I was recently searching for an 'o' ring replacement for the felt seal, FF35, used to seal the bottom of the steering head. I know that some people have use 'o' rings with success but I thought that an 'x' ring might make a better seal. I found one. They are called 'quad rings' and the one supplied as a test piece is a good fit on the 2" diameter part of the steering head and has about a forty thou nip on compression. That might sound like a lot but note that top, bottom and both inside and outside faces are hollowed to produce a nice wiping edge. They will be a few tens of pence each depending upon how many I order. If anyone would like one, or more, contact me on enw07@btinternet.com and I will place an order. Postage will be extra.