UKH

Any recommendations for a fairly high volume one that will work with a dropper post on a medium travel full sus?

looking for something that would fit a sleeping bag and cook set, preferably waterproof.

Cheers

I was going to reccomend the Restrap, which can take a 14 litre dry bag, but I don’t think it will work too well with your dropper post. You might still find you can drop a little. 

I have an Apidura, Mrs B has an Alpkit one. The Alpkit is half the price and doesn't swing around so much. Check the clearance between your back tyre and the bottom of the bag on full bounce. You won't get much use out of your dropper post, though mine will drop about 2cm which is enough for sketchy descents.

Aye, figured there might have to be some compromise some where.

Thanks for the tips, I’ll check those out.

I have an Alpkit Big Papa, which I have used with my dropper post on my Giant Anthem SX (with a bit of extra protection to the post cobbled together I forget how). Its excellent, and was barely noticeable when riding, even though it does sway a little. Alpkit have recently added an "Exo-Rail" to the range, which is designed to stop sway, and to work with a drop post. 

Some pictures on a blog I wrote here, though most are of my mate. Mine's the blue/silver/yellow Giant, nto the red/black Scott: https://www.wildernessisastateofmind.co.uk/bikepacking-the-south-downs-way

https://www.alpkit.com/featured/bike-luggage-seat

Decided to give the Alpkit Fiana a go, I don’t need anything as big as the big papa. It a little more low profile than the other offerings at the same volume, so should give a bit more play on the rear hopefully.

Thanks for the tips everyone. WHW next week weather permitting...