RealClassic SQ4

[simon.holyfield]

These swinging arm Squares are OK but a Healey 1000/4 is better, IMHO.

Ah... But perhaps a PRF SQ4 is more attainable? You don't see too many Healeys on the market.

[david.anderson]

If you are going to build a SA 4, the proper way to do it is as the Ariel factory did, with a single front downtube.

David

[allan.walker]

Hello David,
An old thread, I know, but is there any evidence that this was a factory-built bike (or even a copy of a factory-built bike?)
Allan.

[david.anderson]

Alan
The bike in the photo is/was owned by Eric Parker from Nuriootpa South Australia. Eric has a very large collection of Ariels (Australia’s largest, as well as a large collection of Chevs). Eric had pictures of a prototype mk4 swing arm 4 and claims the bike in the photo was original. The frame certainly looked original, but I failed to record frame or engine numbers. Photos of the prototype mk4 square 4 in Mick Walkers “Ariel the Complete Storey” are both single down tube with a caption “Note single downtube” alongside one photo. The leading link swing arm mk3 square 4 photo is also single down tube. I spent an entire day looking at Erics collection, including the Ariels in his museum, in his house and the huge amount of parts in the many shipping containers that he has.
David

[allan.walker]

Thanks for the background information, David.

[Roger Gwynn]

In my opinion the s/arm sq4 to build would be a copy of the original factory proposal that was never built, which is a version of the standard PRF frame but with rear end offset, as in the SQ4 frame and the front down tubes bent forward at the lower end. It also had a steering head angle of 64 instead of 62 degrees, the dual seat mountings are different, petrol tank mountings were to be on plunger/rigid centres. Many years ago I drew the assembly using the works drawing of the assembly dated 23/4/53. There are many individual drawings for this frame in the archives so it would appear that the factory were quite a long way down the road to making this frame. Word document copy of the drawing, if anyone is interested I can supply a CAD

MK IV Frame.docx

(119.88 KiB) Downloaded 52 times

[allan.walker]

That's very interesting, Roger. I wonder how difficult it would be to register a bike built using a frame modified to these specs with a Square Four engine in it.