Hi guys and girls, must make sure I include everyone these days,lol. Anyway I was at Stafford show just gone and while I was there I bought a set of tyres and tubes for a RD400D (cast wheels). Not knowing the sizes I relied on the chap I bought from. He gave me a 90/90/18 and a 100/90/18 and two different sized inner tubes. They've Ben in the garage since I got back but I've measured the wheel width and the front and back wheels are the same width so do I have one wrong tyre? Thanks in advance.