Fraser Cunningham wrote that he had a 1inch x 3/16 block chain and was looking for a chain ring to match.Prior to this I had assumed that all single speed chains were 1/8 wide due to the supposed extra strength.Although it is hard to imagine that climbing some of the hills in The Tour don't stress a chain just as much,just in a different way.None the less I am interested in the fact that track chains in both 1 inch and 1/2 inch, block or otherwise may vary in width.Can anyone enlighten me on this topic.I would also add that until recently I thought all 1 inch pitch chains were block chains.Thanks to this list I now know differently Geoff Duke in wintery Melbourne Australia