but then it seems all the other "standard" sized stuff would be the weakest link.


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...Before I put this setup on any coach I owned I would measure the amount of torque it takes to turn the GMC steering wheel full lock
left to full lock right "WITH THE GMC STATIONARY ON PAVEMENT" ...

KB wrote on Thu, 06 November 2014 15:54

but then it seems all the other "standard" sized stuff would be the weakest link.


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Standard size??
Where is the standard size parts?
only the tie rod ends IMHO

The steering gear is huge, the drag link is huge, it's all huge

USAussie wrote on Thu, 06 November 2014 17:05

...Before I put this setup on any coach I owned I would measure the amount of torque it takes to turn the GMC steering wheel full lock
left to full lock right "WITH THE GMC STATIONARY ON PAVEMENT" ...

Say the steering wheel is 24" in diameter (most are less), that means you have at most a 12" lever. There ain't no way in hell that you, or me, or Hulk Hogan or even El Presidenti has the arm strength to twist the DD shaft or break one of these Ujoints using a 12" level. No way in hell.

Using a typical 12" long ratchet and socket, you can't even twist off a 1/2" bolt and these are MUCH tougher than that.

Obviously, you do what you want but I wouldn't loose a moments of sleep over it.

Besides, who would try to steer while parked? Steering while moving is much easier.

My assumption was always that the shaft was an addaptatiin of an off the shelf Spicer truck part and still available. My concern is that in the video the upper joint appears to be a U joint and not a CV. That would provide non linear speed transmission from the wheel to the box. That could provide a wierd non linear driving experience.

I thought Alex was concerned with centering both the gear box (relative to the wheels) and the u-joint (relative to the gearbox), but maybe I misunderstood.

What I was trying to ask is which is better: a CV joint and a single non-linear u-joint (OEM configuration), or two u-joints phased to mostly cancel out the non-linear rotation? I've no clue. Maybe it doesn't much matter in a non racing application. High speed cornering in a GMC upsets the dog (and the passenger...)

Karen
1975 26'

JohnL455 wrote on Sat, 08 November 2014 06:49

My assumption was always that the shaft was an addaptatiin of an off the shelf Spicer truck part and still available. My concern is that in the video the upper joint appears to be a U joint and not a CV. That would provide non linear speed transmission from the wheel to the box. That could provide a wierd non linear driving experience.

Interesting point. My current theory is that they used a CV joint at the top because it can handle bigger angles than most u-joints, so could apply to more vehicles. I think the non-linear u-joint response you mention helps explain why it's so critical to get the steering shaft aligned correctly to the center of the steering box.

Two u-joints, phased correctly, mostly counteract each other and act more like a CV joint.
I wonder if having a u-joint at the top, phased with the lower joint, would help counteract the non-linearity of the lower u-joint?

If we added a third u-joint (a double at the top, a single at the bottom), we'd have to add an intermediate support,
which adds more complexity than I'd want to deal with.

just thinking out loud...

Karen
1975 26'