Wheels and tyres upgrade what you need to know
If your car looks a little tired, it may be time for a general spruce-up. One way of adding style is to fit a set of new wheels and tyres. Carefully matched, they may even improve your car's handling .Fitting wider than standard wheels, together with suitable tyres, is among the simplest and most popular methods of customizing a car,giving it an individual, personalized appearance which distinguishes it from others of the same type.
The concept was first developed to give improved traction and cornering grip on the racetrack and the image is still associated primarily with high-performance vehicles. Thus, replacing a model's original equipment wheels and tyres with wider ones can bring considerable benefits. There are, however, a number of actual or potential disadvantages which should be in mind.
One of the first things you must consider when deciding to fit different wheels and tyres to your car is which sizes will fit, most people fit wider wheels to improve the car's looks but the other main advantage is the gain in grip which will normally occur. In the dry, at least, the larger area of rubber in contact with the road will give better adhesion, resulting in improved cornering and braking capabilities.
Pros and cons
If the wide tyres are fitted to a suitably large rim, steering feel may also be Improved and the car could handle better. You might also find that wider tyres wear more slowly due to the weight of the car being spread over a larger tread area than before Unfortunately, this larger tread area can also work against you in poor conditions Because there is the same weight of the car on a larger tread area, the downward pressure per unit area that the car exerts will be less than with the standard tyres.
This means that if the road surface is wet it will be as though there is less weight available to push the water out of the way to let the tyre's tread contact the road surface. In extreme conditions the tyre may not be able to push the water out of the way at all and will 'aquaplane'. This means that the tyre rides on top of a thin layer of water and is completely separated from the road surface, resulting in a loss of braking and steering control. Fortunately, these problems do not usually make themselves apparent unless you fit excessively wide wheels and tyres,
Other possible disadvantages of fitting wide wheels and tyres are reduced wheel bearing life and heavy steerng at low speeds; however, if you choose
your insets and outsets care fully these problems can be minimized Inset and outset are the names used to describe the distance between the wheel-to-hub mating face and the centreline of the tyre's tread. If (as on most front-wheel-drive cars) the tread centre Iis inboard of the mating face between the hub and the wheel, the wheel is Inset; If the wheel is dished the other way it is outset. On most car wheels, Inset or outset is dictated by the brakes wheel hub suspension components that they will have to clear.
Your main consideration, though, will be to make sure that the wheel has enough outsets to clear the brake and suspension parts, but has enough inset make sure that the tyre stay inside the wheel arch. Manufacturers,publish exhaustive tables of the Insets and outsets available with their wheels and will also advise you which are the best wheel and tyre sizes for your car, together with any slight modifications which will be required. You should not have to make too many difficult modifications as there is now an enormous range of styles to fit almost every car. Fitting much larger diameter wheels than standard is not normally possible unless you have carned out suspension and bodywork modifications,but it is becoming increasingly popular to fit wheels larger than the standard wheel, together with very low profile tyres.
To do this the wheel is larger, but the tyre is 'shallower' than standard, ensuring that the wheel and tyre combination remains at the same overall diameter as the originals. However, if you do modify your car to accept wheels and tyres of a larger overall diameter than standard, bear In mind that this will raise the gearing. This will affect your car's performance and economy and will give an lnaccurate and illegal speedo-meter reading.
The last thing to check is that you get wheels which have the right pitch circle diameter (PCD). This is the parameter of the imaginary circle which the wheels studs or bolts lie on: if your studs and wheels do not match, the wheels will quite simply not fit the car, The manufacturer of the car of wheel Will supply you with the PCD measurement, or you can check it yourself by measuring (on a 4 stud wheel) from stud to stud across the wheel centre, or (on a 5 stud wheel) from one stud across the wheel centre to the point on the imaginary circle opposite the stud you started from.
When you decide to fit alternative wheels to your car, new tyres will probably be required, particularly if the new wheels will be larger, so it is a good idea to wait until your existing tyres are well worn before making the decision to change wheels However, if you are only fitting slightly larger wheels you may be able to keep your old tyres as a particular tyre sue will fit on to a small range of rim widths. For instance, a 165 section tyre (165 mm across at its
widest point) which is normally fitted to a 5 lnc. wide rim, can also be fitted to a 41/2 in. or 51/2 in. rim without any problems. So if your
car has, say, 165 x 15 radial tyres on 4 1/2 J steel wheels, you could have those tyres fitted to some 5 1/2 J alloy wheels. 5 1/2 J x 15 is, in fact, the most popular aftermarket wheels in previous years .
But to get the best out of wider wheels with larger diameter ,Unless you have a rugged or of road car you should fit lower profile tyres at the same time if you can afford it. If you do not, you may be disappointed with your expensive new wheels unless you have chosen them for appearance alone. Lower profile tyres generally Improve roadholding because the shorter sidewalls prevents the tread flexing and so more of the rubber is in contact with the road at all times. The shorter sidewalls also absorb less of the input from the steering, so the tyre follows your intentions more closely. At the wheel you should be able to feel better steering response and easier handling in extreme conditions.
Unfortunately each low profile tyre costs about the same as an alloy wheel, so get some expert advice before you buy .
You will also need to check that the wheel nuts or bolts are correct size and length for the new wheels check with the seller .