Does anyone have experience using the RS basic carry on bag (Through the Back Door) on European carriers as carry on? We will be flying between Paris and Tallinn on Baltic Air and wondering if these will comply with the European carrier requirements. By my calculations the RS bag is just slightly larger in one dimension but since it's soft sided it may not be an issue. Maybe the 8kg weight requirement will be more of an issue than the size!
That depends on the airline, they all don't all have the same size limits.
I have flown Air Baltic.
For soft sided, non-wheeled bags, as long as you don't pack it to the limit, they will "squish" a little and should be fine in the sizer.(The RS bag is only one cm over the Air Baltic limit. But again, it's a soft sided bag.)
The weight may be an issue.
You are allowed up to a combined weight of 8 kg for your carry on and personal item. You can pay a bit more and get a 12 kg allowance.
There is no such thing as European carrier requirements. Every airline has its own and differences may be quite considerable. You have to check the limits on their websites every time you fly.
If this is the bag https://store.ricksteves.com/shop/p/classic-backpack ( 21 x 14 x 9)
and airbaltic is the airline , then the the dimensions [ 1 cabin bag (55 x 40 x 23 cm) ] reveals the RS bag is within limits
55cm = 21.66 inches
40cm = 15.7 " "
23cm = 9 inches
Assumes you don't over stuff it.
The 8kg limit is going to be the tough nut to crack.
( The max. weight is 8 kg for all pieces.) https://www.airbaltic.com/en/baggage/cabin-baggage