Quote:
Originally Posted by 1project2many
Looking down at frame rails, center line of trans and center line of pinion should be in line with truck frame rails. Angles auto-magically cancel. More offset of one to the other doesn't matter. If axle is set back to make big thrust angle, or trans and engine are not parallel to rails, then you might see a problem.
WRT to vertical plane, pinion angle is not parallel to ground, trans angle not parallel to ground, shaft must be installed so angles cancel.
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This is correct on all counts (except for the "magic" part
).
Quote:
Originally Posted by Port&PolishMan
OK - Keith I think I understand the Canceling out Point - in 1 Plane
as We look at it ( Side View ) - how about ( Top View ) or as I always say
The Other Plane `\ : - )
That's the Trans Offset & Pinion Off Set - I'm concerned with ?
So Both the Out Put Shaft on Trans Tail and Input on Pinion - would
need to be Same Dim. Off - ( Center Line of Chassis )
Hence - Top View .. |
When I referred to the "plan view" that is the "top" view (plan view = view from the top).
So we've answered your question twice now, in a couple different ways.
It is a geometric principle that if a line bisects two parallel lines then the opposing angles will be equal. In the diagram below angles "A" are equal and opposite, as are angles "B". So the offset doesn't need to be the same; only that all of the components need to be square to the vehicle centerline.
Also - the u joints can easily tolerate a difference of +/- 3 degrees; considering the amount of offset compared to the length of the shaft(s) the resulting angle is usually much smaller than this and does not result in a disturbance.
That's why the angles in the top view are generally discounted and all of the focus /discussion is on the view from the side.
Quote:
Originally Posted by Port&PolishMan
Also - May I add seeing many Trucks have Center Shaft Bearing - Total Length of Drive Shaft would be ( Considered )
Both Half's and ADD .500 to the Dia. - due to extra Support OR
Just Consider the Longest Drive - Shaft - Minus .500 Dia. Due to the Presence of a Bearing Support ?
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Variations of shaft length (in fractions of an inch) are not significant in terms of effects on U joint working angle. Increasing the length of the rear shaft in the basic design can affect launch shudder (a u joint disturbance that manifests itself upon initial acceleration from a stop).
The working length of the shaft is from the center of the u joint cup (front) to the center of the u joint cup (rear).
K