brakes AUDI TT ROADSTER 2008 User Guide

-Intelligent t echnology
--- =---- ----"-!...!-------------------------------
After 15 cycles (deploy and retract), manual operation is suspended
fo r up t o 2.5 minutes . Above 75 mph (120 km/h), operation swi tches
to automatic mode .
& WARNING
Driving at higher speeds witho ut the re ar spoiler deployed can
impair handling characteri stics, making the vehicle harder to
c ontrol.
• Always make sure that the spoiler i s deployed when driving at
speeds over 85 mph (140 k m/h). If the rear spoiler warning /ind i­
c ator light in the in strument clu ster come s on , the rear spoiler
may not have deployed .
• Never drive at speed s higher than 85 mph (140 km /h ) if the
spoiler is not deployed . Have the spoiler inspe cted as soon as
po ssible by an authorized Audi dealer or qualified workshop.
• Always obey speed limits and other traff ic law s.
& WARNING
Improper operation of the rear spoiler can cause crushing injuries.
• Always make su re that nobody , especially children , is in the
way when the rear spoiler is deployed or retracted.
0 Note
Never push the vehicle or a pply force to the rear spoi ler -it cou ld be
damaged .
[ i ] Tips
Clean the spoi ler compartment every 2 to 3 months . The spoiler
compa rtment must always be free of ice, snow, leaves or other
debris. •
Braking
General "nformation
What aff ects braking effi cie ncy?
Operating condition s and driving habits
The brakes on today's automob iles a re sti ll sub ject to wea r,
depending large ly o n operati ng co nditions and driving habits~&.
On vehicles which are driven mostly in stop -and -go city traffic or
whic h are driven hard, the brake pa ds shou ld be checked by your
authorized Audi dea ler more often than specified in the
Mainte ­
nance
& Warranty booklet.
On steep slopes, you should use the braking effect of the en gine.
Th is way, you prevent u nneces sary wea r on the brake syste m. If you
must use your brakes, do not ho ld the brakes down continuous ly.
P ump the brakes at interva ls.
Moisture or road salt
U nde r certain co nditi ons, for example, when driving th rough water
or v ery heavy rain, or eve n after washing your vehicle, the braking
effec t can be red uced d ue to mo isture (o r in freezing c onditions ice)
o n the brake pads . A few cautious brake appl ica tions should dry off
the brake pads or remove any ice coat ings.
T he effe ctiveness of the brakes can be reduced when the ve hicle is
driven on a sa lt -covered road and the brakes are not used. Li kewise,
you clean off accu mulated sa lt co atin g fr om bra ke discs a nd pads
with a few cautious applications of the brake~&.
Corrosion
There may be a tendency for dirt to build up on the brake pads and
corr osi on to for m on the d iscs if the ca r is no t driven regu lar ly or
only for short trips with litt le use of the brakes .
I f the b ra kes a re not used frequently, or if co rros ion ha s formed on
the d iscs, it is adv isable to clean off the pads a nd discs by braking
firm ly a few times from a moderately high speed~& . .,_

Faults in the brake syst em
If you shou ld notice a sudden i ncrease in brake pedal travel, then
one of the two brake circuits may have failed=>
& -
Low brake fluid level
Ma lfunctions can occur in the brake system if the brake fluid leve l is
t oo low. The brake fluid level is moni tored e lect ronica lly .
Brake pow er assist unit
The brake p ow er assist un it increas es th e pressure that you
generate with the brake peda l. It works only when the engine is
running.
& WARNING
• You should perform braking maneuver s for the purpose of
c leaning the brake system only if road conditions permit . Other
road users must not be put at ri sk -you may cause an accident!
• Before des cending a steep grade , redu ce speed and sh ift trans­
mi ssion into a lower gear or lower driving position . Do not ride the
br akes or hold the pedal down too long or too often . This could
cause the brakes to get hot and diminish braking efficiency .
• Do not "ride the brakes " by resting your foot on the pedal when
you do not intend to brake . Thi s may cause the brakes to overheat,
premature we ar and increased stopping distan ce .
• Under certain cl imatic and operating condit ions such as
pas sing through water , driv ing in heavy rain or after washing the
vehicle, the effectiveness of the brake s can be reduced . In winter ,
ice can ac cumulate on the brake pads , linings , discs and drums .
Cautiously apply brakes for a te st. Brakes will dry and ice coatings
will be cleaned off after a few cautious brake appli cations .
• Driving for an extended period of time on salt -covered road s
without using your brakes can also affect brak ing effic iency . Clean
off accumulated salt coating from brake discs and pads with a few
c autiou s brake applications .
Controls and equip­ ment Safety first Vehicle operation
Intelligent technology
& W
ARNING (continued )
• If you damage the front spo iler , or if you install a different
s poiler , be sure the air flow to the front brakes is not obstructed.
Otherwise the brake system could overheat redu cing the effective­
ness of the entire br ake system.
• Failure of one brake circuit will impair the braking capability
resulting in an increa sed stopping distance. Avoid driving the
vehicle and have it towed to the nearest Audi dealer or qualified
workshop.
• Never let the veh icle roll to a stop with the engine shut off .
• If the b rake booster is not working , for e xample when towing
your vehicle, or because the brake booster has somehow been
damaged , the brake pedal must be pre ssed considerably harder to
make up for the lack of booster assistance . •
Anti- lock brake system (ABS)
ABS p revents the wheel s from loc king unde r br ak ing.
The anti -lock brake sys te m (ABS) makes a major contri but ion to
i ncreasing act ive d riv in g sa fety . You should not expect that brakin g
distances wi ll be
shortened unde r all c ircums tances wi th ABS.
B rak in g distance may even become somewhat
longer , for e xa m ple ,
on gravel or in new snow on s lippery ground, even if you are driving
carefully and slowly.
ABS operation
W hen a veh icle speed o f about 10 mph (20 km/ h) is reac hed , an au to ­
matic test sequence is run. Some noise from the pum p may be
audible.
I f the speed of a wheel s lows down too much re lative to vehicle
speed and i t starts to lock, br ake pressu re to th is whee l is reduce d.
T his adjustment process can be felt as a
pulsing motion of the b rake
pedal ,
accompanied by some noises. Yo u as the d rive r are in tent io n­
a lly being g iven the in fo rmation that the wh eels a re tendin g to lock
Vehicle care Do-it-yourself service Technical data

--~ln~t~ e~ l~ li ~g ~e~ n~ t~ te ~ c~h ~n ~ o~ l'..!: o ~g~ yL ________________________________________ _
(ABS control range). In order for ABS to be ab le to operate optima lly
in th is range, you m ust keep the brake pe dal depressed -do not
"pump the brakes" .
Brake ass istant
T he brake power assist unit increases the pressure that you
ge nera te wi th the brake pedal. I t wo rks only whe n the e ngine is
running .
Automatic full braking
This function al lows fu ll braking in spite of high brake pedal forces
(e .g. whe n the b rakes are seve rely s tresse d beca use the veh ic le is
ful ly loaded). The driver notices this function through a reduction of
pedal force a nd i ncrease d pe dal trave l. W hen the brake peda l is
released, fu ll braking assist switches off again automatically .
If there is an ABS fail ure , the brake assistant and automatic fu ll
brak in g ass ist are not ava ilable.
& WARNING
• ABS cannot suspend the la ws of physics . You should keep this
in mind in particular on an icy or wet road . If ABS control of braking
intervenes , you should adjust your speed immediately to road and
traffic condit ions. Do not be tempted by the increased safety
provided to t ake risks -danger of an accident.
• Please keep in mind that the risk of an accident is increased by
dri ving too fast, pa rticularly in bends and on icy or wet roads , and
by driving too close to the vehicle ahead . The increased risk of an
accident cannot be reduced by the brake as sistant - danger of an
accident .
[ i ] Tips
If a ma lfunction occurs in the ABS, this is signa lled by an indicator
lig ht, see
=> page 20. •
Electro-mechanical power assist
-----
The e lec tro -m ec han ical pow er as sis t h el ps th e dri ver
w he n steering.
T he degree of power assist is electronically matched to vehic le
sp eed .
Th e power steering system ass ists the driver so that he can steer the
ve hicle wi th re duced phy sica l eff ort .
P ower steer ing w ill not wo rk if the engine is o ff. As a result, the
steering wheel wi ll be hard to turn.
& WARNING
If the system develops a problem, you must seek qualified profes­
sional assistance .
0 Note
If there is an electronic ma lfunction , servotronic will still funct ion
l ike a conventional power stee ring system, providing a constant
steer in g suppo rt fo rce t hat is no lon ge r proportionate to t he veh icle
speed . This is most noticeable when turning the steering wheel at
lo w spe eds (fo r examp le w hen park ing), -mo re effor t will be
required than usual.
• B e awa re of the d iffer ent than usua l ste ering response and
adjust your steering force accordingly.
• H ave the problem chec ked and set ri ght by an authorized Audi
dea ler as soon as possible .
• I f a steering ma lfunct ion occurs, this is signaled with the~ or.
@ in d ica to r ligh ts and a war ning tone, see . ._

New brake pads
Remember that new brake pads do not have a full braking
effec t during the first 250 miles (400 kilometres) after they
are installed.
New brake pads have to be "burnished in" before they have optima l
grab=> &.
During the break -in period, you should avoid putting severe loads
on the brakes. Severe loads include, for example, sudden hard
braking, in particular at very high speeds or, for example, on moun ­
tain passes.
& WARNING
U ntil the y develop the m axim um "b ite " fo r be st stoppi ng p owe r,
th e s urfaces on new br ake p ads re quir e some " brea king -in " during
th e ini tia l 100 to 150 miles 1 150 to 200 k ilom etres) of nor ma l c ity
driving . You can comp ensa te fo r thi s by press ing the brak e ped al
more fi rml y. T his appl ie s w henev e r ne w pad s a re in sta lled . •
Catalytic converter
It is very important that your emission control system
(catalytic converter) is fu nctioning properly to ensure that
y o ur vehicle is running in an environmentally s ound
manner.
- Always use lead-free gasoline~ page 214, "Fuel supply".
- Never run the tank down a ll the way to empty.
- Never put too much motor o il in your engine~
page 225,
"Adding engine oi l 'l=:;r\11
•
- Neve r try to push -or tow -s tart your ve hicle.
Controls and equip­
ment Safety first Vehicle operation
Dri
ving and environm ent
The catalytic converter is an efficient "clean-up" device built into the
exhaust system of the vehicle . The cataly tic converter burns many
of the pollutants in the exhaust gas before they are re leased into the
atmosphere.
The exclusive use of un leaded fuel is critica lly important for the l ife
of the catalytic converter and proper functioning of the engine.
& WARNING
• Do not park or oper ate th e ve hi cle in are a s whe re the hot
exha ust sys te m may c ome in conta ct wi th dr y grass, bru sh , fu el
s pill or other mat eri al which can cau se a fi re.
• Do not app ly a dditi onal u nder co at ing or ru stpr oofing on or
near the exhau st m anifold , exh au st pipe s, cata ly tic convert er or
he at shi elds. During dri ving, the s ubstance use d f or und ercoa ting
c ould ov erheat an d ca u se a fire.
0 Note
• Be aware that just one tank fi lling with
le ad ed fuel wi ll a lready
seriously degrade the performance of the catalytic converter.
• Do not exceed the correct engine oil level =>
page 225.
• Do not drive until the fuel tank becomes completely empty. The
engine could misfire . Unburned fuel could a lso get into the exhaust
system and this could cause the catalytic converter to overheat .
• Do not turn off the igni tion wh ile the vehicle is moving.
• Do not continue to operate your vehicle under these conditions,
as otherwise fue l can reach the cata lytic converter. This could resu lt
in overheating of the converter, requiring its replacement .
• To assure efficient operation of the Emiss ion Control System:
- Have your vehicle maintained properly and in accordance with
the service recommendations in your Maintenance & Warranty
booklet.
Vehicle care Do-it-yourself service Technical data

___ D_ r_ iv _i_ n-' g"'""'- a_ n_d_ e_ n _ v_i_r _ o _n_ m_ e_ n_t _____________________________________________ _
- Lack of proper maintenance as well as improper use of the
vehicle will impair the function of the emission con trol system
and could lead to damage.
Even when the Emission Control System is operating properly, the
exhaust gas can have a su lfur -like exhaust gas smell under some
operating states . This depends on the su lfur content of the fuel
being used. Using a different brand of fuel may he lp, or filling the
tank with lead-free super grade gasoline. •
Avoid damaging the vehicle
When you are driving on poor roads, or over curbs, steep ramps,
etc., make certain that low-lying parts such as spoilers and exhaust
system parts do not bottom out and get damaged.
This is especially true for vehicles with low-slung chassis (sports
chassis) and fully loaded vehicles. •
Operate your vehicle economically
and minimize pollution
General
Your personal style of driving will determine the economy
of your vehicle, as well as exhaust and noise levels.
Fuel economy, environmental impact, and wear on your engine,
brakes and t ires largely depend on three factors:
• your personal driving style
• operating condit ions
• technical limitations If
you anticipate what you need to do next and drive economically,
you can easily cut your fuel consumption by 10-15 percent . This
section will give you some tips on how you can he lp the environ­
ment and your pocketbook .
[ i ] Tips
The consumption estimates as published by ENVIRONMENTAL
PROTECTION AGENCY (EPA) and Transport Canada may not corre­
spond to your actua l consumption on the road, which will vary
depend ing upon vehicle load and speed, road and weather condi­
tions, trip length, etc. •
Drive smoothly and keep a lookout ahead
Vehicles use the most fuel when they are accelerating.
Avoid unnecessary accelerating and braking.
Vehicles use the most fue l when they are accelerating . If you antici­
pate what is going to happen next, you will need to brake less and,
thus, accelerate less. Let the vehicle coast whenever possible -for
example when you see that the next traffic light is red. •
Avoid full throttle
Driving at moderate speeds saves fuel and improves your
mileage.
- Try and keep well below your car's maximum speed.
Acce lerating gently reduces fuel consumption, engine wear, and
does not disturb the environment.
Fuel consumption, exhaust emissions and engine noise increase
disproportionately at high speeds. If you drive at approximately
three quarters of top speed, fuel consumption wil l be reduced by
9J,,

___ C _l_e _a _ n_ in_g ~_ a_n _ d ___ p ___ r_ o _t _e _c_ t_ i_o _ n _____________________________________________ _
Cleaning and protection
General information
Regular care preserves vehicle value.
Any automobile is exposed to industrial fumes, corrosive road salt,
muddy dog feet, etc . A wel l cared for Audi can look like new many
years after purchase. Regu lar and correct ca re will contribute to
maintaining the beauty and value of your Audi.
Furthermore, good care may be a conditi on for substantiating a
war ranty claim should co rros ion d amage or p aint defec ts occur .
Your authorized Audi dealer has a variety of dedi cated vehicle- care
product s
and can advise whic h ones to use for cleaning the exterior
and interior of your vehicle.
Whether you use p roducts recommended by Audi or other commer ­
cially availab le cleaning agents , please make sure you apply them
correctly.
& WARNING
• Cleaning agents may be poisonous . Keep them out of the reach
of ch ildren .
• Heed all caution label s.
• Alway s read directions on the contai ner before u sing any
produ ct. Follow the di rection s carefull y.
• Most chemical cleaner s are concentrated and have to be
d iluted .
• Use s pot removing fluids only in well ventilated area s.
• Do not us e gasoline , ker osene , die sel fuel , nail polish rem over
or oth er volatile fluid s. They may be toxi c, flammable or ha zardous
in other way s. Do n ot w ash, wa x or dry the vehicle w it h the igni ­
tion on or the engine running.
& WA RNIN G (conti nued)
• Do not clean the under side s of chassis , fe nder s, wheel cove rs,
etc . without protecting your hands and arm s. You may cut yourself
on sha rp -edg ed metal part s.
• Moisture and ice on brakes may impair braking eff iciency
=> page 188 , "General info rm ation ". Test the brake s carefully each
time you wa sh the vehicle.
~ For the sake of the environment
Se lect only environmenta lly friend ly c leaning products . Leftover
clean ing products should not disposed of in the household waste. •
Care of exterior
Washing
Frequent washing protects the vehicle.
Th e best protection against envi ronmental influences is frequent
washing and waxing .
H ow often t his is required depends on:
• H ow much the vehic le is used
• Where the vehicle is pa rked (garage, in the open under t rees,
etc.)
• The seasonal and weather conditions
• Environmental influences
T he longer bird droppings, insects, tree resin, road a nd industrial
grime, tar, soot, road salt and other materials remain on the vehicle
p aint, the more lasting their dest ructive effects will be . _,,,

___ C_ le_ a _ n_i_n ~g _ a_ n_ d __ p_r _o _t _e _c_ t_ i_o _n ___________________________________________ _
Never dry windows with the same chamois that you use to dry
painted s urfaces. Wax residue on the chamois can impair vision
through the windows .
& WARNING
• The windshield must not be treated with water-rep ellent mate­
r ial s. They can increa se glare under poor visibility conditions such
a s w etne ss, darkne ss, or when th e sun i s lo w on th e hori zon. In
addition , they can c ause the wind shield wipers to chatter .
• Alw ays re ad and heed all WARNINGS and oth er infor matio n
=>
pa ge 200.
0 Note
• Never use warm or hot wa ter to remove snow and ice from
windows and mirrors. This could cause the glass to crack.
• To prevent damage to t he w ires of the rear defogger, do not p lace
any adhesive stickers on the inside of the rear window over the
wires.
• To he lp prevent dirt from scratching the w indow, always scrape
in a forward direction - pushing the scraper away from you -never
back and forth .•
Weatherstrips
C omplete car care includes the weatherstrips as well.
- App ly a suitable rubber co nditioner to the weat herstr ips
f rom t ime to t ime .
To be able sea l properly, the weatherstrips around the hood, doors,
rear lid, etc. must remain pliable . Spray the weath erstrips with si li­
cone or coat them w ith ta lcum powder or glycerine to retain the
flexibili ty of the rubber and to protect them against free zing in the
winter .
& WARNING
Always read and he ed all WARNINGS and the inf orm ation
=>
page 2 00 .
[ i ] Tips
Keep si licone sp rays o ff the windsh ield to avo id wiper smear in
rain .•
A pplies to vehi cles : w it h s tee l w hee ls
Steel wheels
The wheels also have to be cleaned.
Always include the hub caps and wheel rims when
washing your vehicle to remove road dirt, sal t sprays and
brake dust.
If necessary, use a commercial wheel cleaner to remove accumu ­
l ated brake dust.
The wheel rims are eas ier to keep clean i f they are regularly coated
wi th liquid wax .
Paint scratches should be touc hed u p as soon as possible to prevent
corrosion=>
page 205, " T ouch -up paint".
& WARNING
• Moisture and ice on brakes m ay affe ct br aking efficie ncy -
=>
page 188 , "Gene ral information ". Te st the brake s carefull y after
e ac h vehi cle wa sh .
• Alway s read and heed all WARNINGS and the information
=>
pa ge 200. •

Cleaning and prote ction BIii
------------------------------------=-----=-------
•
Ap plies to vehi cles : w it h C ast a llo y wh eels
Cast (light) alloy wheels
Cast (light) alloy wheels require special care.
-Wash the wheels w ith a sponge or hose brush eve ry
ot her week .
- For de ep cleaning afterwar ds, use only a dedicated
acid ­
free cast alloy wheel cleaner .
- Ru b a c oat of
liquid wax on to t he rims every t hree mon th.
B e sure t o reach and treat all parts of the rim .
To preserve the decora tive appearance of the cas t alloy whee ls,
some special care is necessary . In addition to road dirt and sa lt ,
b rake dust is also co rro sive . If left o n fo r to o long, brake dust can
cause pitting .
Use only special
ac id -free cleaners formulated for alloy rims . Safe
products are available at your Audi dea ler . Never leave the cleaner
on the r ims longer than specified on the label. If not rins ed off
promp tly, the acid contained in some cleaners can a ttack the
threads on the wheel bolts .
Never use abrasive or me tal po lishing cleaning agents . If the protec ­
tive coat ing has been chipped, e .g . by kicked up road dirt. touch it
up as soon as possib le .
& WARNING
• Moi sture and ice on brakes may affect braking efficiency
=> page 188 , "General information ". Te st the b rake s c arefully ea ch
time you wash the vehicle.
• Alway s read a nd heed all WARNINGS and other informat ion
=> page 200 . •
Body cavity sealing
T he body c avity sealing d oes not need t o be checke d.
A ll body cavities which could be aff ected by corrosion hav e been
given thor ough protecti on a t the facto ry.
This sealing does not require any inspection or add itional treat ­
ment . If any wax shou ld seep out of the cavity when the ambient
tempera ture is high , it can be removed wi th a p las tic sc raper and a
suitable solvent.
& WARNING
Solvent s can be dangerous.
• Benz ine is flammable and to xic . If you use benz ine for removing
the wax , keep sparks , flame and lighted cigarettes away . Never
dump benz ine on the ground , into open streams or down sewage
drains .
• Be sure to observe all safety and environmental regulat ions .
Follow all instru ctions on the container.
• Always read and heed all WARNINGS and the information
=> page 200 . •
Chassis
Have the undercoa ting checked for damag e from time to
time .
The lowe r body shell of your Audi is a lso thoroughly protected
against corros ion.
Any damage to the undercoating caused by road ha za rds sh ould be
repaired promp tly .
& WARNING
Too much unde rcoat ing in the wrong pla ces can cause a fire .
Vehicle care
I t •

________________________________________________ T_ i _r_e _s_ a_n_ d_ w_ h_ e_e _ l_s __ l'III
•
& W ARNING (continu ed )
crashes and serious personal in jur ies . Have worn or da maged t ires
replaced immediately .
• Tires age even if they are not being u sed and can fail suddenly ,
especially at high speeds. T ires that are more than 6 years old can
only be used in an emergency and then w ith special care and at
low speed.
Glossary of tire and loading terminology
Accessory weight
means the co mbined we ig ht ( in excess o f those sta nda rd items
which may be rep laced) of automatic transmission, power steering,
power brakes, power w indows, powe r seats, rad io, a nd heater, to
the extent that these items are avai lab le as factory-installed equip­
m ent (w hether insta lled or not).
Aspect ratio means t he ratio o f th e height to t he w idt h of the tire in perce nt.
N umbers of 55 or lower indicate a low sidewa ll for improved
steer ing respo nse and b ette r overall ha ndl ing on dry pave ment.
Bead
means the part of the tire that is made of stee l wires, wrapped or
reinforced by ply cords and that is shaped to fit the rim.
Bead separation
means a breakdow n of the bond be tween co mponents i n the bead.
Cord
m eans the strands fo rmi ng the plies in the ti re.
& W ARNING (continued )
• Never mount used tires on your vehicle if you are not sure of
their "previous history. " Old used t ire s may ha ve been damaged
even though the damage cannot be seen that can lead to sudden
tire failure and lo ss of vehicle control.
• If you noti ce unusual vibration or if the vehicle pulls to one side
when driving , always stop as soon as it is safe to do so and check
the wheels and tires for damage . •
Cold tire inflation pressure
mea ns t he ti re pressure reco mm ended by the ve hicle ma nufacturer
for a tire of a designated size that has not been d riven for more tha n
a cou ple o f miles (k ilometers) at low speeds in t he t hre e ho ur per iod
before the tire pressure is measured or ad justed .
Curb weight
means the weight of a moto r vehic le with standard equipment
i nc lud ing the max imu m capac ity o f fue l, o il, and coola nt, a ir c ond i­
tioning and additiona l weight of optional equipment.
Extra load tire
means a tire designed to ope rate at higher loads and at higher infla­
tion pressures than the corresponding standard tire. Extra load tires
my be identified as "XL", "xi", "EX TRA LOAD", or "RF" on the side ­
wa ll.
Gross Axle Weight Rating ("GAWR ")
means the load -carrying capacity of a sing le ax le system, measured
at the ti re -ground interfaces.
Gross Vehicle Weight Rating ("GVWR "l
mea ns the ma ximum tot al l oade d weigh t of the vehicle.
Vehicle care
I t •

-~_T_ ir_e_ s_ a_ n_d _ w_ h_ e_e _l_s _________________________________________________ _
Groove
means the space between two adjacent tread ribs.
Load rating (code)
means the maximum load that a tire is rated to carry for a given
inflation pressure . You may not find this information on all tires
because it is not required by law.
Maximum load rating
means the load rating for a tire at the maximum permissible infla­
tion pressure for that tire.
Maximum loaded vehicle weight
means the sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight, and
(d) Production options weight
Maximum (permissible) inflation pressure
means the maximum cold inflation pressure to which a tire may be
in flated. Also called "maximum inflation pressure ."
Normal occupant weight
means 150 lbs. (68 kilograms) times the number of occupants
seated in the vehicle up to the total seating capacity of your vehicle.
Occupant distribution
means distribution of occupants in a vehicle .
Outer diameter
means the overall diameter of an inflated new tire.
Overall width
means the linear distance between the exteriors of the sidewalls of
an inflated tire, including elevations due to labeling, decorations, or
protective bands or ribs .
Ply
means a layer of rubber -coated parallel cords.
Production options weight
means the combined weight of those installed regular production
options weighing over 5 lbs. (2.3 kg) in excess of those standard
items which they replace, not previously considered in curb weight
or accessory weight, including heavy duty brakes, ride levelers,
heavy duty battery, and special trim.
Radial ply tire
means a pneumatic tire in which the ply cords that extend to the
beads are laid at substantially 90 degrees to the centerline of the
tread.
Recommended inflation pressure
see =:> page 239, "Cold tire inflation pressure".
Reinforced tire
means a tire designed to operate at higher loads and at higher infla­
tion pressures than the corresponding standard tire. Reinforced
tires my be identified as "XL", "xi", "EXTRA LOAD", or "RF" on the
sidewall.
Rim
means a metal support for a tire or a tire and tube assembly upon
which the tire beads are seated .
Rim diameter
means nominal diameter of the bead seat. If you change your wheel
size, you will have to purchase new tires to match the new rim diam ­
eter.
Rim size designation
means rim diameter and width.
Rim width
means nominal distance between rim flanges .