General characteristics

Rim hornwear

The wheels are exposed to mechanical wear. A big and pulsed weight, when the wheel is rotating do that a wear comes up. A very loaded part is the contact area between tyre and rim.

Most exposed is the outside diameter of the rim horn. The tyres are constructed so that they are leaned on this area. A track comes up in the middle of the rim horn more or less on all wheels, as well steel as aluminium. If the truck is used on places where sand, salt or other wearing material exists the wear come about faster. Under normal circumstances is this wear no problem on our casted rims. Of aluminium rims the casted rims of Tunaverken has the best resistance against wear. This because of that the alloy contains silicon. With casting small silicon particles are founded, which stand very big wear. Forged rims contain no silicon.

It is very important that the air pressure in the tyre is the right. To low air pressure give rise to bigger wear.

See our manual for the maximal allowed wear.

• Inspect the wheel carefully.
• No damage is allowed on the bead seat.
• Mounting holes has to comply with the nuts that will be used.
• If any bad impact marks on the rim, then check the roundness of the wheel.
• Both sides of the disc have to be free from raised marks.

Used wheels

• Look for excessive wear on the rim edge and the bead seat according to figure 1. If any doubt contact Tuna Wheel. The wheel has to be scraped if not conforming with the figure.
• Take off corrosion, which should not be deeper than 1, 0 mm.
• The bead seat and the both sides of the disc have to be carefully cleaned from dirt and corrosion.
• Look for damaged mounting holes.
• The wheel has to be scraped for any crack.
• Look for impact marks.

Valve mounting

• Use only nickel or chrome plated valves to avoid corrosion.
• It has to be screwed on type
• Standard valve, straight or bent: Thread diameter 9.7mm, Tightening torque 9-14Nm
• Valve for reversible wheels: Two airfilling stems. Thread diameter 15mm. Tightening torque 32 - 36Nm
• When mounting the valve on the wheel the sealing surface on the rim and the O-ring on the valve have to be absolute clean and smooth. Put on some water free grease as corrosion protection.

Tyre mounting

• Use only tyre dimensions that are recommended for the wheel.
• The tyre bead has to be clean and undamaged.
• Do not use a tube inside the tyre.
• Use tyre mounting lubricant.
• Mount the tyre from the side where the drop well is closest to the rim edge.
• Use only proper tools and machines for tyre mounting in order not to damage the tyre or the wheel.
• Inflate the tyre inside a cage for protection.
• Do not over-inflate. Maximum 9, 5 bar at cold tyre.
• Check that the tyre bead is properly seated after inflation.
• Warning: An inflated tyre has a very high internal power. If the tyre or the wheel brakes there is a risk of personal casualties.

Balancing

• The wheel itself does not need to be balanced. The unit, wheel and tyre might need to be balanced.
• We recommend balancing of all units that will be used on the front axle.
• Use a surface protected lead weight with an adhesive soft tape on one side.
• Use dynamic balancing.

Spigot

The spigot has to go into the wheel at least 5 mm. This is very important when 26 mm mounting holes and standard nuts are used. Before mounting the wheel on the hub lubricate only the spigot and the centre hole of the wheel. Use grease, which is not water-based and without heavy metals.

Mounting on the vehicle

Tuna Wheel wheels have a hub-centred system. Since the thickness of the disc on an aluminium wheel is twice that of a steel wheel, other fastening arrangements have to be used than on steel wheels. Two types of nuts are used.

If the same studs as with steel wheels are used a special sleeve flange nut has to be used. (Fig.3 and Fig. 4.) For dual mounted wheels the sleeve is longer than for a single mounted wheel.
The mounting holes in the wheel
have to have a diameter of 32 mm. The mounting torque has to be 550-650 Nm.

If 26 mm mounting holes in the wheels are used longer studs have to be mounted.
( Fig. 4 and Fig 5.) From the wheel attachment surface to the end of the stud it has to be the following measurements:

Single mounted wheel:

• • 8,25x19,5: Min 50 mm
• • 8,25x22,5 and 9, 00x22,5: Min 52 mm
• • 11,75x22,5: Min 55 mm

Dual mounted wheels:

• • 8,25x19,5: Min 74 mm
• • 8,25x22,5 and 9,00x22,5
  Min 78 mm

The thread engagement between the stud and the nut has to be at least 0,8 x diameter of the thread in all cases. This has to be checked very carefully.

The standard type nut for aluminium wheels have to be used. The mounting torque has to be 550-650 Nm.

The nuts have to be very light oiled with a thin oil in the threads and between the nut and the washer in order to get the right clamping force. Do not use grease.

Procedure when tightening the nuts.

The wheels have to be right positioned on the hub. Hands tighten all nuts. Increase the torque a little and tighten all nuts in a sequence shown in fig 2. Continue to increase the torque until recommended torque is reached using the sequence shown in fig 2.

Fig 2. Nut tightening sequence

When tightening the nuts use only tools that gives the absolute right torque.
Check the torque after 100 – 200 km and then frequently.

Maintenance

• For cleaning use a mild detergent and water. Acid, salt and alkaline products are highly corrosive to aluminium and have to be washed off.
• When cleaning look for damages, impacts, cracks or unusual wear. If air is leaking through the rim the wheel has to be scraped.
• After an accident wheels and tyres have to be carefully inspected.

Repair

• Repair is not allowed or possible because of the heat treatment of the wheel.
• Do not straighten or weld wheels, because of the heat treatment of the wheel
• Do not heat up the wheel
• Do not machine off metal or redrill the wheel.
• Do not use a tube inside the tyre.

Single mounted wheel Standard stud and sleeve flange nut. 32 mm mounting holes.	Dual mounted wheels Standard stud and long sleeve flange nut. 32 mm diameter mounting holes.
Single mounted wheel. Longer studs, Standard nut and 26 mm diameter mounting holes.	Dual mounted wheels Longer studs, Standard nut and 26 mm diameter mounting holes.