Triumph TR6 PI Operation Manual page 379

WHEELS AND TYRES
Type Size
Pressures
Front
Rear
Ib/in
2
kg/cm
2
Ib/in
2
kg/cm
2
**
Radial ply - Tubeless
165HR - 15 All Conditions 22 1'5 26
1'8
High Speed
28
1"9
32
2"2
Tubes are fitted to
185SR - 15 All Conditions 20 1'4 24
1'6
wire wheels
**
Tyres of the correct type and dimensions at the correct
cold inflation pressures are an integral part of the vehicle's
design, therefore regular maintenance of tyres contributes
not only to safety but to the designed functioning of the
vehicle. Road holding, steering and braking are impaired by
incorrectly pressurised, badly fitted, and worn tyres.
Tyres of the same size and type but of different make
may have widely varying characteristics. It is therefore
recommended that tyres of the same make and type are
fitted to
all
wheels.
Radial tyres are fitted as original equipment. It is
both dangerous and in the U.K. illegal to
use
on the public
roads a vehicle fitted with unsuitable combinations of tyres.
The following recommendations should therefore be
observed.
I. Do not mix radial-ply and cross-ply tyreson the same
axle.
2. Do not fit radial-ply tyres to the front wheels and
cross-ply tyres to the rear wheels.
3. With suitable tyre pressure adjustments it may be
possible to obtain acceptable handling wi,th cross-ply
tyres on the front wheels and radial-ply tyres on the
rear wheels, 'but this combination is not
recommended.
Tyre pressures
The tyre pressures recommended (refer chart), provide
optimum ride and handling characteristics for all normal
conditions. Tyre pressures should be checked and if
necessary, adjusted weekly. This should be done with the
tyres cold, Le. not immediately f<;>llowing a run as pressures
and temperatures increase when running. 'Bleeding' a warm
tyre to the recommended pressure will result in under
inflation which may be dangerous as well as harmful to the'
tyre. Pressure loss, with time, is normal, but if a pressure
drop exceeds 2 Ib/in
2
(0.14 kg/cm
2
)
in a period of one
week, investigation should be made. In the U.K. it is an
offence to use a vehicle with tyres improperly inflated.
The spare wheel tyre should be maintained at rear tyre
pressure and adjusted if fitted to the front of the car.
Triumph TR6 Manual. Part No, 545277 Issue 2
Wear
All tyres, fitted as original equipment, incorporate wear
indicators in the tread pattern. When the tread has worn to
a remaining depth of approximately 1.5 mm the wear
indicators are exposed as bars which connect the tread
pattern across the width of the tread. In the U.K. and some
other countries it is illegal to use tyres when the tread is
worn to a depth of less than 1 mm.
The properties of many tyres alter progressively with
wear, particularly with regard to 'wet grip' and aquaplaning
resistance, which are gradually but substantially reduced.
Extra care and speed restriction should therefore be
exercised on wet roads as the effective tread depth
diminishes.
Tyre wear is influenced by driving techniques, incorrect
inflation, types of road surface and also by misalignment
and mechanical defects. Investigations into tyre wear must
therefore consider a variety of factors.
Continued
HIll
uw
ml l
74.10.00 Sheet 1