I posted on this ages ago and have researched possible offerings, but decided to do something along the lines of the bedrock rail wing. Using readily available bits off ebay. Cost < £10

It has virtually eliminated any sway and you have to grab and rock pretty hard to get the pack moving. My guide also details a much better and stronger buckle system that will not break!

https://onemanandhisbike.com/diy-seat-pack-stabiliser/

I hope people might find it helpful.

could do with a couple of pics pulled back, seeing it all together sorta thing. Also could do without fuzzy pics.

could do with a couple of pics pulled back, seeing it all together sorta thing. Also could do without fuzzy pics.

Will do.

I just use an appropriate size bungee cord which obviously isn’t adjustable but does pretty much the same job

I like that. I hadnt seen the original, but fair play for fabricating something that, as you say would be pretty pricy once it made it over here. What would be of interest is whether you could make the plate a T-shape with the middle leg going towards the seatpost. That would then give a three point attachment for dropper post use 8)

Oh and I dont get much waggle with mynApidura seatpack. Some seem more prone than others

It does seem to be a solution for a non-problem but then it might make cheap seat packs more viable as the better ones (e.g. Revelate and Wildcat) don’t seem to need this.

A few more pictures added to hopefully convey what I mean about how much easier it is to now load the bag. The velcro on the strap attached to the saddle and that on the top of the bag means you just press it up and it sticks in place and then you just give the side straps a good yank.

I Like that! Bookmarked for future reference, I was actually looking at 3D printing something to do it and had started to mock the CAD up, so might be able to do a hybrid of the designs…

It does seem to be a solution for a non-problem but then it might make cheap seat packs more viable as the better ones (e.g. Revelate and Wildcat) don’t seem to need this.

Given they are all made the same way why are the Revelate and Wildcat offerings so much better when it comes to the sway problem?

Really curious as all seat packs use the same design that feeds over the saddle rails and it is only compression of the pack up and against the saddle rails that stops sideways movement.

Given they are all made the same way why are the Revelate and Wildcat offerings so much better when it comes to the sway problem?

But they’re not. Yes the straps go under the rails, but it’s the way in which they do this means they don’t move.
Can’t talk for the Revelate version, but the Wildcat doesn’t move at all (to the point where you wonder if it’s fallen off, as you don’t notice it)
Apidura is the same. 99% of the time you’re oblivious to it, unless riding out of the saddle.

@flanagaj – as Chew says the Wildcat version really doesn’t move.

You are describing a simple strap from the centre of the bag over each rail to the outside of the bag. This means there’s a large slot/loop between bag and strap that the rails can slide along back and forth.

The Wildcat doesn’t do this: the strap goes from the centre of the bag outwards *under* the rail then back inwards *over* the rail to then thread through a D-loop, only then does it thread back outwards *over* the rail to fix to the outside of the bag. Now when you tighten the straps you don’t end up with a loop between strap and bag that the rail can slide along, the loop is fixed to the centre of the bag at both ends.

If you get chance have a look at one, it’s probably easier to see than I’ve described.

@whitestone – thanks for the explanation. Maybe I should have just amended my bag to use the same style top strap. I can see how that would improve sideways sway.

I also now see why the under and over strap design you mention would only be useful for the harness type holders. It must be quite a fiddle to take the strap over the rail, through a d-ring and then back out and therefore something that would be quite tough to do if you were trying to fit a full seat pack to your bike each day at camp.

That’s the ugliest mudguard I’ve seen in my life, bet it works well though 🙂

Yes, the Wildcat design is for a harness/bag combo rather than a bag. It’s a bit fiddly the first time you fit it but after that it’s only a couple of minutes.

Personally I find a harness with separate bag to be better as you can simply unhitch the bag at camp, use the contents then in the morning repack the bag, possibly under cover if it’s raining, and refit to the harness. In the case of the Wildcat and other harnesses this is either one or two clips. Filling the bag is also much easier off the bike than on.

Edit: More pros for the harness system. With a harness system you aren’t limited to one size of bag. I have an Alpkit 13L tapered Airlok and an 8L Wildcat tapered bag so can choose which suits my intended load. If the bag gets damaged then I only have to replace that and not the whole system. YMMV of course.

Personally I find a harness with separate bag to be better as you can simply unhitch the bag at camp

Yep. I can see that now. My routine is always, tent up first, tent packed away last.