Looking at the large 37 pattern pack and I think they are pretty much there or thereabouts for size.
Contemplating adapting a pair for my M20, thoughts, anyone done it before?
Scott

email (option): larkesrATgeemail.com

Scott, you can indeed use 37 pattern webbing large packs but they may require some thought and adaptation to secure them to the pannier frames..........

Original pannier bags were made of heavy cotton duck/canvas rather than webbing, and were secured together across the top of the rear-carrier by a single wide webbing strap that buckled to the other pannier strap.............additional fittings to each pannier bag were a pair of shaped leather "pockets" with a press-fastener to secure the top corner of each bag to the frames, plus on the bottom of each bag a pair of sprung steel clips to secure each bag to the pannier tray.............further reinforcement was provided with a pair of "Y" straps to support the bags in position and particularly useful if the bags are heavily laden............

Whilst similar in shape, I think the best thing you can do is to place a large pack on a pannier frame and then work out a suitable method of securing the packs...........when heavily laden, without proper securing they are likely to move around so well worth time and effort to establish a solution............

Having ridden both an Ariel and a Norton to Normandy and back with pannier bags laden to critical and with a pile strapped to the rear carrier of similar height to a small pillion passenger the weight at the rear of the bikes always made the journey "interesting".........on one occasion the weight and bulk of the load actually fractured one of the pannier frames that was temporarily fixed by a number of industrial cable ties..........

Yes it's been done lots of times, The large 'Backpacks' are roughly the same size as pannier bags but are of course webbing material as opposed to the correct weight canvas and are also missing the leather corners, reinforcing webbing and the bottom securing metal clips.

Frank Brown does make quite nice repro pannier bags.... pegasus-drive@sky.com

Ron

PS. Typing together with Steve!

email (option): ronpier@talk21.com

Does anyone have good reference images of the attachment points and bottom attachments Ron mentioned??

email (option): larkesrATgmail.com

The large packs are slightly narrower, so fixing the leather pieces to the back requires careful positioning to match the frames...With the Y straps fitted the lower sprung steel clips are not really needed as the straps stop the bags moving about...Ian

email (option): ian@wright52.plus.com

email (option): ronpier@talk21.com

PS there is also info from Hans on making the leather corners.

http://www.wdbsa.nl/download/Pannier%20bag%20corners.pdf

Ron

email (option): ronpier@talk21.com

This is an original NOS bag. Here are the spring metal clips that slide onto the carrier tray. These are backed up on the inside by same size flat plates.

Also a shot of the back showing the corners and 2" reinforcing webbing. Ron

email (option): ronpier@talk21.com

Scot, I have used 37 Pattern large packs for 3 years in Normandy and many other events on my 3HW and they have worked well but as Steve said you need to adjust and add some extra straps and I used shoulder straps cut to size and you will need to have a strong sewing machine to fix them, hopefully the photo's will show where I moved the steel helmet strap loops to be directly above the D wire loops and then fixed the extra straps on the stop which hold the top of the bags.

https://www.flickr.com/photos/146584797@N07/shares/5r2RbC

email (option): ian_chatfield@hotmail.com

Gents,
Thanks for all the info and picture, think I'll give it a go once the bike is built.
Have an old singer which according to the MIL will stitch anything!
I'll take some pics and do a write up for those interested, but don't expect it next month!
Cheers!
Scott

email (option): larkesrATgeemail.com

Hi Scott

I have instructions on making your own in the technical section, you will save a lot of cash and they look great.

http://www.wdbsa.nl/images/Panniers.pdf

Regards

Stuart

email (option): deepsea@vol.net