Tyre Buying process
Do I have to fit the tyres
myself?
No. If you select the fully fitted option, your tyres
will be delivered to a fitting centre of your choice
and they will fit the tyres for you. This is all included
in the price.
Are valves and wheel balancing
included?
Yes. Both of these things are included when you select
the Fully fitted option.
Do my local garages have an
issue with me buying tyres online?
No. People have been buying tyres online for years
now. The garage or tyre centre is paid to fit the
tyres, so they still make a profit.
Do I have to change all four
tyres?
If you have one worn tyre there is no need to change
all four tyres. However there are benefits in changing
tyres in pairs. It is best to have the same level
of grip on both sides of each axel. So, depending
on how worn your tyres are it is best to change either
both front tyres or both rear tyres at the same time.
Can I have my tracking adjusted?
Check with the fitting centre where your tyres will
be fitted. Most specialist tyre fitting centres have
the equipment to carry out these adjustments. There
will be a separate charge, payable to the fitting
centre directly.
Tyre Technical Questions
How do I find my tyre size?
The tyre size can be found on the sidewall of the
tyre. Take a look at the picture for details.
What do all these numbers mean?
The tyre sidewall markings explained.
At first glance the tyre sidewall seems to contain
a lot of confusing numbers and letters. This information
tells you about the dimensions, speed rating and tyre
pressure setting.
To buy tyres online, all you really need to know are
the 4 main pieces of information:
Tyre Width
The tyre width is shown in millimetres and is the
width from one side of the tyre to the other. Wider
tyres give the car more contact with the road and
therefore more traction.
Tyre Profile
The tyre profile is actually a ratio, not a metric
measurement. The profile is the ratio of tyre width
to profile height shown as a percentage.
For example: If the tyre has the dimensions shown
- 205/50. Then the profile is 50% of the width, so
50% of 205mm is 102.5mm. The tyre height from the
rim to the tread is 102.5mm
Tyre Speed Rating
All tyres have a speed rating letter. The letter
denotes a maximum speed that the tyre can sustain
for a 10 minute period without falling to pieces.
Each speed rating is 10Km/h above the previous. This
is a very important parameter, as there is a
legal requirement to fit tyres to your vehicle with
the correct speed rating.
Note: the letter R is nothing to do with the
speed rating. This letter denotes the tyre construction,
so if your tyre is a 255/35 ZR19, it just means that
it's a Z rated tyre of Radial construction. This letter
is redundant really, because nearly all tyres are
radial these days.
| Symbol |
Max
Speed |
Symbol |
Max
Speed |
| Km/h |
MPH |
Km/h |
MPH |
| L |
120 |
75 |
S |
180 |
113 |
| M |
130 |
81 |
T |
190 |
118 |
| N |
140 |
87 |
U |
200 |
125 |
| P |
150 |
95 |
H |
210 |
130 |
| Q |
160 |
100 |
V |
240 |
150 |
| R |
170 |
105 |
W |
270 |
168 |
| |
|
|
Z |
240+ |
150+ |
For most people these speed ratings are not relevant
to their driving habits as the UK speed limit is just
70MPH or approximately 120Km/h. However if you plan
on stretching your vehicle's legs a bit on the German
Autobahn, 130MPH may not seem that fast, but on H
rated tyres, according to the chart you have 10 minutes
max before your tyre comes apart!
Wheel Size
This is the diameter of the wheel rim in inches that
the tyre is designed to fit. It's strange that they
mix metric and imperial measurements, but they just
do.
Load Rating
On some tyres you will see an extra number after the
R eg. 205/50/R/16/91/V. In this format the
figure 91 denotes the tyre's load rating. The load
rating is the weight in Kilos (multiplied by 10) that
the tyre can support at speeds of up to 130MPH. It's
worth noting that above speeds of 130MPH the load
rating decreases.
If you're car weighs 2 metric tons (2,000Kg) then
if we do a simple calculation we can assume that there
will be roughly 500Kg supported by each tyre. This
gives us a tyre load index rating of 84. If you then
add a further 20% for passengers and a nice safety
margin that takes the up to 600Kg per tyre, giving
us a load rating of about 91.
Legal requirements around tyre
speed ratings
Although the UK speed limit is just 70MPH, most vehicles
are more than capable of exceeding this speed. Therefore
vehicle insurance companies will insist that the tyres
of the correct speed rating are fitted to your vehicle.
This is a legal requirement in the UK.
What is the legal limit on
tread depth?
Here in the UK the legal minimum tread depth is 1.6mm.
However independent tests have proved that a tyre
at 1.6mm is 40% less efficient as stopping in the
wet than a tyre at 3mm. For safety's sake we would
advise people to aim to replace their tyres at 3mm
of tread.
How can I measure my tyre
tread depth?
You can use a tyre depth gauge. However most tyres
have a tread wear indicator to help you to visually
identify when you are close to the tread depth limit.
If you're looking at your front tyres, lock your steering
wheel to either the left or the right and look around
the tread carefully, you should see a small rubber
bar running across the tread grooves. The wear indicator
is usually placed in the tyre at a depth of 2mm. If
the tyre tread is flush with this rubber bar then
it's time to replace your tyres.
Can they repair my puncture?
Not all punctures are safe to repair, especially if
the tyre has been driven on. The guide below shows
the areas that can be repaired. If you have Run Flat
Tyres read this page which explains why tyre fitters
have issues repairing
run flat tyres.
What are RFT tyres and why
are they so expensive?
RFT stand for Run Flat Tyre. These tyres can survive
a puncture and still be driven on, albeit at a reduced
speed and limited distance. The RFT tyre is more expensive
partly because of the thicker tyre wall that prevents
the tyre from collapsing due to a loss of pressure.
Typically you should be able to drive approximately
100 miles at 50MPH on a punctured run flat tyre. There
are several benefits to the RFT system; RFT tyres
are safer, if you lose pressure with a conventional
tyre you could career off the road. The RFT keeps
you on the road as the tyre does not collapse. If
you sustain a puncture in a dangerous area or on a
busy wet motorway, you don't have to change the tyre
there and then, just drive on and find a tyre repair
centre. With RFT there's no need for a spare wheel,
which saves you money and boot space.
Upgrading to RFT on a non RFT vehicle is not really
practical or cheap to do. RFT tyres only work with
specially designed RFT rims, so you'll need to buy
4 new rims from BMW / Audi etc. Then you'll need to
source and install an Electronic Tyre Pressure Monitor
System (ETPMS or TPMS). Because a RFT puncture may
not always be obvious to a driver, an electronic tyre
pressure monitor is required to alert the driver to
the loss of pressure.
Follow this link for information on Run
Flat Tyre repairs | alternative
to runflat tyres
