Manual Tyre Fitting & Removal (Mounting and De-mounting) Identifying the Types of Wheels Servicing single and multi-piece rims/wheels is a serious job, for service professionals. As tube type wheels assemblies are becoming less frequently used then this chapter will only deal with tubeless single piece versions. Tubeless wheel rims are called drop centre rims and have a relatively low flange height compared with tube type rims to facilitate tyre fitting and removal, these rim flanges have a 15 taper to ensure an airtight seal. It is important that we understand the different types of tubeless rims currently being used, some are described as follows: - a) Original Drop Centre Rim Tyre fitted with this side facing upwards Original drop centre rims (or sometimes known as type A rims) are less commonly used. Mainly restricted to smaller diameter wheels the narrow ledge is found at the front and hence the tyre is always fitted from the front facing side of the rim.
b) U type drop-centre rim Tyre fitted with this side facing upwards Narrow ledge U type (U is for under-ledge) is the most commonly used tubeless commercial wheel. The narrow ledge is found at the back and hence the tyre is always fitted from the back facing side of the rim. 2
c) Wide based rims and their valve types Straight valve Single bend valve Triple bend valve 3
c) Wide based rims (continued) Wide based rims are commonly used in trailer applications. As can be seen in the diagram on the previous page a wide based rim may use various different types of valve designs. Straight Valve These usually fit in a 9.7mm hole at the side of the rim well. With this type of valve it is important that the hole is clean and undamaged. Where the O ring sits should be clean and fully lubricated. Care should be taken that the O ring is positioned in the gutter in the valve base, and then the valve in the hole. The lock nut should be locked in place using the appropriate spanner. Single Bend Valve This is one of the most commonly used types of valves and fits in a 16mm valve hole in the base of the rim well. A rubber bush should be in place on the valve, the valve should then be positioned correctly in the hole and the nut tightened correctly using the appropriate spanner ensuring the washer in correctly positioned. Triple Bend Valve This valve is also fairly common and also fits into a 16mm hole. 4
d) Drop - Centre Rims with Safety Humps These rims today are more commonly called EVA (External Valve Hole) wheels. With the introduction of disc brakes on certain commercial vehicles the rim design differs from the standard Drop Centre rim shown earlier in order to enhance safety on cornering at speed and ensure increased clearance between the valve and the disc brake calipers. This relatively new rim design has an external valve hole, and encompasses a safety hump. The valve is positioned above the wheel nave. This is in contrast to conventional rims where the valve protrudes through the nave of the wheel. External Valve Hole Additional Safety Hump Due to the introduction of the safety hump, the de-seating (breaking) of the tyre beads on the rim usually requires an additional mechanical un-seating (bead breaking) tool, of which there are different types available. Pictured below is the type that we use in our demonstrations. 5
Manual Tyre Removal Using Conventional Levers 1. Tyre Deflation Safety Consideration Remove the wheel from the vehicle using the correct procedures. ~ Remove the valve core completely and allow the tyre to deflate. Always wear safety goggles to prevent eye injury from possible debris escaping from the valve at high speed. Never stand in front of a tyre during deflation. Stand to either side of the tyre in case there is an explosive separation, which could cause serious injury. An option could be to run a piece of heavy wire through the valve stem to make sure the stem is not blocked with bits of rubber or other debris, which could allow the tyre to remain inflated. The practice of thumping the tyre is not an accurate method of testing if the tyre is fully deflated. It is recommended that you use a tyre gauge to measure the pressure. 6
2. Bead breaking Safety Consideration Safety footwear with steel toe protection must be used during this operation. Safety footwear with ankle support is the preferred and recognized type that should be used. The wearing of gloves is highly recommended. Position the assembly flat on the floor ensuring with aluminum and chrome wheels that the assembly is laid on either a rubber mat or cardboard to prevent damage to the wheel. Remove any balance weights. Loosen both beads using the appropriate tool, we recommend using the double handed bead breaker as shown opposite. Always ensure the tool is correctly positioned between the tyre bead and rim flange at the angle shown opposite, ensure the force is applied at the correct point of the tyre. Apply the force from the bead breaker tool at small intervals around the tyre until the bead is fully dislodged. NO MORE than 2 blows With the bead breaker at one point should be made, otherwise the bead could be damaged. Lubricate the bead at this point. Turn the assembly over and repeat the procedure for the other side. Drop centre rims with a safety hump, may need the assistance of a mechanical bead breaking device as shown opposite, as the force required to dislodge the beads cannot be achieved using standard manual devices. The use of Angle Iron must be avoided, as it will cause damage to the tyre beads rendering the tyre scrap. 7
3. Removal of the first bead Identify the type of rim design (as mentioned in the previous section) Lying the assembly flat on the floor with the short narrow ledge, side up. Lubricate both beads and rim using an appropriate lubricant. (if not already done) We suggest an appropriate liquid lubricant as it permeates in-between the rim flange and bead. Select two tubeless tyre levers and insert them, curved ends between the tyre and rim at the valve. Step on the tyre opposite the valve to direct the first bead into the well, whilst applying slight downward pressure to the levers. Before attempting to lift the bead over the flange ensure the bead opposite is in the well of the rim. Stand in / on the centre part of the wheel rim to assist in controlling the movement of the assembly and pull the levers toward the centre of the rim until they touch both of the rim flanges. Hold one tyre lever in position with your foot and remove the second lever, then re-insert the second lever in-between the rim flange and bead and pull it towards the centre of the rim. Progressively work the tools around the rim until the first bead is off the rim. It is important to remember to take small re-insertions with the second lever, as this will make the operation easier. Also it will eliminate tyre lever damage to the beads and reduce the chance of lower back injury. 8
4. Removal of the second bead and wheel rim from the tyre Lift the tyre and wheel assembly carefully, and then with the assembly in the vertical position and the valve at the top, apply more lubrication to the second bead and rim (if required) Maneuver the wheel so that a portion of the second bead is located in the well of the rim. Standing in front of the wheel assembly, at the valve place a lever between the second bead and the rim flange. At the side of the first lever insert a second lever next to the first lever and step backwards hold both levers firmly. Allow the wheel rim to drop while firmly holding the tyre levers, the tyre should slide over the rim (you may need to jerk the levers to assist the tyre to drop out of the tyre). Alternative Lift the tyre and wheel assembly carefully and turn it over then carefully lower the assembly back to the floor. Insert the first lever between the rim and tyre until it touches the floor; press this lever down to expose the rim flange. Then insert the cranked end of the second lever and press down, remove the first lever and turn it around, re-insert it using the cranked end and locate it on the rim flange. Using both levers push down and the rim will pop out of the tyre, remove the rim fully from the tyre. Place rim and tyre in a safe position and return tools to storage. 9
Manual Tyre Fitting Using Conventional Levers 5. Preparation of the wheel and tyre Safety Consideration When a tyre has been run significantly underinflated, the sidewall flexes excessively and also generates heat. This internal damage may not be obvious until the tyre is re-inflated. Always check the wheel dimensions to ensure the compatibility of tyre to rim. Check the wheel for obvious damage particularly in the nave area and also check the stud holes for wear or elongation. Ensure the rim flanges are clean and the complete rim is free from rust, rubber or dust. Use a wire brush to clean any required areas. It may be good practice to replace the valve, to ensure continued reliable service. Remove the old valve by undoing it with a suitable spanner. (never use a chisel to remove it as this may cause damage to the rim) Fit the new valve by placing the stem through the valve hole, ensure the rubber grommet sits flush. Screw on the valve nut from the opposite side, making sure the valve is centered and fits snugly in the valve hole. Tighten the valve nut again with the correct spanner, taking care not to over tighten. When re-fitting part worn tyres or repaired tyres, pay particular attention to the condition of the tyre, check the beads, check to make sure any repairs are sound and also that the tyre has not been Run Underinflated as this damage could lead to a zipper failure when the tyre is inflated. Ensure the tyre is free internally from all foreign matter. No part worn tyre should be refitted if its condition contravenes legal requirements. 10
6. Fitting the tyre to the wheel Position the assembly flat on the floor, with the short narrow ledge upwards, ensuring with aluminum and chrome wheels that the assembly is laid on either a rubber mat or cardboard to prevent scratching to the wheel. Lubricate both rim flanges and both tyre beads with an approved tyre lubricant. (never use petroleum, petroleum based, silicon, or water based lubricants as these may damage the tyre rubber or cause rust build up on the rim) Push the first bead onto the rim until it bites. With the correct tyre lever, working towards the valve position, fit the remainder of the first bead onto the wheel. (a hammer should not be used as an alternative to a lever to fit the first bead however if one is used it must be with great care) The use of a clamp on the rim flange is permissible with care, so as not to damage the flange (mole grips should not be used as a clamp) Position the clamp 15 20 cms to the right of the valve position and locate the second bead under the clamp. Ensure all is secure and that there is no possibility of damage to the bead. Using the correct tyre lever by progressively levering around the rim fit the second bead on the rim, by working away from the clamp taking small bites with the tyre lever. Remove the clamp and return tools to storage. 11
7. Tyre Inflation Safety Consideration When using any bead seating device, ear and eye protectors must be used. Additional Inflation Safety information NEVER use an unrestricted airline to fully inflate a tyre. (i.e. without a gauge or pressure control device) NEVER allow the control valve to be jammed or held open (which could allow the operator to leave the inflating tyre unattended) NEVER stand kneel or crouch over a tyre whilst it is being inflated. Inflate the tyre with the valve core removed until both beads are seated onto the rim to a maximum of 1 bar (15psi). If difficulty is experienced in seating the beads then the use of a bead seating device as illustrated opposite is permitted. Always follow the bead seating manufacturer s instructions. Re-insert the valve core and continue tyre inflation paying attention to the following; Place the wheel assembly in a suitable and secure tyre safety cage, (or a mobile device such as a Bag IT) inflate the tyre to the recommended working inflation pressure. Check the condition of the tyre for any obvious bulges, cracks or splits, and that the bead seating line is equally distanced around the entire circumference of the wheel rim. Listening at all times for any creaking or popping sounds that may indicate the start of a potential zipper failure. A minimum of 6ft (1.8m) of airline must be used between the valve and air control gauge. Under no circumstances should a wheel assembly be left unattended during inflation. When the tyre in the safety device has reached the required pressure remove the tyre from the cage / device. The wheel assembly MUST be then checked again for any bulges etc. Fit a high pressure valve cap onto the valve and place the assembly in a safe position or refit to vehicle. 12
8. Tyre Inflation when working off site / at customers premises / or at the roadside Additional Inflation Safety information ALWAYS inflate a tyre at arms length and out of the trajectory area. (stand to the side of the tyre / or face the tread) (always stand outside the trajectory area fig 1) WATCH & LISTEN ALWAYS watch the tyre while inflating you are looking for bulges in the sidewalls or tread area. ALWAYS listen for the tell tale sounds; creaking / popping this is the noise made by the casing body plies breaking. Information Tyre inflation may be more hazardous when the safety aids mentioned earlier (fixed safety Cage / or Bag - IT) are not readily available. Inflated tyres contain a large amount of stored energy a typical truck tyre can have 34 tonnes of force acting on it. New or Retreaded tyres can normally withstand this force. However if the tyre is a Part-Worn tyre or its history is not known i.e. it may have been in service underinflated which causes undue stresses on the body plies. It may have a faulty repair or that the tyre has been damaged in service. It is vital that a full and proper internal inspection takes place, if you are unsure get a second opinion if this is not possible DO NOT fit the tyre to the wheel. Fit a new or retread tyre and have the worn type inspected back at the depot and or have it pressure tested before refitting it. The force inside an inflated tyre could be released suddenly and violently when reinflating the tyre. Very often through the tyre sidewall (called a zipper) resulting in a destructive if not fatal air blast including ejection of steel particles, rubber and dirt at very high speed, which can cause damage to eyes and penetrate the skin. Also if the wheel is not restrained or contained, it can fly metres through the air. These types of tyre explosions have over the years led to numerous fatalities. 13
9. Tyre Inflation when working off site / at customers premises / or at the roadside (cont) Additional Inflation Safety information ALWAYS inflate a tyre at arms length and out of the trajectory area. (stand to the side of the tyre / or face the tread) (always stand outside the trajectory area fig 1) WATCH & LISTEN ALWAYS watch the tyre while inflating you are looking for bulges in the sidewalls or tread area. ALWAYS listen for the tell tale sounds; creaking / popping this is the noise made by the casing body plies breaking. Require an image of wheel attached to vehicle being inflated Require an image of a wheel being inflated under the trailer side guard Tyre Industry Best Practice; If a fixed safety device or similar is not available; Best Practice is to re-fit the partially inflated, (1 bar 15psi) built up assembly back onto the vehicle, all wheel nuts must be pinch / nipped tight 60 nm and then continue to inflate to the correct operating pressure. This procedure will contain the assembly during the inflation process. Upon completion of tyre inflation wait five minutes before completing wheel nut tightening, following the vehicle manufacturers recommendations in the correct sequence with a calibrated torque wrench. If the above best practice is not possible (i.e. the wheel is loose) place the assembly under the vehicle / service vehicle. Regarding a trailer, if the wheel cannot be re-fitted for inflation slide it under the nearside side guard (as illustrated) this will help contain the force if there is a violent explosion. Alternatively position the wheel assembly in front of a protective barrier, e.g. a wall / crash barrier, an embankment or the side of a vehicle and using the maximum length of the airline KEEP as far away as possible during inflation. Carry out your own Dynamic Risk Assessment of the potential hazards and keep others in a place of safety at all times. 14
Minimum Fitting Hand Tools Required 15