Hi Charlie
Going back several years there was considerable discussion on The Forum about the tyres for the EW model. I certainly remember contributing to this. The basic facts are that the EW model and some CW models were issued with 25" x 3" beaded edge tyres. It appears that this size tyre was only used on Douglas machines and as time went by and beaded edge tyres went out of fashion new sources had to be found for replacement beaded edge tyres and common sizes used on many makes and models were provided and are still made in small quantities with the exception of the 25" x 3". My 1925 CW was also supplied with this size of tyre. The only available BE tyre approved for use on this rim is 24" x 2.1/4" and indeed my CW came with this size on the rear wheel which looked ridiculous especially as the CW has the large section mudguards. The front tyre was the original 25" X 3" which was so rotten you could see the fabric through the side walls. Most CWs were issued with 26" x 2.1/4/2.1/2" tyres so my solution was quite simple; to rebuild both wheels with correct rims for 26" tyres. For some time EW users were officially advised to fit 26" X 3" tyres but it was observed that they were a loose fit. When "Health and Safety" started to rear its head official advice was withdrawn and no one was prepared to risk being sued for recommending the incorrect tyre. I am currently restoring a 1924 model Douglas which was originally issued with 26" x 3" BE tyres. I have purchased new BE rims from the Netherlands to suit the available 26" x 3" BE tyres and these are approximately 1/2" larger in overall diameter than the rims you have measured as part of your EW project. I hope this helps.
Chris.
