I've been riding on the same rear inner-tube for several months without issue. I topped up the rear tube last week, went on ~10mi ride (including a rest in the middle), and had no problems. I was about to ride again today, but when I looked at my rear wheel I noticed the tube was completely flat. While removing and inspecting the tube I found two obvious bumps/bulges/protuberances/knobs on the inner-tube. These bumps are near a spoke. They are on the **inner** wall of the tube. [![two bumps on bicycle inner-tube][1]][1] [![bike tube adjacent to the wheel to show where the bumps align][3]][3] I found the source of the leak. One of two bumps has a sizeable hole/cut. It's **not** a slow leak. If I try to pump it does not hold any air. [![one of two bumps on bicycle inner-tube has a cut][2]][2] I remember now that last week, after that ride, I had heard an odd noise from my kitchen (where I store my bike) and couldn't find the source when I went to check on it. I thought, "that's odd", but didn't think twice. In hindsight that noise must have been my rear inner tube very suddenly deflating. It wasn't a bang, but a sound vaguely similar to a bag of rice falling on its side and the grains coming out quickly then slowly then stopping. Sort of like a deflation now that I remember it! The issue [isn't glass or debris](https://bicycles.stackexchange.com/questions/31708/third-tube-puncture-in-3-weeks), and the [tire does not have a bubble and otherwise is not deformed](https://bicycles.stackexchange.com/questions/10099/how-did-bubbles-form-on-my-tire/10100#10100) or damaged when I inspect it. A [similar question and answer](https://bicycles.stackexchange.com/a/52183/36431) makes me think that perhaps I overinflated it when I thought I was doing things like normal, but I've never experienced this particular behavior before and was curious. Also, that user did not notice these obvious deformities like I did, so I thought it could be a different scenario. On feeling the rim tape, I do **not** notice the spoke protruding out at this spot, but I do notice an obvious dimple/depression in the rim tape at that spoke! [![a red circle highlights an area of the bike wheel rim tape][4]][4] * **What may have caused these bubbles?** * **If poor rim tape may be at fault, must the rim tape be re-done?** Unfortunately I'd have to bring the bicycle to a shop mid COVID-19 lockdown for anything beyond changing the tube, as I'm only really equipped to swap out the tube with my skillset. _For context, the tire says 700x28c, the wheel says 700x18c/23c. That discrepancy between 28c and 23c always bothered me, but I have no idea if it matters. The bike has been like that since I bought it ~7 years ago and multiple mechanics at multiple shops have replaced my tubes and tires with similar ones and never mentioned it. The max PSI is 115 and I usually only inflate to ~100 PSI, if my pump can be trusted._ [1]: https://i.sstatic.net/bspFQm.jpg [2]: https://i.sstatic.net/JIvlel.jpg [3]: https://i.sstatic.net/kwE0qm.jpg [4]: https://i.sstatic.net/6n7p2l.jpg