Cool. You might actually find that it's 40mm and Evans listed it incorrectly:
http://bikethomson.com/small-parts/
They don't make a 42mm shim anymore, though I believe they did use to make one to fit the old Elite stem. So unless they have old stock, Evans may just not have updated the item spec when the new size came in.
@Regal started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Cool. You might actually find that it's 40mm and Evans listed it incorrectly:
http://bikethomson.com/small-parts/
They don't make a 42mm shim anymore, though I believe they did use to make one to fit the old Elite stem. So unless they have old stock, Evans may just not have updated the item spec when the new size came in.