Bongo Fury

Hi guys
I've just picked up a cheap Thule 973 rack which has no bike support rails. I wanted to put a backup box on it but see from thules instructions they place the box on top of these rails with a fixing plate going into the v of the bike rail. Does anyone know if it would be safe to put the box on the frame without the bike rails (obviously still secured with bolts and straps)?

Also wondering if the Thule easybag would fit on it as an alternative?

Thanks

The Backup Box has very little inherent strength so needs to be be bolted to something flat and rigid. This is what I did when I fitted mine to an Atera Strada DL3 rack. I made some rails to fit the flat base of the box to the curved surface of the rack.

Ok thanks, thought that might be the case! Yours is a good idea compared to cost of bike rails, thanks