| New Tail Wag/Sway problem [message #87938] |
Thu, 10 June 2010 12:04  |
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1977Production#0001
Messages: 197
Registered: January 2010
Location: Vallejo, California
Karma: 0
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OK first off, I know some play in steering is normal, this coach probably has more than normal. This is on the list to fix. Even with the steering play, the coach had 16.5's with Michelin XPS in the rear and seemed very stable even with a slight over correction of steering. Bushings were missing on rear shocks so I replaced all 6 shocks...Still stable on the highway. Now with brand new 16" Alcoa's and BFG Commercial T/A highway tires the coach is REALLY smooth at high speeds (65+) BUT, the problem is that a slight movement of the steering wheel causes the back end to wag quite a bit. The first time I drove it I had to grit my teeth and plan my next steering wheel move 5 seconds in advance. I have learned how to deal with the steering play and not overcorrect- this solved the wagging problem. My main question is: Why didn't the coach wag before the new tires? Were the Sidewalls of the 11 year old Michelin XPS's that much stiffer? Were they steel sidewall? This is not a subtle difference..its a whole new driving style needed.
Giovanni(Carlo) 1977 GMC Kingsley 26ft
"Carbon Footprint"
Rear Twin, Dry Bath, Original Headliner
[Updated on: Sat, 12 June 2010 18:28] Report message to a moderator |
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| Re: New Tail Wag problem [message #87944 is a reply to message #87938] |
Thu, 10 June 2010 12:42  |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
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the old tires have steel sidewalls and the new ones are rag sidewalls. it does make a difference. it is now showing up the loosness in the front end.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: New Tail Wag problem [message #87955 is a reply to message #87946] |
Thu, 10 June 2010 14:05 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Last year I went from the Michelin XPS to the BFG T/A's and have never looked back. I hated those rock hard Michelins due to the ride, rut running, and poor traction. I certainly haven't picked up anything I would call tail wagging, but the on-center rsponse is down slightly, but nothing even remotely bothersome. The rut running is gone and the ride is dramatically better. What pressures are you running?
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: New Tail Wag problem [message #87956 is a reply to message #87955] |
Thu, 10 June 2010 14:28 |
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1977Production#0001
Messages: 197
Registered: January 2010
Location: Vallejo, California
Karma: 0
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| Bob de Kruyff wrote on Thu, 10 June 2010 12:05 |
Last year I went from the Michelin XPS to the BFG T/A's and have never looked back. I hated those rock hard Michelins due to the ride, rut running, and poor traction. I certainly haven't picked up anything I would call tail wagging, but the on-center rsponse is down slightly, but nothing even remotely bothersome. The rut running is gone and the ride is dramatically better. What pressures are you running?
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I will agree that the BFG T/A's are riding much smoother, and the cabinets do not rattle as much... Fixing the front end is the big issue; it magnifys the on-center response. I do not know what the best pressure to run is and I have never weighed the coach. I think the Tire shop set the rear at 65 or 70psi. I have yet to confirm this.
Giovanni(Carlo) 1977 GMC Kingsley 26ft
"Carbon Footprint"
Rear Twin, Dry Bath, Original Headliner
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| Re: New Tail Wag problem [message #87962 is a reply to message #87957] |
Thu, 10 June 2010 15:22 |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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Drives like a new caddy and rides like an airplane. That is what I want. Dan what tires do you run again?
| WD0AFQ wrote on Thu, 10 June 2010 12:48 |
Check the tire pressures. I run 65 in front and 70 in back. Sometimes a bit more.
I am thinking what Fred said may be your problem. If you are anywhere close to Applied GMC go let Donnie drive it. He is spot on when comes to diagnosing a loose front end. I know this for a fact.
Mine drives like a new Cadillac and rides like an airplane. I do have the Q Bag.
Dan
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-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: New Tail Wag/Sway problem [message #87966 is a reply to message #87938] |
Thu, 10 June 2010 16:21 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| 1977Production#0001 wrote on Thu, 10 June 2010 10:04 |
OK first off, I know some play in steering is normal, this coach probably has more than normal.
he first time I drove it I had to grit my teeth and plan my next steering wheel move 5 seconds in advance. I have learned how to deal with the steering play and not overcorrect- this solved the wagging problem. My main question is: Why didn't the coach wag before the new tires? Were the Sidewalls of the 11 year old Michelin XPS's that much stiffer? Were they steel sidewall? This is not a subtle difference..its a whole new driving style needed.
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I remember a friend with a Blazer in the early 70s who put new tires on and it was so squirrely he had me drive his wife and son down to Santa Fe. A week or so later, and the tires stiffened up. I have never heard of it before or after. A once in a lifetime thing?
That being said, I put Toyo rag walls on our coach and it is a hands off cruiser. Wind, towing, etc. Runs straight as can be. I have had steel walls on another GMC and rag walls are for me.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: New Tail Wag/Sway problem [message #87974 is a reply to message #87970] |
Thu, 10 June 2010 18:04 |
klassic kampers
Messages: 93
Registered: July 2008
Location: greer,s.c./ellijay,ga
Karma: 0
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here is some info from my experiences on road wander....first are your rear bogie pins and bushings tight??....if loose the previous tires "wore" in a pattern from running crook-ed...the new tires are trying to track correctly and are squirming....
if the steering box is not "centered" you will get road wander.....the steering box is designed to run in a centered position and if not the internal valves are fighting against each other to find the true center....this is noticed by tugging on the wheel to correct your driving line and then the coach darts in the opposite direction.................
these are opinons and experiences of a country plow boy and not an engineer.........please take this post as such...
Mike Stewart
1973 GMC 26' Canyonlands /
1973 B.S.A. B50 street tracker-----
Greer,S.C/Ellijay,Ga
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| Re: New Tail Wag/Sway problem [message #87977 is a reply to message #87974] |
Thu, 10 June 2010 18:31 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Check the tire pressures. It would be great to weight the coach and adjust the pressure on front and rear, based on the amount of weight they are asked to carry. My coach tires are 65 front and 55 rear. Check the ride height. The suspension was designed for rag walls (bias ply, anyone?).
check easy things first.
Hoping for scales at International this Fall.
Tom Phipps,
75 GMC Ex-Avion
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] New Tail Wag problem [message #88026 is a reply to message #87942] |
Fri, 11 June 2010 01:04 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| Ray Erspamer wrote on Thu, 10 June 2010 12:36 |
Ride Height set correct ??? This made a huge difference in our coaches handling.
Ray
Ray & Lisa Erspamer
78 Royale Center Kitchen
TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: Carlo <carlodifabio@hotmail.com>
To: gmclist@temp.gmcnet.org
Sent: Thu, June 10, 2010 12:30:28 PM
Subject: Re: [GMCnet] New Tail Wag problem
Dan,
Wheels on tight...New shocks on tight... newish airbags with no leaks... I need to recheck rear psi...I have never weighed the coach.
--
Carlo
77 GMC Model 26 Kingsley~ "Carbon Footprint"
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Also what pressure are you running in the tires? If it is 80, then drop it to 65 all the way a round and try again. You should set the air pressure depending on the weight on each axle but 65 is a good starting point unless you are hauling a lot of lead or gold inside.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] New Tail Wag problem [message #88031 is a reply to message #88026] |
Fri, 11 June 2010 05:07 |
klassic kampers
Messages: 93
Registered: July 2008
Location: greer,s.c./ellijay,ga
Karma: 0
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exactly tom and ken.............if the rear tire pressures are too high, the tire does not "work" and feels like the rear end is on ice or mud...........
Mike Stewart
1973 GMC 26' Canyonlands /
1973 B.S.A. B50 street tracker-----
Greer,S.C/Ellijay,Ga
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| Re: New Tail Wag/Sway problem [message #88278 is a reply to message #87938] |
Sat, 12 June 2010 18:33 |
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1977Production#0001
Messages: 197
Registered: January 2010
Location: Vallejo, California
Karma: 0
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Senior Member |
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As many of you suspected, the problem was air pressure too high. The tire shop set the pressure at 70-71 all around. At the suggestion of net'ers I set the PSI to 65 in the rear. Test drove it and wow it actually feels back to normal! No more excessive sway. I can't believe how 5 PSI too high can make a difference...
Giovanni(Carlo) 1977 GMC Kingsley 26ft
"Carbon Footprint"
Rear Twin, Dry Bath, Original Headliner
[Updated on: Sat, 12 June 2010 18:34] Report message to a moderator |
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| Re: [GMCnet] New Tail Wag/Sway problem [message #88280 is a reply to message #88278] |
Sat, 12 June 2010 18:49 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Carlo,
If I did not know you, I would have made a comment to you that you
were imaginings things.
What tires are you running?
On Sat, Jun 12, 2010 at 4:33 PM, Carlo <carlodifabio@hotmail.com> wrote:
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>
> As many of you suspected, the problem was air pressure too high. The tire shop set the pressure at 70-71 all around. At the suggestion of net'ers I set the PSI to 65. Test drove it and wow it actually feels back to normal! No more excessive sway. I can't believe how 5 PSI too high can make a difference...
> --
> Carlo
> 77 GMC Model 26 Kingsley~ "Carbon Footprint"
>
> _______________________________________________
> 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
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www.appliedgmc.com
1-800-752-7502
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