Home » Public Forums » GMCnet » [GMCnet] Braking performance of the standard system
| [GMCnet] Braking performance of the standard system [message #108918] |
Sat, 18 December 2010 22:30  |
Charles Aulgur
Messages: 78
Registered: March 2006
Karma: 0
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------------------------------
Message: 15
Date: Sat, 18 Dec 2010 17:29:24 -0800
From: Jim Kanomata <jimkanomata@gmail.com>
Subject: Re: [GMCnet] Braking performance of the standard system
To: gmclist@temp.gmcnet.org
Message-ID:
<AANLkTi==Pa+zgzHKt4VSef3fivBBf9oHf8HTPDpA9BcO@mail.gmail.com>
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Gary,
I 'm with you in saying that we can out stop any with the reaction
arm system.
On Sat, Dec 18, 2010 at 12:11 PM, Kosier <gkosier@roadrunner.com> wrote:
>
> ----- Original Message -----
> From: "Hardie Johnson" <hardie.j@gmail.com>
> To: <gmclist@temp.gmcnet.org>
> Sent: Saturday, December 18, 2010 1:03 PM
> Subject: Re: [GMCnet] Braking performance of the standard system
>
>
>
>>
>>
>> Gary Casey wrote on Sat, 18 December 2010 08:32
>>
>>> I've done some calculations related to the braking performance
>>> of the standard braking system using a spreadsheet. ?I the
>>> results are interesting, but not too startling. ?Some of the
>>> assumptions:
>>> 1. ?The braking effort on each wheel is proportional to the
>>> static weight distribution, which I assumed is 36% on the
>>> front and 64% on the rear (32% on each rear wheel).
>>> The rear suspension pivot is 12 inches from the ground and the
>>> swing axles are 18 inches long. ?The front suspension has no
>>> anti-dive geometry.
>>> Here are some of the results: ?At about 0.5 G decceleration
>>> the rears will lock.
>>> <trim the rest>
>>>
>>
>> That is a very interesting analysis and much in line with what
>> I have worked out with basic mechanical statics diagrams. It is
>> why I think no amount of fooling around with the rear
>> suspension will make a big change in braking distance.
>>
>>
>> --
>> Hardie Johnson "Crashj"
>>
>
> You guys can do all your calculating and make your spreadsheets,
> but I have the reaction arm brake set-up and I can out-brake
> you and all your spreadsheets. ?And that's reality.
>
> Gary Kosier
>
Gary, I could not say it any better then you did. I developed the
rear brake reaction arm system over five years ago and have given
numerous seminars on the subject but very few people understand what
I have been talking about. As Steve F has stated to me several times
"when I start talking about rocket science and vector analysis I just
turn people off and everyone goes to sleep."
I just got a call from Jim K. talking about the brake discussion
taking place on the net and he wanted me to help him explain the
reaction arm system so I will try once again. I'm not sure the GM
engineers knew what was going on when they came up with the swing arm
suspension. It was great for providing the smoothest riding RV on
the market and the lowest "step-in" of any other RV but the rear
braking system was not up to par with the rest of the outstanding
design they came up with.
The brakes on a swing arm suspension act totally different then
brakes on most any other vehicle. When the brakes are applied on the
mid-axle of a GMC, all of the restive torque generated by the brakes
has to be reacted thru the backing plate to the outer end of the
suspension arm, which applies an equal and opposite torque trying to
rotate the suspension arm in a CW direction around the wheel axle.
This torque has to be reacted thru the suspension arm rotation pen to
the vehicle frame. The loads on the pen are determined through
vector analysis (I can hear Steve now). The friction between the
tire and the road surface is what determines the loads applied to the
suspension pen which results in a force (vector) pointing from the
center of the tire/road interface upward in a straight line to the
suspension arm pen. The resulting rearward horizontal load on the
support pen is the force that is slowing the vehicle. The almost
equal upward vertical load on the support pen is reacted by lifting
the rear of the vehicle and is not providing any force to help slow
the vehicle and is totally wasted energy.
The rear wheel brakes act just opposite to the mid-axle brakes in
that the force vector from the tire/road contact point is pulling
down in a straight line on the rear suspension arm pen. Same as the
mid wheel, only approximately 1/2 of the forces generated by the
brakes is pushing rearward horizontally and is helping slow the
vehicle. The downward vertical force on the pen is reacting the
nearly opposite vertical force generated by the mid wheel and cancel
each other out during normal braking conditions. Thus, during normal
driving only approximately 1/2 of your braking ability is being
utilized in slowing your vehicle and the other 1/2 is totally wasted.
Things get much worse when you do a panic stop. Within a fraction of
a second after applying full brake pressure, the mid wheel brakes
lifts the rear of the coach until the shock bottoms out, shifting
most all the rear coach weight to the mid wheels and lifting most of
the weight off the rear wheels. That is the screeching that everyone
hears making them think they have good brakes. It is almost
impossible to slide the mid wheels with drum brakes unless you have 2
3/4" wide CM shoes and much larger brake cylinders.
In conclusion, by installing the rear brake reaction arm system that
is available from Jim K, you gain back the 50% you are now wasting
with the OEM brakes during normal driving and the best part you gain
back the 150% you lost with the OEM brakes during a maximum pressure
stop. With the reaction arm system you have full six wheel brakes
with each rear wheel having approximately the same braking capability
as as an OEM front wheel. Your rear brakes will last about twice as
long and you only need to apply about 1/2 the brake petal pressure
during normal driving.
Chuck Aulgur
La Mesa, CA
76 Royale with the same great brakes as Gary Kosier and a few others
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| Re: [GMCnet] Braking performance of the standard system [message #108922 is a reply to message #108920] |
Sat, 18 December 2010 23:35  |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| Robert Mueller wrote on Sat, 18 December 2010 21:09 |
G'day,
IMHO think this discussion / argument could be settled by someone with the
system installed doing some controlled tests to show just how effective the
system is.
Once the testing is done we could do the same tests on a GMC with standard
OEM brakes or any other configurations.
As a group we could come up with a test plan that satisfied everyone's
requirements.
Waadaya reckon?
Regards,
Rob M.
USAussie
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There are a couple of videos in JimK's website, taken with a camera in the back... one with and one without reaction arms.
http://www.appliedgmc.com/level.itml/icOid/973
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Braking performance of the standard system [message #108923 is a reply to message #108920] |
Sat, 18 December 2010 23:37 |
James Hupy
Messages: 6806
Registered: May 2010
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Rob, do you mean a full NASA type stress test analysis, with strain gages &
telemetery & video or Digital or high speed photography, and full
instrumentation or kinda like old Motor Trend decel tests using the bicycle
wheel apparatus clamped to the rear bumper. If you look on Jim K.s Web site
you will see a video of a system before & after the reaction arm complete
with sound. It wasn't rocket science but pretty darn good "bench racer"
tech. Do we need more than test rides? I am willing to help.
Jim Hupy
Salem, Or
78 Royale 403
On Sat, Dec 18, 2010 at 9:09 PM, Rob Mueller <robmueller@iinet.net.au>wrote:
> G'day,
>
> Despite being born in Hoboken, growing up in NJ, and winding up in
> Australia
> I'm going to make believe I'm from Missouri and note "show me!"
>
> I don't doubt for one second that installing the reaction arm system will
> give you a brake system as good as it gets on a GMC.
>
> IMHO think this discussion / argument could be settled by someone with the
> system installed doing some controlled tests to show just how effective the
> system is.
>
> Once the testing is done we could do the same tests on a GMC with standard
> OEM brakes or any other configurations.
>
> As a group we could come up with a test plan that satisfied everyone's
> requirements.
>
> Waadaya reckon?
>
> Regards,
> Rob M.
> USAussie
>
>
> _______________________________________________
> GMCnet mailing list
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> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Braking performance of the standard system [message #108931 is a reply to message #108923] |
Sun, 19 December 2010 01:19 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Jim,
Actually I was thinking of just some simple distance tests. Apply the brakes
hard at 30/35 and 60/70 miles per hour and see how far the GMC goes before
it stops. The idea of the Motor Trend decel test with the wheel is a better
idea if we could get a hold of a rig like that cheaply.
Just to refresh my memory I went to Jim K's website and re-viewed the
videos.
I was at Santa Rosa convention when Chuck showed HIS videos of the prototype
system which are essentially the same as what Jim posted to his website.
What is saw impressed me and I decided it would be a good mod to
incorporate. In fact I was so impressed that when I met Chuck at the Pueblo
convention he was standing behind a table that had half of that system on
it. I asked him why it was there and he said since Jim had provided him with
one of the first production systems he was selling it. I asked him how much
he wanted for it and he noted $500. I said SOLD and wrote him a check then
and there and carried off the parts. Unfortunately he only had one side
there and when he took the other side off he found that the forces that the
system under went were so great that the torque box had deformed and he was
reticent to ship it to me. He sent me pictures and while I felt I could beef
it up (which is what was done in the production system) I respected his
desire and returned the half I had.
Jim K contacted me and asked me if I could write up a simpler explanation of
how the system worked which I did and sent it to Chuck for review. He
thought is was good, made a few minor changes and forwarded it to Jim K.
I have had LOTS of discussions regarding this system and have heard
statements along the lines of:
"I'm interested but it's really expensive."
"I don't think it will do much for me except in panic stops."
"The videos don't show how much quicker (shorter distance) the GMC stops."
"I can drive defensively and accomplish the same thing."
"The only time it would help is if someone ran a red light in front of me."
And so on.
My suggestions for controlled testing to document how much quicker the GMC
stops would answer those questions and more.
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of James Hupy
Sent: Sunday, December 19, 2010 4:37 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Braking performance of the standard system
Rob, do you mean a full NASA type stress test analysis, with strain gages &
telemetery & video or Digital or high speed photography, and full
instrumentation or kinda like old Motor Trend decel tests using the bicycle
wheel apparatus clamped to the rear bumper. If you look on Jim K.s Web site
you will see a video of a system before & after the reaction arm complete
with sound. It wasn't rocket science but pretty darn good "bench racer"
tech. Do we need more than test rides? I am willing to help.
Jim Hupy
Salem, Or
78 Royale 403
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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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| Re: [GMCnet] Braking performance of the standard system [message #108934 is a reply to message #108931] |
Sun, 19 December 2010 06:34 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Rob,
I wished to heck I had it. I was coming down a 6% grade on I-8 into San
Diego with a curve so I couldn't see the bottom of the grade. I was pulling
a 12' enclosed trailer behind the GMC. At the bottom of the hill, when it
finally came into view, CALTRANS had necked down the fwy into a single lane
across the highest bridge in San Diego County. Two feet on the brake pedal
and pulling up on the bottom of the steering wheel did nothing. I aimed for
the smallest vehicle in the front of the pack, blew through the cones and
somehow ended up ON the bridge instead of in a 900 foot fall into the canyon
below. With the reaction arm system I would have been able to find a comfy
place at the rear of the string of vehicles and not have had to find a place
to pull over and change my shorts.
I guess what you admitting is that you haven't test driven the system yet.
EVERY stop is comfortable, easy and instills confidence. Driving a GMC in
stop and go traffic is a real pain. The BRAS makes it very much like being
in a car.
What Chuck said, ZZZZZZZZZZZZZZZZzzzzzzzzzzzz. All negative comments will
go away once you drive a GMC with the system installed.
On Sun, Dec 19, 2010 at 12:19 AM, Rob Mueller <robmueller@iinet.net.au>wrote:
>
> "I can drive defensively and accomplish the same thing."
>
> "The only time it would help is if someone ran a red light in front of me."
>
> And so on.
>
> My suggestions for controlled testing to document how much quicker the GMC
> stops would answer those questions and more.
>
>
>
Steve Ferguson
Sierra Vista, AZ
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| Re: [GMCnet] Braking performance of the standard system [message #108948 is a reply to message #108934] |
Sun, 19 December 2010 07:53 |
gmcrv1
Messages: 839
Registered: August 2007
Location: Memphis
Karma: -1
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Way back in the day, the old guideline was to allow one CAR length per 10
mph. So, at 70 mph in a CAR (3,000-4,200 lbs.) that would be about 150 feet
or half the length of a football field. Now, I am sure there are not to
many of us that followed that rule - especially if you commuted on any good
highway system. And 70 was not the average speed.
So, with my limited experience driving a GMC (I have logged a total of 17
miles on the Glacier since I acquired it) I think about driving 60-70 mph
and ask what is the distance someone should allow to the vehicle in front of
me? We haven't even mentioned towing a Grand Cherokee or the like.
Potentially one could have a gross rolling weight of 20,000 pounds. And
the GMC was originally designed to tow a maximum of 2,000lbs. That would
give a gross weight of 14,000 pounds. What does that added 6,000 pounds do
the the brakes? Did GM build in a safety factor to allow that kind of
service on the original brakes. The fact that no one has experienced warp
rotors is kind of interesting. The original system if properly maintained
should do the...but then, extra braking power is always a good thing to
have.
Dan and Jim K's experience last year is a perfect example of the real world.
With all the "other" things my coach needs to hit the trails, I'll
concentrate on making sure the coach is up to OEM specs, has good brake
hoses and cylinders all around etc. etc. And build a higher level in
confidence in the drive train.
I really like the reaction arm system and disc all around and I appreciate
all the incredible work that has been put into the RA system.
Just my 2 cents...
Tom Eckert N2VWN
73 Glacier
Oakland, TN
So, what does everyone do?
On Sun, Dec 19, 2010 at 6:34 AM, Steven Ferguson <botiemad11@gmail.com>wrote:
> Rob,
> I wished to heck I had it. I was coming down a 6% grade on I-8 into San
> Diego with a curve so I couldn't see the bottom of the grade. I was
> pulling
> a 12' enclosed trailer behind the GMC. At the bottom of the hill, when it
> finally came into view, CALTRANS had necked down the fwy into a single lane
> across the highest bridge in San Diego County. Two feet on the brake pedal
> and pulling up on the bottom of the steering wheel did nothing. I aimed
> for
> the smallest vehicle in the front of the pack, blew through the cones and
> somehow ended up ON the bridge instead of in a 900 foot fall into the
> canyon
> below. With the reaction arm system I would have been able to find a comfy
> place at the rear of the string of vehicles and not have had to find a
> place
> to pull over and change my shorts.
> I guess what you admitting is that you haven't test driven the system yet.
> EVERY stop is comfortable, easy and instills confidence. Driving a GMC in
> stop and go traffic is a real pain. The BRAS makes it very much like being
> in a car.
> What Chuck said, ZZZZZZZZZZZZZZZZzzzzzzzzzzzz. All negative comments will
> go away once you drive a GMC with the system installed.
>
> On Sun, Dec 19, 2010 at 12:19 AM, Rob Mueller <robmueller@iinet.net.au
> >wrote:
>
> >
> > "I can drive defensively and accomplish the same thing."
> >
> > "The only time it would help is if someone ran a red light in front of
> me."
> >
> > And so on.
> >
> > My suggestions for controlled testing to document how much quicker the
> GMC
> > stops would answer those questions and more.
> >
> >
> >
> Steve Ferguson
> Sierra Vista, AZ
> _______________________________________________
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> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Braking performance of the standard system [message #108953 is a reply to message #108918] |
Sun, 19 December 2010 09:37 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Just to add to the current thread.
And in the case that you did not believe Chuck's analysis - Read On.
When the GMC coaches were built, they were heralded for the remarkable brakes. (This was about 40 years ago and many passenger cars and almost everything "truck" were still drum-drum.) For many years and until recently, I had a 1965 Jeep pickup. At maximum load, the brakes were almost useless. We tend to forget just how bad "good enough" used to be.
As to the coach brakes. Shortly after we acquired ours (a23'), I became concerned with the rear lock up. I though it might be rusted drums - No everything was as good as could be expected. As I have done a great deal of mathematical modeling of mechanical systems and owned a license to software to do it, I tried to see if there was some easy explanation and possible remediation.
I didn't have access to good drawings, but I do have some measuring tools and did a pretty good "as built" of both the front suspension and complete rear. Estimating the CG was not all that hard, This is some a naval architect does all the time. I got it for elevation and fore-aft position, but I had no means to get thwartships (right-left location).
I also got a hold of some friends that did foundation brakes and got lots of solid technical information about both the 11*2 Bendix and the 11" Delco-Moraine.
What followed was a almost complete waste for several days of processor time that took my primary system (2.8g AMD dual core w/ 2g) off line for a day at a time for three different days. Yes, I would set up the run and let the machine crunch overnight and frequently to late the next day. It was a good thing I had the laptop to answer e-mail.
What that analysis showed was that the trailing brake would never be worth squat. It lifts just like the old motocrosser I had like to tuck when you worked the rear brake. The final development for this was an isolated backing plate connected to the frame so it did not rotate the swing arm on retarding. It tested well. My son was arriving that fall and the bike racing got shelved about then.
It also told me that there was no way the leading brake could ever apply the brake power to use the leading arm's increased load and if it did, the tire would be at risk of overload. Did anybody else here ever drive a BMW with the Earle's front fork? Remember how it would climb in a stop? Same-Same
In my case, the 140" wheelbase and the very low CG made much of the weight transfer issue much less a factor than it is in a passcar situation. I expect that this would even more true with a 26' coach.
I would have the Chuck Aulgur in a heartbeat if my situation permitted it. As I have very limited capital to put towards the coach, improvements to the rear suspension and brakes are not in the near future.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Braking performance of the standard system [message #108976 is a reply to message #108922] |
Sun, 19 December 2010 12:09 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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We have data in our files that Rick Flanagan keeps on the performance.
Rick F. took at least 12-16 people for a really hard stopping ride at
Western States atAuburn,CA and 6month later at LasVagas, NV.
He was taking 2-3 people at a time and had them drive it and slam on the brake.
All came back convinced that it was stopping more like a car than a motor home.
At las Vagas, we were concerned about the road surface due to rain and
also the blown sand on the streets. We did not have any problems.
I know at Auburn, Rick would take a group out and pick up more and wen
out.I thought that the brakes would heat up and not perform after so
many panic stops, not so as it kept on working great.
There is a paper that Marc Trubert wrote for us on the system that is around .
Marc has Masters Degree in Mecanical and Electrical Engineering so I
asked him to write the paper.
Marc will be having us put on the reaction arm in January.He presently
has the Q Bag system and the Applied 6 disc system. Be interesting to
see what differance he will notice with the reaction arms.
This kit has so much machining, that the cost is high.We had some made
that Rick F. refused to let us use.
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Jim Kanomata
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Braking performance of the standard system [message #108977 is a reply to message #108953] |
Sun, 19 December 2010 12:14 |
gmcrv1
Messages: 839
Registered: August 2007
Location: Memphis
Karma: -1
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Senior Member |
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Matt,
Couldn't agree more. The most Spartan car built today runs technological
rings around anything from the 70's. My first Mercedes was a 1969 280 that
had four wheel disc brakes. Wow! How did they do that?
Now almost everything is four wheel disc.
All it takes is time & money & money and I too would have the RA setup.
Tom Eckert N2VWN
73 Glacier
Oakland, TN
On Sun, Dec 19, 2010 at 9:37 AM, Matt Colie <mcolie@chartermi.net> wrote:
>
>
> Just to add to the current thread.
>
> And in the case that you did not believe Chuck's analysis - Read On.
>
> When the GMC coaches were built, they were heralded for the remarkable
> brakes. (This was about 40 years ago and many passenger cars and almost
> everything "truck" were still drum-drum.) For many years and until
> recently, I had a 1965 Jeep pickup. At maximum load, the brakes were almost
> useless. We tend to forget just how bad "good enough" used to be.
>
> As to the coach brakes. Shortly after we acquired ours (a23'), I became
> concerned with the rear lock up. I though it might be rusted drums - No
> everything was as good as could be expected. As I have done a great deal of
> mathematical modeling of mechanical systems and owned a license to software
> to do it, I tried to see if there was some easy explanation and possible
> remediation.
>
> I didn't have access to good drawings, but I do have some measuring tools
> and did a pretty good "as built" of both the front suspension and complete
> rear. Estimating the CG was not all that hard, This is some a naval
> architect does all the time. I got it for elevation and fore-aft position,
> but I had no means to get thwartships (right-left location).
>
> I also got a hold of some friends that did foundation brakes and got lots
> of solid technical information about both the 11*2 Bendix and the 11"
> Delco-Moraine.
>
> What followed was a almost complete waste for several days of processor
> time that took my primary system (2.8g AMD dual core w/ 2g) off line for a
> day at a time for three different days. Yes, I would set up the run and let
> the machine crunch overnight and frequently to late the next day. It was a
> good thing I had the laptop to answer e-mail.
>
> What that analysis showed was that the trailing brake would never be worth
> squat. It lifts just like the old motocrosser I had like to tuck when you
> worked the rear brake. The final development for this was an isolated
> backing plate connected to the frame so it did not rotate the swing arm on
> retarding. It tested well. My son was arriving that fall and the bike
> racing got shelved about then.
>
> It also told me that there was no way the leading brake could ever apply
> the brake power to use the leading arm's increased load and if it did, the
> tire would be at risk of overload. Did anybody else here ever drive a BMW
> with the Earle's front fork? Remember how it would climb in a stop?
> Same-Same
>
> In my case, the 140" wheelbase and the very low CG made much of the weight
> transfer issue much less a factor than it is in a passcar situation. I
> expect that this would even more true with a 26' coach.
>
> I would have the Chuck Aulgur in a heartbeat if my situation permitted it.
> As I have very limited capital to put towards the coach, improvements to
> the rear suspension and brakes are not in the near future.
>
> Matt
>
>
> --
> Matt & Mary Colie
> '73 Glacier 23 Chaumiere (say show-me-air)
> SE Michigan - DTW 3.2/4R
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Braking performance of the standard system [message #109009 is a reply to message #108934] |
Sun, 19 December 2010 14:55 |
|
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Steve,
When I bought Double Trouble it had six wheel disk brakes (Caddy rears) with
80mm calipers on the front. I had Ken Frey remove the rears and install
drums as I needed a manual emergency brake to pass NJ inspection. The brakes
were OK but I found (like you did) it took an inordinate amount of pressure
on the brake pedal to stop. While on tour that year the master cylinder
failed and I had to install a new P-30. That didn't help the braking.
At the end of our tour that year tour I stopped in at the Coop and
installed:
1) Stainless steel brake line kit
2) Brass proportioning valve
3) Rebuilt 80mm front calipers with carbon metallic pads
4) New front brake disks
5) Braided SS brake lines
6) Rebuilt middle calipers with carbon metallic pads
Braking performance improved but still left something to be desired.
Before our tour this summer while at the COOP I installed one of Jim B's
sensitized boosters. After installation Jim told me to head out on to Anno
Drive, get up to about 30 and hit the brakes. I followed his instructions
and the difference was UNBELIEVABLE. With a modicum of foot pressure Double
Trouble came to a VERY quick stop. On our tour this summer I was no longer
worried about not being able to come to a quick stop.
Next summer when I arrive I have two new drums, a set of carbon metallic
brake shoes, and a spring kit for the rears which I will be installing which
will make the rears as good as they get.
Once again I state UNEQUIVOCALLY that I KNOW the reaction arm system WORKS
and is "STATE OF THE ART" and "AS GOOD AS IT GETS" when it comes to a brake
system on the GMC - PERIOD END OF STORY!
Yes I "admit" I have not driven a GMC with the reaction arm system therefore
I cannot make a comparison to see if it is worth removing quite a bit of new
hardware and installing the disk brake kits and reaction arm system. The
reason I'd like to see some stopping tests is so I can repeat them in Double
Trouble so I can quantify just how much better the reaction arm system is
and if that improvement is worth four grand.
BTW Dan Gregg drove Double Trouble this past summer while I was down the
back trying to figure out which rear wheel bearing was shot and he was
impressed with how good the brakes were!
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: Steven Ferguson
I guess what you admitting is that you haven't test driven the system yet.
EVERY stop is comfortable, easy and instills confidence. Driving a GMC in
stop and go traffic is a real pain. The BRAS makes it very much like being
in a car.
What Chuck said, ZZZZZZZZZZZZZZZZzzzzzzzzzzzz. All negative comments will
go away once you drive a GMC with the system installed.
Steve Ferguson
Sierra Vista, AZ
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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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| Re: [GMCnet] Braking performance of the standard system [message #109014 is a reply to message #108920] |
Sun, 19 December 2010 15:58 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
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Senior Member |
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| Robert Mueller wrote on Sat, 18 December 2010 23:09 |
G'day,
Despite being born in Hoboken, growing up in NJ, and winding up in Australia
I'm going to make believe I'm from Missouri and note "show me!"
I don't doubt for one second that installing the reaction arm system will
give you a brake system as good as it gets on a GMC.
IMHO think this discussion / argument could be settled by someone with the
system installed doing some controlled tests to show just how effective the
system is.
Once the testing is done we could do the same tests on a GMC with standard
OEM brakes or any other configurations.
As a group we could come up with a test plan that satisfied everyone's
requirements.
Waadaya reckon?
Regards,
Rob M.
USAussie
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i like your idea. i helped Ken H. do brake testing on the yellow pads a year or so ago. he had a neat system for getting repeatable accurate results.
some thoughts:
just adding disk brakes to the rear will help braking so a test with all OEM brakes as a control should be done.
then a test with the sensitizes booster.
then a test with disk/drum rear brakes.
then a test with the reaction arm and disk brakes.
i think with that done there would be no need to talk vector analysis or spread sheets or anything else. the numbers would say it all and i believe the reaction arm system would start selling.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] Braking performance of the standard system - measuring deceleration [message #109206 is a reply to message #109135] |
Mon, 20 December 2010 20:52 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Jay,
I heard someone at the Las Vegas rally saying that they took a
acceleration reading in Rick F's coach when they were doing the demo
panic stops.
On Mon, Dec 20, 2010 at 11:39 AM, Jay Rabe <jayrabe@hotmail.com> wrote:
>
> There's a free app for the iPhone called “AccelGraph”—which records acceleration in separate X, Y and Z axis on either a graphical strip chart of in numerical printout which can be emailed. A friend used it for a study of how bodies move when dancing, but certainly seems it would work to measure braking deceleration too.
>
> FYI
>
> J
> 76 PB
> Portland, OR
>
>
>
>
> _______________________________________________
> GMCnet mailing list
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>
--
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
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| Re: [GMCnet] Braking performance of the standard system - measuring deceleration [message #109287 is a reply to message #109206] |
Tue, 21 December 2010 12:45 |
Douglas Norton
Messages: 191
Registered: April 2008
Karma: 0
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Senior Member |
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I was the one with the accelerometer. It showed a maximum stopping g force of .60 with the reaction arm. Most of the stops were in the .58 range. It was less than pure science as the g forces are impacted by the angle of the sensor and the angle was impacted slightly by the rotational forces on the meter and the coach (nose dipped while stopping). I understand someone else had found the stock setup to be near .5 g.
Doug Norton
--- On Mon, 12/20/10, Jim Kanomata <jimkanomata@gmail.com> wrote:
From: Jim Kanomata <jimkanomata@gmail.com>
Subject: Re: [GMCnet] Braking performance of the standard system - measuring deceleration
To: gmclist@temp.gmcnet.org
Date: Monday, December 20, 2010, 6:52 PM
Jay,
I heard someone at the Las Vegas rally saying that they took a
acceleration reading in Rick F's coach when they were doing the demo
panic stops.
On Mon, Dec 20, 2010 at 11:39 AM, Jay Rabe <jayrabe@hotmail.com> wrote:
>
> There's a free app for the iPhone called “AccelGraph”—which records acceleration in separate X, Y and Z axis on either a graphical strip chart of in numerical printout which can be emailed. A friend used it for a study of how bodies move when dancing, but certainly seems it would work to measure braking deceleration too.
>
> FYI
>
> J
> 76 PB
> Portland, OR
>
>
>
>
> _______________________________________________
> 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
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
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_______________________________________________
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List Information and Subscription Options:
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| Re: [GMCnet] Braking performance of the standard system [message #109295 is a reply to message #109275] |
Tue, 21 December 2010 13:06 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| WD0AFQ wrote on Tue, 21 December 2010 11:29 |
Larry, I won't be opposed to that. My problem doing it before is my brakes are not up to snuff again. One reason I am tired of dealing with the drums. We will see how it works out. If I can get my brakes working again this might be a good comparison.
I had very good brakes when I had them but they were not as good as Rob's single disc and rear drum setup that I drove back in October. He has great braking power.
Dan
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Save the old drums when you do the upgrade / change on the rears.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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