For the correct and safe use of light alloy wheels
Customers, please ensure that you read the instruction manual!
Thank you very much for purchasing our wheels. This instruction manual tells you how to use the wheels correctly, how to check them, etc. Please ensure
that you read the manual so that you can make the most of the wheels while using them with safety awareness.
[Before mounting the wheels]
1. Wheel specifications [Check]
Each wheel comes with a certain combination of wheel size, no. of holes, PCD, offset and mounting surface shape. The combination determines if the wheel
matches your vehicle. Please never use wheels that do not match your vehicle. Please consult your local dealer, and ensure that you use wheels that
match your vehicle.
2. Temporary nut fastening [Check]
· Before assembling a wheel and a tyre together, please check that there is no interference between the wheel and the vehicle (suspension, etc.), and
that you can turn each nut more than 5 times to tighten it (note: short stud bolts are used in recently manufactured vehicles). Long stud bolts are used in
older vehicles; please ensure that each nut does not hit the bottom.
· We use tapered nut seats for wheel mounting. Please check the diameters and pitches of the bolts on your vehicle, and ensure that you use bolts and
nut seats that match each other (or use our dedicated nuts and bolts). Using mismatched nuts and bolts causes insufficient torque, and a very serious
accident may be caused by loose nuts and bolts followed by wheels coming off the vehicle while driving. Please never use any mismatched nuts and bolts.
Insufficient torque may also be caused by grease, oil, sand, etc., adhered to the tapered surface of nut seats, making nuts become loose.
1. Handling the tyre [Caution]
· When attaching the tyre, use a rubber mat so as not to damage the flange section.
· Be careful not to damage the flange section by accidentally hitting the wheel with the tyre lever. Place an old rubber tube or a rubber sheet
between the wheel and the tyre lever to prevent such damage.
2. Attaching the air valve [Caution]
Please ensure that you use the enclosed dedicated air valve (or a valve of a specified type). If the valve does not fit in the valve hole properly, it may
cause air leakage. The deterioration of the grommet (air seal packing) with age may also cause air leakage. Please ensure that the valve is replaced with a
new one on a regular basis (every 12 months).
3. Working air pressure [Caution]
The air pressure for assembling the tyre must be 5 kg/cm2 or less. Please contact us if the bead does not rise even at the maximum pressure of 5
4. Air leakage [Check]
Please ensure that there is no air leakage from the tyre assembly. For example, the engaging part between the tyre and the rim and the area around the air
valve are typical places to check. Air leakage while driving could cause damage to the wheels and make it difficult to steer, resulting in an accident.
5. Balance adjustment [Check]
Once all the tyres have been assembled, adjust the wheel balance. Incorrect balance could cause abnormal vibrations, uneven wear, etc., to the tyres.
1. Tightening the nuts and bolts [Caution]
Tighten the nuts and bolts using the following recommended torques: M12 9-12 kgf×m or 88-118 N×m, M10 5-10 kgf×m or 49-69 N×m.
Excessive tightening can cause distortion to the bolt holes and damage to the nuts and bolts, whereas insufficient tightening is the cause of loose nuts
and bolts. Please do not use any impact wrench.
2. Mounting depending on the vehicle type [Caution]
The adjusting screw and the like may be designed to protrude from the brake drum, depending on the vehicle type and model. If this is the case, remove the
adjusting screw, etc., before mounting the wheel to prevent any accidental damage by knocking with the wheel set plate, etc.
[Precautions after wheel mounting]
1. Checking the mounted state of the wheel [Warning]
Once each wheel has been mounted on the vehicle, please ensure that each tyre is not in contact with the vehicle body, any part of the suspension, etc. (as
for the front wheels, check at the maximum steering angles to the left and right). Please ensure that there is absolutely no wheel protruding from the
vehicle body. Please check once again.
2. Checking the air pressure [Caution]
Please check the air pressure of each tyre and ensure that the pressure is set to the specified level before driving. A tyre with insufficient air pressure
may be easily damaged even by a slight impact. While checking the air pressure, also check that the air valve nut is tightened properly and there is no air
leakage from the air valve.
<Appropriate air pressure>
With excess air pressure, tyres become more sensitive to road surface variations; vibrations pass through the vehicle body, causing discomfort to the
driver and the passenger alike as well as poor braking performance. Meanwhile, insufficient air pressure could increase the likelihood of losing steering
control, and reduce combustion. Please check and adjust the air pressure on a regular basis, in response to temperature changes, four times in spring,
summer, autumn and winter for example.
3. Additional tightening [Check]
After mounting and rotating the wheels, you may find that some nuts and bolts became loose. Tighten them up, using the recommended torques, after
approximately 50-100 km mileage. Check for any loose nuts and bolts on a regular basis and tighten them up as necessary, using the recommended torques (for
the torques, please see [Wheel mounting] 1. Tightening the nuts and bolts).
4. Precautions when driving [Warning]
Unreasonable or reckless driving, e.g., abrupt starting, sudden braking, sharp turning, etc., will cause damage to the wheels and tyres, possibly resulting
in a serious accident. Please refrain from unreasonable and reckless driving at all times.
[Dealing with abnormalities]
1. Abnormalities [Caution]
If you notice abnormal vibrations, abnormal noise, etc., pull over in a safe place as soon as possible, and check for the abnormality.
2. Hazards [Caution]
Please be aware that driving over pavements, kerbs or uneven surfaces can cause distortions and cracks to the wheels.
3. Repairs and modifications [Warning]
· Wheels are key vehicle safety components. They are manufactured in accordance with the technical standards stipulated by the Japanese government.
· Never repair or modify by machining by yourself any wheel that is distorted, cracked, etc. Applying repairs and machining, including welding,
bending, etc., to a wheel after it was manufactured could compromise the strength of the wheel due to the influence of welding heat, invisible distortion
to the entire wheel, etc., possibly resulting in a serious accident.
· Should the wheel suffer any distortion, cracks, etc., stop using the wheel immediately and contact us or contact your local dealer.
4. Assembling-type wheels [Warning]
· The bolts that connect together the rim and disc of an assembling-type wheel are fastened using a specified torque at the time of manufacturing the
wheel. Never make the bolts tighter or looser, or the bolts may become deteriorated or the connection between the rim and disc may become loose.
· Should you find any bolt being loose, stop using the wheel immediately and contact us or contact your local dealer.
[Routine check, care and storage]
1. Care [Check]
Do not leave dirt, such as mud adhered to alloy wheels. Over time this may cause an uneven finish and possible corrosion. Always use alloy wheels in a clean condition.
2. Corrosion [Check]
· We use anti oxide-coating films. Product surfaces are treated with a special chemical processes for oxide prevention / surface hardening where
applicable. In order for the protective coatings to last for a long time, please do not use any aggressive tools and materials for washing the wheels, such as carwash machines, scours and industrial soap.
· All wheel surfaces are treated to prevent oxidising. However, anti-freezing agents, seawater, sea breezes, etc., are extremely harmful to light
alloy wheels. Please ensure that you wash the wheels thoroughly with water after driving.
3. Cleaning agent [Check]
If you are using a commonly available wheel cleaner or a body cleaner, please ensure that you read the instructions carefully before use.
4. Storage [Check]
Remove the wheels from the vehicle body, wash the wheels and dry them thoroughly before storage. Avoid direct sunlight and any warm and humid place.
Wheel Quality Control Standard Conformity Marks
JWL (Japan Light Alloy Wheel)
‘Technical standard that applies to light alloy disc wheels for passenger cars’
This standard is a safety standard that applies to light alloy disc wheels for passenger cars (excluding vehicles that carry 11 or more passengers,
two-wheel vehicles and two-wheel vehicles with a sidecar). Wheels are tested, using the testing methods approved by the standard, by individual
manufacturers under their own responsibility, and wheels that satisfy the requirements are indicated by the JWL mark.
JWL-T (Japan Light Alloy Wheel Truck & Bus)
‘Technical standard that applies to light alloy disc wheels for trucks and buses’
This standard is a safety standard that applies to light alloy disc wheels for trucks and buses. Wheels are tested, using the testing methods approved by
the standard, by individual manufacturers under their own responsibility, and wheels that satisfy the requirements are indicated by the JWL-T mark.
VIA (Vehicle Inspection Association)
The VIA is an independent public organisation which inspects that JWL or JWL-T wheels truly conform to the corresponding standard. This mark is given, in
addition to the JWL or JWL-T mark, to wheels that have passed the most stringent quality and strength tests in accordance with the JWL or JWL-T standards.
As you mount each wheel on your vehicle, if the wheel has a load symbol, please ensure that the load displayed by the load symbol and the wheel load correspond to each other. If the wheel load is greater than the load displayed by the load symbol, do not mount the wheel at all.
Wheel load calculation
Wf = wf + a1p1 + a2p2 / L
Wr = W – Wf
W: Total vehicle weight
Wf: Front axle weight when the vehicle is fully occupied
Wr: Rear axle weight when the vehicle is fully occupied
wf: Front axle weight stated in the vehicle inspection certificate
L: Wheelbase (the horizontal distance between the front and rear axles along the vehicle centre line)
a1, a2: Horizontal distances from the operative positions of p1 and p2 (20cm horizontally from the front edges of the seats) to the rear axle
p1, p2: Load by no. of passengers (55 kg load/passenger)
Wheel weight = Wf/2 or Wr/2, whichever load value is the greatest.
Names of parts
4. No. of Js (JJ)
5. Inner rim
6. Outer rim
7. Hub hole
8. PCD (pitch)
For further information please see our website: www.retroracecar.com
Or contact us by email: [email protected]