Small frame bag for large frame

[saldegracia]

So I have fairly large gravel bike, a 61cm Fuji Jari Carbon and I was looking for a smallish frame bag, something just for long day rides, not for actual bike packing, around the 2l volume mark. While looking around I got the impression frame bag sizing actually depends more on the frame size than on how much stuff you want to carry...is that right?

However, I really don't want a massive frame bag to just carry around a couple of sandwiches, inner tubes and mini pump.

I came across this one from Wiggle's inhouse brand which should be exactly what I want sizewise. It also doesn't have a strap to the seat-tube which would make sense because it would be a very long way from the bag to my seattube.

https://www.wiggle.co.uk/lifeline-adventure-frame-bag

However, I have one doubt: in the product pictures the bag fits snugly into the front triangle of the frame. However, my headtube is a lot longer than the one in the picture. So it would probably look a little weird but also the way down to the downtube would be a lot longer, so I am wondering if this type og bag would even work with my bike.

Anyone with a big bike here who can share their experience with frame bags and frame bag sizing?

[Tifosiphil]

Maybe take a look at the Restrap options. They do something similar to the one you are looking at or will even custom make one to your specs for a relatively small price; https://restrap.com/collections/frame-bags

[saldegracia]

thanks, yes, had seen that one but I think it I'd have the same doubts about that one...I don't really want to go down a custom route yet...would like to try something fairly affordable first and see if I even like riding with a frame bag, that why the Lifeline seemed a good option but I also really like the design...but even Wiggle could not tell me if it would fit...the Restrap straps definitely seem to be longer...so I might risk it...