Rick's Free Auto Repair Advice

How far can you drive on a donut spare tire?

How far can you drive on a donut spare tire?

Answer: You can only drive 50 miles on a donut spare tire

The carmakers say can only drive 50 miles on a donut tire and they mean it. Here’s why:

They have a smaller diameter, they’re narrower, thinner and have little-to-no tread

• Most donut tires only have 4/32″ tread. 4/32″ on regular tires is considered the lower limit of safety. As you wear below 4/32″ on a regular tire, your braking distances increase dramatically and it’s even worse on wet, snow and ice covered pavement.

spare tire size comparison

They wear much faster than regular tires

Why? Because donut tires have a smaller diameter and width, the load is carried on a much smaller contact patch, so you have more weight/stress resting on a smaller patch of rubber.

It’s a different rubber compound

Donut spare tires are designed for one purpose, to get you to the nearest tire shop to get your flat tire repaired or replaced. That’s it. So the tire’s rubber compound doesn’t have to be made from the expensive formula; it just needs to last for 50-miles.

Donut tires can’t handle high speeds, hard cornering or hard braking

The more you use a donut spare tire as if it’s a regular tire, the faster you’ll wear it out and the poorer the performance.

Then there’s the differential issue

If you drive a FWD vehicle and you place the spare tire on the front wheels, you’ll force the differential to constantly compensate for the differences in tire diameters. If you drive more than 50 miles with a donut spare tire, you can actually cause damage to the differential.

The same issue applies if you drive a RWD or AWD vehicle. They all have to compensate for the large difference in tire diameter.

Donut spare tire rules

• Inflate the recommended pressure listed on the donut spare tire or the spare tire inflation pressure listed on the label in the driver’s door area

• Do not drive faster than 50-MPH.

• Use extra caution on wet and snowy pavement because you’ll have less traction

• The smaller diameter tire may cause your ABS and traction control systems to illuminate a warning light. If that happens, you won’t have anti-lock braking, traction control or stability control.

• You should only install a donut tire on rear wheels. It’s not designed for use on steering wheels. If you must install on a front wheel, drive it only for a short distance and be extra careful in turns.

©, 2023 Rick Muscoplat

Posted on by Rick Muscoplat


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