I bought a set of Continental Contact Plus 700 32 tires 3 1/2 years ago and put 500 miles on the rear tire. I just installed the front tire yesterday. I noticed that the rear tire has tiny cracks in the sidewall. The bike was stored in the garage, constant temperature between 45 and 60 degrees year round, pretty humid down there. I'm surprised at the cracks. Given the robust construction of this tire, are these cracks a problem?

See https://www.amazon.com/Continental-C...p?ie=UTF8&th=1

P.S. Review: The rear tire was surprising easy to install by hand, no tools. The front tire was extremely difficult---took 30 minutes of heating with a hair dryer and manhandling the last 6 inches. It was very difficult to seat the bead plus incredibly tight, as reviews note.

If you want a useful answer, post a photo.

I was just reading my bike notes from several years ago. My previous tire was the Continental Touring Plus. It only lasted one year and 500 miles before the sidewall cracked.

I just mounted a set of new tires on a bike last week, and the sidewalls had small cracks. Unusual, slightly unsightly, but not alarming. The rubber still seemed quite supple.

My personal experience is here in Arizona, which is a hostile environment for just about any polymer. I'll use tires until the tread wears through, the cords separate (which typically happens under the tread and not on the sidewall), or the bead tears & blows. The bead tears & the cord separations seem unrelated to sidewall cracking. Sometimes I'll run into an even older tire where the tread delaminates while riding, and this is associated with sidewall cracking, but the tire is sufficiently "experienced" that they are both just symptoms of age.

To get directly to the issue: I have never in 40+ years of riding had a sidewall failure or blowout directly attributable to a sidewall crack. All the sidewall blowouts have been bead failures or accidental brake wear at the rim lip.

Old rubber "dries up" (actually it's oxidative polymerization) and cracks. As long as it's surface cracks, it only means you need to get out and ride more to wear the tread out before the cracks grow.

FWIW, my pre-bought tires stay in a plastic bag under the bed; climate controlled, dark, and protected from ozone. I really need to start labelling them with purchase date, some of them have been around for a while. But I can rarely (if ever) correlate age and flaws.

Where are you getting these tires? I get about 3K miles out of a rear Conti GP 5000, and that means the tread is worn down to near the casing. Cracked rubber is a sign of oxidation, which results from extreme conditions (ozone, heat, strong sun exposure) or old age.

The rubber on the outside of the sidewall doesn't add much if anything to the tires strength. It does make it look pretty and it does help keep the cords in the tire casing from getting abraded or cut. So I don't worry about cracks in my sidewalls when I see them.


Still, I am sort of curious about your notes from so long ago. Might need to post those as well as a picture of the tire in question.

To clarify, the tire that cracked is the one I installed on the bike 3 1/2 years ago. The new one that I had been storing for the same number of years has no cracks. I had just hung it on the wall in the garage.

To the best of my recollection, I bought one tire at an LBS and another from Amazon (sold by Amazon). Unfortunately I can't remember which one I installed 3 1/2 years ago. The tread isn't worn. There are just tiny cracks all along the sidewall around the whole tire. I would think that the storage conditions in my below-grade garage would be ideal for tires---cool and not dry.

Are there any electric motors in the garage that the tires may have been close to?

Fridge, freezer, box fan, etc?

The tires are probably fine.

SkinGriz, no. I'm leaning toward the problem being the age of the tires when I purchased them, since they came from two different sources and only the installed tires has cracked.

Realize the strength of the tire is from the casing (threads) not the rubber outside. So it’s possible your tire is ok to ride. That said, if the tread that contacts the road is crumbling away it’s not going to last long.

Agree pics would help bigly.