New inner tube bulges near the valve when inflated

Question

I've installed a new inner tube in my wheel. I checked the tube doesn't make a knot. When I inflate the tube, it bulges near the valve, and this rubs against  the brakes.

REF tube: 32/47 609/642

REF tyre: 42-622 700 x 40C

What could be the cause of this (wrong size of inner tube?) and how can I fix it?

PS: I'm not sure if it's a dup of Uneven inner tube when inflated inside the tyre?

Thanks.

Argenti Apparatus · Accepted Answer

Unless the tire bead (the re-enforcing wire around the edges) is damaged your tire is simply not seated on the rim properly near the valve and has popped off as the tube was inflated.

Tube size seems OK. 32/47  possibly means it's compatible with 32-47mm tires. If it's about the same as your old tube that it's OK.

Deflate the tube and re-seat the tire. It's probably a good idea to get one side of the tire off the rim and make sure the tube is installed correctly too.

There are many good videos on YouTube that show correct procedure (try this one). but some key points:

Make sure the tube is not pinched between the tire and rim.
Make sure the reenforced valve area of the tube is pushed up into the tire
Make sure the tire is evenly seated on the bead all the way around. There is often a line moulded into the tire around the bead that lines up with the rim you can use a a reference.

Christian Lindig · Answer

This is not uncommon. The inner tube is not evenly distributed around the tyre. To fix it, remove almost all air from the inner tube, remove the tyre on one side from the rim and put it back on, this time starting at the valve and moving towards the side opposite of it. To make it easier, put some detergent on the rim to make it slippery. Make sure the inner tube does not get caught between rim and tyre. This has a good chance of fixing it by distributing the inner tube evenly inside the tyre.

Answered by Christian Lindig on January 8, 2021

biketoeverything.com · Answer

In this case, looking at the picture, it looks like your tire bead is not properly set. So the other answers of deflating and making sure it's set correctly before re-inflation make sense.
However, I came here via searching for a similar problem where my tire was set  properly, but it was not straight after partially inflating. Some of the tire was farther inside the rim than other parts. This was a newish bike, so it was the first time I fixed a flat.
After attempting to re-set the tire multiple times, I realized that I needed to inflate the tire to the maximum PSI (in my case 85 PSI) and ride it around a  little bit to allow the tire to slip back into place. Then my tires were straight again!

Brian · Answer

Check that the rim tape hasn't stretch or bulged. Try to cut off the edge of the tape if it's extended beyond the flat part of the rim. Might need to replace the tape if it is interfering with the tyre bead seating into the rim's hook.

Answered by Brian on January 8, 2021

New inner tube bulges near the valve when inflated

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