #361895] |
Thu, 21 January 2021 12:58 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
|
Senior Member |
|
|
Ken,
pretty sure the holes in the upper A arms are same size front and rear.
Sully,
Bellevue wa
On Thu, Jan 21, 2021 at 10:03 AM Ken Henderson via Gmclist <
gmclist@list.gmcnet.org> wrote:
> IF the eccentric bushings fit both front and rear, as I suspect, then I
> agree with John. I think I know someone who's about ready to try that
> arrangement so maybe we'll have some good empirical data soon.
>
> Ken H.
>
>
> On Thu, Jan 21, 2021 at 11:59 AM John R. Lebetski via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Adding only a rear offset correctly would:
>> Increase positive caster
>> Increase negative camber
>>
>> Adding only a front correctly would:
>> Increase positive caster
>> Increase positive camber.
>>
>> In theory adding a front and rear would:
>> Markedly increase caster
>> Minimally change camber.
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361897 is a reply to message #361896] |
Thu, 21 January 2021 13:45 |
Bill Van Vlack
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
|
Senior Member |
|
|
sgltrac wrote on Thu, 21 January 2021 12:58Ken,
pretty sure the holes in the upper A arms are same size front and rear.
Sully,
Bellevue wa
Yes, they are.
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361898 is a reply to message #361896] |
Thu, 21 January 2021 13:34 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
They are the same. The offset bushings and the standard bushings share the
same outside diameter. Todd is correct. The welded on perches on the GMC
frame are located different places, depending upon the year model of the
coach. Why? Because somewhere along the way, radial tires
replaced bias ply tires on the coaches. This precipitated moving upper
control arm perches to accommodate the contact patch moving. Can't say
exactly when this change occurred. More than likely during mid year
production changes.
Jim Hupy
Salem, Oregon
On Thu, Jan 21, 2021, 10:59 AM Todd Sullivan via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Ken,
>
> pretty sure the holes in the upper A arms are same size front and rear.
>
> Sully,
> Bellevue wa
>
> On Thu, Jan 21, 2021 at 10:03 AM Ken Henderson via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> IF the eccentric bushings fit both front and rear, as I suspect, then I
>> agree with John. I think I know someone who's about ready to try that
>> arrangement so maybe we'll have some good empirical data soon.
>>
>> Ken H.
>>
>>
>> On Thu, Jan 21, 2021 at 11:59 AM John R. Lebetski via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> Adding only a rear offset correctly would:
>>> Increase positive caster
>>> Increase negative camber
>>>
>>> Adding only a front correctly would:
>>> Increase positive caster
>>> Increase positive camber.
>>>
>>> In theory adding a front and rear would:
>>> Markedly increase caster
>>> Minimally change camber.
>>> --
>>> John Lebetski
>>> Woodstock, IL
>>> 77 Eleganza II
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361899 is a reply to message #361896] |
Thu, 21 January 2021 14:46 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
Todd,
yes, your right, they are the same.
On Thu, Jan 21, 2021 at 10:59 AM Todd Sullivan via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Ken,
>
> pretty sure the holes in the upper A arms are same size front and rear.
>
> Sully,
> Bellevue wa
>
> On Thu, Jan 21, 2021 at 10:03 AM Ken Henderson via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> IF the eccentric bushings fit both front and rear, as I suspect, then I
>> agree with John. I think I know someone who's about ready to try that
>> arrangement so maybe we'll have some good empirical data soon.
>>
>> Ken H.
>>
>>
>> On Thu, Jan 21, 2021 at 11:59 AM John R. Lebetski via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> Adding only a rear offset correctly would:
>>> Increase positive caster
>>> Increase negative camber
>>>
>>> Adding only a front correctly would:
>>> Increase positive caster
>>> Increase positive camber.
>>>
>>> In theory adding a front and rear would:
>>> Markedly increase caster
>>> Minimally change camber.
>>> --
>>> John Lebetski
>>> Woodstock, IL
>>> 77 Eleganza II
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
| Re: [GMCnet] Increased Caster [message #361900 is a reply to message #361748] |
Thu, 21 January 2021 16:18 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
As on any GM vehicle where caster snd camber are set via the upper arm, they interact. Pulling the rear of the arm inboard to get more positive caster adds NEGATIVE CAMBER. (See my previous post where I listed the scenarios). Therefore you need to evaluate what you have BEFORE you change bushings. This means what are your current readings and where are your cams in respect to that for usable range. If for example your camber is negative, adding a rear offset will make this worse and you can only add so much OUTBOARD on the front cam to add positive camber.
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
Goto Forum:
Current Time: Wed Oct 02 15:54:28 CDT 2024
Total time taken to generate the page: 0.00884 seconds
|
GMCforum
Search
Help
Register
Login
Home
