I have a bmx bike with the tire size being 20" x 2.4. Will a 20" x 1.5- 2.125 fit or should I get a 20" x 1.7 - 2.25 instead. If I get a slime inner tube will it be noticable on the weight or just a bit.

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    Does this answer your question? What is the maximum or minimum tire width I can fit on my bicycle Jan 12, 2020 at 1:59
  • I think, given similar availability and price point, choosing the tube with the correct width range for the tire it is to be used in is the way to go. These proposed tubes with the smaller width range than your tire are gonna have thinner walls and greater stress on the seams when pressurized in the larger tire. Harder to successfully patch a blown seam or a blown out area of a tube, so you'll have another opportunity to choose a new tube.
    – Jeff
    Jan 12, 2020 at 2:07
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    Here's a link where BMXers discuss tube sizes and self sealing tubes. Apparently a slime tube blow out can be nasty. I've not found self sealing tubes spec'd for greater than 2.125 wide tires in brief searches. However, many options exist for normal tubes for 20x2.4 tires and carry similar prices to the narrower tubes. Thus, little reason to compromise by using a smaller tube.
    – Jeff
    Jan 12, 2020 at 2:32
  • Hi Bryan - welcome to the site. I think this question will be closed as a duplicate and your other question about slime is likely to get lost. Instead, consider asking that as a separate question so it can earn its own answers... I don't see a duplicate, so its worth asking separately.
    – Criggie
    Jan 12, 2020 at 3:06

1 Answer 1


I see this as a two part question.

  1. A 1.5- 2.125 width tube will fit in a 2.4" tyre fine.

I carry 2" wide tubes in my seat pack when I go cycling as a spare tube for my 2.35 tyres. I do so purely as it fits nicer in my pack and my tyres are tubeless. So if I get a puncture, I put the tube in and fix the tubeless when I get home.

  1. You won't notice the weight but Slime might not work as well with over streched inner tubes.

When you fit a slimmer inner tube in a wider tyre, it streches more. So if you get a puncture with a slimmer inner tube, the slime has to work harder (than with a correct size tube) to plug the hole as it is more likely to burst bigger due to the over streching.

Personally I would rather invest in a more puncture proof tyre than in using Slime.

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    That last point cannot be stated clearly enough. Slime is nothing but a bad crutch in my experience. Slime may get you from one puncture in 100km to five silent punctures in 500km before it fails you, a good puncture resistant tire may give you 10000km before the first puncture. (Always "may": It's perfectly possible find that one big fat shard that cuts through any tire on the first kilometer. It's just very unlikely with a good tire.) Jan 14, 2020 at 15:53

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