Please choose a question from the options below:
1. Vehicle vibration due to
a propshaft out of balance
2. The driveline vibrates
at a certain speed
3. There is a clunk when the
clutch is released
4. Is there a standard for
propshaft manufacture?
5. Can a propshaft be made
stronger?
Answers
1. Vehicle vibration due to a propshaft
out of balance
A propshaft vibration is very similar to a wheel vibration
and may be caused by one of the following:
a) A new vehicle where there is a driveline fault.
b) A modified vehicle where angles or installation are incorrect.
c) An old propshaft with worn components.
d) A balance weight falling off.
e) Accident damage to the propshaft or mating flanges.
f) A poorly repaired shaft
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2. The driveline
vibrates at a certain speed
Most propshaft vibrations are worse within a 15-25mph
band. i.e. comes in at 50mph and goes at 65mph. If the vibration is over
the complete speed range either the propshaft has been bent or damage
has occured to other transmission components (gearbox or differential).
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3. There is a clunk
when the clutch is released
This can be due to worn components in the propshaft
either a universal joint or if fitted, sliding splines or wear between
splines and connecting flanges when a centre bearing support is used.
A propshaft with worn components cannot be successfully
balanced to known tolerances
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4. Is there a standard
for propshaft manufacture?
There is an Internationally recognised standard for
the dynamic balance of rotating bodies which include propshafts. It is
not neccessary to balance a propshaft to very fine limits if the application
does not require it. It is as important that the propshaft is straight
with minimal runout on tube and forgings as it is to dynamically balance
the shaft. The shaft should be balanced at a set speed equivalent to the
speed that the application will spend the majority of its life doing.
It is pointless balancing a shaft at 5000rpm if it will spend most of
its life spinning at between zero and 3000rpm.
The standard for the dynamic balance of propshaft is
generally accepted as follows:
| ISO
1940 G40 |
(VDI
2060 Q40) for shafts with slight wear |
| ISO
1940 G25 |
(VDI
2060 Q25) for new shafts |
| ISO
1940 G16 |
(VDI
2060 Q16) for special application |
To certify that a shaft is within the recognised tolerance
we must know the speed required, the weight of the shaft and which of
the above grades is required.
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5. Can a propshaft
be made stronger?
In some cases it is possible to upgrade a propshaft
within reason. A propshaft must be viewed as a "fuse" in the
driveline. If the shaft is upgraded without consultation, premature failure
may occur in other driveline components.
Propshaft tubing is NOT standard tube, it is made to
a specification that controls straightness, ovality and wall thickness
and allows a certain degree of flexibility.
