Tyre care and repair
CARE OF TUBES
Repairs to tubes should ideally be carried out by an expert and should be vulcanized – hot or cold process. It is recommended that a new tube should be fitted with a new tire. Tubes which have given long service become stretched and when fitted with new tires may fail prematurely because of creasing or thinning of the tube rubber.
Tubes with several repairs should be discarded.
Damage which exposes the casing is dangerous and contravenes tire legislation. Replace damaged tires immediately.
Ensure wheels are correctly aligned and inspect regularly. Be aware of your tires through frequent visual examination and before any long journey. Worn tires are more susceptible to damage and road holding is reduced in the wet. To maintain full stability on high performance machines it is advisable to change the tires before the legal 1mm (1/32”) remaining pattern depth is reached.
Avon tires are made to fine tolerances but it is essential that the tire/ wheel assemblies should be balanced – particularly if high speed runs are contemplated. The wheels themselves should run true to within 1mm (1/32”) and be free from distortion. Tubeless tires and wheel assemblies can be balanced by using self-adhesive or clip-on weights. Spoked wheels should be balanced by using spoke weights, or by wrapping the outer end of the spoke adjacent to the light spot with lead wire until the wheel, freely rotating on its bearing, shows no tendency from one particular section (a heavy spot) to swing to the bottom-most point. If using lead wire, bind the lower end with the adhesive tape to prevent moving. Fine balance is more important on front than rear wheels.
REPAIRS TO TUBELESS TIRES
The main advantage of a tubeless tire is its ability to withstand penetration by nails etc without a rapid loss of air. This also means that a rider can be unaware of a puncture and if the tire continues to be used for long distances, the area of damage will spread and could become serious. Tires must therefore be inspected regularly for nails etc, and repairs carried out as quickly as possible.
In instances where deflation has occurred, such as a nail penetration, it is essential to remove the tire from the rim for a full external and internal examination before attempting any form of temporary or permanent repair.
Providing there is not other damage to the tread or casing Cooper-Avon recommends that only certain types of repairs should be carried out and these only in the crown area of the tire. Plug repairs to punctures in the shoulder or sidewall area of the tire are not recommended.
It is essential to follow the material manufacturer’s instructions. Repair by buffing the tubeless lining and applying a cold cure, or vulcanized repair, of minimum 25mm (1”) diameter to seal a penetration of not more than 3mm (1/8”) diameter. The external hole should be sealed with rubber sealant to prevent the ingress of moisture which could affect the casing cords.
NB. Straight plug type repairs must not be attempted as there may be insufficient tread rubber and casing material to provide sufficient security for the plug location.
In the event of an emergency ‘get-you-home’ repair, it is permissible to use an inner tube of the correct size and type but the Motorcycle Manufacturers’ Instruction Manual should be consulted. In some instances, an adapter collar may be required if car-type rubber tubeless valves of greater diameter than the standard metal type have been used originally.
If tire foam filler repairs are used as an emergency measure the tire will have to be replaced when you return home. The chemicals in these products decompose the rubber linings of tires.
For repairs other than those already described, a tire fitter, working to the BS159F repair condition standard and expert in permanent repairs, should be consulted. If any major reinforcement is required to repair the damage the tire must not be used, particularly on a high performance machine, because of possible problems with impaired vehicle stability and imbalance at speed.
These recommendations may appear to be over-cautious, but riders who have experienced sudden tire deflation will appreciate how dangerous this can be.