I noticed recently that one of the tires has a small crack on the sidewall. It hasn't deflated yet but I'm worried about whether I can keep driving the car or if I need to change it right away.
Lateral tire pressure is what kills a tire with a sidewall crack, not so much time. Every turn, every braking, every pothole makes that crack open up more, and when you least expect it you blow out on the road. It's not like a slow puncture that warns you little by little; a sidewall crack can fail suddenly and without warning.
The most practical thing you can do right now is stop using it for long trips or highway driving. If you need to get to the shop, do it carefully, at low speed, and bring a spare tire or have the roadside assistance number handy. In the meantime, get under the car with a flashlight and check carefully whether the crack is only in the outer rubber or if it's reached the inner fabric (that's much worse). If you see it's just surface-level, you've got a bit more leeway, but it's not something that can be repaired, so you're better off replacing it.
The truth is driving with a sidewall crack is playing with fire. A new tire doesn't cost as much as what an accident could cost you, so if you can this weekend, head to the shop. If you have to wait, only use it for short trips around town at easy speeds.
A crack on the side of a tire is pretty serious and it's not something you should ignore. The sidewall is the thinnest and most vulnerable part of the tire, and that crack can grow quickly under pressure and movement, even if it doesn't look bulging or deflated right now. The real danger is that it can burst suddenly while you're driving, especially if you accelerate, take sharp turns, or hit potholes.
My recommendation is that you change that tire as soon as possible, preferably before you use the car again for a long trip. This isn't one of those things that can wait until next month. If the crack is very small and you don't have an immediate option, try to drive only on quiet streets and at low speed until you get to the shop, but honestly, the best thing is to fix it now. A blowout on the highway or in a situation where you need to brake hard can be really dangerous for you and for whoever is with you in the car.
In the meantime, check the pressure on that tire regularly (even if it doesn't have a crack, it's a good habit). If you see it deflating progressively or the crack becomes more visible, then definitely don't use it even to drive to the shop - call for a tow truck.
If you see a crack on the side of your tire, that's definitely not something you can ignore. The problem is that the sidewall of the tire bears a lot of pressure and stress every time you turn, brake, or accelerate, and that crack is going to grow way faster than you think 😬. Even if the tire isn't deflated right now, the crack can burst open suddenly while you're driving, especially on curves or at higher speeds.
The safest thing is not to use the car for long trips or highways. You can drive slowly to a tire shop to have it replaced, but if the crack looks deep or pretty large, don't even try and call someone to pick you up or have them replace it where you are. It's not an expense worth avoiding because a tire blowout suddenly on the road is way more dangerous and expensive than just changing it now.
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