"Conor" wrote in message
.. .
In article , ian henden
says...

Shame it's wrong. Having actually driven a 15ft 9in high trailer quite
a lot, it is no worse than a normal height one.

Maybe, but a DD bus in high sidewinds, at motorway speed, is hairy.

Only to those with no experience of driving them.

'Spose 30+ years isn't enough? Initially Peterborough - Huntingdon -
Cambridge? Fen land, where wind whips striaght in from the Urals across the
North Sea and nothing much to abate it across East Anglia?

An artic rig will have

a) more axles (so rather more weight low down) and

b) they will be distributed over a greater length of the vehicle (which
must contribute to directional stability) and

c) the load distribution of a truck is different. In a bus, half loaded,
then that half load will usually go and sit upstairs.... leaving the
bottom
deck empty save for a few grannies....

And a bus has ballast weights.....

None that I am aware of, and I've seen a fair few buses and coaches being
broken up, never seen anything that might be called a "ballast weight".

Buses are subject to a "tilt" test, the angle of dangle being not so severe
for a DD as it is for a SD, but I can't remember off-hand what the angles
actually are. But we are not talking about being blown *over* .... the
problem is being blown *off-course*. With the smaller wheelbase of a bus,
that is a bigger problem than with a lorry's longer wheelbase. The problem
is also magnified with increased speed.

The reasons for a buses smaller wheelbase, compared with its length, are to
do with: having a wide door at the absolute front of the vehicle so the
driver can collect fares; that decides the location of the front axle; also,
a smaller wheelbase gives more manoeverability; rear overhang is a
"balancing" act with the front, and somewhere to put the engine. If the
engine were under the centre floor (an ideal location for stability, if not
servicing access), then the lower deck aisle would be too high (look at
1960s single deck Bristol MW, for example.) Can't get wheelchairs and
buggies up steps.

Biggest masses must be chassis and engine/gearbox, and the latter is usually
right at the back, 5 ft or so aft of the rear wheels - not the ideal
location for directional stability, but easy to get at when Things Go Wrong.
There are other, good, reasons for having the engine there.... out of the
way of passenger area, for a start. If the PTB could get away with having
engines at the front still, next to the driver, then we would still all be
using manual gearboxes. It's only the remote location of the engine that
prompted first, semi-automatics, and latterly, fullly automatic gearboxes.
Saves having complicated linkages under the floor (where ther isn't much
clearance anyway). (DAF BOVA has rear engine, and manual gearbox.... many
points of potential linkage wear twixt gearlever and gearbox... :0( ... try
driving a worn one, where you haven't a clue WHAT gear you might be in until
you try it!! )

Coming off M27 onto M275, where the road is high above other roads and the
foothills of Mount Solent, the wind has been whipping in over the harbour
recently. OK at reduced speeds, but, above 40 mph, it most certainly does
start to get hairy. The timetable demands 55mph plus for this ..... the
bus runs late instead, due to excessive wind conditions

Also a head wind can easily knock 10 mph off the top speed of 60 and a
tad mph (same as going up shallow hills on the motorway). (For some
reason, going the other way, you can't seem to acquire an *extra* 10 mph)...
You must have noticed some buses can overtake your lorry on the flat, but
then you can overtake them on an uphill?

One of Stagecoaches DDs got blown off the A10 near Streatham a few weeks ago
in similar circumstances. Made the national papers, AND the Sun. Buses don't
get blown *over* - just blown to one side or the other.... an involuntary
lane change, which one can cope with if there IS an empty lane to the
side... but not so much fun when there is only a drainage ditch!

Whilst I am quite happy to accept that you know a fair bit about driving an
artic, I am not so sure that you have had a lot of experience driving buses.
There are some differences, not all of which might be obvious.


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IanH