Run-flat and Temporary use Spare Tyres
It
is important to understand what the law requires in regard to the condition and
care of tyres. Regulations govern many aspects of tyre condition of which the
following are the principal points:
1.
Tyres must be suitable (i.e. of the correct specification and size) for the use
to which the vehicle is being put and must be inflated to the vehicle or tyre
manufacturers' recommended pressures.
2.
Tyres of different types must not be fitted to opposite wheels of the vehicle
(for example, radial-ply tyres must not be fitted to a wheel on the same axle as
wheels already fitted with cross-ply tyres and vice versa, and a two-axle
vehicle with single rear wheels must not have radial ply tyres on the front axle
if cross ply tyres are fitted to the rear axle).
3.
No tyre must have a break in its fabric or a cut deep enough to reach the body
cords. No cut must be more than 25mm or 10 per cent of the tyres section width
in length, whichever is the greater.
4.
There must be no lump, bulge or tear caused by separation or partial fracture of
its structure, neither must any portion of the ply or cord structure be exposed.
Tyres
on cars, light vans (not exceeding 3,500kg gross weight) and light trailers must
have a tread depth of at least 1.6mm* across the central three-quarters of the
breadth+ and in a continuous band around the entire circumference of the tyre.
*
For goods vehicles over 3.5 tonnes the minimum tread depth
requirement
remains at 1mm (along with other requirements).
+
Breadth means the width of that part of the tyre which is in contact with the
road surface under normal conditions.
Regulations
permit the legal use of 'run-flat' tyres (provided they are identified as such)
in a partially inflated or flat condition, and what are described as temporary
use spare tyres. When a temporary use spare tyre is being used, the vehicle
speed must not exceed 50mph, and a special high inflation pressure is normally
used, otherwise the legal provision which permits their use ceases to apply. The
temporary use spare must have a label of different colour attached to the wheel
giving clear information about the precautions to be observed when it is being
used.
Tyres
fitted to lightweight trailers since 1 April 1987 must be designed and
maintained to support the maximum axle weight at its maximum permitted speed (ie
currently 60mph).
The
use of a vehicle on the road with defective (or incorrectly inflated) tyres can
result in prosecution for which the penalties are heavy. Maximum fines for such
offences are now set at level 4 on the standard scale, namely £2,500 for each
offending tyre (£5,000 if committed with a goods vehicle) and the driver's
licence will be endorsed with 3 penalty points. If the offences result in danger
to other road users, heavier penalties and driving licence disqualification may
follow.
A
random survey by the police and the Tyre Industry Council recently showed that
there may be as many as 12 million illegal tyres in use on vehicles in Great
Britain.
The
essential ingredient for keeping tyres in good condition, to provide optimum
performance and give maximum life is air. It is air that keeps tyres fit and
safe and carries the weight of the vehicle and its load, not the rubber or the
casing material.
Tyres
should be checked regularly either at home or when visiting a garage or filling
station. Particularly, prior to any journey they should be examined for obvious
signs of under-inflation, wear, cuts in the tread or sidewalls, bulges in the
sidewalls and stones and foreign objects trapped in the tread grooves (which
should be removed). It is useful to check for leakage at the valves (especially
following inflation) and to replace missing valve caps. A small tool can be
obtained to check remaining tread depth. If the tyres show any sign of uneven
wear the vehicle should be checked to ensure correct alignment and balance of
the wheels.
Tyre
pressures should not be checked during or immediately after a journey while the
tyres are still warm. This will result in an incorrect pressure reading. (NB: It
is worth investing just a few pounds in a pencil-type, pocket tyre gauge so you
can check pressures regularly - unfortunately some garage forecourt gauges
suffer abuse and may give misleading pressure indications).
Tyres
will provide greater life if they are properly maintained - it is an inexpensive
task which takes only a few minutes at regular intervals. The following Check
List will be helpful in this task:
1. Check the correct pressures against the
manufacturer's recommendations as given in the vehicle
Handbook.
2. Adjust pressures as necessary.
3. Clean dirt from valves and fit valve caps all round.
4. Remove stones and other foreign objects from treads.
5. Have the steering alignment corrected if front tyres
show signs of excessive or uneven wear.
6. Examine brakes if tyres show signs of wear through
wheel locking.
7. Have front wheels and tyres balanced if there are
signs of vibration, wheel wobble or patchy tyre wear.
The
way in which a car is driven can contribute to excessive tyre wear and damage.
For example, not adjusting the pressures when the car (or van) is fully laden or
when driven at high speeds are major contributors. The following additional
advice will help to protect your tyres:
1.
When undertaking long journeys, especially at speed on motorways, examine the
tyres both before and during the journey
(but do not check pressures while the tyres are warm).
2.
Avoid harsh braking, fierce acceleration and fast cornering (the steering wheel
of cars with
power-steering should not be turned while the car is stationary).
3.
Avoid driving over or scrubbing against kerb edgings or other raised
obstructions.
4.
If it is absolutely necessary to drive over rough, uneven, unmade ground or over
ground littered with debris, check the tyres soon afterwards to ensure that no
foreign objects have become trapped in the tread patterns and examine the
sidewalls for cuts or bulges.
There
are many individual causes of tyre troubles. However, the three abuses which
will cause most problems, and the greatest costs, are under-inflation,
overloading and speeding.
Surveys
by Dunlop Tyres Ltd, tyre service engineers show that at least 25 per cent of
all tyres examined are under-inflated by more than 10 per cent. Neglect of
inflation pressures is one of the principle causes of rapid shoulder wear,
uneven tread wear and premature tyre failure and it is an abuse which surveys
show to be on the increase. (NB: It should be stressed that over-inflation may
also result in inferior vehicle handling, excessive tyre wear and premature
failure).
Loading
cars, light vans and lightweight trailers above what they are designed to carry
is illegal. It is also likely to put excessive strain on the tyres resulting in
greater than normal deflection and overheating which, in turn, leads to more
rapid wear, greater susceptibility to impact damage and the danger of premature
failure. (NB: The vehicle Handbook will give increased inflation pressures for
full load conditions).
Travelling
for long distances on motorways at sustained high speeds and generally exceeding
statutory speed limits imposes strenuous demands on tyres especially in terms of
heat generation. Tyres in good condition and correctly inflated are designed to
withstand the heat build-up at their maximum rated speeds. However, if inflation
pressures are significantly below those recommended then excessive heat will be
generated, and in consequence wear will be accelerated and deflection will be
greater with the risk of premature, and sometimes catastrophic, failure.
Tyre
suppliers commit an offence if they sell a passenger car radial ply tyre which
does not have an 'E' mark showing that it complies with the load and speed
requirements of ECE regulations. With certain exemptions (ie tyres for pre-1949
vehicles and for off-road and competition use), from 1 January 1997 new car and
light trailer tyres (including 'VR' and 'ZR' radials) must be ECE or EU approved
and 'E' or 'e' marked respectively (and from 1 June 1997 for motorcycle tyres).
Since
1 January 1995 it has been illegal for any person to supply re-treaded tyres
unless they are marked to indicate compliance with the current BS AU 144
standard. It is also illegal for any person to supply a part-worn tyre which
does not comply with legal requirements and which does not have tread grooves at
least 2mm deep.
This
’Facts About’ bulletin is one of a series published in the interests of road
safety which currently includes the following titles:
1
Tyres and caravanning
2
The use of seat belts
3
Speed limits and safe driving
4
What to do in the event of a road accident
5
Parking and waiting restrictions
6
Tyre law, care and maintenance
7
Using the Channel Tunnel
8
Driving safely
9
Tyre life and performance
10
Motoring abroad
11
Your journey
12
Penalties for road traffic offenders
13
Winter motoring
'Facts
About’ information is issued in the interests of road safety.
Copies
in leaflet form may be obtained from:
Product Support
DUNLOP TYRES Ltd
Fort Dunlop
Birmingham B24 9QT
Telephone: +44 (0)121-384 4444
Fax: +44 (0)121-306 2359
Email: marketing@dunloptyres.co.uk.
Note:
To
the best of our knowledge, the information in these leaflets or above is correct
at the time of preparation (September 1996) but the law is subject to change
from time to time and may differ from country to country. If you need specific
legal advice you should consult a solicitor for a full appraisal of the relevant
aspects of the law.
Further
technical information concerning the use of tyres may be obtained from:
Product
Support Services
DUNLOP
TYRES Ltd
Fort
Dunlop
Birmingham
B24 9QT
Telephone:
+44 (0)121-384 6060
Fax:
+44 (0)121-306 2662
Email:
p.support@dunloptyres.co.uk.