Hi Paul, I bought a pair of 'Heidenau' 21 x 2.5 tyres for my '55 New
Hudson, from a company on the continent. Unfortunately I have lost
track now of even which country they came from, which is why I did not
answer to your earlier request. The tyres are quite chunky, I have
only so far fitted the back one. It was quite difficult to fit but
went on the rim OK eventually. When fitted to the bike the wheel would
not turn until (like Burt Monro in the worlds fastest Indian) I had
cut off the blocks of tread on the sides of the tyres. It now misses
the frame by not much more than a millimeter each side, only after I
had very carefully centred the wheel in the frame, and spent an hour
or two with a spoke key getting the wheel to run dead true! I have yet
to fit the front one, but it looks like I shall have to do the same.
The blocks of tread trimmed off were so far up the side of the tyre
that the only time they could possibly contact the road is while you
are falling off it! Good luck, and let us all know how you get on.
Cheers, Bob