Flat tyre advice

Soldato
Joined
18 Oct 2002
Posts
8,968
Location
UK
I had a tyre one my car (not a daily driver, in storage) that was looking a little bit flat one week, well all 4 of them were hadn't been pumped up in months, but then when I checked it 2 weeks later it was dead flat?

Would it suddenly go flat like that all by its' own, faulty valve or something?
Or was it some kids being punks? I doubt this though as it's in a secure apartment parking lot.

But anywhoo, if I go out and pump it up today, if its been knived or something or the valve is obviously crook it will be easy to spot, but how long will it take to go flat with the weight of the car not on it? Or would it even? If I take it to a tyre place can the check it in anyway, last time I had this problem it was a weight not seated on the rim correctly and they spotted this by dunking it in water, similar deal this time?

Yeah, bit long winded eh?
 
Car tyres don't have inner tubes unlike bike tyres, meaning if there's a slight issue with the bead (the seal between the rim and the tyre's edge) you will lose air...as you say, it depends how much pressure is on the rubber...on the car standing still if there's an issue with the bead then it could go to around 5-10psi (ridiculously flat) in a week no problem...without any pressure on it through weight you'll hardly lose any air (though you will lose some)

Since the balance weights go around the rim of the wheel...they could cause a break of the bead...but very unlikely...possibly if it's an old tyre gone brittle so it doesn't wrap itself around the rim properly...another problem with a faulty bead could be that the tyre has turned on the rim (you'd probably notice a vibration when driving if that was the case as the tyre wouldn't be balanced anymore) but this is practically unheard of in road cars...happens a lot in racing but very very unlikely on a road car (even if you drive it vigorously!). If it's just one tyre my guess would be something to do with that rim or tyre rather than sabotage (as I'd gather more would be affected that being the case!)

If you get it checked out chances are you wont find a solution to the problem but a temporary fix...the only way you could trully tell is if you bought a new tyre...which is an expensive option obviously..especially if you hardly drive the car!

Anyway, sorry if it's been confusing and babbling but short answer...you will lose air if taken off the car...but nothing noticable...and it wont prove much. best way to check for a leak is to put as much pressure on it as possible and keep monitoring it.

Hope that helps
 
yah! I think the extreme long-windedness of both our posts kinda sums up the case, to many odd variables. The tyre has been sweet for the last year, so nothing wrong with the tyre or the rim, I think even the dodgy weight issue was on a different wheel entirely.

Decided to just bite the bullet and go through the hassle of going out and getting it up to 40psi then coming back and swapping it over which is a real PITA as the car came with a weedy jack and the saggy sus means the jack is near its limit (well I wouldn't want it any higher!) and I don't have the speed bar for the jack, and its dark in the garage, and a bit cold and dusty, real bohoo for me!

reckon 24 hours on it will do what it will to the air in the tyre?
 
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