I have never changed a bike tube/tire before, and I’m having some trouble in the process. I wanted to replace my rear bike tube, as it had a hole in it. I have Kylin Brand tires, 26x1.95, and have not ridden the bike in years.

The old bike tube states its measurements as 26x2.0-2.4. And I bought a new Kenda bike tube with measurements 26x1.9/2.125.

When inserting the bike tube on the rim, I try to inflate it with the tire, and it creates a gap between the rim and the tire. When looking at the tire, you can clearly see the tube in between the rim and the tire, and the lip of the tire does not touch the rim. This is also at a very minimum PSI, around 5-10.

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I just don’t know what I am doing wrong. I am not sure if it’s an issue with the bike tube sizing, or my old tire. Any help would be greatly appreciated, thank you.

  • 5
    Did you actually insert the tyre bead into the rim? There are many tutorials for changing a tyre on Youtube and many descriptions are in answers on this very site. Jul 13, 2023 at 19:44
  • Vlad is spot on. Check out the video mentioned at the start of the following question: bicycles.stackexchange.com/questions/68454/… - based on the pictures shown, the left and right tire beads are outside of the well of the metal rim. They need to be inside the rim well. You will need to let most of the air out of the tube to allow you to do this. Take the tube out. Put one side in first, then put the tube in with just enough air to give a little form to it. Then put the other tire bead in the well of the rim.
    – Ted Hohl
    Jul 13, 2023 at 23:48
  • Don't listen to these pranksters. Just give it more air and the tire will suddenly insert itself into the rim. The first time I saw this, I couldn't believe my eyes! It's like magic! (humour)
    – Kaz
    Jul 19, 2023 at 1:11

1 Answer 1


The tyre is not within the sides of the rim. Your tube size is totally fine for this tyre.

Compare with your other wheel, and you will see the rubber of the tyre goes inside the metal of the rim.

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From Wikipedia

To fix it, let all the air out of the tube. Also, check the tyre to make sure the cause of the puncture is gone.

Then seat one side of the tyre in the valley inside the rim. Do this all the way around the rim.

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Then put the tube in place. The valve should be through the one valve hole.

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Now the hardest part.... you need to get the last side over the metal rim, trapping the tube inside, and not pinching the tube. The tool for this is a plastic tyre lever, you probably need two.

Start with your hands - you should be able to get around 3/4 before it gets tight. Then you have to work the last bit of the sidewall into the rim. Focus on where they cross.

Sometimes a single pump of air in the tube can help here. If it just won't go, check the far side of the whole rim - pushing the bead of the tyre together allows it to drop into that valley, allowing a bit more slack.

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One both tyre beads are in the rim give it a quick inspection all round, then inflate with an air pump to your required riding pressure.

Fitting tyres is a manual process. It may pay to have someone show you in-person - many people learn better that way.

You can do this - give it a try, and if you have problems then ask.

  • 1
    Thank you for your help! Was able to change both my tires with this info, thanks again
    – JeffSmithy
    Jul 31, 2023 at 14:05

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