I recently bought a pair of inner tubes and when I partially inflated one of them before putting it into the tire (only a few pumps with a floor pump), I noticed a portion of it was bulging out considerably. It looked like a snake who had swallowed a giant mouse, there was a huge bulge on one section of the tire. I went to get my camera to take a photo of it, but it then burst before I could take a photo.

Went back to the LBS and got a replacement tube, and when I partially inflate this one it also bulges quite a bit too, although not nearly as extreme as the last one that popped.

Is it normal for an inner tube to bulge out as much as this? I'm just worried this one will pop as well.

enter image description here

  • 5
    That is perfectly normal. Jul 7, 2015 at 12:16
  • 1
    If the tube bulges in the tire it's because you do not have the tire properly seated on the rim (or possibly you have the tube twisted or kinked inside the tire). Jul 7, 2015 at 12:21
  • 1
    Not only is buldging normal, they can get ridiculously long too.
    – Criggie
    Jan 14, 2017 at 9:59

1 Answer 1


Yes, inner tubes do that. They are like balloons, except that the butyl rubber they are made of doesn't stretch like natural latex rubber.

You are not supposed to inflate tubes outside a tire. Tires have fabric casing to withstand the pressure.

  • 1
    O.K thanks, good to know. I thought you were meant to partially inflate the tube a little to give it shape before inserting it into the tire though?
    – suskie
    Jul 7, 2015 at 10:47
  • 2
    You are, but its really very little air you use (most floor pumps will use less than 1 stroke for this).
    – Batman
    Jul 7, 2015 at 10:50
  • 1
    You should inflate it a little before installing to prevent it kinking.
    – Alexander
    Jul 7, 2015 at 11:14
  • 2
    It's perfectly OK to slightly overinflate an inner tube when checking for leaks. I inflate a bit more than in the above picture. (And, as @Alexander says, when installing the tube you should first inflate it slightly (so it's still limp) before stuffing it into the tire.) Jul 7, 2015 at 12:18

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