I've got numerous Alpkit drybags but I'm after something harder wearing to fix onto my Aeroe rack.

20 litres

Any ideas?

Not sure about exact material weights but Lomo and Overboard certainly do heavier weight versions.

The Revelate bags are pretty sturdy. I've the Saltyroll for the front harness, it's not quite the ballistic nylon used by the likes of Ortlieb for their panniers but it's not far off. Don't know if they do anything similar for rear racks.

Might be worth checking caving suppliers as roll top bags in ballistic nylon are common in caving for carrying kit.

Rich, if it's an Airlok, it'll be made of

Fabric: 320D Taslan Nylon Coating: PU

TPU itself is no warrant for higher abrasion resistency. You may want to look into 400D Nylon with either PU or TPU coating for example.
Most heavier denier Nylon seem to come with TPU (anyways) and will have bonded seams, which I find to last longer than taped/sewn seams. At least within Seatosummit and Exped var. lines of bags.

I'd google for 400 or 420D Nylon TPU drybags and see what shows up, has a preferable shape and is available.

No experience with these, but seem handy and sturdy
https://www.exped.com/en/products/stora ... 0147764378

PX ones were sturdy. I assume they still make / sell them?

I like (and use) the Ortlieb ones https://www.ortlieb.com/uk_en/products/water/dry-bags

Not the lightest but strong and waterproof.

I have some PX bags if you want them? Red and orange (one of each). Can't remember volume but say if of interest and will confirm.

Thanks all for your input.

Might be worth looking at Lomo?I have a couple of their bags and they are cheap as chips, totally waterproof and excellent quality!

I bought a couple of the Northcore bags which seem to tick the needed boxes at £20 each

https://www.amazon.co.uk/dp/B07QNLT35N