Originally Posted by
john_mct
That dry bag is 850mm wide/long, his road drop bars are probably 460mm wide max...
Not sure why so many people are suggesting handlebar bags when they were clearly designed for flat bar mtn bikes, yes you can stuff them in but it will often result in losing some of the useful hand position options that drop bars afford.
People work around the extra length and bulk through compromise. I have limited fork mount options just like the OP. I use a Topeak Tourguide handlebar bag that fits between the drops. Much smaller overall and not for bulk but that was my compromise. I really wanted to make a backpack work and tried several times and still try again occasionally but in the end, even a lightly loaded backpack with a few pounds in it on a drop bar just hurts my back after an hour or so.