BSA D14/4 BANTAM SUPREME D14/4 BANTAM SPORTS, Workshop Manual

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D14/4 WHEELS, BRAKES AND TYRES F7
Periodically test the tension either by "ringing", that
is striking with a metal tool or by placing the finger
and thumb of one hand over two spokes at a time and
pressing them together.
If tension has been lost there will be no ringing tone
and the spokes will move freely across each other.
When a spoke needs tensioning, the nipple through
the rim must be screwed further on to the spoke but at
the same time, the truth of the wheel must be checked
and it may be necessary to ease the tension at another
part of the wheel in order to maintain its truth.
It will therefore be obvious that spoke replacement,
spoke tensioning or wheel truing are not operations to
be treated lightly.
Careful examination of the wheel will show that for
every spoke there is another pulling in the opposite
direction and that the adjacent spoke goes to the
opposite side of the hub.
Increasing the tension tends to pull the rim so, to
counteract this, it is sometimes necessary to increase
the tension on the spoke or spokes either side to
maintain the truth of the wheel.
With a little care and patience it is possible for the
unskilled to at least re-tension the spokes but, turn
each nipple only a little at a time as, once the spoke is
under tension only a fraction of a turn is sometimes
sufficient to throw the rim badly out of truth.
WHEEL BALANCING
When a wheel is out of balance it means that there is
more weight in one part than in another. This is very
often due to variation in the tyre and at moderate
speeds will not be noticed but at high speeds it can be
very serious, particularly if the front wheel is affected.
FIG. F9. Balance weights.
Weights are available for attaching to the spokes to
counteract any out-of-balance but, before starting,
ensure that the wheel is absolutely free and revolves
quite easily. If the rear wheel is being treated remove
the driving chain.
With the wheel clear of the ground spin it slowly
and allow it to stop on its own. Now mark the top of
the wheel or tyre and repeat two or three times to
check.
If the wheel stops in the same place the extra weight
must be added at the marked spot.
The next step is to ascertain how much weight is to
be added, this can be done by sticking small pieces of
plasticine to the nipples and re-checking until the
wheel will stop in any position without moving.
Having ascertained how much weight is required, a
balance weight of exactly the same amount must be
attached to the spokes at the spot originally marked.
WHEEL ALIGNMENT
Steering will be affected if the wheels are the slightest
bit out of alignment (out of track).