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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.

enter image description here

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.

  • Basically, the tube is not seated right within the tire. There is a reenforced portion of the tube around the valve, and care must be taken to assure that this area gets inside the tire rather than being trapped between tire bead and rim. – Daniel R Hicks Jul 4 '18 at 17:11
  • The tire and tube are not mounted correctly. The tire bead is popping out when it should be hooked into the rim lip. See DanielRHicks comment for a description of why that happened. – Rider_X Jul 4 '18 at 19:57
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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.
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    Inflate the tyre, while the valve stem is still pushed well into the wheel, and let the inflation push it out. This ensures the thick rubber around the stem is over the tyre beads, pushing the bead inward and not under them, pushing the bead outwards.. – Henry Crun Jul 5 '18 at 2:06
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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.

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    Good advice, bead seating is key. Too clarify you don't need concentrated detergent, dilute soapy water will do fine, like you would use for hand washing. But this is generally only needed on thicker tires such as motorcycles and cars, I've never needed it after thousands of bicycle tires. What I do recommend is talcum powder on the tube or inside the tire so they can slide against each other. – Max Power Jul 4 '18 at 19:30
  • I have rarely needed soap or other lubricant when mounting a tire -- this is really only necessary for exceptionally stiff, tight tires (or slightly over-large rims). – Daniel R Hicks Jul 4 '18 at 22:32
  • Lubrication in my experience helps in two ways: the tyre becomes easier to mount, thereby minimizes the risk of damaging the inner tube with the leavers. And it helps to put it on more evenly, avoiding bulges and problems like the one here. This is not a hard and fast rule, I use it based on experience. – Christian Lindig Jul 5 '18 at 6:45
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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!

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