FAQ

What are the different methods of making wheels?

What are the different methods of making wheels?

In todays marketplace, steel and aluminum are the most common wheel materials. Steel wheels are made in two pieces. The inner piece, which is called the center, bolts on to the car. The outer piece is known as a barrel and receives the tire. The two pieces are welded together to form the wheel. Most original equipment wheels are made this way. Many aftermarket wheels are created this way as well, especially ones made for trucks. Steel is durable and easy to repair. For these reasons, it has remained a popular material for wheel manufacturing. The other material, aluminum, is by far the most popular type of wheel. Its light weight, superior heat dissipation, and seemingly endless design variations make it the material of choice for most buyers. Aluminum wheels can be manufactured in many ways, and each method offers advantages.

One-piece cast wheels

Pouring molten aluminum into a mold creates a cast wheel. The metal then takes the molds shape as it cools and hardens. There are three types of casting methods: low pressure/gravity, counter pressure, and high counter pressure molding (HCM). Each method has its place in todays market. A wheel manufacturer will select a particular method according to the weight, strength, and finish that they have specified for that design. Naturally, the more sophisticated and costly methods produce lighter and stronger wheels but at a higher price.

FlowForm

A FlowFormed wheel starts out the same as a cast wheel, but with a noteable exception in the barrel. The barrel is spun, heated and then pressed between steel rollers that pull the rim to its final width and shape. This create a lighter and stronger rim compared to regular cast wheels, but without the expense of a forged wheel.

Forged / Billet wheels

The two words "forged" and "billet" have become synonymous. However, the manufacturing process is called forging, while the material used is a billet. Billet is the term used for a solid piece of dense aluminum. The forge, a huge machine that exerts thousands of pounds of pressure on the metal, basically presses or rolls the billet into its fundamental form. This forging is then machined to a final finish. This process allows wheels to be built with much less material. This results in lighter weight and unique designs, because the process creates a much stronger wheel than other methods.

Multi-piece wheels

The processes mentioned above can be combined to produce a wheel of a particular strength and weight at a particular price. For example, some wheels have a cast aluminum center, welded to a steel outer, or barrel. Another type of two-piece construction features a billet center welded to a rolled outer (extruded aluminum rolled into a hoop). Still other wheels feature a split outer so that widths and offsets can be made to custom specifications. This last method is the three-piece type construction. In this type of wheel, the center can be cast, billet or forged, and is usually attached to the outer assembly by special screws or rivets.

What features should I look for when buying wheels?

First and foremost, wheels are purchased for styling the vehicle. Youve got to like how they look. Second, decide on the build method and quality. The discussion of manufacturing methods above was intended to inform you of the different ways wheels are made. Choose the manufacturing method you want at the price you are happy with. Finish quality is important, so demand a nicely finished wheel. Finally, decide on the price. We realize there are many tradeoffs between the various features and price and thats why we carry a wide selection of wheels for every budget.

What are hub-centric rings. Do I need them?

Most aftermarket wheels are manufactured with a center hole that will fit a wide range of vehicles. The hub-centric ring is an installation tool used to help hold the wheel perfectly centered during installation. Use of a hub centric ring can help in reducing minor vibrations. Proper installation and torque sequence is required to correctly center a wheel with or without a hub centric ring.

I just hit something in the road. How do I find out if my wheel is ok?

Take the wheel to a dealer for inspection as soon as possible. Following an incident, immediately inspect the wheel for damage. If you see any damage do not drive on the wheel. If you drive the vehicle and notice any vibration, pulling or other sensation previously unnoticed do not drive on the wheel. You should take the wheel to a dealer for inspection whether or not you see damage or feel anything unusual. Your dealer can advise if the wheel(s) needs to be replaced.

How can I tell if my tires are directional and properly mounted/rotated?

Directional tires will have a rotation arrow branded on the tires sidewall. The arrow indicates the direction in which the tire should turn. Unless they are dismounted and remounted on their wheels to accommodate use on the other side of the vehicle, directional tires are to be used on one side of the vehicle and are intended to be rotated from the front axle to the rear axle. If different tire sizes are used on the front vs. rear axle, the tires become location-specific and prohibit tire rotation unless remounted.

Can I mount a tire on its wheel myself?

Do not attempt to mount tires on your own, you run the risk of seriously injuring yourself as well as the rim. See a qualified professional with proper training and experience.

Why do my tires need to be balanced?

Properly balanced tire/wheel assemblies are important for driving comfort and long tire life. An unbalanced tire/wheel assembly can cause vibration, resulting in driver fatigue, premature tire wear and unnecessary wear to your vehicles suspension. The assembly should be balanced when tires are mounted on wheels for the first time or when they are mounted after repair. The tire/wheel assembly should be re-balanced at the first sign of vibration or "shimmy." Vibration may also be due to vehicle misalignment or mechanical problems.

How many miles should I get out of my tires?

There are many factors that contribute to the wear of your tires. Because driving habits and conditions vary it is impossible to predict the exact life of your tires. To ensure the longest life out of your tires take good care of them by:

Maintaining proper inflation.
Rotating your tires.
Inspecting tires once a month.
Practicing good driving habits.
Ensuring that wheels are properly aligned.

Replacing Air with Nitrogen

Using Nitrogen to Inflate Passenger and Light Truck Tires in Informal Service Applications

Introduction & Purpose Nitrogen is being offered as an alternative to air for tire inflation. The purpose of this bulletin is to provide general information about inflating tires with nitrogen.

Tires are designed and built to provide many miles of excellent service but must be maintained properly. The key element of proper tire maintenance is maintaining the recommended tire inflation pressure. The proper tire inflation pressure is recommended by the vehicle manufacturer and can be found on the vehicle’s tire placard or in the vehicle owner’s manual. Continental Tire recommends that the consumer check his/her tire inflation pressure at regular intervals of at least once per month and before every long trip or twice per month depending on local regulations, customs, or conditions.

Using Nitrogen in Tires Nitrogen is an inert (non-flammable) gas – basically, nothing more than dry air with oxygen removed. For example, ambient air contains about 78% nitrogen. Because of nitrogen’s inert properties, it is often used in highly specialized tire service applications and/or demanding environments. These tire service applications usually include aircraft, mining, and commercial/heavy use. Also, nitrogen is used in professional motor racing involving extreme vehicle speeds. We understand that dry nitrogen is used in this regard to help reduce tire pressure variations where even small differences in pressure can affect vehicle handling at the extreme limits of performance. For normal everyday consumer tire service applications, nitrogen tire inflation is not required. However, nitrogen tire inflation does not harm tires and may marginally contribute to reductions in tire inflation loss by permeation. Nevertheless, nitrogen will not prevent any tire inflation loss caused by punctures, tire/rim interface (bead) leaks, valve leaks, valve/rim interface leaks, wheel leaks, and other mechanical leaks. Again, the use of nitrogen alone does not substitute for the importance of regularly checking tire inflation pressure. If the tire inflation pressure is below the pressure specified on the vehicle placard, the tire must be re-inflated – whether with air or nitrogen – to the proper inflation pressure. Do not operate tires underinflated and/or overloaded (see “Warning”). Whether inflated with air or nitrogen, regular tire inflation pressure maintenance remains critical and necessary. Use of nitrogen alone is not a replacement for regular tire inflation pressure maintenance.

WARNING ! Underinflation and/or overloading tires will create excessive stresses and heat build up that can lead to tire disablement, such as by a tread-belt separation and/or detachment, causing serious injury or death.

Tire Repair

A consumer should never repair a damaged tire. Only a trained tire specialist who can base his/her assessment on a thorough and comprehensive inspection of the specific tire can determine whether an individual tire is suitable for repair or should be removed from service. This assessment should also take into account the complete service life history of the tire including inflation, load, operating conditions, etc.. If the tire specialist decides to repair the tire, then he should strictly follow all appropriate national tire industry repair standards regarding the inspection process and repair procedures. Continental is not responsible for the specialists decisions or the repaired tire. Continental advises that a repair to one of its tires invalidates the manufacturers warranty.

SSR TIRES: Even a trained tire specialist may be unable to recognize internal structural damage to a Self Supporting Run Flat (SSR) tire resulting from having been driven in an under inflated or zero pressure condition. Such damage may not be visible on the surface of the inner liner or sidewall making it impossible to determine the tire suitability for repair or reuse. General Tires does not recommend any repair to or reuse of Run Flat (SSR) tires.

Where do I find the proper inflation for my tires?

The vehicle manufacturer specifies the proper inflation pressure for your original equipment tires, (this also applies to aftermarket tires of the same size and type). The proper inflation for your vehicles tires can be found in several places:

Located in your vehicles owner manual.
Listed on the inside of your glove box or center armrest compartment.
The placard on the edge of the drivers or front passengers door or frame.
On the vehicles fuel door. Some vehicles may have LT-metric (prefix for light truck tires) size tires installed although the vehicle calls for P-metric (prefix for passenger tires). In this case please contact us to obtain the proper inflation pressure for the LT-metric tires.

Tire Rotation and Tire Mixing

TIRE ROTATION:

To achieve uniform wear and to maximize tread life, your tires should be regularly rotated. Follow the vehicle manufacturers recommendation for the rotation pattern and interval. Unless otherwise specified by the vehicle manufacturer, rotate your tires every 6,000 to 8,000 miles (10,000-12,000 kilometers) or sooner if uneven tread wear begins to appear. If tires start to show uneven tread wear, ask the service person to check and/or correct any vehicle wheel misalignment or other mechanical problem.

Full-size spare tires (not temporary spares) of the same size and construction as the ground contact tires should be included in the tire rotation. Always check and adjust the inflation pressure of the full-size spare when incorporating it into rotation.

Adjust the tire inflation pressures according to the vehicle manufacturers recommendation for the new wheel position (specified front and rear position tire pressures may be different).

Rotation of your tires may affect the Tire Pressure Monitoring System (TPMS). Consult your vehicle owners manual or a qualified service professional to make the proper adjustments or recalibration of the system. Please note: Do not reverse the rolling direction of directional tires.

TIRE MIXING:

It is recommended that the tire size, load index and speed symbol are in accordance with the vehicle manufacturers specification for all wheel positions. In many countries, this is a legal requirement. Driving your vehicle with a non-recommended mix of tire sizes, constructions, and speed ratings can be dangerous. Follow the vehicle manufacturers recommendations and/or seek the advice from a trained tire specialist if you consider upgrading your tires with different sizes, constructions, load ratings or speed ratings.

Some vehicles may come factory equipped with different size tires fitted to the front and rear axle. Do not change this configuration unless approved by the vehicle manufacturer.

Do not operate your vehicle with more than one temporary spare in use. A temporary spare may only be used at the limited speeds and distances as indicated on the sidewall and/or the label attached to the tire/wheel.

On which axle should the new tires be fitted?

It is recommended to replace all ground contact tires at the same time. If you do not replace all ground contact tires at one time, then at least, replace all the tires on one axle.

If only one axle set of tires is replaced, then it is recommended to install the newest tires on the rear axle. This may complicate tire rotation, and caution is urged if the tires have significant differences, such as state of wear, tire size, construction, and speed ratings. Consult a trained tire specialist for best practices.

Placing greater traction on the rear axle is recommended to prevent a possible oversteer condition and loss of vehicle stability on slippery surfaces.

Other important considerations:

The date of manufacture and condition (e.g., signs of cracking, remaining tread depth) of the spare tire should also be checked and considered for replacement.

For 4-wheel drive and All Wheel drive vehicles, especially those equipped with electronic systems such as anti-lock brakes, traction control or stability control, consult your vehicle owners manual for any special tire fitment requirements. If you do not follow these requirements it may even cause damage to your vehicle/ transmission. Winter tires should be fitted to all wheel positions, not mixed with all season or summer tires. If only one axle set of winter tires are used, then it is recommended to install them on the rear axle. Placing greater traction on the rear axle is recommended to prevent a possible oversteer condition and loss of vehicle stability on slippery surfaces.

How often should I rotate my tires?

To achieve uniform wear and to maximize tread life, your tires should be regularly rotated. Follow the vehicle manufacturer’s recommendation for the rotation pattern and interval. Unless otherwise specified by the vehicle manufacturer, rotate your tires every 6,000 to 8,000 miles (10,000-12,000 kilometers) or sooner if uneven tread wear begins to appear. If tires start to show uneven tread wear, ask the service person to check and/or correct any vehicle wheel misalignment or other mechanical problem.