At 18:20 06.07.99 +0100, David Hill wrote:
>Hi Asgeir,
>
>Strikes me that the thing has to be exactly aligned and perfectly
>central. The Sod's Law bit is that the one on the car-i.e. behind the
>trailing arm and inboard of the wheelarch-went on easily.
Well, anyway, I have had trouble (through times) fitting the two driveshaft
parts in-car, and when I have taken the parts out, they have fitted like a
glove.... Strange how much more difficult things get when you're on your
back under your car with some oil and dirt in the corner of your eye, isn't
it? Hehe...
>Re. the UJ thing. How can the the shaft be in height other than with the
>car at rest?
Well, it doesn't matter how it is while standing still, because there is no
load on the U/Js. However, the car will have the same height or suspension
travel when moving, so the neutral balanced situation will be the
prevailing one also when driving.
And I am talking about the angle of the UJs, i.e. if the driveshaft goes in
a straight line from the diff and to the wheel, and not at any angle. It is
the angle that wears the UJ, the same can be said about the propeller
shaft. The wear is definetely bigger with the O/D cars than manual, and
this is because the gearbox has been lowered on the O/D cars, and this
makes the propeller shaft more off-line than it is with manuals.
>The suspension travel clearly dictates that the shaft must
>go off height when the car is in motion.
Well, it will when you brake, corner and accelerate, but it will, most of
the time, be around the height (and angle of UJs) your car has when
standing still.
When you brake, the driveshaft will go out of line, but the load won't be
big if anything at all (unless you downshift in a rather rude manner...),
so the UJ won't be affected by braking
When you corner, you won't normally do this under heavy acceleration (but
on a track you would, and the wear of the driveshaft UJs would be
significant while cornering). The outside would compress and the inside
expand, this would make both UJs heavy loaded AND out of line.
This leaves us with acceleration. Both rear tires compress, goes out of
line and are under heavy load. And the UJ are worn ditto. Perhaps it is
sensible to adjust the rideheight so that the driveshaft are slightly
angled downwards toward the hub so that it will straighten out while under
heavy acceleration? What do I know, it might be that way from production,
sometimes it surprises me how considerate the Triumph engineers were.
>This is puzzling me, unless you mean that the height difference should
>be minimal with the car at rest and therefore under 'normal' driving
>conditions. Could you clarify this please?
Yes, I hope I just did. I have seen a lot of triumphs and I have never seen
two with the same rear ride height. So I think there must be a lot of
sunken rears around... And that might explain some exessive UJ wear.
Cheers.
---Asgeir---
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