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Buick and Winston cup cars


2carb40

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People cuss Buicks "torque tube" style of suspension for its difficulty in terms of, for instance, clutch replacement. Im fond of referring folks to the fact that new Corvettes have a torque tube. They have some advanced engineering not available on the early cast iron Buick rear ends. The Winston Cup cars use whats commonly called "truck arm" style rear suspension, so called from my reading, as used on the rear of GM pickup trucks. These are "long trailing arm" design. If you visualize the rear end from the side looking as though "sighting" down the line the axes form when viewed from that angle and imagine what occurs when you jack under the axle on one side. The brake drum does not move in a straight vertical line or stay in "plumb" for us carpenter types. Its attaching arm is  designed to be parallel with the ground at rest and will move toward the front of the vehicle as it is raised or lowered going out of parallel with the ground. The brake drum swings in a slight arc )! Hold that thought! Picture this happening at 120 mph in a curve on the track. Your car is only supposed to be steered at the front! If one side of the rear axle is forced up and foward because of body lean at high speed in that curve the relative position of the axle on the outside toward the curve is raised in that wheel opening and has moved slightly forward compared to the othe side. Its "steering the rear of the car"! So? Engineered almost totally away on those cars, its drivers are aware of it by training. Your stock Buick when racing around unexpected sharp curves also shares some of this "advanced" engineering. The arms on the torque tube attach close to the center of the chassis, Gm truck arms and Winston Cup cars attach close to the center of the chassis. This length is important; the longer the arms, the less tight the arc the axle makes as it moves up or down=less rear axle steering compared to short arm four link suspension which travels a tighter arc moving up and down. Clear as mudd right? Damn! When did those Buick engineers figure they were gonna go up against Winston Cup cars anyway? Maybe with Corvettes! Thoughts? Critics? Fans of Buicks?

Edited by 2carb40 (see edit history)
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Actually, Buick optimized the connection by haveing the whole works swivel even closer to center with that method of attaching the arms to the tube. Thanx for highlighting that aspect as I was tired and not clear enuff about that and probably other excellent engineering features not mentioned. Thanx for takn' time to read thru that long winded treatise!

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3 hours ago, 2carb40 said:

Actually, Buick optimized the connection by haveing the whole works swivel even closer to center with that method of attaching the arms to the tube. Thanx for highlighting that aspect as I was tired and not clear enuff about that and probably other excellent engineering features not mentioned. Thanx for takn' time to read thru that long winded treatise!

 

 I  ALWAYS  read your stuff.

 

  Ben

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Torque Tubes were not always as Buick did them.  Rather "closed driveshaft" designs.  In the 1951-era GM pickups, Chevrolets had a closed driveshaft as GMCs had an open driveshaft, from my experiences with them.  Both had rear leaf springs.

 

GM pickups went to the trailing arm rear suspension when they went to rear coil springs in the earlier 1960s, even with torsion bars on the front inm '61-'62.  This continued untilo 1973.  BUT, Chevies were standard with the rear coil springs as GMC used rear leaf springs and Dana rear axles . . . AND Chevies could be had with that leaf spring rear suspension and Dana rear axles as GMCs could be optioned with the Chevy rear coil spring suspension and corporate rear axle.  Key thing is that they all bolted into the same place.

 

Which brings up a suspicion I've had that the Buick rear suspension could be removed and an Oldsmobile rear axle/suspension could be substituted, which used rear leaf springs.

 

In any rear suspension, rubber bushings are needed in the suspension flex points for "flex" as the wheels move in relationship to the body and road surface.  This conpliance and resistance is controlled.  To me, the Buick designs have a more unified suspension and also a unified pivot point in the torque ball, around which all arcs originate from.  More later, got to get to work . . .

 

NTX5467    

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Just to supplement NTX’s comments: prior to 1955 Chevrolet and GMC half-tons had torque-tube drive.  Half-tons got an open drive shaft with the 55-1st Series.   3/4-tons had a two-piece driveshaft with the front piece enclosed and the rear piece open with exposed U-joints.  By 1954 both driveshaft sections were open.  All models had leaf springs.

The coil spring rear suspension started in 1960 and went thru 1972.  As he said some models of Chevy and GMC during this period, usually 3/4-ton and larger, had rear leaf springs.  

Edited by 50ChevyFrank (see edit history)
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Thanks for the additional comments, but the Chevy/GMC coils or leaf spring rear suspensions were also operative on the 1/2 pickups.  Most of those trucks were ordered with their "standard" suspensions (coil for Chevy, leaf for GMC) I highly suspect.  Unless somebody got into the order guide and looked at all of the options, they would not have kniown about that deal.  Just as '67-'72 wide-bed models had a steel load floor as the GMCs had a wood floor, which could also have been flip-flopped.  

 

One of our late chatper members, Mr. David Corbin, found a Buick Self-Shifter at a swap meet one summer.  One of those lucky finds that HE knew what it was when he looked at it as the sellers didn't really know what it was, other than it was different.  He later did a complete history of the car and that transmission, which was highly interesting.  THEN he found another running car close to where he lived.

 

One of the things he figured out, as to why so few Buicks were sold with that transmission, compared to Oldsmobiles, had to do with the Buick's Torque Tube Drive arrangement.  Which needed a "car push rod" to locate the axle, front to rear and support vehicle propulsion activities.  With the "lateral rod" doing the side-to-side location.  So, as the rotational pivot of the torque tube suspension, at the front, being the torqur ball, the lateral rod keeping the torque tube located, plus the car push rod in that mix to keep the torque tube centered in the chassis, Mr. Corbin noticed where the car push rod was attached to the chassis.  Basically under the front seat, driver's side.  NOT much different that the more modern '82+ Camaro/Firebird use for rear axle location.  Except that the Self-Shifter shifted "very positively", which transferred that force to the front of the push rod directly underneath the driver.   Whereas the Oldsmobiles, with their rear leaf springs, absorbed that shock via the rear springs and their mountings.  In other words, the Olds was perceived to not shift as hard as the Buicks did, although the transmissions were the same and acted the same.

 

To me, the Buick Torque Tube set-up is a more positively-located rear suspension, with possibly fewer pivot points than other rear suspensions, which produced a more friction-free situation for a smoother ride (not to forget the frictionless coil springs) that was also very strong and reliable.  Each control arm in other suspensions needs some level of rubber bushings to allow for suspension component movement in normal driving, by observation.  Which can also mean that some amount of latent tension or bias can affect how they work.  Even with anti-friction liners between the leaves in a leaf spring assy, it can never approach the frictionless performance of a coil spring, which is why coil springs ride smoother than a leaf spring, other than shock absorber calibrations.  AND . . . less places for rubber to squeak with age!

 

Enjoy!

NTX5467  

 

 

Edited by NTX5467
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