Tyre care

Tyre Pressures

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Having tyres inflated to the correct pressure is of paramount importance for safety on the road.  Under inflation can lead to an abnormal rise in the temperature of a tyre’s components.  This damage is irreversible and may result in the destruction of the tyre and a sudden deflation.  The negative effects of under inflation are not necessarily immediate, and may not become apparent until a while after correction. 

Check your tyre pressures regularly and before long trips and do not forget the spare. The pressure should be checked when the tyres are cold as tyre pressure increase while the vehicle is driven.  Finally, the valve cap is an essential component for a completely air tight seal.  We can supply plastic dust caps to our customers free of charge.  If you are unsure of your tyre pressures or how to set them please tell us using the contact page or give us a call. 

Many vehicles are fitted with a Tyre Pressure Monitoring System (TMPS), these systems are designed to warn of tyre deflation.  We have experienced some cases when certain TPMS systems have failed to correctly worn of a tyre deflation or indicated deflation when the pressure is correct, these issue have mainly been with systems that use the vehicle traction control systems for measurement.

Tread depth limit

For Cars, vans & 4x4s, in the UK the minimum legal tread depth is 1.6mm in a continuous band, comprising the central three quarters of the tread area, around the entire circumference of the tyre.

Tyres also have tread wear indicators (TWI) which give the driver an indication as to whether or not they are approaching their limit of wear.  With reduced remaining tread depth, the risk of skidding on wet surfaces increases.

Valves

For safety reasons, a new tubeless valve should be fitted whenever a tyre is mounted to a tubeless wheel, this is important when a new tyre is fitted or when repairs to current tyre takes place.  Where tyre pressure monitoring valves are present, the valve should be fitted using the correct service kit.

New to Rear

-..-albums-PRESS-02_PNEUS-TYRES-VOITURES-CARS-MICHELIN-XIN3-Dag2-Alex_25For reasons of road holding, when replacing tyres in most cases we recommend, whether your vehicle is front or rear wheel drive, the newer / younger tyres are placed on the rear axle of the vehicle.  This is to stabilise the vehicle and the higher tread helps when under breaking the rear axle load decreases. On a front wheel drive the new to rear rule helps as aged tyres would be moved to the front axle were they can be worn before age related issues occur.

Why do you not offer Nitrogen Inflation?
[one_half_]There appears to be increasing numbers of people promoting Nitrogen as a tyre inflation media in preference to normal air.
The claimed advantages are:

 

  • The molecules of Nitrogen are allegedly larger than oxygen thus providing a more stable inflation pressure.
  • Nitrogen is more stable under temperature fluctuations hence maintaining a more consistent inflation pressure.
  • Nitrogen has a lower moisture content and hence has less corrosive effect on the tyre and wheel.

Promoters use the more stable and consistent inflation pressure argument as providing better tyre mileage, better fuel consumption and better tyre casing durability.

All of this may be true, but to what degree?

The size of a Nitrogen molecule is very comparable with that of oxygen and as air is made up of about 80% nitrogen the effect on slow leakage will be very small.

The temperature fluctuation in tyres in everyday use is small and pressure increases or decreases have never presented a problem, providing the tyre is correctly inflated in the first instance.

Given that tyres have been designed around normal air inflation for approaching a century and Nitrogen even longer, then if there was any significant advantage, Nitrogen would be the common inflation media, which it is not.[/one_half_]

With regard to the “less moisture” argument, tyre ‘inner liners’ have developed to a sophisticated level and are designed to take account of moisture in normal air. Therefore providing the tyre is not damaged air remains a safe practical inflation media. If however the tyre does become damaged and the steel reinforcement becomes exposed there is a risk of corrosion taking place. Nitrogen would have a marginal positive effect under these circumstances. However, given that nearly all damage to a tyre that could cause exposure of the steel wire, comes from external sources it is most likely that the atmosphere and not the inflation media would cause any corrosion of the steel.

There are positive arguments for the use of Nitrogen in specialist areas such as Formula 1 racing and applications where tyre temperatures are high (Aircraft) or where the risk of explosion is high (hazardous materials). In these circumstances Nitrogen offers advantages of better stability during rapid temperature changes.

In conclusion Nitrogen may offer some small advantages over air, but in everyday usage of tyres the effect would be extremely difficult to measure and any benefit marginal. Users would have the added complication, of having to return to their specialist tyre dealer to have tyre pressures adjusted, as the use of airlines at local garages would nullify any advantage that is offered by nitrogen.

Tyre Damage

perishingAny visible damage i.e. sidewall or tread deformation, deep cuts or split etc., must be inspected quickly to prevent premature failure or possibly to facilitate a repair.  Abnormalities in vehicle ride or handling i.e. vibration, pulling to one side, excessive noise, etc. also requires early diagnosis to establish whether the tyre is defective and to prevent wear to other components.

Common Wear Issues

_MG_7027Alignment Wear

Observation:       Wear increasing from one edge to the other with a fine rubber flash or feathering present on the longitudinal edges.

Probable Cause:    Incorrect alignment of the front or rear wheels.

Advise : Tyres   Can be kept in use if they meet the legal requirements.

Vehicle – Adjust the wheel alignment to the manufacturers.

Centre Wear

Observation:      Wear more pronounced in the centre of the tread than the shoulders.

Probable Cause:     Tyre over inflated.

Advise:       Verify and reset the tyre pressures to the manufacturer specification. The tyre can be       kept in use if it meets the legal requirements.

Rounded Wear

Observation:      Wear more pronounced on the shoulders than the centre of the tread.

Probable Cause:     Tyre under inflated or over loaded.

Advise:      Look for the cause of under inflation and correct it (negligence, puncture, heavy tools      etc.  The tyre can be kept in use if it meets the legal requirements and the structure      of the tyre has not been affected.

Irregular Wear

Observation:       Irregular wear in ripples, bands facets.  Droning noise similar to that of a worn       wheel bearing.

Probable Cause(s): Generally found on trailing rear axles.  This kind of wear can be a result of the       combination of several vehicle factors such as incorrect geometry setting or         suspension faults although this wear issue is often present on vehicles without       such issue so may be considered normal wear.

Advise:      Tyre – can be kept in use if it meets the legal requirements and does not cause      vibration.  Move the tyre to a driven axle as long as it meets legal requirements and      does not cause vibration, this should help prevent the wear irregularities from      worsening.

    Vehicle – Check the wheel alignment and suspension.  If no fault is found frequent      tyre inspection will be required for this vehicle.      

Deformation

Observation:      Localised blister(s) or bulge(s) with or without signs of impact (cut, grazing ect.).

Probable Cause:     Accidental Damage, rupture of one or more cord in the tyres casing structure caused           by contact with an obstacle (pavement, pot hole etc.) or nipping of the sidewall      between an obstacle and the wheel rim edge.  This type of damage is exacerbated by      under-inflation and overloading.

Advise: Tyre – To be discarded.

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