The frame used for the high performance Standard AS500 motorcycle was a copy of the 500cc HRD Super 90, with the 3 frame tubes to the rear axle and many other features were copied such as the distinctive HRD saddle tank etc., Although Standard switched from using JAP to other manufacturers engines, the frame, petrol tank and overall appearance of the “higher end” Standards remained very much based on the HRD. However, Standard produced a much wider range of machines than HRD in Wolverhampton and the smaller Standard Two strokes and smaller capacity machines had a much more conventional frame and appearance.
It’s worthy of note that Standard made their own forks in Germany based on Brough Superior Castle forks under a formal agreement with George Brough.
Although HRD ceased manufacture by 1928, Standard were more fortunate and carried on motorcycle manufacture into the 1950s, with top end models continuing the HRD styling into the 1930s, though with minor differences such as the castle type forks.
If you have a grasp of German
http://www.standard-gutbrod.de/ is a website for the marque.
There is a member of the club who has a superb 1928 AS500 Standard with a Motosacoche engine and Hurth gearbox, I’ve alerted him to this post in the forum.
There are a couple of photos of my 1926 HRD in the “about” page of my website
www.vincentblackshadow.co.uk including one with the machine stripped down for the start of Ramsey Sprint at the 1999 international.
Andy Davenport