Why do inner tubes pop on bikes?

Question

Just purchased a bike and had the inner tube of the front tire blow out after 20 mins of riding... just my luck :(

Was it overinflated? Will I need a new tire, or rim? Is that possibly the problem? Or do these things just happen sometimes? Thanks in advance.

Answer 1

Unless you hit something (particulalry if the tire is underinflated) you should get a 1000 km or more out of a tire.

The type of flat is indicative of the problem (and frequency varies with type of wheel/bike and tire and tube type).

- If the tire came off the rim and the tube blew out there will be a long rip in the inner tube. This would mean the tire was improperly mounted. Go back to the store and complain.

- If the tire has a cut and the tube was blown out the cut it sould be you hit something (e.g glass bottle, sharp metal). If so this is unfortunate, but a fact of life on a bike. You don't have a comeback on the store.

- If the tire went flat relatively slowly (15 seconds?) you may have got a "snakebite" flat (there will be two small holes in the tube), or hit a nail or small piece of wire. Snakebite punctures are due to underinflated tires, and hitting a stone or similar object. Basically you pinched the tube between the rim and the stone.

Most flats are either snakebites or occur on older tires when the tread gets thin. mewer tires usually only get flats due to cuts or actual punctures.

Contrary to most belief glass is unlikely to pucture a good tire (unless it gets stuck in a tread and gets a chance to work it's way through). On the other hand hitting a 1-1.5" stone can often cause a flat on a road bike (but not likely a mountain bike).

Mountain bike tires take lower pressure than road bike tires. Typically 40-60 psi for mtb and 100-115 psi for road ... BUT check the sidewall of the tire for the recommended pressure and RESPECT IT.

As to will you need a new tire or rim? New tire only if the old one is visibly cut or damaged. New tube ... probably unless the hole is small (pinhole >> ~ 0.5 mm) in which case you can patch it). Rims only need to be replaced if damaged (not likely from a flat), and even then can sometimes be fixed.

Answer 2

Next time when you have the tire off, check the back of the nipples. There should be a strip of cloth or plastic covering the nipple ends. Run your fingers along the strip to see if anything is protruding. Also run your finger inside the tire to see if there isn't any foreign objects. If both is okay, then check to see if the tube with is within the size for your tire. You do not want a tube that is either too small or big. If you suspect the tube is being pinched when inflating then get some talcum powder and rum the tube before installing it in the tire.  And last thing, make sure you use a tire iron to install the tire, not a screwdriver. A set of two cost $1 at Walmart.

Answer 3

Blowout?, or Blowoff?   I had the same problem with my Schwinn Suburban with S6 rims. The tires are marked inflate to 90 lbs. I had 90 lbs and 4 times the tire blew off the rim and the tube had a 6" split in it. ALWAYS WHILE IT WAS PARKED! I researched on the internet and found out the old Schwinn S6 rims don't hold well to high pressures, I checked the manual for the bike, it recommends 70-80 lbs. I inflated to 70 lbs., and haven't had a blowOFF since. The bike is 35 years old and I have well over 15,000 miles on it.

Answer 4

Did you inflate this yourself? if so, how? If you bought from a shop, go back and talk to them, but also check if tyre is damaged, has it been cut, allowing the tube to swell out of the hole.

If no damage, the tyre probably wasn,t seated properly on the rim, usually by the valve.

When you fit a new tube, make sure you seat the tyre all round and watch as you inflate that it is not pushing off anywhere, MTB tyres are a fairly loose fit on the rim.

Typical pressure for general use is 45psi, at this pressure you should just be able to slightly indent the side walls with finger pressure.