2019 MERCEDES-BENZ SL CLASS tire pressure

Important notes on tire pressure
GWARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
RCheck the tire for foreign objects.
RCheck whether the wheel is losing air or
the valve is leaking.
If you are unable to rectify the damage, con-
tact a qualified specialist workshop.
GWARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded
and malfunction, which can cause tire pres-
sure loss. Due to their design, retrofitted tire
pressure monitors keep the tire valve open.
This can also result in tire pressure loss.
There is a risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check thetire pressure. The outer appearance of a tiredoes not permit any reliable conclusion aboutthe tire pressure. On vehicles equipped withthe electronic tire pressure monitor, the tirepressure can be checked in the on-board com-puter.
The tire temperature and pressure increasewhen the vehicle is in motion. This is depend-ent on the driving speed and the load.
Therefore, you should only correct tire pres-sures when the tires are cold.
The tires are cold:
Rif the vehicle has been parked with the tiresout of direct sunlight for at least three hoursand
Rif the vehicle has not been driven furtherthan 1 mile (1.6 km)
The tire temperature changes depending onthe outside temperature, the vehicle speedand the tire load. If the tire temperaturechanges by 18 ‡ (10 †), the tire pressurechanges by approximately 10 kPa (0.1 bar/1.5 psi). Take this into account when checking
the pressure of warm tires. Only correct thetire pressure if it is too low for the currentoperating conditions. If you check the tirepressure when the tires are warm, the result-ing value will be higher than if the tires werecold. This is normal. Do not reduce the tirepressure to the value specified for cold tires.The tire pressure would otherwise be too low.
Observe the recommended tire pressures forcold tires:
Ron the Tire and Loading Information placardon the B-pillar on the driver's side
Rin the tire pressure table on the inside of thefuel filler flap
Underinflated or overinflated tires
Underinflated tires
GWARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addi-
tion, they also suffer from excessive and/or
irregular wear, which can severely impair the
braking properties and the driving character-
istics. There is a risk of an accident.
Avoid tire pressures that are too low in all
the tires, including the spare wheel.
Underinflated tires may:
Roverheat, leading to tire defects
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on fuel consumption
Overinflated tires
GWARNING
Tires with excessively high pressure can
burst because they are damaged more eas-
ily by road debris, potholes etc. In addition,
they also suffer from irregular wear, which
can severely impair the braking properties
and the driving characteristics. There is a
risk of an accident.
Avoid tire pressures that are too high in all
the tires, including the spare wheel.
298Tire pressure
Wheels and ti res

Overinflated tires may:
Rincrease the braking distance
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on ride comfort
Rbe more susceptible to damage
Maximum tire pressures
CExample: maximum permissible tire pres-sure
Never exceed the maximum permissible tireinflation pressure. Always observe the recom-mended tire pressure for your vehicle whenadjusting the tire pressure (Ypage 296).
iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
Checking the tire pressures
Important safety notes
The tire pressure monitor does not warn youof:
Rincorrectly set tire pressure
Rsudden loss of tire pressure, e.g. from a for-eign object that has penetrated the tire
Observe the notes on tire pressure(Ypage 296).
Information on air pressure for the tires onyour vehicle can be found:
Ron the vehicle's Tire and Loading Informa-tion placard on the B-pillar
Ron the tire pressure table in the fuel fillerflap
Rin the "Tire pressure" section
Checking tire pressures manually
To determine and set the correct tire pressure,proceed as follows:
XRemove the valve cap of the tire that is tobe checked.
XPress the tire pressure gauge securely ontothe valve.
XRead the tire pressure and compare it to therecommended value on the Tire and LoadingInformation placard or the tire pressuretable (Ypage 296).
XIf the tire pressure is too low, increase thetire pressure to the recommended value.
XIf the tire pressure is too high, release air.To do so, press down the metal pin in thevalve, using the tip of a pen for example.Then check the tire pressure again using thetire pressure checker.
XScrew the valve cap onto the valve.
XRepeat these steps for the other tires.
Tire pressure monitor
General notes
If a tire pressure monitor is installed, the vehi-cle's wheels have sensors that monitor the tirepressures in all four tires. The tire pressuremonitor warns you if the pressure drops in oneor more of the tires. The tire pressure monitoronly functions if the corresponding sensorsare installed in all wheels.
Information on tire pressures is displayed inthe multifunction display. After a few minutesof driving, the current tire pressure of each tireis shown in theServ.Serv.menu of the multifunc-tion display.
Example: current tire pressure display
For information on the message display, referto the "Checking the tire pressure electroni-cally" section (Ypage 301).
Tire pressure299
Wheels and tires
Z

Important safety notes
GWARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure rec-
ommended by the vehicle manufacturer on
the Tire and Loading Information placard on
the driver's door B-pillar or the tire pressure
label on the inside of the fuel filler flap. If
your vehicle has tires of a different size than
the size indicated on the Tire and Loading
Information placard or the tire pressure
label, you should determine the proper tire
pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires are significantly underinflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a signifi-
cantly underinflated tire causes the tire to
overheat and can lead to tire failure. Under-
inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle's han-
dling and stopping ability.
Please note that the TPMS is not a substi-
tute for proper tire maintenance, and it is
the driver's responsibility to maintain cor-
rect tire pressure, even if underinflation has
not reached the level to trigger illumination
of the TPMS low tire pressure telltale.
USA only:
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
detects a malfunction, the warning lamp will
flash for approximately a minute and then
remain continuously illuminated. This
sequence will be repeated every time the
vehicle is started as long as the malfunction
exists.
When the malfunction indicator is illumina-
ted, the system may not be able to detect or
signal low tire pressure as intended. TPMS
malfunctions may occur for a variety of rea-
sons, including the mounting of incompati-
ble replacement or alternate tires or wheels
on the vehicle that prevent the TPMS from
functioning properly. Always check the
TPMS malfunction telltale after replacing
one or more tires or wheels on your vehicle
to ensure that the replacement or alternate
tires and wheels allow the TPMS to continue
to function properly.
It is the driver's responsibility to set the tirepressure to that recommended for cold tireswhich is suitable for the operating situation(Ypage 296). Note that the correct tire pres-sure for the current operating situation mustfirst be taught-in to the tire pressure monitor.If a substantial loss of pressure occurs, thewarning threshold for the warning message isaligned to the taught-in reference values.Restart the tire pressure monitor after adjust-ing the pressure of the cold tires(Ypage 301). The current pressures aresaved as new reference values. As a result, awarning message will appear if the tire pres-sure drops significantly.
The tire pressure monitor does not warn you ofan incorrectly set tire pressure. Observe thenotes on the recommended tire pressure(Ypage 296).
The tire pressure monitor is not able to warnyou of a sudden loss of pressure, e.g. if thetire is penetrated by a foreign object. In theevent of a sudden loss of pressure, bring thevehicle to a halt by braking carefully. Avoidabrupt steering movements.
The tire pressure monitor has a yellow warninglamp in the instrument cluster for indicatingpressure loss or a malfunction. Whether thewarning lamp flashes or lights up indicateswhether a tire pressure is too low or the tirepressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, thetire pressure on one or more tires is signifi-cantly too low. The tire pressure monitor isnot malfunctioning.
Rif the warning lamp flashes for approx-imately a minute and then remains lit con-
300Tire pressure
Wheels and ti res

stantly, the tire pressure monitor is malfunc-tioning.
In addition to the warning lamp, a messageappears in the multifunction display. Observethe information on display messages(Ypage 227).
It may take up to ten minutes for a malfunc-tion of the tire pressure monitor to be indica-ted. A malfunction will be indicated by the tirepressure warning lamp flashing for approx-imately one minute and then remaining lit.When the malfunction has been rectified, thetire pressure warning lamp goes out after afew minutes of driving.
The tire pressure values indicated by the on-board computer may differ from those meas-ured at a gas station with a pressure gage. Thetire pressures shown by the on-board com-puter refer to those measured at sea level. Athigh altitudes, the tire pressure values indica-ted by a pressure gage are higher than thoseshown by the on-board computer. In this case,do not reduce the tire pressures.
The operation of the tire pressure monitor canbe affected by interference from radio trans-mitting equipment (e.g. radio headphones,two-way radios) that may be being operated inor near the vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in positionH(Ypage 126) in the ignition lock.
XPress theYorebutton on the steer-ing wheel to select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPressv.The current tire pressure of each tire isshown in the multifunction display.
If the vehicle has been parked for over20 minutes, theTire pressure will beTire pressure will bedisplayed after driving a few minutesdisplayed after driving a few minutesmessage appears.
After a teach-in process, the tire pressuremonitor automatically detects new wheels ornew sensors. As long as a clear allocation ofthe tire pressure value to the individual wheelsis not possible, theTire Pressure MonitorTire Pressure MonitorActiveActivedisplay message is shown instead ofthe tire pressure display. The tire pressuresare already being monitored.
Tire pressure monitor warning mes-
sages
The tire pressure monitor detects a pressureloss in one or more tires:
RIf the tire pressure monitor detects a pres-sure loss in one or more tires, a warningmessage is shown in the multifunction dis-play. The yellow tire pressure warning lampthen lights up.
RIf thePlease Correct Tire PressurePlease Correct Tire Pressuremessage appears in the multifunction dis-play, the tire pressure in at least one tire istoo low. The tire pressure must be correctedwhen the opportunity arises.
RIf theCheck TiresCheck Tiresmessage appears in themultifunction display, the tire pressure in atleast one tire has dropped significantly. Thetires must be checked.
RIf theWarning Tire MalfunctionWarning Tire Malfunctionmes-sage appears in the multifunction display,the tire pressure in at least one tire hasdropped suddenly. The tires must bechecked.
Observe the instructions and safety notes inthe display messages in the "Tires" section(Ypage 227).
If the wheel positions on the vehicle are rota-ted, the tire pressures may be displayed forthe wrong positions for a short time. This isrectified after a few minutes of driving, and thetire pressures are displayed for the correctpositions.
Restarting the tire pressure monitor
When you restart the tire pressure monitor, allexisting warning messages are deleted and thewarning lamps go out. The monitor uses thecurrently set tire pressures as the referencevalues for monitoring. In most cases, the tirepressure monitor will automatically detect thenew reference values after you have changedthe tire pressure. However, you can also setreference values manually as described here.The tire pressure monitor then monitors thenew tire pressure values.
XSet the tire pressure to the value recom-mended for the corresponding driving situa-tion on the Tire and Loading Informationplacard on the driver's side B-pillar(Ypage 296).
Tire pressure301
Wheels and tires
Z

Additional tire pressure values for differentloads can also be found on the tire pressuretable on the inside of the fuel filler flap(Ypage 296).
XMake sure that the tire pressure is correcton all four wheels.
XEnsure that the SmartKey is in positionHin the ignition lock.
XPress theYorebutton on the steer-ing wheel to select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPressv.The multifunction display shows the currenttire pressure for the individual tires or theTire pressure will be displayedTire pressure will be displayedafter driving a few minutesafter driving a few minutesmessage.
XPress thedbutton.TheUse Current Pressures as NewUse Current Pressures as NewReference ValuesReference Valuesmessage appears in themultifunction display.
If you wish to confirm the restart:
XPressv.TheTire Press. Monitor RestartedTire Press. Monitor Restartedmessage appears in the multifunction dis-play.
After driving for a few minutes, the systemchecks whether the current tire pressuresare within the specified range. The new tirepressures are then accepted as referencevalues and monitored.
If you wish to cancel the restart:
XPress8.The tire pressure values stored at the lastrestart will continue to be monitored.
Radio type approval for the tire pres-
sure monitor
CountryRadio type approval number
USAFCC ID: MRXMW2433A
FCCIC ID:MRXGG4 This devicecomplies with part 15 of theFCC rules and with licenseexempt RSS standards of Indus-try Canada. Operation is subjectto the following conditions. (1)This device may not causeharmful interference, and (2)This device must accept anyinterference received, includinginterference that may causeundesired operation. Le presentappareil est conforme d'indus-trie Canada applicables auxappareils radio exempts delicence. L'exploitation estauthorisee aux deux conditionssuivantes. (1) L'appareil ne doitpas produire de brouillage, et(2) L'autisatuer de l'appareildoit accepter tout brouillageradioelectrique subi, meme si lebrouillage est susceptible d'encompromettre le fonctionne-ment. WARNING: Changes ormodifications not expresslyapproved by the party responsi-ble for compliance could voidthe user's authority to operatethe equipment. The term "IC:"before the radio certificationnumber only signifies Canadatechnical specifications weremet.
FCC ID:MRXMC34MA4 Thisdevice complies with part 15 ofthe FCC rules and with licenseexempt RSS standards of Indus-try Canada. Operation is subjectto the following conditions. (1)This device may not causeharmful interference, and (2)This device must accept anyinterference received, includinginterference that may causeundesired operation. Le presentappareil est conforme d'indus-trie Canada applicables auxappareils radio exempts de
302Tire pressure
Wheels and tires

CountryRadio type approval number
licence. L'exploitation estauthorisee aux deux conditionssuivantes. (1) L'appareil ne doitpas produire de brouillage, et(2) L'autisatuer de l'appareildoit accepter tout brouillageradioelectrique subi, meme si lebrouillage est susceptible d'encompromettre le fonctionne-ment. WARNING: Changes ormodifications not expresslyapproved by the party responsi-ble for compliance could voidthe user's authority to operatethe equipment. The term "IC:"before the radio certificationnumber only signifies Canadatechnical specifications weremet.
CanadaIC: 2546A-MW2433A
IC:2546A-GG4 This device com-plies with part 15 of the FCCrules and with license exemptRSS standards of Industry Can-ada. Operation is subject to thefollowing conditions. (1) Thisdevice may not cause harmfulinterference, and (2) This devicemust accept any interferencereceived, including interferencethat may cause undesired oper-ation. Le present appareil estconforme d'industrie Canadaapplicables aux appareils radioexempts de licence. L'exploita-tion est authorisee aux deuxconditions suivantes. (1) L'ap-pareil ne doit pas produire debrouillage, et (2) L'autisatuer del'appareil doit accepter toutbrouillage radioelectrique subi,meme si le brouillage est sus-ceptible d'en compromettre lefonctionnement. WARNING:Changes or modifications notexpressly approved by the partyresponsible for compliancecould void the user's authorityto operate the equipment. Theterm "IC:" before the radio cer-tification number only signifiesCanada technical specificationswere met.
CountryRadio type approval number
IC: 2546A-MC34MA4
Loading the vehicle
Instruction labels for tires and loads
GWARNING
Overloaded tires can overheat, causing a
blowout. Overloaded tires can also impair
the steering and driving characteristics and
lead to brake failure. There is a risk of acci-
dent.
Observe the load rating of the tires. The load
rating must be at least half of the GAWR of
your vehicle. Never overload the tires by
exceeding the maximum load.
Two instruction labels on your vehicle showthe maximum possible load.
(1) The Tire and Loading Information placardis on the B-pillar on the driver's side. TheTire and Loading Information placardshows the maximum permissible numberof occupants and the maximum permissi-ble vehicle load. It also contains details ofthe tire sizes and corresponding pressuresfor tires mounted at the factory.
(2) The vehicle identification plate is on theB-pillar on the driver's side. The vehicleidentification plate informs you of thegross vehicle weight rating. It is made upof the vehicle weight, all vehicle occu-pants, the fuel and the cargo. You can alsofind information about the maximum grossaxle weight rating on the front and rearaxle.
The maximum gross axle weight rating isthe maximum weight that can be carriedby one axle (front or rear axle). Neverexceed the maximum load or the maxi-mum gross axle weight rating for the frontor rear axle.
Loading the vehicle303
Wheels and tires
Z

wall of the tire. You will find this after the let-ter that identifies the speed rating(Ypage 307).
RIf no specification is given: no text (as in theexample above), represents a standard load(SL) tire
RXL or Extra Load: represents a reinforcedtire
RLight Load: represents a light load tire
RC, D, E: represents a load range thatdepends on the maximum load that the tirecan carry at a certain pressure
iTire data is vehicle-specific and may devi-ate from the data in the example.
Maximum load rating
Maximum tire loadCis the maximum permis-sible weight for which the tire is approved.
Do not overload the tires by exceeding thespecified load limit. The maximum permissibleload can be found on the vehicle's Tire andLoading Information placard on the B-pillar onthe driver's side (Ypage 303).
iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
DOT, Tire Identification Number (TIN)
US tire regulations stipulate that every tiremanufacturer or retreader must imprint a TINin or on the sidewall of each tire produced.
The TIN is a unique identification number. TheTIN enables the tire manufacturers or retread-ers to inform purchasers of recalls and othersafety-relevant matters. It makes it possiblefor the purchaser to easily identify the affectedtires.
The TIN is made up of manufacturer identifica-tion codeD, tire size

Tire characteristics
This information describes the type of tire cordand the number of layers in sidewallCandunder tire treadD.
iTire data is vehicle-specific and may devi-ate from the data in the example.
Definition of terms for tires and load-
ing
Tire ply composition and material used
Describes the number of plies or the numberof layers of rubber-coated fabric in the tiretread and sidewall. These are made of steel,nylon, polyester and other materials.
Bar
Metric unit for tire pressure. 14.5038 poundsper square inch (psi) and 100 kilopascals (kPa)are the equivalent of 1 bar.
DOT (Department of Transportation)
DOT-marked tires fulfill the requirements ofthe U S Department of Transportation.
Normal occupant weight
The number of occupants for which the vehicleis designed multiplied by 68 kilograms(150 lbs).
Uniform Tire Quality Grading Standards
A uniform standard to grade the quality of tireswith regards to tread quality, tire traction andtemperature characteristics. The quality grad-ing assessment is made by the manufacturerfollowing specifications from the U.S. govern-ment. The ratings are molded into the sidewallof the tire.
Recommended tire pressures
The recommended tire pressure applies to thetires mounted at the factory.
The Tire and Loading Information placard con-tains the recommended tire pressures for coldtires on a fully loaded vehicle and for the maxi-mum permissible vehicle speed.
The tire pressure table contains the recom-mended pressures for cold tires for variousoperating conditions, i.e. differing load andspeed conditions.
Increased vehicle weight due to optional
equipment
The combined weight of all standard andoptional equipment available for the vehicle,regardless of whether it is actually installed onthe vehicle or not.
Rim
This is the part of the wheel on which the tireis mounted.
GAWR (Gross Axle Weight Rating)
The GAWR is the maximum gross axle weightrating. The actual load on an axle must neverexceed the gross axle weight rating. The grossaxle weight rating can be found on the vehicleidentification plate on the B-pillar on the driv-er's side.
Speed rating
The speed rating is part of the tire identifica-tion. It specifies the speed range for which thetire is approved.
GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weightof the vehicle including fuel, tools, the sparewheel, accessories installed, occupants, lug-gage and the drawbar noseweight, if applica-ble. The gross vehicle weight must not exceedthe gross vehicle weight rating GVWR as speci-fied on the vehicle identification plate on theB-pillar on the driver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible grossweight of a fully loaded vehicle (the weight ofthe vehicle including all accessories, occu-pants, fuel, luggage and the drawbar nose-weight, if applicable). The gross vehicle weightrating is specified on the vehicle identificationplate on the B-pillar on the driver's side.
All aboutwheels andtires311
Wheels and tires
Z