Hi Varun, the overall height of both front and back tyres is the same, since front tyre sidewall of 70 mm is higher than rear sidewall of 65 mm.But since rear is wider so in actual terms overall height fall the same.So no worries what so ever in any scenario of puncture.
Nope it is called innovative engineering.Nano is a rear wheel drive tall boy car, so having a fatter rear tyre enhances its balance and counters any chances of toppling over.Hope you understand now
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