Unique Bargains 3 Pcs Bike Inner Tube Rubber 45mm Long Bent Valve Bicycle MTB Inner Tubes 14" x2.50"

I bought two 3 pc 14" inner tube sets, 14x2.125 and 14x2.50. I returned the 14x2.125's unopened and that was smooth. My buddy had a friend put one of these 14x2.50 inner tubes on his rear e-bike wheel that required an angled valve. That first inner tube worked and then went flat by the next morning. My buddy had that friend put a second 14x2.50 inner tube on his rear wheel. That one went flat while away from home and 4.5 miles from his car. He walked the scooter all the way back. There's one new 14x2.50 inner tube left. I'll install this one. The reason I gave these tubes good reviews is because I know that the installation process is where most problems begin. Perhaps the valve stems internals needed tightened. I have that tool. Perhaps there was a bur on the rim or a sharp object in the tire that weren't dealt with. I'll install the last one and do a thorough inspection and install and reliability check. Both sets of inner tubes I purchased were marked professionally and they were physically different. If I can't get the third inner tube to perform reliably that'd be sad but I see that many of these 14x2.50's are challenging to install successfully.