| [GMCnet] Tid Bit. When making changes to your GMC. Does that change differ from proven automotive engineering practices. [message #332088] |
Tue, 15 May 2018 09:20  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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I can’t say I ever did a skid pad comparison, but I can share some direct experience with stock and modified coaches. Our 1977/1994 Clasco was bone stock with a good, tight front end, stock air bag rear and well adjusted stock brakes. Our 1978 Royale had just about everything done one could do to “modernize” a GMC. That included the one ton front end, six wheel reaction arm disk brakes, etc. But, it retained the stock one air bag system as well. Both had the same wheels and tires aired to the correct pressures for measured weight on each wheel. Both had the wireless air system with the ride height set to factory specs. Both were aligned properly with as much caster as they would allow and still be the same on both sides. The offset bushing allowed a bit more caster in the Royale than in the Clasco - one degree difference as I recall. The Royale was heavier by a few hundred pounds than the Clasco due mainly to the fact that it had four 6v golf cart batteries mounted in the rear PS compartment where the Clasco had one 4D 12v AGM and one group 31 AGM house battery bank centered in the rear.
Bottom line, both drove equally as well and we put a lot of wonderful miles on each of them. The only difference I could ever really tell from the drivers seat was a tendency of the Royale to shimmy a bit on low speed hard turns going up hill under acceleration. Other than that, they both were one hand on the steering wheel rides. I never had either one in a full lock brake situation, never flat spotted a tire and never heated the brakes to fade. Probably more from placebo effect than anything objective, I always thought I preferred the brakes in the Royale even though the pedal went further towards the floor and the bogy mount location for the reaction arms had a tendency to come loose from time to time.
My experience with these two coaches over a number of years is that proper ride height, proper alignment, and proper inflation of the tires made more difference in ride and handling than all the mods put together. I never did understand why the Royale with the six wheel reaction arm disk brakes and the larger front rotors from the one ton front end didn’t really stop any better than the well adjusted stock brakes on the Clasco. That might have been because I am a very conservative driver and never put myself in a position where I had to rely on them in an extreme emergency.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
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Message: 13
Date: Tue, 15 May 2018 06:39:14 -0600
From: Johnny Bridges
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Tid Bit. When making changes to your GMC. Does
that change differ from proven automotive engineering practices.
Message-ID:
Content-Type: text/plain; charset="utf-8"
Your comment on the one ton front end reminds me of stereo freaks who spent beaucoup dollars on connecting cables. When they say it sounds much
better, they're reporting the truth. Not because the cables were any better than what you get from MonoPrice though. Because they removed a piece of
#24 wire to the speaker and replaced it with #10 or #6 conductors which can handle the current. Or replaced the frayed cheeep input cables with one
with proper shields. "Oxygen - Free" and "Minimum Skin Effect" are basically bullshit in this application. The IEEE tested these double blind, the
results were as I note. Also, there's 'placebo effect' which essentially says "I paid money therefore it's better".
Now this doesn't say the one - ton or the four-bag is or isn't a Good Thing. What I'd like to see is a pair of coaches with normal (100K plus)
mileage on them on a skid pad. Then put the one ton on one of them, and renew all the same parts in the other but leave it stock (All bushings,
bearings, etc.) Then test them again. The same with air bag systems. The results might well convince us to make the mod or mods. Alls we have right
now is subjective experience.
--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] Tid Bit. When making changes to your GMC. Does that change differ from proven automotive engineering practices. [message #332091 is a reply to message #332088] |
Tue, 15 May 2018 10:26  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Well, on both my coaches, I could tell the difference in braking after the reaction arm install. More braking before lockup. One of the arm anchor designs looks to me like it is going to loosen in normal use. The other - which I use - has a laser cut piece of channel which is contoured to the bottom of the bogie mount precluding any movement. At least after several years on two different coaches it never has loosened. You might ask Briere about it, he bought my 23' with one of the earliest reaction arm setups.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Tid Bit. When making changes to your GMC. Does that change differ from proven automotive engineering practices. [message #332103 is a reply to message #332091] |
Tue, 15 May 2018 12:05 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Johnny Bridges wrote on Tue, 15 May 2018 11:26Well, on both my coaches, I could tell the difference in braking after the reaction arm install. More braking before lockup. One of the arm anchor designs looks to me like it is going to loosen in normal use. The other - which I use - has a laser cut piece of channel which is contoured to the bottom of the bogie mount precluding any movement. At least after several years on two different coaches it never has loosened. You might ask Briere about it, he bought my 23' with one of the earliest reaction arm setups.
--johnny
I am with Johnny on this one.
The improvement with rear reaction arms is remarkable.
I have one of the earliest of the drum reaction arm installs, and I can lock some rear tires and it is usually one of the middle ones. It does not make flat spots on the rears anymore. Breaking is now a lot like tossing out an heavy anchor on a short chain. It has required some attention in 40K miles, but nothing that is remarkable. And, the brakes are all Box-Stock....
I wish I could get carbon metallic for the rear, but the company that made those has dropped the 11X2 Bendix shoes.
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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