Tire Repair & Replacing

The inner structure of pneumatic tires and the way the tire is assembled is quite complex. A tire has a combination of rubber, steel, fabric and adhesives that are all vulcanized together to ensure durability and long tread-life. Very occasionally some part of the tire manufacturing process can go wrong. The result could be a bulge on the side of your tire. If the bulge is evident when the tire is first installed and inflated, then the cause is likely related to a manufacturing defect.

This type of defect could be caused by production equipment falling out of specification just enough for the plies of the tires to not perfectly align under the rubber. When inflated, the bulge will show in the weakest part of the tire, in this case, the part of the tire where the reinforcing casing plies under the rubber are thin, or non-existent. If the bulge on the side of the tire is elongated, at a 90-degree angle to the top of the wheel, then this is likely the cause. The condition is usually first recognized by the technician installing your tire, however a bulge related to a manufacturing defect could become increasingly apparent with usage. If you detect a bulge in your tire, it is a warrantable condition. You should return to your vehicle service provider or tire installer for an inspection, and potentially a no-charge replacement tire per the manufacturer's warranty policy.

More commonly, a bulge in the sidewall of your tire is related to an impact with a pothole or other road hazard. A hard impact can cause “pinch shock”. This is when the sidewall of the tire is severely compressed between the object and rim of your wheel. The the inner cords of the fabric ply are squeezed together and can break. The spot where the break occurred no longer has the reinforcement of the under-lying plies, and the tire will bulge out. Most tire installers will be able to tell if the bulge is the result of a severe impact vs a manufacturer's defect. The flange of the wheel will be damaged, or there will be marks on the rubber showing that the sidewall rubber was in contact with the wheel. The impact may not have been severe enough to break the rubber, but if left on the vehicle, the bulge will eventually rupture.

Remember to do a visual inspection of your tires occasionally. In addition to looking at the tread for excessive or irregular wear, you should check the sidewall for bulges. Any sign of a bulge warrants a trip to your nearest service station to assess the severity of the bulge and the likely cause. If the cause of the bulge was a road hazard impact within one year of purchase on Tires-easy.com, you may be eligible for a no-charge replacement. Please see the Road Hazard Policy for details.

Never try to repair a tire yourself. Take your punctured tire to a professional tire installer for a complete inspection to ensure that the tire can be safely repaired. A puncture in the tread area is usually repairable, whereas a penetration in the sidewall is likely not. Your tire installer will be able to make this determination for you.

If the tire is repairable, there are a few different ways to repair a flat tire. The most common repair technique, and the most reliable is a patch and plug combination. For this, the tire must be removed from the wheel. The mechanic will then mark the spot where the tire is punctured and remove the foreign object that caused the flat. Typically a screw, nail or metal shard that became embedded in the tread. The surface of the inside of the tire around the damage is then roughed up using an angle grinder. If the hole is large, a rubber plug may be inserted to fill the hole. Rubber cement is then applied, followed by the patch itself over the plug and cement. The cement actually chemically vulcanizes the rubber of the patch and plug to the tire for an air tight repair. Once the tire is patched it is mounted back on the wheel, and the tire/wheel assembly is balanced.

Again, only a qualified tire technician and installer can decide if a tire is repairable. If the tire was run flat for an extended period of time, the location of the damage is on the sidewall or too close to a previous repair, or the tire tread is close to being worn out, most reputable tire service centers will recommend a new tire over a repair.

The first step is to evaluate your surroundings and situation for safety. Is it a safe area to change the tire yourself, or should you call for help?  If you elect to change the tire yourself, make sure to pull over to a safe space out of the way of oncoming traffic, and that the roadway is level. The following are general instructions for changing tires. Your owner’s manual will have more detailed instructions about the operation of the specific equipment:

1. Make sure your car is in “park”. If you have manual transmission, make sure it is in gear. 

2. Block your other tires with a rock, etc., to keep the car from rolling.

3. Use your tire iron to loosen the wheel lugs, but don’t remove them yet. When the lugs are stuck, and you need to break them free. To do so, you can elongate the tire iron with a length of metal pipe around its handle to significantly increase its torque. Remember to turn the lugs counter-clockwise to loosen them.

4. Be careful of hot asphalt, as your jack can push down into it when carrying the weight of your car. You can spread out and diffuse that weight by placing a strong wooden board under the jack.

5. Attach the jack to the specific pre-selected spots on the frame of your vehicle. You can find those spots in your Owner’s Manuel. Sometimes, the diagram is also pasted in the interior of your trunk or even on the jack itself.

6. Jack up the car. Make sure it is high enough to put on the spare, which will be taller than the flat tire because it is full of air.

7. Remove the tire lugs completely and remove the wheel. You may have to gently kick the tire on the left and right sides of the sidewall to loosen the wheel if it is stuck. Be very careful not to not knock the car off the jack.

8. Clean the hub of any loose debris to allow the new wheel to seat correctly.

9. Hold the wheel up and line up the holes with the wheel studs. Your spare can be rather heavy, so be careful. Push the wheel onto the studs, and screw on the lugs lightly with your fingers.

10. Use the tire iron to tighten them more, but not to the ultimate tightness. You want to do this in stages working in a star pattern tightening the lug opposite.

11. Check to assure that the wheel is seated correctly against the wheel hub.

12. Lower the car to the ground for the final tightening. The weight of the car on the tires will keep them from turning when you apply more pressure to tighten them as much as you can.

After changing the tire, you should drive directly to a tire dealership or garage for repair of the flat tire or replacement.  Remember that if your spare tire was a ‘temporary’ spare, it probably has a maximum speed of 50 mph. Check the maximum speed details, and any other restrictions listed on the side of the tire or owner’s manual.

Different tire sizes, tire brands, and tire styles should never be mixed on the same axle. Tires of different sizes can be mounted on the front and rear axles if approved by the vehicle manufacturer. It is common on high performance sports cars and luxury sedans for the rear tires to be wider than the front tires.

If your vehicle does come equipped with a different size on the rear, you should keep the same size combination front to rear when it comes time for replacement tires. In this situation, it is also okay to replace 2 tires at once, but it is recommended to be the same brand and model as the tires paired on the other axle. The reason for not mixing brands and tire styles is that each tire brand and even tire model has different performance attributes. The most predictable handling is when all four tires are the same brand and model, and aligned with the size recommendations of the vehicle manufacturer.

The mixing of winter, summer or all-season run-flat tires with non-run-flat tires on the same vehicle is not recommended under any circumstances. Run-flat tires handle very differently to standard tires, and mixing them could cause very unpredictable handling and other safety issues.

A pair of winter tires can be mixed with all-season or summer tires, but they should always be installed on the rear of the vehicle. Ideally four winter tires should be installed during the winter months in northern climates.

Finally, you want to rotate your tires every 5,000 miles so all four tires on your vehicle wear out at the same time. This allows you to purchase 4 new tires for optimal performance and safety.

It is common for quarter ton, and even half ton pick-up trucks to be equipped with P-metric tires from the factory. The original equipment tires are always rated to carry the maximum load capacity of the vehicle. This means that from a load capacity perspective, P-metric tires are perfectly adequate. In fact, if you drive a pick-up truck or full-size SUV and rarely carry a load or go off pavement, then a p-metric tire will be a better choice for your replacement tire. They are typically less expensive, ride smoother, last longer, and are more fuel efficient than a LT-rated tire in the same size.

For pick-up truck owners that go off-road, routinely carry heavy loads, or tow a trailer, LT rated tires may be a better option. This is because LT tires have heavy cords and are more resistant to damage due to overloading or off-road conditions.

Putting LT tires on a vehicle that came with P-metric tires as original equipment is acceptable, but never replace original equipment LT tires with P-metric tires. This is because they have different load capacity ratings at recommended, and maximum air pressures, and the vehicle is designed for heavier duty use that may be beyond the capabilities of the lighter weight P-metric tire.

Plus sizing is when the tire and wheel combination is changed out for a larger wheel and lower profile tire. It is a popular option since most people like the look of a larger wheel. But it is important to know that plus sizing your wheel and tires will also change the performance of the vehicle.

Typically, a small increase in wheel diameter will mean more responsive handling because of the shorter sidewall. For drivers that like sport driving and high performance cars, then a plus one fitment will have a noticeably positive impact on the ride quality. Conversely a large increase in wheel diameter can degrade the ride quality and handling of the vehicle.

Extreme plus sizing of 3 or more inches of wheel diameter will negatively impact the ride and handling of the vehicle since plus-sizing involves combining larger wheels with shorter, wider tires. For example, to plus size a 17" wheel, you would buy a new 18" wheel. As with any plus size, the overall diameter of the tire must be equal to the original tire and have the same or greater volume of air to support the weight of the vehicle. Therefore, the tire on the 18” wheel must have a shorter sidewall and a wider section width. The shorter sidewall ensures that the overall diameter is respected, while the wider tire compensates for the lost volume of air due to the decrease in tire profile (height).

Most experts agree that it is best not to plus size more than 2 inches. A sidewall that is much shorter will not flex as much as a tall sidewall, and the greater width can make the tire float too much on wet and snowy roads. This could lead to a loss of traction on dry roads, and the risk of hydroplaning on wet roads. Very short sidewalls often lead to broken wheels as the tire cannot absorb as much of the impact from pot-holes and other road hazards.

It you do elect to change out the wheels and tires for plus sized custom wheels, you must get the advice of a tire professional. A tire professional can easily find the right wheel and tire size to give you the look you want, while keeping your vehicle performing safety.

When you change out your tires and wheels for a larger wheel, you always want to respect the overall diameter (OD) of the original tire. A lower profile tire must be placed on a larger wheel to keep the OD close to the same as the tire/wheel combination being replaced. You certainly never more than a 5% difference in OD to the original tire. Too large a variation could impact the gearing and correct operation of the vehicle. Also, any change in the tire OD will give you a false reading of speed and distance on your odometer.

When your vehicle was new, the speedometer was calibrated by the factory according to the exact size of the intended tires. If you change to a taller tire, the circumference of the tire will also be greater. What this means is one rotation of the tire will take you further on your new tires than on your old tires. If the speedometer was never re-calibrated with the new tires, it will register a slower speed than you are travelling. For example, if your tire was 3% taller (still within approved guidelines for plus fitments) the gearing and operation of the vehicle would be fine, however your speedometer would show 60 mph, when in fact you are traveling 63.3 mph.

An easy way to measure your speedometer accuracy it to run a road test. Freeways have mile markers that indicate the length of each mile you are traveling. The safest and most accurate way to execute this test is to have a passenger in the car with a stopwatch. Set your cruise control at 60 mph, and start the stopwatch when you pass the mile marker. It should take you 60 seconds to pass the next mile marker. Repeat the test three or four times to be sure, and average the resulting times. If your average time is off by 3 seconds or more, your speedometer is likely in need of re-calibration. If you have changed out the tire and wheel package, the OD and resulting change in revolutions per mile is likely the cause.