Can I use a 27.5x2.125 tube in my 27.5x3 tire in a pinch? I don’t do any crazy stuff just light trails and if I can do I put in the same amount of air? I only want to use this if I happen to get a flat…
In my experience, yes, it will work. Tube quality varies a lot, so buy a good one. (I’ve been running a 2.125 tube in my 3" tire for several years with no issues.) I use the same pressure as always. (Although this is kind of low, since this tire is ridden exclusively off road. Between 15 and 16 psi, typically.)
My opinion/experience only. As always, “your mileage may vary.”
Tubes are pretty flexible when it comes to sizing. You should be fine but it wouldn’t hurt to get the correct size.
Not a dumb question at all, but not a great subject line for the future. The question itself would have been better.
3" tubes can be heavy, especially if they’re made to be puncture resistant. So I bet a lot of people use skinnier tubes and carry patch kits.
People stretch 29" tubes onto 36" wheels. Tubes are stretchy.