2018 AUDI TT ROADSTER wheel size

Intelligent Technology
Intelligent Technology Electronic stabilization
control (ESC)
Description
Elect ronic stabili zation control ( ESC) suppo rts
driver safety. It red uces the risk of slipping and
improves dr iving stabi lity. ESC detects crit ica l sit­
uations such as the vehicle overstee ring and un­
dersteeri ng or the w heels are sp inning. The vehi­
cle is stabilized by app lying the brakes or reduc ­
i n g e ngine torque . When the ESC engages, the
liJ indicato r light bli nks in t he instr ument clus­
t er.
The fo llow ing systems are in tegrated in the ESC:
Anti-lock braking system (ABS)
ABS p reve nts the whee ls from lock ing whe n brak ­
ing. The vehicle can st ill be steered even d uring
hard brak ing. Apply steady press ure to the bra ke
pedal. Do not pump the pedal. A puls ing in t he
b rake pedal indicates that the system is act ing to
s tabili ze the vehicle .
Brake assist system
The brake assist system can decrease brak ing dis­
tance . It inc reases brak ing power when the d river
presses the brake pedal q uick ly in eme rgency sit­
uations . You must press and hold t he b rake pedal
until the dangerous si tuatio n is ove r.
Anti-slip regulation (ASR)
ASR red uces eng ine power when the d rive wheels
begin sp inning a nd adapts the force to the road
conditions . This makes it easie r to start, acceler­
ate and dr ive u p hill s.
Electronic differential lock (EDL)
E DL applies the brakes to a wheel that sta rts
spi nning and t ransfe rs the d rive power to the
other driving wheels. This f unction is not availa­
b le at higher speeds.
In extreme cases, EDL automatically sw itches off
to keep the brake on the b raked wheel from over­
heati ng. The vehicle is st ill work ing correctly. EDL
86
will swi tc h on again automatically when condi ­
tions have retu rned to normal.
Power steering
The ESC can also support veh icle stab ility
t hr ough stee rin g.
Selective wheel torque control
Se lective wheel to rque con trol is used when d riv­
i ng on curves . The front whee l on the ins ide of
t h e curve or bo th whee ls on the i nside of th e
cu rve are braked se lective ly as needed. This al­
l ows mo re pre cise dr iving in curves .
_&. WARNING
-The E SC and i ts in teg ra ted systems cannot
overcome the lim its imposed by natura l
phys ica l laws. This is es pec ially important
on s lippery or wet roa ds.
If the systems be­
gin acting to stabilize yo ur vehicle, you
should immediately a lter your speed to
match the road and traffic conditions. Do
no t le t the inc reased safety p rovi ded tempt
you into taking risks. This could increase
y o ur r is k of a c oll is ion.
- Please note the r is k of a coll is ion increases
w hen dr iv in g fast, especially t hrough curves
a nd on sl ippery or wet r oads, and w hen dr iv­
ing to o cl ose to obje cts ahead. T he ES C and
it s i ntegrated systems cannot a lways pre ­
vent co llisions
-there is st ill a risk of acci­
dents!
- Press the accelerator peda l caref ully when
accelerating on even, slippery sur faces such
as ice and snow. The drive wheels can spin
even when these control systems a re instal­
led and this can affect driving stability and
increase the risk of a collision.
(0 Tips
- The ABS and ASR only funct ion correctly
when a ll four wheels have a sim ila r wear
co nditio n. D iffere nt tire sizes can lead to a
red uction in engin e power.
- You may hear noises when the systems de­
sc ribed are working .

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seat backrests; never place them between
these areas and you or any other person in
the vehicle.
- Never attach objects to the windshield
above the passenger front airbag, such as
accessory GPS navigation units or music
players. Such objects could cause serious in ­
jury in a collision, especially when the air­ bags inflate .
A WARNING
A person on the front passenger seat, espe­
cially infants and small children, will receive
serious injuries and can even be killed by be­
ing too close to the airbag when it inflates.
- Although the Advanced Airbag System in
-
your vehicle is designed to turn off the front
passenger airbag if an infant or a small child
is on the front passenger seat, nobody can
absolutely guarantee that deployment un­
der these special conditions is impossible in
all conceivable situations that may happen
during the useful life of your vehicle.
- The Advanced Airbag System can deploy in accordance with the "low risk" option under
the U .S . Federal Standard if a child that is
heavier than the typical one-year old child is
on the front passenger seat and the other
conditions for airbag deployment are met.
- For its own safety, a child should always ride
properly restrained for its age and size.
Advanced front airbag system
Your vehicle is equipped with a front Advanced
Airbag System in compliance with United States
Federal Motor Vehicle Safety Standard (FMVSS)
208, as well as Canada Motor Vehicle Safety
Standard (CMVSS) 208 as applicable at the time
your vehicle was manufactured.
The front Advanced Airbag System supplements
the safety belts to provide additional protection
for the driv er's and front passenger's heads and
upper bodies in frontal crashes . The airbags in­
flate only in frontal impacts when the vehicle de­
celeration is high enough.
Airbag system
The front Advanced Airbag System for the front
seat occupants is not a substitute for your safety
belts. Rather, it is part of the overall occupant re­
straint system in your vehicle. Always remember
that the airb ag system can only help to protect
you, if you are sitting upright, wearing your safe­
ty belt and wearing it properly . This is why you
and your passengers must always be properly re­
strained, not just because the law requires you to
be.
The Advanced Airbag System in your vehicle has
been certified to meet the "low risk" require­
ments for 3 and 6 year-old children on the pas­
senger side and very small adults on the driver
side. The low risk deployment criteria are intend­
ed to help reduce the risk of injury through inter­
action with the front airbag that can occur, for
example, by being too close to the steering wheel
and instrument p anel when the airbag inflates.
In addition, the system has been certified to
comply with the "suppression" requirements of
the Safety Standard, to turn off the front airbag
for infants 12 months old and younger who are
res trained on the front passenger seat in child re­
straints that are listed in the Standard
~page 218, Child restraints and Advanced front
airbag system .
"Suppression" requires the front airbag on the
passenger side to be turned off if:
- a child up to about one year of age is restrained
on the front passenger seat in one of the rear­
facing or forward-facing infant restraints listed in Federal Motor Vehicle Safety Standard 208
with which the Advanced Airbag System in your
vehicle was certified . For a listing of the child
restraints that were used to certify your vehi­
cle's compliance with the US Safety Standard
~page 218,
- When a person is detected on the front passen­
ger seat that has an electrical capacitance that
is more than the total electrical capacitance of
a child that is about 1 year old restrained in one
of the rear-facing or forward-facing infant re­
straints (listed in Federal Motor Vehicle Safety
Standard 208 with which the Advanced Airbag
System in your vehicle was certified), the front
.,,.
199

Child sa fety
Advanced front airbag system and children
Your veh icle is equipped w ith a front "Advanced
A irbag System" in comp liance w it h United States
F edera l Motor Vehicle Safety Standard ( FMVSS)
208, as well as Canada Motor Vehicle Safety
Standard (CMVSS) 208 as applicable at the time
your vehicle was manufactured.
The Advanced Airbag system in your veh icle has
been certified to meet the " low-risk" require ­
ments for 3- and 6-year old children on the pas­
senger side and small adults on the driver side.
The low risk deployment criteria are intended to
reduce the risk of injury through interaction with
the airbag that can occur, for example, by being
too close to the steering wheel and instrument
panel when the a irbag inflates. In addit ion, the
system has been certified to comply w ith the
" su ppress io n" req uirements of the Safety S tand­
ard, to tu rn off the front airbag for infants up to
12 months who are restrained on the front pas­
senger seat in child restraints that are listed in
the Standard.
E ven tho ugh yo ur vehicle is equipped with an
Ad a
vanced Airbag system, a chi ld should a lways ride
in the seat proper ly restrained for its age and
size. The airbag on the passenger side makes the
front seat a potentially dangerous p lace for a
child to r ide . The front seat is not the safest place
for a child in a forward-facing child safety seat .
It
can be a very dange rous place for a n infant or a
larger child in a rearward-fac ing seat.
The vehicle's Advanced Airbag System has a ca­
pac itive passenger detect ion system in the front
passenger seat cush ion that ca n detect the pres­
ence of a baby or a child in a ch ild restraint sys­
tem on t his seat .
The capac it ive passenger detect ion system regis ­
ters the changes that result in an electr ical field
when a c hild, a child restra int, and a baby blanket
a re on the front passenge r seat. The change in
t he meas ured capacitance due to t he p resence o f
a child, a chi ld restraint, and a baby b lanket on
the front passenger seat is re lated to the chi ld
restraint system resting on the seat . The meas ­
ured capacitance of a ch ild restraint system var-
218
ies depending on the type of system and specific
make and mode l.
The elect rical capac ita nce of the va rious types,
makes, and models of child restra in ts speci fied
by the U.S . National Highway Tra ffic Safety Ad­
ministration (NHTSA) in the relevant safety
standard are stored in the Advanced Airbag Sys ­
tem control unit together with the capacitances
typ ica l of infants and a 1-year old child. When a
c hi ld restraint is used on the front passenger
seat w it h a typical 1 year-old infant, t he Ad­
vanced Airbag System compares the capacitance measured by the capacitive passenge r detect ion
system wi th the data stored in the e lec tronic co n­
tro l unit .
Child restraints and Advanced front airbag
system
Regardless of the ch ild restraint that you use,
make sure that it has been certified to meet Safe­
ty Standards and has been cert ified by its manu ­
factu rer for use w ith an airbag . If in exceptional
c ir cumstances you m ust use it on the front pas­
senger seat, ca refully read all of the information
o n chi ld safety and Advanced Airbags and heed
a ll of th e app licab le WARNINGS . Make certain
that the chi ld and chi ld restraint are correctly
recognized by the capacitive passenger detection
system in the front passenger seat, that the front passenger a irbag is turned off, and that the air­
bag status is always correct ly signa led by the
PASSENGER AIR BAG OFF ~; light.
Many types and models of child restra ints have
been available over the years, new models are in­
troduced regularly incorporating new and im­
proved designs and older models are taken out of
production . Ch ild rest rai nts are not standa rdized .
Child res tra ints of the same type typically have
d iffe rent weights and sizes and diffe re nt "foot ­
pr ints", the size and shape o f th e bo ttom of the
ch ild restraint that sits on the seat, w hen they
are installed on a vehicle seat . These differences
make it virtua lly impossib le to certify comp liance
with the requirements for advanced a irbags w ith
each and every child restra int that has ever been
sold in the past or will be sold over the course of
the useful life of your veh icle .
.,.

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Tire designations
Fig. 187 Tire designation on the side­
wall
(D Tires for passenger vehicles
(if applicable)
"P" indicates a tire for a passenger
vehicle . "T" indicates a tire desig­
nated for temporary use.
@ Nominal width
Nominal width of the tire be­
tween the sidewalls in millime­
ters. In general: the larger the
number, the wider the tire .
@ Aspect ratio
Height/width ratio expressed as a
percentage .
Wheels
@Tire construction
"R" indicates a radial tire.
® Rim diameter
Size of the rim diameter in inches.
® Load index and speed rating
The load index indicates the tire's
load-carrying capacity.
The speed rating indicates the
maximum permitted speed. Also
see
¢ &. in General information
on page 244.
"EXTRA LOAD", "xl" or "RF" indi­
cates that the tire is rei nforc ed or
i s an Extra Load tire .
Speed rat-
Maximum permitted speed
ing
p up to 93 mph (150 km/h)
Q up to 99 mph (160 km/h)
R up to 106 mph (170 km/h)
s up to 110 mph (180 km/h)
T up to 118 mph (190 km/h)
u up to 124 mph (200 km/h)
H up to 130 mph (210 km/h)
V up to 149 mph (240 km/h)a)
z above 149 mph (240 km/h)a)
w up to 168 mph (270 km/h)a)
y up to 186 mph (300 km/h)a)
a) For tires above 149 mph (240 km/h) ,
tire manufacturers sometimes use the
code "ZR".
245

windows, power seats, radio, and heater, to the extent that these
items are available as factory- in­
stalled equipment (whether in­
stalled or not) .
Aspect ratio
means the ratio of the height to
the width of the tire in percent .
Numbers of 55 or lower indicate a
low sidewall for improved steer­
ing response and better overall
handling on dry pavement .
Bead
means the part of the tire that is
made of steel wires , wrapped or
reinfo rced by ply cords and that is
shaped to fit the rim .
Bead separation
means a breakdown of the bond
between components in the bead .
Cord
means the strands forming the
plies in the tire.
Cold tire inflation pressure
means the t ire pressure recom­
mended by the vehic le manufac­
turer for a tire of a designated
Wheels
three hour period before the tire
pressure is measured or adjusted .
Curb weight
means the weight of a motor ve­
hicle with standar d equipment in ­
c luding the maximum capacity of
f u el, oi l, and coolant, air condi ­
tioning and additional weight of
optional eq uipment.
Extra load ti re
means a t ire designed to operate
at higher loads and at higher in ­
flation pressures than the corre­
sponding s tandard tire. Extra load
ti res may be identified as
"XL",
"xl" "EXT RA LOAD" or "RF" on , ,
the sidewall.
Gross Axle Weight Rating
(" GAWR ")
means the load -carrying capacity
of a single axle system, measured
at the tire -ground interfaces.
Gross Vehicle Weight Rating
( " GVWR ")
means the maxim um total loaded
weight of the vehic le .
Groove
size that has not been driven for means the space between two ad -
~ more than a co uple of miles (kilo -jacent tread ribs . .,.
"
8 meters) at low speeds in the
" "' a:,
2 47

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" N .... 0
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beads are laid at substantially
90 degrees to the centerline of
the tread .
Recommended inflation
pressure
see ¢ page 247, Cold tire infla­
tion pressure .
Reinforced tire
means a tire designed to operate
at higher loads and at h igher in ­
flation pressures than the corre­
sponding standard tire. Rein­
forced tires may be identified as
"XL", "xl", "EXT RA L OAD", or "RF"
on the sidewa ll.
Rim
means a metal support for a tire
or a tire and tube assemb ly upon
which the t ire beads are seated .
Rim diameter
means nominal diameter of the
bead seat . If you change your
whee l size, you will have to pu r­
c h ase new t ires to match the new
rim diameter .
Rim size designation
means rim diamete r and width .
Rim width
means nominal distance between
rim flanges .
Wheels
Sidewall
means that portion of a tire be ­
tween the tread and bead .
Speed rating (letter code)
means the speed at which a tire is
designed to be driven for extend­
ed periods of time. The ra tings
range from
93 mph (150 km/h)
to
186 mph (298 km/h) ¢ table
on page 245 .
You may not find
this informat ion on all tires be ­
cause it is not required by law .
The speed rating letter code,
where applicable, is molded on
the tire sidewall and indicates t he
maximum pe rmissible roa d
speeds . See also ¢
A in General
information on page 244.
Tire pressure monitoring
system *
means a system that detects
when one or more of a vehicle's
ti res are underinflated and illumi ­
nates a low tire pressure warning
telltale .
Tread
means that portion of a ti re that
comes into contact with the road .
.,.
249

0
Vehicle maximum load on the
tire
means that load on an individual
tire that is determined by distrib­
uting to each axle its share of the
maximum loaded vehic le we ight
and dividing by two .
Vehicle normal load on the tire
means that load on an individual
tire that is determined by distrib ­
uting to each axle its share of the
curb weight, accessory weight,
and normal occupant weight (dis­
tributed in accordance
with ¢ ta­
ble on page 256)
and dividing by
two .
Occupant loading and distri­
bution for vehicle normal load
for various designated seating
capacities
Refer to the tire inflation pres­
sure label for the number of seat ­
ing positions . Refer to the tab le
¢
table on page 256 for the
number of people that corre­
spond to the vehic le normal load .
New tires or wheels
Audi recommends having all wo rk
on t ires or wheels performed by
~ an authorized Audi dealer or au-N
" ~ thorized Audi Service Facility. 0
" "' a:,
Wh eel s
These facilities have the proper
knowledge and are equipped with
the required tools and replace­ ment parts.
.,. New tires do not yet have the
optimum g ripping properties.
Drive carefully and at moderate
speeds for the first 350 miles
(500 km) with new tires .
i,.Qnly use tires w ith the same de­
sign, size (rolling circumfer ­
ence), and as close to the same
tread pattern as possible on all
four whee ls .
.,. Do not replace tires individually .
At least replace both tires on the
same axle at the same t ime.
.,. Audi recommends that you use
Audi Original Tires. If you would
like to use different tires , please
note that the tires may perform
differently even if they are the
same size
¢ ,& .
.,. If you would like to equip your
vehic le w ith a tire/r im combina­
tion that is different from what
was installed at the factory, con­
sult w ith an authorized Audi
dealer or authorized Audi Service
Facility before making a pur-
chase¢ ,&.. .,.
25 1

Wheels
Because the spare tire* is differ­
ent from the regular tires instal­ led on the vehicle (such as winter
tires or wide tires), only use the
spare tire* temporarily in case of
emergency and drive carefully
while it is in use. It should be re­ placed with a regular tire as soon
as possible.
Applies to: vehicles with all wheel
drive: all four wheels must be
equipped with tires that are the
same brand and have the same
construction and tread pattern so
that the drive system is not dam­
aged by different wheel speeds.
For this reason, in case of emer­
gency, only use a spare tire* that
is the same circumference as the
regular tires.
& WARNING ~ -
-Only use tire/rim combina­
tions and suitable wheel bolts
that have been approved by
Audi. Otherwise, damage to
the vehicle and an accident could result.
-For technical reasons, it is not
possible to use tires from oth­
er vehicles - in some cases,
you cannot even use tires from
the same vehicle model.
252
-Make sure that the tires you
select have enough clearance
to the vehicle. Replacement
tires should not be chosen simply based on the nominal
size, because tires with a dif­
ferent construction can differ greatly even if they are the
same size. If there is not
enough clearance, the tires or
the vehicle can be damaged and this can reduce driving
safety and increase the risk of
an accident.
-Only use tires that are more
than six years old when abso­
lutely necessary and drive
carefully when doing so.
-Do not use run-flat tires on
your vehicle. Using them when not permitted can lead to ve­
hicle damage or accidents.
- If you install wheel covers on
the vehicle, make sure they al­ low enough air circulation to
cool the brake system. If they
do not, this could increase the
risk of an accident.