Carradice expedition support struts or similar.....help please.

[Tea Man]

I have a Carradice Super C saddle bag with a QR tour saddle support. I was looking at buying a set of carradice expedition struts to further strenghthen/support the saddlebag when heavy. My frame would require the carradice seatpost attachement as there aren't any rack mounts on that part of the frame (Sonder Frontier). However, the issue I have is that with the current bike setup, the struts would actually be pointing down from the seat post to their attachment onto the saddle bag support, which I don't imagine is anywhere as good as having them pointing up and taking some of the weight. The setup would be on a rigid hard tail for off road touring etc.

The following site shows what I consider to be the ideal setup but does anyone have any ideas on what support struts they are using and where they can be purchased from or do I just go for a minimal rear rack?

https://bikepacking.com/wp-content/uploads/2021/01/Readers-Rig-Josies-Rawland-Drakkar-15-2000x1334.jpg



Thanks,

Andy

[BFC]

That is about the worst place to apply stress to the seat stays on a standard frame design.

Any supports should go to the top or bottom of the seat stays, not the middle, also avoid the few mm (cm?) around any welds - uneven material surface is more likely to create stress risers and fatigue failures are always more likely next to the welds.

[Tea Man]

Thanks for the reply. I've just ordered a Tortec Tour ultralight rack which I'll probably use and it will mean I can get panniers on as well if need be.

[andrew_s]

I just let my Camper Longflap on Bagman QR bounce, with no struts, on the grounds that it's like having suspension for the bag.
I do have fairly generous clearance below the saddlebag though, and on a smaller bike it would probably hit the tyre or mudguard, possibly fairly hard.

There doesn't really seem to be any reason not to use a seatpost collar for the struts. It's what's shown on the Carradice website, and most of the flex will be at the top of the support, so a reduction in forwards/backward movement at the bottom of the vertical section would be as effective as a reduction in up/down movement a little further back.