Take the 2-minute tour ×
Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. It's 100% free, no registration required.

Recently I went to a chain tire shop/garage. My left rear tire had a bulge just above the hub cap. I looked online and it appears that this could be really bad if I didn't fix it.

So, the serviceman told me that I should replace the rear two tires so that the wear is even going forward.

He also checked my spare tire. He said that because my car is a 2003, the spare should be replaced. So he took my good right rear tire and put that in the spare tire compartment.

The spare was never used...why did I need to replace it? When do I need to replace my spare? If I didn't go to the my tires services, I would have never thought to replace the spare.

share|improve this question
add comment

2 Answers

up vote 7 down vote accepted

Rubber degrades over time, it looses flexibility, micro-cracks appear. When put under load the tire could fail catastrophically.

It is usually said that normal lifespan for a tire is ~6 years, then it should be replaced (irregardless of wear).

The structural integrity of a tire can degrade over an extended period of time. When that occurs, tires are more prone to catastrophic failure, which could, at best, cause an inconvenience, or, at worst, lead to a crash. The degradation of a tire occurs over time, mostly the result of a chemical reaction within the rubber components. That aging process can be accelerated by heat and sunlight.

Quoted from: safercar.gov

share|improve this answer
add comment

Tires have expiry dates.And when the expiry date comes, it does not necessarily mean that the tire will not perform but the quality lowers. This means that even if the tire is used on the car or the bike, its performance will be low and it will eventually wear out quicker than supposed. This type of tire can even put you at risk of accidents. This is the reason why you were advised to get a new spare tire. You should use your spare tire before it expires and always check the expiry date.

share|improve this answer
    
and how would a person determin the expiry date? –  JerryOL Jan 31 '13 at 17:45
    
you can determine the age of a tire from the DOT code on the side. This is a legal requirement on tires sold in the US and common on tires worldwide. The last four digits are the week and year of manufacture - so 1314 would be the 13th week of 2014, or 24th-30th March 2014. see tyresforlife.co.uk/www/tyres_for_life_uk_en/themes/… –  Colin Pickard Mar 26 at 16:08
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.