Motorcycle Tyres

SAFE TYRES SAVE LIVES tyresafe.org Motorcycle Tyres and Your Safety

General Advice in tyre size or type (construction) Tyres are the only parts of the should not be undertaken without motorcycle which are in contact seeking advice from the motorcycle with the road. Safety in acceleration, or tyre manufacturers, as the effect braking, steering and cornering all on motorcycle handling, safety and depend on a relatively small area clearances must be taken into account. of road contact. It is therefore of The tyre industry has long recognised paramount importance that tyres the consumer’s role in the regular care should be maintained in good condition and maintenance of their tyres. The at all times and that when the time point at which a tyre is replaced is a comes to change them suitable decision for which the owner of the replacements are fitted. tyre is responsible. The original tyres for a motorcycle In some other European countries it are determined by joint consultation is illegal to use replacements which between the motorcycle and differ in certain respects (e.g. size, load, tyre manufacturers and take into construction, and speed rating) from account all aspects of operation. the tyre fitted originally by the vehicle It is recommended that changes manufacturer. DIAGONAL RADIAL PLY BIAS-BELTED (CROSS PLY)

BELTS

ANGLED FABRIC ANGLED FABRIC PLIES FABRIC BELT AT PLIES (NOT ANGLED) PLIES SIMILAR BEAD FILLER ANGLES TO PLIES INNER INNER INNER TUBELESS TUBELESS TUBELESS LINING WIRE BEAD LINING WIRE BEAD LINING WIRE BEAD (ON TUBELESS TYRES) (ON TUBELESS TYRES) (ON TUBELESS TYRES)

Choosing the Right Tyre All three construction types can be manufactured in differing tread profiles Today’s motorcycles vary in design and patterns which may also be and specification including scooter and available for front and rear fitment. all-terrain to suit a variety of pursuits including; race, street, sport, touring, It is recommended that tyres be off-road and leisure. fitted in matched pairs for optimum performance (in certain European Tyres should be chosen with both the Motorcycle Tyres and Your Safety countries it is illegal to mix brands on motorcycle and the application in mind. the same bike. Local tyre regulations For guidance, or if in doubt, you should be checked when taking your should: bike abroad). a) Refer to the owner’s manual Special tyres are available for b) Consult a tyre specialist sporting events, some of which are c) Use the tyre manufacturer’s unsuitable for road use and are marked fitment guide book accordingly (normally NHS – Not for Highway Service). Types of Tyres Mixing of Tyres There are three basic tyre construction types: It is illegal and could be dangerous • Diagonal (cross) ply to mix tyres of different construction • Radial ply on motorcycles in certain ways; for permitted fitments refer to table • Bias belted (overleaf). Depending on the wheel type, these If in doubt a tyre specialist should may be tubeless (no tube required); be consulted, but to avoid any or tube type (requiring an inner tube). misunderstanding it is recommended that both tyres on a motorcycle, and should be sought from the tyre all tyres on a combination, should be specialist or tyre manufacturer. Specific of the same construction and from the advice from the tyre manufacturer is same tyre manufacturer. recommended for tyres fitted to classic Where sidecars are fitted and the and vintage motorcycles pre 1960 sidecar axle aligns with either of the where pressures quoted in the original motorcycle axles, the sidecar tyre handbook may be inappropriate. must be of the same construction An indication of maximum load at a as the tyre with which it aligns. given pressure is marked on all tyre sidewalls. This should not be used as a recommended pressure. Pressures Front fitment Rear Option must be adjusted appropriately for solo X-ply X-ply and for pillion and pannier loads. It is Bias belt X-ply dangerous to re-inflate a tyre which Radial has been run flat or seriously under inflated. Such tyres should be removed Bias belt Bias belt Bias belt for inspection by a tyre specialist. Radial Prolonged under-inflation causes Radial Radial Radial excessive flexing, deterioration of the casing and rapid wear of the tread Keep the Pressure Correct shoulders/edges. Your motorcycle may The correct tyre inflation pressure is also consume more fuel. vitally important for safe handling of Over-inflation may result in an the motorcycle. The recommended uncomfortable ride, a reduced area tyre pressures for original equipment of contact with the road, accelerated tyres will be stated in the motorcycle wear on the tread centre and makes owner’s manual. For fitment of the tyre more susceptible to impact aftermarket alternative tyres, advice damage.

CORRECT UNDER OVER INFLATION INFLATION INFLATION

TREAD CONTACT TREAD CONTACT TREAD CONTACT WITH ROAD WITH ROAD WITH ROAD Inflation pressures should be checked tread depth, cracking or crazing of the once a week when the tyre is cold, tread or sidewall rubber, cuts or bulges, since there is an increase in pressure foreign objects, as well as being alert when the tyre has warmed up after to any change in dynamic performance being run. A reliable and accurate or behaviour such as air loss, noise or pressure gauge should be used. vibration. Running-in Tyres Driving over pot holes, kerbs and speed bumps, even at low speeds, can The running-in period allows the tyre result in the weakening or fracture of to settle itself onto the wheel rim, the tyre structure. serves to “scuff-in” the tread surface The consumer should be the first to and allows the rider to adjust to the recognise an in-service impact and ‘feel’ and handling of the new tyres. then ensure immediate inspection by After fitting, before moving off, ensure a tyre professional, who can also offer the tread surface is not contaminated advice and guidance. Lumps or bulges in any way: clean off fitting lubricant, could indicate internal damage and buff around the tread circumference should be examined by a tyre specialist with a dry cloth, and ensure the label without delay. is removed. Confirm correct tyre Oil and grease should be removed with pressures. a suitable diluted detergent. Each time new tyres are fitted, the motorcycle should be driven very Watch your Tread cautiously and the tyres not subjected Tyre treads are designed to give good to maximum power or speed for wet grip but the road surface condition the first 100 miles, i.e. avoid sudden also plays a significant role in tyre to acceleration, maximum braking or hard road adhesion. In general, wet grip cornering. Particular care should be decreases as tyre tread patterns wear taken on wet or greasy road surfaces. down and as the depth of surface After 100 miles, the tyres should then water increases. Motorcyclists should be checked to ensure the correct take this into consideration and reduce seating and inflation. After this initial speed when it is wet. period, lean angles, acceleration Motorcycle tyres normally have tread and braking forces can be gradually wear indicators in the tread grooves increased. and as these are approached during Inspection and Maintenance the service life of your tyre you should consider replacement. Once Regular inspection becomes the indicators are level with the tread increasingly important the longer the surface the tyre should be renewed tyre is kept in service. Consumers are - but this should not be the only strongly encouraged to be aware of deciding factor on tyre replacement. their tyres’ visual condition such as The legal limit of tyre tread depth in Motorcyclists should consult their tyre the UK for motorcycles over 50cc is specialist, the vehicle manufacturer or 1mm across 3/4 of the width of the relevant tyre manufacturer regarding tread pattern and with visible tread advice on the service life of their tyres. on the remaining 1/4. For motorcycles The manufactured date of a tyre can up to 50cc the law requires that all be determined by the numbers at the the grooves of the original tread end of the “DOT CODE” located on pattern must be clearly visible. The one lower sidewall of each tyre legal requirements may differ in other (E.g. “ DOT XX XX XXX 2716” was countries. manufactured in the 27th week of It is recommended to consider 2016). replacing motorcycle tyres in advance Tyre Load and Speed Markings of the legal requirement i.e. at 2mm Motorcycle tyres have markings Remove any stones or other objects to indicate their load and speed that may become embedded in the capabilities. These are moulded on the tread. If left, they may penetrate sidewall adjacent to, or part of, the size through the casing and cause a designation as a service description puncture. comprising a load index (e.g. ‘73’ in Tyre Service Life and Ageing table 2) for load carrying capacity and a speed symbol (e.g. ‘W’ in table 1) for Tyres can deteriorate with age which speed capability. may show as cracking of the tread and sidewall rubber, sometimes Details of load indices and speed accompanied by carcass deformation. symbols can be found in tables 1 & 2 overleaf. Cracking is usually an indication that tyres have been in service for It is strongly recommended to always an extremely long time, but rubber fit tyres that have a load index and deterioration may be brought about speed capability at least equal to or by poor storage conditions. If cracking higher than those originally specified is evident seek professional advice or by the motorcycle manufacturer. replace the tyre. NB: Load carrying capacity is reduced Tyres should be removed from service for speeds in excess of 210 km/h for for several reasons including tread ‘V’ speed rated tyres and 240 km/h wear (down to legal limit), damage for ‘W’ and above speed rated tyres. (cuts, cracks or bulges etc.) or abuse Consult the relevant tyre manufacturer (overloading or underinflation etc.). for guidance on this issue. Deterioration of the tyre may not It is important that tyres are suitable always be visible and may become for the maximum speed capability apparent through loss of performance, of the motorcycle. In some other noise or vibration etc. countries this is a legal requirement. Motorcycle Tyre Markings Chart

SIZ SITI MIL RIM STI SPT IMTR WITH RTI (IHS) (mm) MTRL (M/) TR R US M/ RIM L PRSSUR MRKI RQUIRMT 0/55 ZR SRVI SRIPTI 18 17 L SP M IX SMBL L AX. LOAD 365 k IA M g (8 TS TP 290 kPa (4 05 / D AT 2 PSI LB C STRUTI A ) CO S LD ) ( R D 7 CE 3 R W O M ” F A ) D 0 N V PTIL MXIMUM SP MMRIL M I SPT RTI IS TH TR E 0 MRKI (.. 280 km/h) E I 2 R ITIT 2 R STI HIHT N 8 XPRSS S G P PRT R 0 D I TH STI WITH E K M A

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TUBLSS R TUB TP RRW TI IRTI (B. I ITHR IS SHW WHL RTTI TUB MUST B ITT)

Items in red indicate that the information does not apply in the UK. Speed Maximum motorcycle speed for which tyre is suitable Symbol Table 1 km/h mph Tyre Speed Moped 50 31 Marking J 100 62 Table K 110 68 L 120 75 M 130 81 The maximum P 150 93 speed approved Q 160 99 may be marked R 170 106 on the tyre S 180 112 as for example T 190 118 V230, U 200 124 meaning H 210 130 a maximum V 240 149 speed of W 270 168 230 km/h (W) over 270 over 168 ZR over 240 over 149

Load Load Load Load Load Load Load Load Load Load Index kg Index kg Index kg Index kg Index kg Table 2 20 80 35 121 50 190 65 290 80 450 Tyre 21 82.5 36 125 51 195 66 300 81 462 Load 22 85 37 128 52 200 67 307 82 475 Indices 23 87.5 38 132 53 206 68 315 83 487 and 24 90 39 136 54 212 69 325 84 500 Related 25 92.5 40 140 55 218 70 335 85 515 26 95 41 145 56 224 71 345 86 530 Maximum 27 97 42 150 57 230 72 355 87 545 Loads 28 100 43 155 58 236 73 365 88 560 29 103 44 160 59 243 74 375 89 580 30 106 45 165 60 250 75 387 90 600 31 109 46 170 61 257 76 400 91 615 32 112 47 175 62 265 77 412 92 630 33 115 48 180 63 272 78 425 93 650 34 118 49 185 64 280 79 437 94 670 95 690 Tubes Valves

Tyres which are marked ‘Tube Type’ A new valve should be fitted when or are not marked ‘tubeless’ must be replacing tubeless tyres. When checking fitted with an inner tube. or adjusting inflation pressure always Ensure that the correct size and type ensure that the valve is not leaking is fitted. Always use a new tube when and a cap with a rubber seal in good fitting a replacement tube type tyre or condition is used. a tubeless tyre requiring an inner tube. The fitment of a valve core with a steel Tubes which are stretched, thinned spring is necessary for high speed or excessively repaired may deflate usage. without warning and should not be re-fitted. Particular care must be taken to ensure that the valve is the correct size and Tubes must always be used with type for the rim. tyres fitted to wire spoked wheels, irrespective of whether the tyre is When a tube is fitted and the rim valve tubeless or tube type, except for those hole is designed for a large diameter wire spoked rims specifically designed rubber snap-in tubeless valve, it will be for tubeless tyres. A rim band or a rim necessary to fit an adaptor collar or tape of the correct type must be fitted skirted lock nut to ensure correct valve to protect the tube from spoke head location. damage. Wheels and Rims

Tubes in Tubeless Tyres It is essential that the wheel size and Inner tubes of the correct size may design/type is an approved and only be used with tubeless tyres if suitable fitment for the tyre and correctly fitted, and approved by the motorcycle concerned. individual tyre manufacturer. It must, Tyres must not be used on damaged or however, be emphasised that the distorted wheels since this could result result of fitting tubes in tubeless tyres in tyre damage, deflation and possible is that, in the event of a puncture, loss of control of your motorcycle. the assembly will behave in exactly Car and motorcycle rims of the same the same way as a tube type tyre nominal diameter code (e.g. 17) have and tube assembly. different dimensions and therefore car NB: Tubes should not be considered and motorcycle rims and tyres must a puncture remedy. not be inter-changed. Where tubes for certain low profile tubeless tyres are not available, an alternative size tube should not be fitted. Motorcycle and Scooter Tyre Repair Limits according to BS AU 159

SPEED SYMBOL UP TO J ABOVE J UP TO AND INCLUDING V ABOVE V

MAX. DIAMETER NON- OF DAMAGE 6 mm 3 mm AFTER REPAIRABLE PREPARATION

MAX. NUMBER OF REPAIRS 2 1 0

BS AU 159 states: Tyres should be removed from the wheel for inspection before repair.

NOTE: it is recommended that tyres with speed symbol above V are not repaired but replaced. Speed symbol details can be found in Table 1.

Repaired Tyres

It is dangerous to re-inflate a tyre hidden damage which could result which has been run flat or seriously in failure. Liquid sealant repairs are under-inflated and such tyres should intended only for emergency, short be removed for thorough examination term use to get a rider or driver to a by a tyre specialist. tyre fitment centre. ‘Plug’ or ‘string repairs’, which may be carried out with Repairs to motorcycle tyres and the tyre fitted to the wheel by inserting tubes should be carried out by a tyre a ‘string’ of rubberised material specialist and in accordance with the through the tread using a probe, are current British Standard AU 159 or tyre equally unsuitable as a permanent manufacturer’s recommendations. This repair. If used for extended periods, states minor penetration repairs should string repairs allow moisture to enter only be carried out on the central 50% the tyre, which increases the risk of of the tyre’s section width and not to failure. Additionally, the repair is only any damage beyond that limit. The superficial and can become ineffective, table above shows the maximum size causing slow punctures. of damage (after preparation) which may be repaired for the appropriate Neither externally applied plug speed symbol. type repairs nor liquid sealants are recommended and tyre manufacturers Permanent repairs can only be cannot be responsible for problems carried out following removal of resulting from their use. On no account the tyre from the wheel to allow a should a tube be considered as a thorough inspection internally as well puncture repair remedy. as externally to ensure there is no Repairable and Non-Repairable Areas for Motorcycle and Scooter Tyres

motorcycle scooter

Repairable areas are shown in green and cover the central 50% of the tyre’s section width. Repairs should not be done outside the repairable area.

BS AU 159 requires a tyre to be Removal and Fitting of Tyres removed from the wheel and These operations should only be thoroughly inspected internally and entrusted to a trained tyre specialist externally to determine suitability who has the necessary equipment and for repair. If the tyre is suitable for expertise. Inexpert fitting can result in repair, the repair should be done in injury and damage to tyres and wheels. accordance with BS AU 159. After repair, the tyre should be thoroughly Direction arrows, where shown on inspected again to ensure that it will the sidewall, indicate the direction of operate as intended and that repairs rotation of front and rear tyres and are free from any defects. must not be ignored.

If you are in doubt about the correct tyre for your motorcycle, consult a tyre specialist. TyreSafe, Peershaws, Berewyk Hall Court, White Colne, Colchester CO6 2QB 01787 226995 [email protected] tyresafe.org Charity Number: 1168354 (England and Wales)