Our Tips on Tyres
Some useful tips on the storage of Tyre covers and tubes
These recommendations set out the best conditions of storage for covers and tubes, so that the maximum service life can subsequently be obtained. Whilst these are specially applicable to bulk storage, the same principles apply to the storage of small quantities.
Where sufficient space is available, racks made of tubular piping provide an admirable structure which combines lightness with strength. These can be erected in sections, the distance between the vertical supports depending on the size of the covers to be stored; obviously large truck covers will require closer supports than car covers.
Depending on the ceiling height of the building two or three tiers can be accommodated. Horizontal piping, fixed at suitable heights on the up-rights to suit the size of the covers, provide the support for the covers.
The covers are stored vertically and side by side so that their weight is supported by the tread at two points. The supports should be arranged so that approx. ¾ of the circumference of the cover is above the supports and ¼ below.
By this arrangement the weight of the cover is taken by the tread and distortion is reduced to the minimum. The placing of more covers horizontally on top of the covers in the racks should be avoided.
Where space is limited, or where the cost of metal racks is considered unjustified, the following method may be employed provided that the limitations on the height of the stacks are observed. This method is not considered to be quite as suitable as method 1 (recommended method), but is frequently used.
Select a clean, level floor and build up a stack of covers by laying them flat one on top of the other, being careful that the covers are centered properly, otherwise the stack will be unstable and accidents may result. The height of the stacks should be limited to 1829 mm. It is most important that this precaution should be carefully observed, otherwise the sidewalls and treads of the bottom covers will be distorted to a dangerous degree, and the subsequent service life may be adversely affected. If the stack exceeds 1829 mm in height the excessive weight of the covers causes the grooves of the tread pattern of the bottom covers to gape open, thereby putting a heavy strain on the rubber below the pattern - this may lead to cracking and splitting when the covers are put into service.
These apply irrespective to whether storage method 1 or 2 is used. Factors that contribute to the deterioration of stored covers and tubes are:
- Light (particularly sunlight, which is rich in ultraviolet rays)
- Ozone (from electrical generators, etc.)
- Air Currents
- Dust and Dirt
Any storage place should therefore be protected from these deteriorating agencies, which adversely affect the physical properties of the rubber, and hence the useful life of the articles.
- The storage place should be kept as dark as possible, windows and skylights should be covered with a dark paint and doors and be left burning beyond the time necessary for work to be carried out in the stores.
- If the store cannot be darkened for some reason, the racks should be covered with tarpaulins or other closely woven fabric to exclude light, air and dust.
- Covers and tubes should not be stored near electric motors, switchgear, etc., as these generate ozone which is very destructive to rubber.
- The storeroom should be kept at a reasonably low and uniform temperature (20° - 25°C). In hot territories where this cannot be achieved the store building should be insulated from the direct sun as far as possible. Such materials as corrugated iron should be avoided. In cool territories covers and tubes should be kept away from radiators and steam pipes.
- Draughts should be avoided where possible, as these supply fresh oxygen which increases the rate of deterioration of rubber.
- Excessive changes in the humidity of the air in the store should be avoided as far as possible as moisture will condense and collect inside the casings.
This is not so serious with new covers, which usually have an adequate layer of rubber protecting the inner ply. Used covers often have cords exposed due to cuts, etc., which allow ingress of water. Rotting of the casing can occur under these conditions.
- It is not good practice to "lace" or stagger the tyres in piles, as this tends to distort the bead wires and casing. If the stack method is used, the covers should be carefully aligned and the height restricted to 1829 mm.
- If the stack method is used, the mixing of sizes should be avoided. Larger and heavier covers should never be stacked on smaller sizes; if mixed sizes must be stacked, the sizes should be graded so that the smallest and lightest is at the top of the stack.
- Before storing used covers they should be inspected and any necessary repairs made. Oil and grease should be cleaned off if present.
- When making issues from a tyre store the principle of "first-in, first-out" should always be adhered to.
- New tubes are usually received packed in cartons or bags and they should not be taken out of these containers until required for use.
- Large stocks of tubes should not be carried, as physical properties tend to deteriorate on prolonged storage, especially in hot climates.
- In cases where tubes are received fitted in the covers, with or without flaps, the pressure should be reduced to the minimum to retain the tube in the cover. The assembly can be stored in the usual way for covers, but it is most important to keep light away from the portion of the tube exposed between the cover beads.
- Used tubes should be deflated by removing the valve core, examined, and any necessary repairs made. The valve core should then be reinserted and a small amount of air put into the tube, which is then folded carefully and stored in a carton or bag of suitable size if available. Used tubes can be stored slightly inflated inside covers as in paragraph 3 above. Whichever method of storage is used, care should be taken to exclude light from the tube.