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Porsche 997: Tires General Information and Specs

The four patches of rubber that touch the road are more important than you think. Learn the basics with this write up.

By Jacob Stumph - April 27, 2015

This article applies to the Porsche 911 (997) (2005-2012).

Having the right tires for your ride can improve handling and precision, not to mention safety. Along with the tires themselves, there are various components to help keep the tires attached to the vehicle. These components work together for a smooth ride, even in poor weather conditions.

There are three basic types of tires on the market: summer tires, designed for warm weather driving, all-season tires for year-round use, and snow tires. Most cars come standard with all-season tires. The OEM tires equipped to your Porsche 997 are summer tires not designed for use in below-freezing temperatures or in the snow and slush of winter. Winter tires can be utilized to maximize your 997's winter time use and will have you conquering all sorts of snowy conditions as the king of snow driving.

You can find specific tire information on your car's driver side door or in the owner's manual. Most placards tell you sizes for the front and rear sizes along with the recommended pressure for standard tire sizes. In some cases, the placards also have ranges to let you know what is (and isn't) likely to fit on your car. Porsche actually has recommendations for winter tire use on the original wheels, along with the use of snow chains in severe conditions.

Wheels

Wheels are a great way to personalize your car. There is a wide selection available, from OEM to custom wheels. OEM wheels often offer easier fitment and greater availability, especially as used or take-offs found for sale on the forums. Aftermarket wheels allow for greater personalization in size and color. When choosing wheels, you have to be cognizant of their diameter, width, and offset (backspacing) to assure good fitment. Additionally, wheels can be too narrow or too wide for your existing tires, so if you're upgrading, keep that in mind. Beyond size, weight and general performance are highly-regarded factors. Advantages of this lighter-weight construction include faster acceleration and stopping.

Figure 1. 997 Turbo wheels on 997 Carrera2.

Wheel Bolt Patterns

Tire bolt patterns are important for replacing or customizing wheels. All modern Porsches share the same 5x130 bolt pattern. When broken down, this pattern means that there are five holes for placing bolts into the wheels and mounting them. The 130 designates the diameter of the wheel's bolt circle in millimeters. However, measuring a wheel's bolt circle diameter can be tough, especially on a five-bolt pattern wheel.

Figure 2. 4-lug and 5-lug bolt patterns.

Scheduled Maintenance

If you still take your car to the dealership for service, it's pretty common that they will inspect your tires, among other things. However, you can assess your tire's health quite easily in between checkups with nothing but a penny. Stick a penny upside down in the tread voids; if Lincoln's full face is visible looking back at you, it's time to replace. This amount of wear is usually about 2/32", and a brand new tire usually measures about 10/32". All tires are sold with a tread wear indicator, which is a raised bar of material 2/32nd of an inch across the tire's tread. When the tire wears down to the indicator, it is no longer legal on the road and requires prompt replacement.

Figure 3. Tire tread wear indicator.

Common Questions

One tire keeps losing air. Should I replace it?

Not necessarily. The most common cause of a single tire that keeps losing air is a slow leak, and that is due to debris that gets stuck in the tire. In this case, the culprit is often a nail. For best results, take the car to a shop as it often needs to be removed from the rim to be fixed properly. While you're there, the mechanic can also recalibrate your Tire Pressure Monitoring System (TPMS), if applicable, once the tire is fixed.

Do I need to replace all four tires if only one is bad?

Replacing tires is costly, especially if you have to replace them all at once. Unfortunately, this is often recommended even if just one tire is bad. This is mainly because it's best if all four tires wear evenly. Putting on a new tire with three worn ones creates a difference in tire size, which could negatively impact the vehicle's performance and safety. If it really comes down it, replace the axle pair if your can't do all four at once. Tire rotations are cited in the owner's manual as to be performed every 5,000 miles (or every oil change).

(Related Article: Porsche 997: How to Check Your Tire Pressure - Rennlist.com)

Can I extended the life of my tires by swapping them from one side to another?

In some cases you can extended the life of the car's tires by moving them from one side to another. For example, if the outer edges on both sides are worn, you may be able to swap the tires so that the inner edge is now on the outside. However, this only works on vehicles with directional tires. Asymmetrical tires have a clear inside and outside, meaning that you cannot substitute one side for the other by swapping tires. Also, your Porsche comes from the factory with a "staggered" wheel and tire setup, meaning that they are differently-sized going front to rear, so they cannot be swapped front to back. If the tires are wearing poorly on the outside or insides, then they can be dismounted from the wheel and "flipped" for more even wear.

Common Issues

My TPMS system (or similar warning) is on

You may need to recalibrate the TPMS system. A mechanic often takes care of this for you. If you recently replaced or rotated your tires and are seeing a TPMS light or similar warning, the tires may be the wrong size.

The tops of my tires rub when turning the car

Tires rubbing on the wheel wells of your car are generally a bit too big for the vehicle. Depending on the size discrepancy, this may be more of a nuisance than an actual hazard. Tires that are too big for the car may alter the vehicle's handling and performance.

My car pulls to the left and/or right

A car that "pulls" to one or more sides often requires an alignment. For best results, bring the car in to a professional to have the alignment checked. In many cases, mechanics often balance the tires at the same time to help extend the life of the tires.

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