Alloy Wheels and Tyres

In dealing with alloy wheels and tyres you need to know the alloy wheel pitch circle diameter PCD dictates how the alloy wheel bolt holes line up so it is important that this is correct. An alloy wheel PCD of 4×100 meaning 4 bolt holes drilled through the centre of a 100mm circle. Another common alloy wheel PCD is 5×114.3 meaning 5 bolt holes drilled through the centre of a 114.3mm circle. If this is different on your chosen alloy wheels you won’t be able to bolt them on.  Sometimes for an extra charge your chosen alloy wheels can be drilled to fit your car at a car shop.  Most European cars with 4 studs have a alloy wheel PCD of 100mm (Vauxhall, Volkswagen, Honda & early BMW), Fords & Peugeots have a PCD of 108mm. Also consider whether your car has metric or imperial hubs. Real Minis & MGs have a PCD of 4″ which is pretty close to 100mm but not exact so you couldn’t swap one with the other. Check the hole in the centre.  Many aftermarket alloy wheels have a plastic ring in the centre to take up the gap. Measure the hole in the centre of your vehicles own alloy wheel and compare it to your chosen alloy wheels, we are more than happy to do these measurements for you.

It is very important to consider the overall diameter. As a rule, if you can achieve the same rolling diameter your original alloy wheels, everything should be fine. Fitting low profile tyres will allow for an increase in alloy wheel diameter. Fitting a larger alloy wheels will help you decide how much of an increase your car can take. Remember a different rolling diameter will affect the reading on your speedometer.  You can use a tyre calculator to show you what the percentage change in your speedometer reading will be.  With our specialist equipment, we can do this for you while you wait.

While looks and design are important factors when designing an alloy wheel, safety and performance must never be compromised.  Alloy wheels quality control is a key and any flaws in concentricity would be evident at most speeds. Any balance problems would quickly become apparent at high speeds and the safety of the vehicle could be at risk.  Of course, all wheels must be balanced after the tyre is fitted.  Many tyres are made on computerized equipment these days, but they are still not as accurate as alloy wheels. Other tests deal with surface perfection, corrosion, paint (where paints are used) and scratch-resistance.  Materials are tested for strength and durability and X-ray examination makes sure there are no casting defects. Other alloy wheel tests include impact testing (such as hitting kerbs or running over obstacles.  Visit one of our shops and we will carry out all the test necessary for your safe drive and the fitting of your alloy wheels and tyres.

Alloy wheels have been around for many years and most people probably believe they’re just for show but this is just the start. Good alloy wheels and tyres reduce what automotive engineers call “unsprung weight” and their use has a beneficial effect on the cars dynamics. You may opt for alloy wheels when you buy a car to enhance styling, but they play a functional role too.  Don’t forget to protect your tyres.  To protect them tyre manufacturers actually recommend a light coating of wax, rather than one of the many tyre cleaners which you can buy. The cheapest solution is ordinary shoe polish applied with a shoe brush. Buff lightly and the polish will bring the tyre to a nice black shine which does full justice to your alloy wheels. It also helps to keep the rubber clean by throwing off water and protecting it from road salt and UV from the sun.

Care must be taken when driving over humps. Many alloy wheels have a deep dish which means the inner rim can be unsupported. The soft aluminium alloy is easily flattened if you hit a speed hump too fast. The outer rim is usually well supported by the spokes. It is also advisable not to run up kerbs when parking etc. Much damage can be caused at a very low speed. A flattened front alloy wheel rim may have a slight wobble on the steering at low speeds, whereas a flattened rear alloy wheel will cause a drone at high speed. If you have a CD player which is prone to skipping and jumping, the cause could be a flattened alloy wheel.

To protect your alloy wheels and tyres, avoid driving over or scrubbing against kerb edgings or other raised obstructions, because if you drive up on them without necessary care, you run a high risk of reducing the life of your tyre. Mounting the kerb can damage the sidewall of the tyre either invisibly or very visibly. Tyre sidewalls are much thinner than the tyre tread and so are easily damaged. Bulging indicates severe damage to the side wall and this will require the immediate replacement of the tyre as there is a danger of a blow-out occurring at high speed with a damaged tyre, either way the tyre life will be drastically shortened.  If the tyre is listed in your owner’s manual, then it is safe to have it fitted. If not, you may need special approval from the vehicle manufacturer. With a tyre choice you must always consider the maximum design speed of the vehicle, MOT regulations and vehicle, wheel and tyre manufacturers’ recommendations.  You can receive all the guidlines and advice you need for your cars, alloy wheel and tyres.

In addition to regularly checking the pressure and tread depth on your tyres, inspecting them for damage and ensuring they are correctly stored, you can also optimise their mileage performance if you bear the following in mind: Tyres on the drive axle are likely to incur greater wear than those on free running wheels, which is why vehicle manufacturers recommend alternating the wheels to ensure even running and avoid unnecessary costs; When fitting summer or winter tyres after a season of storage, it is advisable to always have the wheels balanced at a garage to ensure driving comfort and avoid any unnecessary wear on the suspension elements.