Dry bags on panniers. How big?

[Doberman]

I am driving the bike to Greece in a week and I have to purchase a couple of dry bags to strap on the panniers. I will be riding 2 up, so I have to choose a descent size. I believe Ortlieb do them in 35 and 59 lt.
What size would you recommend?
Thanks in advance.

 

[tonkatoy]

How much gear have you got to pack.

I've got 40L H&B panniers and went away for 6 weeks with my gear packed in a 20L Exped dry bag in one pannier and SWMBO did the same in the other. I'd bought 40L bags as well but we just never needed them. Way too big. So god only knows what 59L bags will look like strapped to the top of a pannier.

 

[Bryn]

Bear in mind that strapping bags on the top of the panniers can make it more difficult for the pillion to get on and off

 

[Doberman]

I ended up getting the 35L from Ortlieb. The dimensions looked right and I believe they leave enough space for the pillion to be comfy.

 

[sockpuppet]

Verns panniers are 20inch long 10 inch wide.

24L rat packs fit just right.

 

[Michael R1150GS Adventure]

35 Litre hein gericke - great quality and air tight!
Amazing value and tough as old boots. Good handle and loads of tie down slots.
Enjoy your trip...

 

[Fanum]

Big as you like