India, Sept. 2 -- A flat or badly deflated tyre is one of those problems you don't think much about until it happens to you. I learned that the hard way on a road trip when a tyre started losing air and I found myself looking for a working air pump while standing by the roadside.

The frustrating part was that I had all the usual things packed for the journey, but not a portable tyre inflator. Had I carried one, I could at least have checked the pressure and, in the case of a slow leak rather than major tyre damage, added enough air to get to a safer location or a tyre shop.

That experience changed how I look at this small car accessory. A portable inflator isn't a substitute for a spare tyre or roadside assistance, but it can be a usefu...