Thinking about mounting old tires onto your existing rims? It might seem like a straightforward way to save some money, perhaps using a set you had in storage or acquired second-hand. However, the process of mounting old tires involves critical safety considerations that should never be overlooked. Before you proceed, it’s essential to perform a thorough check of both the tires and the rims to ensure they are safe and suitable for use. This guide will walk you through the crucial inspection points and considerations involved when mounting old tires, helping you make an informed decision about vehicle safety and performance.
Assessing the Condition of Your Old Tires
Before even thinking about the tools or the process, the absolute first step is a detailed examination of the tires themselves. Not all old tires are suitable for reuse, and mounting unsafe tires poses significant risks.
How Old is Too Old for Mounting?
Tires degrade over time, even if they haven’t been used much or seem to have plenty of tread left. Rubber compounds break down due to exposure to oxygen, sunlight, heat, and moisture, leading to reduced flexibility and strength. This natural aging process, known as rubber degradation, significantly impacts tire safety.
Most tire manufacturers and auto safety experts recommend replacing tires once they reach 6 to 10 years from their date of manufacture, regardless of tread depth. Mounting old tires that exceed this age limit dramatically increases the risk of sudden tire failure causes, such as tread separation or a blowout risk, especially at highway speeds.
Decoding the Tire DOT Code
Every tire sold in the US has a Department of Transportation (DOT) code imprinted on its sidewall. This code provides information about the tire, including where and when it was made. The crucial part for determining age is the last four digits.
For example, a DOT code ending in “3219” means the tire was manufactured in the 32nd week of the year 2019. If the code only has three digits, the tire was made before the year 2000 and is definitely too old to be considered safe for mounting or use. Always check this DOT code before deciding on mounting old tires.
Recognizing Signs of Rubber Degradation
Age isn’t the only factor; visual inspection is key. Look closely for signs that the rubber is breaking down. This includes tiny cracks (often called crazing or weather checking) in the sidewalls or between the tread blocks. The rubber might also feel unusually hard or brittle.
Discoloration or a faded appearance can also indicate advanced aging and exposure. Any signs of significant rubber degradation mean the tire’s structural integrity might be compromised, making mounting old tires in this condition extremely risky.
Checking Tread Depth and Sidewalls
Even if a tire passes the age test, it needs adequate tread and sound sidewalls to be safe. Tread provides grip, while the sidewalls support the vehicle’s weight and absorb shocks.
A proper tire inspection involves checking both these critical areas. Remember, the condition of these components directly impacts handling, braking, and overall vehicle safety impact.
Minimum Legal Tread Depth
Tread depth is vital for traction, especially in wet or snowy conditions. Most states have a minimum legal tread depth requirement, typically 2/32nds of an inch. You can easily perform a tread depth check using a penny: insert it into the tread grooves with Lincoln’s head upside down. If you can see the top of his head, the tread is likely below the legal limit.
However, safety advocates recommend replacing tires when tread depth reaches 4/32nds of an inch for better wet performance. Mounting old tires with insufficient tread compromises grip and increases stopping distances, making them unsafe tires.
| Tread Depth | Recommendation | Safety Concern |
|---|---|---|
| Above 6/32″ | Good condition | Optimal grip |
| 4/32″ – 6/32″ | Monitor closely; consider replacement soon | Reduced wet/snow traction |
| 2/32″ – 4/32″ | Replacement recommended | Significantly reduced grip; potentially illegal |
| Below 2/32″ | Must replace immediately | Very dangerous; illegal in most areas |
Inspecting for Sidewall Cracks and Bulges
The sidewalls are equally important. Carefully examine the entire surface of both sidewalls on each tire. Look for any sidewall cracks, cuts, punctures, blisters, or bulges.
Sidewall damage can severely weaken the tire structure, leading to sudden failure. Bulges indicate internal damage, possibly from hitting a pothole, where the inner layers have separated. Mounting old tires with any significant sidewall damage is asking for trouble.
Were the Tires Stored Properly?
How tires were stored significantly affects their condition. Tires stored improperly can degrade faster or develop hidden damage.
Ideal storage is in a cool, dry, dark place, away from electric motors (which produce ozone), solvents, and direct sunlight. Tires stored outdoors, exposed to the elements, or stacked improperly are more likely to have issues. Tire storage effects are real and can compromise even relatively young tires.
Consider if the tires were stored mounted on rims or unmounted, and whether they were kept inflated. Tires stored under pressure or bearing weight for long periods can develop flat spots or internal stresses. When considering mounting old tires from storage, ask about their storage history if possible.
Evaluating the Rims Before Mounting
The tires aren’t the only part of the equation. The existing rims need to be in good shape too. Mounting even good tires on damaged rims can lead to problems.
Inspecting Rims for Damage
A thorough rim inspection is necessary before mounting old tires. Clean the rims first to get a clear view. Look for any signs of cracks, bends, or significant dents, especially around the lip (bead seat area) where the tire seals against the rim.
Even minor bends can cause issues with proper bead seating, leading to slow air leaks or vibrations. Significant damage can compromise the structural integrity of the wheel itself. Rim damage can occur from potholes, curb impacts, or previous improper tire mounting attempts.
- Check for visible cracks anywhere on the rim.
- Look for bends or flat spots on the inner and outer lips.
- Inspect the bead seat area for gouges, corrosion, or roughness that could prevent a good seal.
- Examine the lug nut holes for elongation or damage.
- Check steel wheels for excessive rust, especially around the bead seat and valve stem hole.
Are the Rims Compatible with the Tires and Vehicle?
Ensure the rims are the correct size (diameter and width) for the old tires you intend to mount. Mounting tires on rims that are too narrow or too wide can lead to poor handling, uneven wear, and potential bead dislodging.
Also, double-check that the rims are compatible with your vehicle – verify the bolt pattern, offset, and center bore. Using incompatible rims can cause vibrations, strain suspension components, or even lead to the wheel detaching from the vehicle. This check is crucial even if the rims were previously on the same vehicle, just to be certain.
Don’t Forget the Valve Stems
Valve stems are often overlooked but are critical for holding air pressure. Rubber snap-in valve stems degrade over time, just like tires. It’s highly recommended practice for valve stem replacement every time tires are mounted, especially when mounting old tires.
Even if the stems look okay, they are inexpensive insurance against future air leaks or failures. If your vehicle uses a Tire Pressure Monitoring System (TPMS), the sensors might be integrated with the valve stems. These also need inspection and potentially servicing or replacement of seals and cores during the mounting process.
The Process and Risks of Mounting Old Tires
Once the tires and rims have passed inspection, the actual mounting process comes next. This can be done professionally or as a DIY project, but both approaches have specific considerations and risks, particularly when dealing with older components.
Professional Mounting Service vs DIY Tire Mounting?
Deciding between professional help and doing it yourself involves weighing cost, convenience, safety, and equipment access.
A professional mounting service at a reputable tire shop offers expertise and specialized equipment. Tire technicians have the skills to mount tires safely, minimizing the risk of bead damage or rim damage. They use tire mounting machines designed for the job and can perform essential services like wheel balancing importance cannot be understated and TPMS reset. However, be aware that some shops may have policies against mounting tires older than a certain age due to liability issues – this is sometimes called tire shop refusal.
DIY tire mounting can save money on labor costs but requires specific tire mounting tools and know-how. It carries higher risks if not done correctly. Improper techniques can damage the tire bead, the rim, or the TPMS sensor, and can lead to improper bead seating resulting in air leaks or even dangerous tire failure later on. Safety precautions are paramount for DIY attempts.
What Tools are Needed for DIY Mounting?
If you opt for DIY tire mounting, you’ll need more than just basic hand tools. Essential equipment includes:
- A bead breaker (manual or part of a tire changing machine)
- Tire irons or pry bars specifically designed for tires (using screwdrivers will likely cause damage)
- Rim protectors to prevent scratching alloy wheels
- Tire lubricant (mounting paste or soapy water) to help the bead slide over the rim
- A reliable air compressor and tire inflator with a pressure gauge
- Valve core removal tool and potentially new valve stems
- Safety glasses and gloves
Manual tire mounting using the pry bar technique requires significant physical effort and careful technique to avoid damaging the tire bead or rim. Proper tools usage is critical for success and safety.
Understanding Mounting Risks and Liability Issues
Mounting old tires carries inherent risks beyond those of mounting new tires. Older rubber is less pliable and more prone to cracking or tearing during the mounting process, especially around the bead area (bead damage). Improper bead seating is a common issue, which can lead to slow leaks or sudden deflation.
If an old tire fails after mounting, determining the cause can be complex. Was it the age and condition of the tire, or an issue with the mounting process? This uncertainty is why many shops hesitate or refuse to mount customer-supplied used or old tires due to liability concerns. If you choose DIY, you assume all responsibility for any subsequent tire failure causes or related incidents.
Key Steps in the Mounting Process
Whether done professionally or DIY, the basic steps for mounting a tire involve:
- Removing the old valve core to deflate the tire completely (if removing an existing tire).
- Breaking the bead seal on both sides of the tire from the rim.
- Removing the old tire from the rim, using appropriate tools and techniques.
- Thoroughly cleaning the rim, especially the bead seat area. Inspecting the rim again.
- Installing a new valve stem or servicing the existing TPMS sensor stem.
- Applying tire lubricant to the beads of the old tire and the rim edges.
- Carefully mounting the tire onto the rim, ensuring the bead doesn’t get damaged.
- Inflating the tire to seat the beads. This often requires a rapid burst of air and may produce loud popping sounds as the beads snap into place. Never exceed the maximum pressure listed on the tire sidewall during seating.
- Inflating the tire to the vehicle’s recommended pressure (found on the driver’s side doorjamb sticker or owner’s manual) after the beads are seated.
- Checking for leaks around the bead and valve stem.
Proper bead seating is crucial. You should hear distinct pops as each bead seats, and visually confirm that the bead is evenly seated all the way around on both sides of the rim.
After Mounting Considerations
Getting the old tires mounted on the rims isn’t the final step. Several post-mounting procedures are essential for safety and performance.
Why is Wheel Balancing Crucial After Mounting?
Whenever a tire is mounted onto a rim, the assembly needs to be balanced. Wheel balancing importance cannot be overstated. An unbalanced wheel and tire assembly will cause vibrations at certain speeds, typically felt through the steering wheel or seats.
These vibration problems are not just annoying; they can lead to premature wear of tires, suspension components, and steering parts. Professional shops use computerized wheel balancers to pinpoint imbalances and apply corrective weights. Skipping this step after mounting old tires negates much of the potential cost savings due to the accelerated wear and tear it causes, not to mention the negative vehicle safety impact from poor handling issues.
Checking for Air Leaks and Proper Pressure
After mounting and balancing, a thorough check for air leaks is vital. Submerging the wheel/tire assembly in a water tank or applying soapy water around the bead seats and valve stem will reveal any bubbles indicating leaks.
It’s also critical to perform a final tire pressure check and adjust it to the vehicle manufacturer’s specification (not the maximum pressure molded onto the tire sidewall). Check the pressure again after a day or two, as slow leaks might not be immediately apparent. Maintaining correct pressure is key for safety, fuel economy, and tire life.
Addressing TPMS and Alignment
If your vehicle is equipped with a Tire Pressure Monitoring System (TPMS), the sensors may need to be reset or relearned after tires have been changed. Consult your owner’s manual for the specific procedure. Failure to do a TPMS reset might result in a persistent warning light on your dashboard or inaccurate pressure readings.
While not always mandatory after simply mounting tires, it’s often a good idea to consider a wheel alignment check. If the old tires showed uneven wear patterns before removal, an alignment issue is likely present. Mounting old tires, especially if they differ slightly in wear from the previous set, can sometimes exacerbate underlying alignment problems, affecting handling and tire wear.
Remember that tire maintenance, including regular pressure checks, tire rotation, and ongoing visual inspections, remains crucial even after successfully mounting old tires. Pay close attention to how the vehicle handles and listen for any unusual noises or vibrations, as these could indicate developing problems related to the older tires or the mounting job.