last year I send a set of tyres to Lahore for a Swiss friend. I send it to the Swiss consulate, after phoning them and asking them for permission. They told me to declare the value very low and write myself a kind of invoice. Thats what I did and I wrapped them only in cheap plastic foil (for kitchen use) with a little bit of duct tape around.
The consulate arranged the customs and paid about 1000 Rupees (maybe 25 US Dollars) on a value of 50 USD tyre value included shipping. My friend just gave this amount of Rupees to the consulate and could collect the tyres.
But shipping was expensive on this end, but I worked in logistics so I could get a big discount.
Maybe you will find tyres in Delhi, at least I found somewhere a link to a big bike shop.
Mika (on the road again)