Cracked tyre


I bought a couple of Michelin comp PRO4 at the end of last year and put them on a few months ago. They have only 325 kms on them but last Sunday I found out that at least one of them has a very evident and not-good-looking crack…

After I bought them at the shop I noticed that the next model (version 2 or something like that) was already released, what reinforces the idea of them being OLD.

I haven’t done anything extreme with them. Yes, I’ve made it to the top 10 in a couple of downhills on Strava which means some stress for the rubber and fibers but it was nothing super fast or in rough roads.

What are my options? I have these parts on Strava so you can see how many kms I’ve put on them, but I don’t really trust Taiwanese shop laobans…

I wanted to take some pictures of them but I’ve been busy and tired… will post them tonight.


There isn’t a hard expiry date for tyres - how its stored (temperature, humidity) has a pretty big effect on its shelf life. I don’t think they would, for example, list an expiry date on the box. A ‘crack’ would suggest that the rubber has hardened and is no longer able to be stretched from contact with the road, I personally wouldn’t be riding on them anymore.

Not local enough to see if the shop will give you replacements if you take it in, sorry. I would expect shops in Australia to do so though.


Yes. Ditto. An example, Continental Grand Prix 4000 s2 are hands down the most popular tire amongst locals and the price for brand new ones fluctuate from 900-1600NT. Which is quite ridiculous because as the consumer, you’re buying new tires, how can price be that different. These are all straight from stores, not people who bought in bulk and re-selling.

For the conti grand prix, there’s a theory that a serial number on the packaging indicates the year the tires were manufactured. However, no one has gotten around to prove this.

@Liuboy will knows tires, so you can trust his judgment, but my rule of thumb is, if you’ve gotten 2 flats in 1 ride, you swap the tires out. It sucks that you waste the inner tubes, but they’re cheaper than buying a new tire when you’re not even sure if the tire needs to be changed or not.

I actually have multiple slits in my rear tires and some showing beads, no flats yet, so I’m still riding them.


you can get Strava awards for going DOWNHILL?

I wish i knew earlier. Sign me right up!

Love me some free speed.

and as for cracks in tires: meh.

It’s cracks in the rim you have to watch out for.




These tyres were not very fresh when I bought them


Did you go back to the store and query them?


Today is the first day I ride after creating this post. I will try to go today after work, and show them on Strava how many km’s I’ve put on them, and I hope they’re reasonable. Otherwise I’m publishing the name of the shop here, and people can judge if the want to take risks buying anything there.


Name of the shop being…

You seem to get really unlucky with your online orders.

Might be a lost cause since you’ve already used it. May have been better if you complained to them when you first got it, but sometimes you can’t return stuff on clearance.


No, it’s not an online shop and you know the shop.


Not going to go on a guessing spree with you, but the cycling community on the forums is so small that flaming them on here may not put the smallest of dents into their sales. I’m pretty sure we haven’t hit double digits in regular posters in the cycling forum.


Sure, it won’t be the end of the shop. But one of the things this form is for is to help people to know places, shops, etc… So the same that I’d like to know others’ experiences with local shops, I will post mine. For the moment I don’t say the name because 1) I don’t remember it and 2) I don’t think it’s necessary.





On a slightly related note, if it was CRC I’m pretty confident they will ship replacements for free. CRC and Wiggle has been good to me like that!


Uhm? do you think I remember those things? lol. Especially if I haven’t gone there since last year.


Car and motor cycle tires have the manufacturing date imprinted on the sidewall, never checked bike tires but it sounds logical there should be something.
Looks like what you call dry rot, resulting from sunlight, heat and UV, probably from bad storing or just age.


Yeah, actually I think I was looking for that date but don’t remember if what I saw made sense or not. Will check again.

And yes, it looks like that type of wear, but I don’t think it’s been especially exposed to light or heat. It has been leaning on a crystal door that separates the living room from the balcony, but there’s literally a wall of plants on the other side of the door… and what the heck, the rear tyre (the one more worn) leans on a proper wall, no direct sun beams over it.

This is sad… to have to change tyres so soon… I guess I will ride them for a while even if I don’t get a free/cheap replacement.


Aaaaand the shop was closed today…


[quote=“jesus80, post:18, topic:160445, full:true”]And yes, it looks like that type of wear, but I don’t think it’s been especially exposed to light or heat
Could have been stored wrongly in the shop already, those cracks only show once you pump them to high pressure.

I had it happen on one of my hardly used mountain bikes with 1" tires, it is actually only the top layer which cracks, not the underlaying belts.
But for peace of mind, you better change them.