The fact that the tires were installed at the same time does not mean that they are the same age. Learn to read the age of a m/c tire by the code that is stamped onto the side wall of each tire.

Replace both tires asap. That very small patch of rubber that makes contact with the road when you are riding makes the difference between safety and disaster.

 

Ehhhhh, sorry guys, wrong answers. Tires can lay out in direct sunlight for 30 years and not crack in the sidewalls. Cracks in the sidewalls are caused by under-inflation.

I have 6 bikes and don't keep them up as well as I should. Checked the inflation on the Sporty tires and they're at 20lbs. Check your tire inflation regularly.

 

Wrong, Sun will cause tires to crack. Seen it on campers over and over when people don't use tire covers. And its even happened to me and I always keep my tires inflated.

 

Ehhh, wrong! these tires haven't sat out in the sun. Indoors all the time.

 

Your record on tyre maintenance is not good, if your various comments above is anything to go by, so don't argue over fine detail. You have cracked tyres - just replace them, there's a good chap!

 

Dry rot causes it too. I wear mine out riding before they have time to crack. LOL

 

So if you have the answers why ask the question?

 

A lot of countries have LAWS that have birthday of tires easy to read on sidewall and if they are more than 7yrs old they tow the vehicle, lot of death's every year in USA from blown tires-but lobbiest and tire companies stop the law here and hide the truth---every day people buy tires that are 4-5yrs old off shelf.