Got Conti tubs on mine, but a quick G**gle of 27x1-1/4 (630 dia, which is what I'm assuming you've got) reveals:
http://www.google.co.uk/products/catalog?q=27x1-1/4+tyre&hl=en&client=firefox-a&hs=3Sb&rls=org.mozilla:en-US:official&prmd=ivns&um=1&ie=UTF-8&cid=16300094505706728024
http://www.google.co.uk/products/catalog?q=27x1-1/4+tyre&hl=en&client=firefox-a&hs=3Sb&rls=org.mozilla:en-US:official&prmd=ivns&um=1&ie=UTF-8&cid=15121697139577289784
http://www.jejamescycles.co.uk/schwalbe-hs159-27-x-1-1-4in-tyre-gumwall-id71419.html
amongst others
If it is 27x1-1/8 that you've got, the Panaracers come in that size too. Not a huge choice, granted, but they are out there. SJS have most of the above in stock.
@vikingfixed started
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Got Conti tubs on mine, but a quick G**gle of 27x1-1/4 (630 dia, which is what I'm assuming you've got) reveals:
http://www.google.co.uk/products/catalog?q=27x1-1/4+tyre&hl=en&client=firefox-a&hs=3Sb&rls=org.mozilla:en-US:official&prmd=ivns&um=1&ie=UTF-8&cid=16300094505706728024
http://www.google.co.uk/products/catalog?q=27x1-1/4+tyre&hl=en&client=firefox-a&hs=3Sb&rls=org.mozilla:en-US:official&prmd=ivns&um=1&ie=UTF-8&cid=15121697139577289784
http://www.jejamescycles.co.uk/schwalbe-hs159-27-x-1-1-4in-tyre-gumwall-id71419.html
amongst others
If it is 27x1-1/8 that you've got, the Panaracers come in that size too. Not a huge choice, granted, but they are out there. SJS have most of the above in stock.