DESIGN D.Wren designs Solid Rubber & Duramatic Tyres as per customer s requirements at its computer aided design facility based on the following data. Selection of Solid Tyres by the users should be based on the following points: I. Loading and Speed Every solid rubber tyre has the ability to produce a certain performance. Performance is power X distance: time = loading X speed. II. Bump Characteristic Bump travel is the radial deflection of the tyre cushion under a certain load. The governing factors are, apart from the cushion cross section, the ratio of cushion height to cushion width and the physical properties of the tyre elastomer. A very long bump travel has a favorable influence on ride comfort but a detrimental one on steering response, cornering forces, lateral and longitudinal stability. III Pressure per Unit Area. Presssure per unit area is the mean specific pressure exerted by a tyre over its standing surface on the ground. A low pressure per unit area is desirable for sensitive floors and unpaved roads. IV Rolling Resistance The rolling resistance of a tyre is part of the total tractate resistance. The lower the tractate resistance (good efficiency ), the more significant the tyre s rolling resistance becomes a low rolling resistance means that only low torques or pulling forces are required. The load on drive units is thus reduce and allows higher travelling speeds to be reached as well as noticeably reducing the consumption of energy. V Traction Traction is a collective term for the ability of a tyre to transmit friction and power in both the longitudinal and transverse directions (driving, braking and cornering forces) VI. Stability The stability of a lift truck is its resistance to tipping, in addition to the many factors which affect the stability in the longitudinal and transverse distribution, track, wheel base, type of suspension and axle springing, engine/motor output and the tyre deformation which occurs when load is applied. D.Wren solid & Duramatic tyres are completely safe owing to their relatively flat cushion, short bump travel & slight lateral deformation.
VII. Type of use, Temperature of surrounding & Choice of Elastomers The temperature of the surrounding & type of use, where the tyre is used has a detrimental effect on the tyre & this effect is taken into consideration during design of the tyres. The rubber compound is designed taking the above into consideration apart from the standard rubber formulations available at D.Wren. We also design specific rubber compounds for specific use of our customers. VIII. Choice of Tread Type The tread type to be used is also dependent on the type of use of the tyre, & ensures long life of the tyre. D.Wren has different type of reads of different applications. If you require a different tread type, D.Wren required. All D.WREN DURAMATIC tyres and Solid Rubber Tyres are balanced in these properties. D.WREN manufactures 4 standard elastomers which cover the widest spectrum of applications. (See Elastomers), with different Treads (See Tread Patterns).
ELASTOMERS D.WREN has developed four basic compounds (given below) for the industrial tyres depending on their use, through experienced & continuous testing. Other specialised compounds can be developed by us, if required by theg user. 1) ST/75 The ST/75 elastomer is designed for maximum wear and cut growth resistance. ST/75 tyres (rim type) are used on vehicles powered by internal combustion engines, fork lift trucks, charging machines, crane systems etc. upto speeds of 10 km/h. 2) AR The AR elastomer has balanced qualities. AR tyres have a low rolling resistance and good wear characteristics. AR tyres are particularly suitable for electrically powered vehicles, electric fork lift trucks, trailers, vehicles travelling on rails, low loaders etc. upto speeds of 15 km/h. 3) ST/80 The ST/80 elastomer is distinguished by its high resilience and minimum rolling resistance. ST/80 tyres are particularly suitable for trolleys & welding rotators. 4) HR A new D.WREN Solid Tyre elastomer Our sales programme is actually extended by the specgial rubber elastomer HR label. HR is a elastomeric compound proven under extremely hard condition like high range of abrasive flooring (e.g. in foundries, furnace etc.) with excellent results. This compound imparts a high degree of heat & abrasion withstanding property on the tyre.
The following advantages are obtained from Nylon Tyre. Made of homogeneous materials from tread to rim. Can t separate. Rubber Compound is interlaced with extra long Nylon Fibres for greater strength. The Nylon Tyres won t go flat, puncture, sang, blowout, separate and tear. Heavier weight lowers centre of gravity to reduce chances of tipping Safely caries upto 35% greater load capacity than Industrial pneumatics. The standard elastomers have proven very successfully and meet the requirements of almost all applications. We supply a number of special elastomers for special applications :- Non marking tyres. Oil and grease resistant tyres Electrically conductive tyres resistance < 10 Q Friction Wheels Two component tyres. DAMAGE CONTROL (A) Mechanical The following points should be noted in order to ensure a long service life: a) Wheel and Rims It is essential to observe the wheel dimensions and their tolerances. If the wheel diameter is too small, there is a risk that the tyre will come off the wheel. On the other hand, if the wheel diameter is too large, the tyre can be destroyed during fitting. The appropriate original pneumatic tyre rim should be used for DURAMATIC tyres. The tyre bead can be destroyed if the rim is too narrow the tyre will not be properly seated if the rim is too wide. b) Fitting The use of the correct mounting rings and tools avoids damage to the tyre during fitting. Never use greases and oils as lubricants but rather grease-free fitting paste or a soft soap solution as grease and oil attack rubber. Steel band tyres must never be shrunk fit or welded to the wheel. High temperatures destroy the chemical adhesives.
c) Load and Speed Exceeding the permissible loading and / or maximum speed can lead to premature failure of the tyre. Overloading causes heat to develop which leads to thermal destruction as a result of the heat built up. On smaller tyre cross sections the effect is extreme material fatigue. The cracks which occur weaken the cross section and cause the tyre cushion to break away from the hard rubber bead or steel band. d) Effect of Foreign Bodies If foreign bodies penetrate the tyre, they cause tyre failure. Chipped tread & tread separation are generally caused by foreign material. e) Wear Although D.Wren tyre elastomers have an excellent wear resistance, the effective service life it terms of operating hours or kilometers varies greatly and is basically dependent on the actual operating conditions. The smoothness of the road surface is important and the style of driving, e.g. quick getaways, sharp braking and fast cgornering, increase the rate of wear. (B) Thermal Prolonged periods of standing under load/exposed to high temperatures causes the tyre to flatten. Exposure to high temperatures results in premature ageing of the tyre i.e., it becomes brittle and cracks. (C) Chemical The resistance of tyre elastomers to chemical influences is dependent on the composition of the elastomer, the duration of exposure and the temperature of the acting medium. Even brief contact (e.g. splashes) has detrimental effect (swelling) on the serviceability of tyres. (C) Ageing D.WREN solid rubber tyres are treated with an anti-ageing preservative. As anti-ageing preservatives do not have an unlimited life, storage for extended periods should be in a horizontal position, kept on a dry, cool place and protected from light. (D) Other 1. Select the Right Tyre for the job- Proper tyre selection is the key to obtaining maximum performance from industrial tyres. Kind of service should determine the types of equipment and tyres to be used. You can expect maximum industrial tyre life only if you
place the right tyres on the right trucks in the type of service for which both were designed. 2. Inspect Tyres Regularly Check tyres at least once a week once every day if at all possible. Look for and remove broken glass, nails, torn pieces of tread, embedded metal chips, etc. Make sure tyres remain centered on wheels to prevent splitting of base band and tread separation. Inspect for uneven or rapid tread wear, usually caused by mechanical irregularities such as prakes out of adjustment or excessive toe-out. If discovered, correct the irregularity immediately. 3. Lubricate Vehicle Regularly Proper lubrication, particularly of the power and braking systems, will assure free rolling operation and reduce tyre drag and skidding stops. Avoid over lubrication, too because overflow of grease or oil is harmful to most rubber compounds. 4. Keep Runways Clean Clean aisles, runways and other truck-travelled surfaces reduce tyre damage. Maintain floors in good repair, free from brakes, ruts, cracks and depression. Nails, cinders and other sharp objects in aisles and runways result in tread-cutting and damage to tyres. 5. To Increase Carrying Capacity - For platform trucks or trailers, a third axle and tandem tyre assembly will help. When this is done, use supporting rings ot reduce tyre damage which could result from bent base bands. 6. Avoid Standing Loads Solid tyres will flat spot when loads are left standing on vehicles overnight or longer. In extreme cases, a spot develops and the tyre will bump with every revolution. 7. Check Axle Alignment and Steering Regular checks of steering apparatus and axle alignment of mechanical irregularities will protect against fast irregular tread wear and base separation. 8. Allows Sufficient Tyre Clearance An overall clearance of at least ¼ between solid tyres and any part of vehicle is recommended for protection against scraping and abrasion. Sufficient clearance helps prevent damage from wedging of loose material between tyres and truck farm. 9. Line travel Routes Marked routes serve as guides in steering vehicles, and can serve as a warning where walls, curbs, stanchions or equipment are dangerously close to a route. Lines serve as a reminder to operator that tyres should not bump or scrape obstacles. 10. Center tyres on Wheels Incorrect mounting of tyres on wheels sometimes results in splitting of the steel base and separation of rubber treads from the wheels. Avoid overhang of more than ¼ in outside position. If wheel is not wide enough to support the steel base of the tyre properly, a steel supporting ring should be used.
11. Use Proper Equipment - Don t try to pinch-hit by using a vehicle which may be too light. A unit load for a heavy duty trailer may be too heavy a load for a lighter trailer or cart, and may damage tyres. 12. Instruct Operators Proper driving can do much to save tyres. Instruct operators in proper care and operation of equipment. Train them to handle trucks right; drive at normal speeds; avoid making sudden stops and jerky starts that spin wheels; check for flat spots and any mechanical irregularities. Common reasons for Tyre failure: Chipped Tread due to foreign materials embedded in rubber. Tread & ply separation caused by foreign materials embedded in rubber. Tread & ply separation caused by severe overloading. Chipped Tread caused due to slip-page, turning too sharply, sudden starts & stop. Base band / Ring ruined by obstacle. Uneven wear & shredding due to misalignment of steering arm or faulty axle. Undercutting of tyre caused by overloading. Separation & chipping caused by injurious chemicals.