tyre pressure SKODA SUPERB 2008 Owner´s Manual

Save tyre pressure valuesFig. 154
Key for storing the pressure val-
ues
Read and observe on page 165 first.
Saving the tyre pressure values is undertaken as follows.
›
Inflate all the tyres to the specified pressure.
›
Switch on the ignition.
›
Press and hold the symbol button 
» Fig. 154 .
The warning light  in the instrument cluster illuminates.
An acoustic signal and the control indicator provide information about the
storage of the tyre pressure values.
›
Release the  symbol button.
The tyre pressure values are always stored in the system, if one of the follow-
ing events occurs.
› Change of tyre inflation pressure.
› Changing one or more wheels.
› Changing position of a wheel on the vehicle.
› Illumination of the warning light
 in the instrument cluster.
WARNINGBefore storing the pressures, the tyres must be inflated to the specified in-
flation pressure » page 198. When storing incorrect pressure values, the
system could possibly not issue any warnings, even with a too low tyre
pressure.
CAUTION
The tyre pressure values are to be saved every 10,000 km or once annually to
ensure correct system functioning.Hitch and trailer
Hitch
 Introduction
This chapter contains information on the following subjects:
Description
167
Adjusting the ready position
167
Fitting the ball head
168
Check proper fitting
168
Removing the ball head
169
Accessories
169
The maximum trailer drawbar load is 80 kg/h.
WARNING■
Check that the ball head is seated correctly and is secured in the mount-
ing recess before starting any journey.■
Do not use the ball head, if it is not correctly inserted into the mounting
recess and secured.
■
Do not use the towing equipment if it is damaged or incomplete.
■
Do not modify or adapt the towing equipment in any way.
■
Never release the ball head while the trailer is still coupled.
■
Keep the mounting recess of the towing equipment clean at all times.
Such dirt prevents the ball head from being attached securely.
CAUTION
■ Take care with the ball bar - there is a risk of paint damage to the bumper.■When the tow bar is removed always place the cover onto the mounting re-
cess - there is a danger of soiling the mounting recess.
Note
■ Operation and maintenance of hitch » page 180.■Tow the vehicle by means of the detachable ball rod » page 214.166Driving

Exterior mirrors
You have to have additional exterior mirrors fitted if you are not able to see
the traffic behind the trailer with the standard rear-view mirrors. National legal
requirements must be observed.
Headlights
The front of the vehicle can be lifted when a trailer is being towed and the
headlights can dazzle other road users.
Adjust the headlight setting on the headlight range control » page 68, Operat-
ing the lights and the instrument illumination .WARNING■
Incorrect or improperly connected electrical installation can cause acci-
dents and serious injury due to electric shock.■
Work on the electrical system must only be carried out by specialist ga-
rages.
■
Never directly connect the trailer's electrical system with the electrical
connections for the tail lights or other current sources.
■
After coupling the trailer and connecting up the power socket, check the
rear lights on the trailer to ensure they are working.
■
The handbrake on the towing vehicle must be applied when coupling and
uncoupling the trailer.
■
Never use the safety eyelet for towing!
CAUTION
Incorrect or improperly connected electrical installations may cause malfunc-
tion of the entire vehicle electronics.
Loading a trailer
The vehicle/trailer combination must be balanced, whereby the maximum per-
missible drawbar load must be utilised. If the drawbar load is too low, it jeop-
ardises the performance of the vehicle/trailer combination.
Distribution of the load
Distribute the load in the trailer in such a way that heavy items are located as
close to the axle as possible. Secure the items from slipping.
The distribution of the weight is very poor if your vehicle is unladen and the
trailer is laden. Maintain a particularly low speed if you cannot avoid driving
with this combination.
Tyre pressure
Correct the tyre inflation pressure on your vehicle for a “full load” » page 198.
Trailer load
The permissible trailer load must not be exceeded under any circumstan-
ces » page 228 , Technical data .
The details given in the vehicle's technical documentation always take prece- dence over the details in the Owner's Manual.
The trailer loads specified apply only to altitudes up to 1,000 metres above
mean sea level.
The engine output falls as altitude increases, as does the ability to climb.
Therefore, for every additional 1,000 m in height (or part), the maximum per-
missible towed weight must be reduced by 10 %.
The towed weight comprises the actual weights of the (loaded) towing vehicle
and the (loaded) trailer.
The trailer and drawbar load information on the type plate of the towing
equipment are merely test data for the towing equipment. The vehicle-specific
values are detailed in the vehicle documents.WARNING■ The maximum permissible axle and drawbar load and the permissible
weight of the trailer must not exceed - this could cause an accident!■
A sliding cargo can significantly adversely affect stability and driving safe-
ty - there is a risk of accident!
Towing a trailer
Driving speed
For safety reasons, do not drive faster than 80 km/h when towing a trailer.
Immediately reduce your speed as soon as even the slightest swaying of the
trailer is detected. Never attempt to stop the trailer from “swaying” by acceler-
ating.
Brakes
Apply the brakes in good time! If the trailer is fitted with a trailer brake, apply
the brakes gently at first and then brake firmly. This will avoid brake jolts re-
sulting from the trailer wheels locking.
On downhill sections shift down a gear in good time to also use the engine as
a brake. 
171Hitch and trailer

WARNING (Continued)■You must have your tyres replaced with new ones at the latest when the
wear indicators have been worn down.■
Worn tyres impair necessary adhesion to the road surface, particularly at
high speeds on wet roads. This could lead to “aquaplaning” (uncontrolled
vehicle movement – “swimming” on a wet road surface).
WARNING■ Having the correct tyre inflation pressure is always the driver's responsi-
bility.■
Too low or too high inflation pressure impairs handling.
■
If the inflation pressure is too low, the tyre will have to overcome a higher
rolling resistance. This will cause a significant increase in the temperature
of the tyre, especially at higher speeds. This can result in tread separation
and a tyre blowout.
■
In the event of very fast tyre inflation pressure loss, such as a sudden tyre
failure, an attempt should be made to bring the vehicle carefully to a stop
without sudden steering movements and without any hard braking.
CAUTION
■ If a spare wheel is used that is not identical to the fitted tyres, the following
must be observed » page 200, Spare and temporary spare wheel .■
The tyres must be protected from contact with substances such as oil,
grease and fuel, which could damage them. If the tyres come into contact with
these substances, then we recommend you have this checked out in a special-
ist workshop.
■
If, in the case of puncture occurring, the spare tyre with a non-bound direc-
tion or an opposite direction of rotation must be mounted, then drive carefully.
The best properties of the tyre are no longer present in this situation.
For the sake of the environment
■ Old and unserviceable tyres are classified in a special environmentally haz-
ardous category. These must be disposed of in accordance with national legis-
lation.■
Tyres that are insufficiently inflated increase your fuel consumption.
Note
■ We recommend that any work on the wheels or tyres be carried out by a spe-
cialist garage.■
We recommend that you use wheel rims, tyres, full wheel trims and snow
chains from ŠKODA Original Accessories.
Service life of tyresFig. 171
Principle sketch: Tyre tread with wear indicators/open fuel filler
flap with a table detailing the tyre sizes and tyre inflation pressures
Fig. 172
Replacing wheels
Read and observe and on page 197 first.
The service life of tyres depends on the inflation pressure, driving style and
other circumstances.
Tyre pressure
Check the tyre pressure, including that of the spare wheel, at least once a
month and also before setting off on a long journey.
The tyre pressures for tyres are shown on the inside of the fuel filler
flap » Fig. 171 –
.
The tyre pressure for the spare wheel should correspond to the highest pres-
sure specified for your vehicle.
Always check the inflation pressure when the tyres are cold. Do not reduce the
higher pressure on warm tyres. 
198General Maintenance

In vehicles with tyre pressure monitoring, tyre pressure values are to be stor-
ed » page 166 .
With greater additional load, adjust the tyre inflation pressure accordingly.
Driving style
Fast cornering, sharp acceleration and braking increase the wear of your tyres.
Wheel balance
The wheels of a new vehicle are balanced. When driving, however, there are a
range of factors that may result in an imbalance. This may become apparent by
“vibration” in the steering. If this is the case, have the wheels checked by a
specialist garage.
Have the wheels likewise rebalanced after replacing the tyres.
Setting the vehicle geometry
Incorrect wheel alignment at the front or rear leads to excess wear on the
tyres and impairs driving safety. With a distinctive tyre wear, we recommend
that you check the setting of the vehicle geometry in a specialist workshop.
Tyre damage
We recommend checking your tyres and wheel rims for damage (punctures,
cuts, splits and bulges, etc.) on a regular basis. Remove foreign bodies (e.g.
small stones) from the tyre tread immediately.
Drive over kerbs and other such obstacles slowly and at right angles wherever
possible in order to avoid damage to tyres and wheel trims.
Immediately replace damaged wheel rims or tyres.
Exchanging the wheels
For uniform wear on all tyres, we recommend that you change the wheels ev-
ery 10 000 km according to schedule » Fig. 172. You will then obtain approxi-
mately the same life for all the tyres.
After a wheel has been replaced, the tyre pressure has to be adjusted.
In vehicles with tyre pressure monitoring, tyre pressure values are to be stor-
ed » page 166 .
Tyre storage
Identify disassembled tyres so that the previous direction of rotation can be
maintained if the tyres are reassembled.
Always store wheels or tyres in a cool, dry place that is as dark as possible.
Tyres which are not fixed to a wheel trim should be stored upright.Wear indicators
The base of the tread of the tyres contains has a 1.6 mm high wear indica-
tor » Fig. 171 - 
. In some countries, different tyre wear rates may apply.
Markings on the walls of the tyres through the letters “TWI”, triangular sym-
bols or other symbols identify the position of the wear indicators.
Tyre age
Tyres age and lose their original characteristics, even if they are not being
used. The service life of the tyres is 6 years. Therefore, we recommend not us-
ing tyres that are older than 6 years.
Wheel bolts
Wheels and wheel bolts are matched to each other in terms of design. We rec-
ommend that you use wheel rims and wheel bolts from ŠKODA Original Acces-
sories.
Note
In some countries, the vehicles have a sticker with tyre inflation pressure val-
ues without pictograms.
Unidirectional tyres
Read and observe
and on page 197 first.
The direction of rotation of the tyres is marked by arrows on the wall of the
tyre .
The indicated direction of rotation must be adhered to in order to ensure the
optimal characteristics of these tyres.
These characteristics mainly relate to the following: › Increased driving stability.
› Reduced risk of aquaplaning.
› Reduced tyre noise and tyre wear.
199Wheels

Spare and temporary spare wheelFig. 173
Fixing the spare or temporary
spare wheel
Read and observe and on page 197 first.
The spare wheel is located in a well under the floor covering in the boot and is fixed in place with a special bolt » Fig. 173.
Taking the wheel out
›
Open the boot lid.
›
Raise the floor covering in the boot » page 100.
›
Remove the box with the tool kit.
›
Unscrew the nut » Fig. 173 anti-clockwise.
›
Take out the wheel.
Stowing the wheel
›
Place the wheel into the spare wheel well with the wheel rim pointing down-
ward.
›
Screw on the nut » Fig. 173 clockwise until the wheel is safely secured.
›
Replace the box with the tool kit into the spare wheel and secure it with the
tape.
›
Fold back the floor in the luggage compartment.
›
Close the boot lid.
Fit a wheel in the appropriate dimensions and design as soon as possible.
If the dimensions or design of the spare wheel differ from the tyres fitted to
the vehicle (e.g. winter tyres or low-profile tyres), it must only be used briefly
in the event of a puncture and if an appropriately cautious style of driving is
adopted »
.
Temporary spare wheel
A warning label is displayed on the rim of the temporary spare wheel.
Please note the following if you intend to use the temporary spare wheel.
› The warning label must not be covered after installing the wheel.
› Be particularly observant when driving.
› The temporary spare wheel is inflated to the maximum inflation pressure for
the vehicle » Fig. 171 on page 198 .
› The tyre inflation pressure of the spare wheel R 18 is 420 kPa.
› Only use this temporary spare wheel to reach the nearest specialist garage,
since it is not intended for permanent use.WARNING■ Never drive with more than one temporary spare wheel mounted!■Only use the temporary spare wheel when absolutely necessary.■
Never use the temporary spare wheel if it is damaged.
■
If the dimensions or design of the temporary spare wheel differ from the
fitted tyres, never drive faster than 80 km/h (or 50 mph).
■
Avoid accelerating at full throttle, sharp braking and fast cornering.
■
The snow chains cannot be used on the temporary spare wheel.
■
Observe the instructions on the warning sticker on the temporary spare
wheel.
Full wheel trim
Read and observe
and on page 197 first.
Before removing the wheel bolts, remove the wheel cover.
Pulling off
›
Hook the clamp found in the vehicle tool kit » page 205 into the reinforced
edge of the wheel trim.
›
Push the wheel wrench through the clamp, support on the tyre and pull off
the wheel trim.
Fitting
›
Press the wheel trim onto the wheel rim at the designated valve opening.
›
Then press the trim into the wheel rim until its entire circumference locks
correctly in place. 
200General Maintenance

CAUTION■Only use the manual pressure and do not hit the full wheel trim – there is a
risk of damaging the trim.■
When using the anti-theft wheel bolt, ensure that it is in the hole in the
valve area.
■
If wheel trims are fitted, an adequate flow of air must be assured in order to
cool the brake system.
Note
We recommend that you use wheel trims from ŠKODA Original Accessories.
Wheel bolts
Fig. 174
Remove the cap
Read and observe and on page 197 first.
Before removing the wheel bolts, remove the covering caps.
Pulling off
›
Push the extraction pliers » page 205 sufficiently far onto the cap until the
inner catches of the pliers are positioned at the collar of the cap.
›
Remove the cap in the direction of the arrow » Fig. 174.
Fitting
›
Push the cap onto the wheel bolt up to the stop.
Manufacturer-approved tyre variants
 Introduction
This chapter contains information on the following subjects:
Explanation of the tyre labelling
201
Superb
202Superb GreenLine202Superb N1203
Approved tyre variants are first to be selected for the model variant (e.g. Su-
perb GreenLine), and then selected according to the engine size of your vehi-
cle.
If the model variant of your vehicle cannot be found in the discrete module,
then the approved tyre variants are to be selected according to the engine size
of your vehicle in module » page 202, Superb .
Only use radial tyres of the same type, size (rolling circumference) and tread
pattern on one axle on all four wheels.
When mounting new tyres the tyres have to be replaced axle by axle.
The information listed in the table corresponds to the information available at the time of going to press.
The approved tyre / rim combinations for your car are given on the sales and
technical vehicle documentation.
Explanation of the tyre labelling
Explanation of tyre markings
For example, 225/50R 17 91 T means:
225Tyre width in mm50Height/width ratio in %RCode letter for the type of tyre – Radial17Diameter of wheel in inches91Load indexTSpeed symbol
The date of manufacture is stated on the tyre wall (possibly on the inside).
For example, DOT ... 11 14... means, for example, that the tyre was manufac-
tured in the 11th week of 2014.
The marking M+Smeans that the associated tyre is suitable for winter use.
Load index
The load index indicates the maximum permissible load for each individual
tyre. 
201Wheels

WARNING■If you are in flowing traffic, switch on the hazard warning light system
and set up the warning triangle at the prescribed distance! The national le-
gal requirements must be observed.■
Park the vehicle as far away as possible from the flow of traffic. Park on
as flat and firm a surface as possible.
■
The following instructions must be followed if the vehicle is subsequently
fitted with tyres or rims that differ from the factory fitted ones » page 201,
Explanation of the tyre labelling .
WARNINGInformation on the wheel bolts■The wheel bolts must be clean and must turn easily. Never treat them
with grease or oil.■
The prescribed tightening torque of the wheel bolts for steel and light al-
loy wheels is 120 Nm.
■
If the wheel bolts are tightened to a too low tightening torque, the rim
can come loose when the car is moving. A tightening torque which is too
high can damage the bolts and threads and this can result in permanent
deformation of the contact surfaces on the rim.
■
In case of incorrect treatment of the wheel bolts, the wheel can loosen
when the car is moving.
Note
The national legal requirements must be observed when changing a wheel.
Preliminary work
Read and observe
on page 206 first.
Before changing the wheel, the following work must be carried out.
›
Have all the occupants get out. The passengers should not stand on the
road (instead they should remain behind a crash barrier, for instance) while
the wheel is being changed.
›
Switch off the engine.
›
Select the 1st gear or place the selector lever of the automatic transmission
in the P-position .
›
Apply the handbrake firmly.
›
Uncouple a trailer.
›Remove the
vehicle tool kit » page 205 and the spare wheel » page 200 from
the boot.
Changing a wheel
Read and observe
on page 206 first.
When changing a wheel, the following instructions must be followed.
›
Remove the full wheel trim or the caps of the wheel bolts.
›
First of all slacken the anti-theft wheel bolt and then the other wheel bolts.
›
Jack up the vehicle until the wheel that needs changing is clear of the
ground.
›
Unscrew the wheel bolts and place them on a clean surface (cloth, paper, etc.).
›
Remove the wheel carefully.
›
Attach the spare wheel and slightly screw on the wheel bolts.
›
Lower the vehicle.
›
Tighten the opposite wheel bolts alternately (cross-wise) with the wheelwrench. Tighten the anti-theft wheel bolt last.
›
Replace the wheel trim or the caps.
When fitting unidirectional tyres, ensure that the indication is cor-
rect » page 197 .
WARNINGIf it is established when changing a wheel that the wheel bolts are corro-
ded and difficult to move, then these must be replaced.
Follow-up work
Read and observe
on page 206 first.
After changing the wheel, the following work must be carried out.
›
Stow and attach the replaced wheel in the spare wheel well using a special
bolt » page 200 .
›
Stow the tool kit in the space provided and secure using the strap.
›
Check the tyre pressure on the installed spare wheel as soon as possible.
›
Have the tightening torque of the wheel bolts checked with a torque
wrench as soon as possible. 
206Do-it-yourself

After changing the wheel, the tyre pressure should be adjusted. In vehicles
with tyre pressure monitoring, tyre pressure values are to be stor-
ed » page 166 .
Replace the damaged wheel or consult a specialist garage about repair op-
tions.WARNINGDrive cautiously and only at a moderate speed until the tightening torque
has been checked.
Loosening/tightening wheel bolts
Fig. 179
Changing a wheel: Loosening the
wheel bolts
Read and observe on page 206 first.
Before removing the wheel bolts, the caps for the wheel bolts must be pulled off.
Releasing
›
Push the wheel wrench onto the wheel bolt as far as the stop 1)
.
›
Grip the wrench at its end and turn the bolt about one turn in the direction of
the arrow » Fig. 179.
Tightening
›
Push the wheel wrench onto the wheel bolt as far as the stop 1)
.
›
Grip the wrench at its end and turn the bolt against the direction of the ar-
row » Fig. 179 until it is tight.
After tightening the wheel bolts, the covering caps must be replaced.
WARNING■ Undo the wheel bolts only a little (about one turn) provided that the vehi-
cle has not yet been jacked up. Otherwise the wheel could become loose
and fall off.■
If it proves difficult to undo the bolts, carefully apply pressure to the end
of the wrench with your foot. Keep hold of the vehicle when doing so, and
make sure you keep your footing.
Raising the vehicle
Fig. 180
Jacking points for positioning
lifting jack
Fig. 181
Attach lifting jack
Read and observe
on page 206 first.
In order to raise the vehicle, the jack from the tool kit is to be used.
Position the car jack at the jacking point closest to the flat tyre . 
1)
Use the appropriate adapter for undoing and tightening the anti-theft wheel bolts
» page 208.
207Emergency equipment and self-help

Puncture set
Introduction
This chapter contains information on the following subjects:
Components of the puncture repair kits
209
Preparations for using the breakdown kit
210
Sealing and inflating the tyre
210
Notes for driving with tyre repaired
211
Use the breakdown kit to reliably repair tyre damage caused by foreign bodies
or a puncture with diameters up to approx. 4 mm.
A repair made using the breakdown kit is never intended to replace a perma-
nent repair on the tyre. Its purpose is to get you to the nearest specialist ga-
rage.
The wheel need not be removed during the repair.
Do not remove foreign bodies , e.g. screws or nails, from the tyre.
The breakdown kit must not be used under the following circumstances. › There is damage to the rim.
› The outside temperature is less than -20 °C.
› The tears or punctures are greater than 4 mm in size.
› There is damage to the tyre wall.
› Driving with very low tyre pressure or with a completely flat tyre.
› If the use-by-date (see inflation bottle) has passed.
WARNING■
If you are in flowing traffic, switch on the hazard warning light system
and set up the warning triangle at the prescribed distance! The national le-
gal requirements must be observed.■
Park the vehicle as far away as possible from the flow of traffic. Park on
as flat and firm a surface as possible.
WARNING■ A tyre filled with sealant has the same driving characteristics as a stand-
ard tyre.■
Do not drive faster than 80 km/h (50 mph).
■
Avoid accelerating at full throttle, sharp braking and fast cornering.
WARNING (Continued)■ The sealant is hazardous to heath. Remove immediately if it comes into
contact with the skin.■
Observe the manufacturer's usage instructions for the breakdown kit.
For the sake of the environment
Used sealant or sealant whose expiry date has passed must be disposed of in
accordance with environmental protection regulations.
Note
■ A new bottle of sealant can be purchased from ŠKODA Original Parts.■Immediately replace the tyre that was repaired using the breakdown kit, or
consult a specialist garage about repair options.■
The national legal requirements must be observed when repairing a tyre.
Components of the puncture repair kits
Fig. 183
Principle sketch: Components of the breakdown kit
Read and observe
on page 209 first.
Components of the set » Fig. 183
Valve remover
Sticker with “max. 80 km/h”/“max. 50 mph” speed designation
Inflation hose with plug
Air compressor
Tyre inflation hose 
12345209Emergency equipment and self-help

Tyre inflation pressure indicator
Air release valve
ON and OFF switch
12 volt cable connector
Tyre inflator bottle with sealing agent
Replacement valve core
The valve remover 1
has a slot at its lower end which fits into the valve core.
The kit is located in a box under the floor covering in the luggage compart-
ment. This contains a sealing means and an air compressor.
Note
The declaration of conformity is included with the air compressor or the log
folder.
Preparations for using the breakdown kit
Read and observe
on page 209 first.
The following preparatory work must be carried out before using the puncturerepair kit.
›
Have all the occupants get out. The passengers should not stand on the
road (instead they should remain behind a crash barrier, for instance) while
the wheel is being changed.
›
Switch off the engine.
›
Select the 1st gear or place the selector lever of the automatic transmission
in the P-position .
›
Apply the handbrake firmly.
›
Check that you can carry out the repairs with the breakdown kit
» page 209.
›
Uncouple a trailer.
›
Remove the breakdown kit from the boot.
›
Stick the appropriate sticker
2
» Fig. 183 on page 209 onto the dashboard in
the driver's field of view.
›
Unscrew the valve cap.
›
Use the valve remover
1
to unscrew the valve core and place it on a clean
surface (rag, paper, etc.).
67891011Sealing and inflating the tyre
Read and observe
on page 209 first.
Sealing
›
Shake the tyre inflator bottle
10
» Fig. 183 on page 209 vigorously several
times.
›
Firmly screw the inflation hose
3
onto the tyre inflator bottle
10
in a clock-
wise direction. The film on the cap is pierced automatically.
›
Remove the plug from the inflation hose
3
and plug the open end fully onto
the tyre valve.
›
Hold the bottle
10
with the bottom facing upwards and fill all of the sealing
agent from the tyre inflator bottle into the tyre.
›
Remove the empty tyre inflator bottle from the valve.
›
Screw the valve core back into the tyre valve using the valve remover
1
.
Inflating
›
Screw the air compressor tyre inflation hose
5
» Fig. 183 on page 209 firmly
onto the tyre valve.
›
Check that the air release valve
7
is closed.
›
Start the engine and run it in idle.
›
Plug the connector
9
into 12 Volt socket » page 91, Cigarette lighter .
›
Switch on the air compressor with the ON and OFF switch
8
.
›
Allow the air compressor to run until a pressure of 2.0 - 2.5 bar is achieved.
Maximum run time of 8 minutes » .
›
Switch off the air compressor.
›
If you cannot reach an air pressure of 2.0 - 2.5 bar, unscrew the tyre inflation
hose
5
from the tyre valve.
›
Drive the vehicle 10 metres forwards or backwards to allow the sealing agent
to “distribute” in the tyre.
›
Firmly screw the tyre inflation hose
5
back onto the tyre valve and repeat
the inflation process.
›
If you cannot reach the required tyre inflation pressure here either, this
means the tyre has sustained too much damage. You cannot seal with tyre with the breakdown kit »
.
›
Switch off the air compressor.
›
Remove the tyre inflation hose
5
from the tyre valve.
Once a tyre pressure of 2.0 - 2.5 bar is reached, the journey may be continued
at a maximum speed of 80 km/h (50 mph). 
210Do-it-yourself