What is a Donut Spare Tire?
A donut spare tire, also called a “compact spare”, is a compact and temporary replacement tire that comes with many vehicles. It is smaller and thinner than a regular tire in order to save space.
The main purpose of a donut spare is to allow you to drive a short distance if you get a flat regular tire, usually to a repair shop or auto service center to get the full-sized tire fixed. It enables basic mobility in an emergency flat tire situation.
Donut spares are meant only for temporary, low-speed operation. They are smaller in diameter and width compared to regular tires, usually around 15-16 inches versus 14-20 inches for full size tires. Since donut spares have short sidewalls and narrow widths, they cannot withstand high speeds or long distances.
Donut tires get their name from the donut shape – they have a large center hole allowing them to fit over the central wheel hub. This compact design with no rim allows them to be stored in a vehicle’s trunk or underside cargo area.
So in summary, a donut spare is a smaller, temporary replacement tire designed to get you back on the road in an emergency until the standard tire can be repaired or replaced. It provides basic mobility for limited distances rather than long-term use.
Donut Tire Sizes
There are two common sizes for donut spare tires:
- Full-size donut: The most common donut spare tire is around 195/75R14 or 195/70R14. This is the same overall diameter as a standard tire for many sedans and small SUVs. It can be used on any of the vehicle’s wheels in an emergency.
- Compact/mini donut: Smaller cars may come with a mini or compact donut spare that is around 125/80D15 or 135/90R16. These are smaller in overall diameter and are meant to take up less space. Mini donuts should only be installed on the rear wheels.
The key difference between a regular tire and a donut is that donut spares have much shorter sidewalls and narrower tread widths. This means they cannot sustain long distances or high speeds. The maximum speed is around 50 mph for a donut spare tire.
Donut tires are designed to get you to a tire shop or auto mechanic after a flat tire. They are not meant for extended use or high performance driving. Only use a donut temporarily until you can have the full-size tire repaired or replaced.
Donut Tire Compatibility
There are several factors that determine if a particular donut spare tire will be compatible with your vehicle:
- Wheel Size – Donut spares are designed to fit specific wheel diameters, usually around 15 or 16 inches. Your regular tires likely have larger wheel sizes of 17 inches or more. The donut must match the diameter of your existing wheels to properly fit.
- Lug Pattern – Vehicles use different lug patterns measured by the number of bolts and spacing between them. Most cars use a 5×114.3 or 5×120 bolt pattern. You need a donut with the identical lug pattern as your regular wheels.
- Tire Size – Donut spares use shorter, narrower tire sidewalls to save space. While the overall diameter is similar, ensure the donut tire width matches your vehicle specs. Standard sizes are around T125/80D15 or T135/80D16.
- Vehicle Specs – Consult your owner’s manual or vehicle door jamb sticker for the exact OEM tire size, wheel diameter, and lug pattern recommended by the automaker. Only use a donut designed for your specific make/model.
- Speed Rating – Donut spares typically have lower speed ratings of around 50-55 mph maximum. Make sure to follow the posted speed limit when driving on a donut. Exceeding it can be unsafe.
- Load Index – The donut spare must have an equal or greater load index than your regular tires to safely carry the weight of the vehicle. Don’t overload the donut or haul heavy cargo when it’s installed.
Checking all these compatibility factors will ensure you select the proper emergency donut tire for your car. Improper fit can lead to catastrophic failure on the road. When in doubt, consult a professional tire shop for assistance.
Installing a Donut Tire
Installing a donut tire is a straightforward process, but there are some important safety precautions to follow:
- Find a safe location to pull over and change the tire. Get as far away from traffic as possible. Turn on your hazard lights.
- Ensure the vehicle is on level, firm ground and engaged in park (automatic) or neutral (manual). Set the parking brake.
- Block the wheels on the opposite side from the flat tire with rocks, bricks, wood blocks or other objects to prevent accidental rolling.
- Locate the donut spare and jack kit, often found together underneath the trunk mat or in the rear storage area. Review the owner’s manual if unsure.
- Loosen each lug nut about one turn using the lug wrench but do not remove them yet.
- Place the jack underneath the car’s frame near the flat tire. Raise the vehicle until the tire is just off the ground.
- Finish unscrewing the lug nuts and remove the flat tire. Set it aside.
- Install the donut tire onto the wheel bolts and hand tighten the lug nuts until snug.
- Lower the car and tighten the lug nuts fully in a star pattern. Check the torque if a torque wrench is available.
- Place the flat tire, jack and tools back in their storage locations.
- Drive slowly and carefully on the donut, obeying all temporary spare tire speed and distance limits.
Follow the vehicle owner’s manual closely and call for professional roadside assistance if unsure of any steps. Safety first when installing a donut on the roadside.
Driving on a Donut Tire
A donut tire is meant for temporary emergency use only. You should not drive long distances or at high speeds when using a donut. Here are some important tips for driving safely on a donut:
- Obey the speed limit. Most donut tires have a maximum speed rating of 50-55 mph. Do not exceed this limit. Driving too fast increases the risk of the tire overheating and failing.
- Drive shorter distances. You should only drive far enough on a donut tire to get to a tire shop. Donut tires are not meant for long highway trips or extended driving. Try to keep trips under 50 miles.
- Watch your mileage. The temporary usage limit for a donut tire is typically around 500-800 miles depending on the vehicle. Keep an eye on the mileage driven on the donut and replace it before exceeding the limit.
- Inflate properly. Make sure the donut is inflated to the vehicle manufacturer’s recommended pressure. Underinflation causes excess heat buildup.
- Load light. Avoid hauling heavy cargo or towing trailers when driving on a donut. The tire cannot handle excess weight.
- Drive cautiously. Take corners slowly and brake early. Donut tires have reduced traction and braking abilities. Allow extra following distance between vehicles.
- Avoid potholes. Watch the road ahead and steer clear of potholes, curbs and other obstacles that could damage the donut’s smaller sidewalls.
- Check tire condition. Inspect the donut for abnormal tread wear, cracks, bulges or other signs of damage each time before driving. Don’t take chances with a compromised tire.
- No off-roading. Keep the vehicle on paved roads only. Donut tires cannot handle off-road conditions.
Following these precautions will help ensure you reach your destination safely when relying on a donut spare. But remember, it’s designed for emergencies, not long-term use. Replace it with a full-sized tire as soon as possible.
Replacing a Donut Tire
When you use the spare donut tire that comes with your car, it is intended to be a temporary replacement until you can get the standard tire repaired or replaced. Donut tires are not meant for long-term use or high speeds. They typically have limited tread life and speed ratings compared to a full-size tire.
So when should you replace a used donut tire? There are a few key times when it’s important to swap in a new spare:
- If the donut spare has been driven on for an extended period or has visible wear and tear. The tread depth is low or the sidewalls are cracked. This means the donut is unsafe for continued use.
- If the tire is older than around 6 years. Like normal tires, the rubber compounds in a spare tire degrade over time. Old donut tires are prone to blowouts. Check the tire date code on the sidewall.
- When you purchase a new set of tires for your car. It’s a good idea to replace an old donut tire at the same time to keep your spare fresh.
- After using the donut. Even if you only drove a short distance on it, the rubber may have been compromised. Get a new spare for full peace of mind.
You have a few options when it comes to replacing a used up or expired donut tire:
- Purchase the same donut tire that came with your vehicle. Check your owner’s manual for the OE spare size and specifications.
- Upgrade to a “full-size” compact spare. These spares are larger in diameter and width for increased durability and performance.
- Switch to a run-flat tire as your spare. Run-flats allow you to drive up to 50 miles with no air to get to a tire shop.
Your owner’s manual will indicate if a larger compact spare can be used. Some automakers do not recommend substituting a different size. When in doubt, stick with the same make/model donut tire that came with your car originally.
Donut vs. Run-Flat Tires
Donut tires and run-flat tires are two types of emergency spare tires. Both allow you to continue driving with a punctured tire, but they have some key differences:
Donut Tire Pros:
- Included as a spare tire on most vehicles
- Inexpensive
- Get you to a repair shop after a puncture
Donut Tire Cons:
- Only meant for temporary low-speed use
- Small size limits driving range
- Reduced traction and braking ability
Run-Flat Tire Pros:
- Allow continued driving at normal speeds after a puncture
- Maintain normal handling and braking
- Don’t take up storage space in the vehicle
Run-Flat Tire Cons:
- More expensive than a donut spare
- Need special rims to work properly
- Still require repair after use to prevent damage
- Rougher ride quality
Overall, donut tires are the more common and affordable emergency spare solution. However, run-flat tires allow you to keep driving normally after a flat tire. Choosing between them depends on your budget and needs. Donuts work for short-term limping to a repair shop, while run-flats provide uninterrupted mobility.
Donut Tire Maintenance
Proper maintenance is crucial to ensure your donut spare tire is ready when you need it. Here are some tips:
Check the tire pressure regularly – Donut tires can lose air over time just like regular tires. Use a tire pressure gauge to check the PSI at least monthly and inflate to the recommended level. Driving on an underinflated donut is dangerous.
Inspect the tire condition – Examine the tread depth and look for any cracks, bulges, or other damage. The tread on donut tires wears faster than regular tires and needs to be monitored closely. Replace if worn or damaged.
Keep it properly stored – Donut tires should be secured in the spare tire compartment as designed by the manufacturer. Don’t store or transport unsecured in the trunk or cargo area. Protect it from sunlight, heat, dirt, and moisture when stored.
Consider routine replacement – Donut spare tires have a shorter lifespan – generally about 3 years. Even if yours looks OK, strongly consider proactive replacement at this interval or according to your owner’s manual. A fresh donut provides maximum reliability.
Have it serviced if needed – Just like regular tires, donuts may need periodic maintenance like rotation or balancing. Have it inspected any time you bring your car in for service.
Taking good care of your donut tire means it will take care of you in an emergency situation! Check it as often as you remember to keep your spare in tip-top shape.
Myths About Donut Tires
Donut tires are often misunderstood. Here are some common myths and misconceptions about donut tires:
- My Donut Tire Can Be Used Long-Term – False. Donut tires are designed only for short-term emergency use to get you to a repair shop. Driving long distances or for an extended time on a donut tire can be dangerous.
- Donut Tires are Just Smaller Spares – Not Quite. While donut tires are smaller than a regular tire, they are specially designed with a short sidewall and reinforced structure. This allows them to safely carry the weight of a vehicle at low speeds for limited distances.
- Donut Tires Can Be Repaired – No. Donut tires should never be repaired if damaged. Their special design means repairs won’t hold safely. Always replace a damaged donut with a new one.
- My Donut Will Fit Any Vehicle – Not Necessarily. Donut tires have limited sizing options and won’t properly fit all vehicles. Check your owner’s manual or tire placard for the correct donut size.
- Donut Tires are Just for Emergencies – Well, Yes. This myth is true! Donuts should only be used temporarily in an emergency, not as a permanent replacement tire. Drive safely on them and get a proper replacement tire installed as soon as possible.
- I Can Drive Fast on a Donut – Dangerous Myth. Never exceed 50mph when driving on a donut tire. The tire is not rated for higher speeds and handling will be compromised. Drive slowly and carefully to a tire shop for replacement.
Knowing the realities behind these common donut tire myths can help you use them properly and safely when needed. Follow the guidance in your owner’s manual if you ever need to install a donut spare.
When to Call a Professional
Most drivers can safely install and drive on a donut spare tire for short distances and limited times. However, there are some situations that require calling for professional help:
- If the lug nuts are stuck or stripped and you can’t remove them yourself. Using excessive force with improper tools can damage the bolts or wheel hub. A technician has the right equipment to remove stuck lug nuts.
- If the jack stand location or jacking points are badly rusted. A professional shop has the heavy duty jacks and jack stands to safely lift the vehicle. Attempting to jack up an unstable frame risks the vehicle falling and causing injury.
- For any major damage beyond just a flat tire. Don’t use a donut if the tire failed due to a crack, bubble, blowout or collision damage. The spare won’t be adequate. Call for a tow truck.
- If the donut spare won’t properly fit the vehicle’s wheel lugs or hub. Using an incompatible spare can be unsafe. Have the correct replacement tire installed by a technician.
- For extended driving trips beyond the 50-mile donut limit. The small temporary spare can’t handle long distances without risk of failure. Have a standard tire installed before a long trip.
- If you don’t know how to safely jack up the vehicle and change the tire yourself. Improper jacking risks collapse and potentially serious injury. Let professionals handle it.
- For low profile, high performance tires. Donuts usually have a much smaller wheel size and aren’t rated for vehicles designed for oversized wheels.
- In bad weather like snow, heavy rain or ice. It’s unsafe to change a tire roadside in hazardous conditions. Call for assistance.
- If you don’t have the right tools and jack for your vehicle. Using the wrong equipment can lead to getting stranded or damage. Have a shop handle it properly.
Anytime you feel unsure about safely installing or driving on a donut spare, get help from a professional technician or towing service. It’s not worth the risk of injury or vehicle damage.
