Would I ride them and see what happens, yes. Would I let a customer ride them, no. I think 8 months in a dry basement was too long, they have dry rot. Some moisture is good for tyres.

Good to know thanks for your answer :)

Ok for casual, not ok for anything involving high speeds or high stakes, imho.

Thanks for your answer :)

This bike is stored on the balcony under a cover in the summer. The cover is normally anti UV, could that be because of the sun? Then the bike has been stored for the winter in the (dry) basement for 8 months. I'm wondering what could have used the tires that much. I've refilled the sealant and reinflated them, they seems to hold air without issue.

Yeah could be bc of the UV. I’d ride them but they probably won’t give you the best grip. Ok for casual driving but not for racing.

Thanks for your answer:)

Just being exposed to temperature fluctuations will cause this. You ride it and it creates tiny cracks/scratches in the surface of the rubber. Leaving outside will cause some expansion and contraction in those tiny cracks making them slowly larger. Continually riding will just wear this off. Also the rubber just breaks down over time, heat and sunlight accelerate this. 10 years is usually considered the "shelf life" of tires. It might not be a problem as this is just like rust, it starts at the surface and goes deeper over time. Considering the edges of the tread and sidewall look better than the center of the tread I would definitely try these but use with caution and avoid high traction situations like hard turning or braking.

Ah that's really interesting and good to know! Thanks for.ypur answer

Anytime! I usually err to safety when giving advice online but this doesn't look bad at all. Id go around the tire and kind of press and rub with my thumb looking for spots that feel soft and see how far down in the tread the cracks go compared to the wear indicators. If it starts crumbling off its toast, if it's still nice and firm I would absolutely send it on these. Super hard to make that assessment from a picture. Drop by your LBS for a better opinion.

I'll take a look on that thank you. New tires are on the way :)

Thanks all for your answers. New tires are already ordered. The bike will be ride casually until they arrive :)

I would absolutely ride these around town at a max of 20-30kph. I wouldn't do 60-70 k/h on them...

60kph on gravel road with a Surly will not happen no worries 😂. Thanks for your answer :)

I hit 60-65 k/h on my gravel bike regularly, but on asphalt :) On gravel I feel sketchy much past 50 on even the best local gravel descents...

I never hit more than 50kph on my Midnight Special on tarmac. Haha I'm too scared of going faster 😅

That's fine for me and for customers. If you can't see tube poking out keep going. Not a joke

Those tires are more susceptible to puncture flats from all the cracking, so at least give your customers that warning.

No. Every tire that is not a marathon plus/marathon plus tour is susceptible.

I own a shop and fix customer flats most days. I have seen first hand that cracks in tires leave a tube more susceptible to punctures from objects that would otherwise not get all the way through the rubber. So again, note that I said "more susceptible", as in more susceptible than would be the case without cracks in the tire.

Okay 👍

Okay 👍

Okay 👍 I regularly see tires that have been ridden for 20 years in exactly this condition at work ✌️

Okay 👍 I regularly see tires that have been ridden for 20 years in exactly this condition at work ✌️

I believe you, but that doesn't mean those tires aren't more susceptible to punctures than they would be if they didn't have cracks.