Hi All!
I come to Ortliebs from decades of using panniers with stiff tempered-aluminum backs and stainless-steel hooks (Kirtland TourPak and my own homemade clones of same...and yes, the hooks carved little divots into my aluminum racks. They tried to on my steel-tube Thorn Low-Loader Mark V front racks when they were on the Miyata 1000LT, but some tape prevented damage from occurring).
It was an...adjustment to come to Ortliebs and their glass-filled nylon hooks after that. And, I was concerned about their durability.
A look at the nylon soles of my ancient Detto Pietro cycling shoes inspired some confidence in the longevity of good-quality nylon, even though it was not glass-reinforced. Long-term reports from tourists worldwide have been encouraging, wrt to Ortlieb. Failures seem to be fairly rare, but they do happen. When they occur, they fall into five general modes...
1) They mainly involved spreading of the hooks and loss of the sizing-adapter inserts (a more extreme version of what Pete has experienced on the one hook of his front pannier). The outright cure is replacement of the hook and/or sizing adapter. Reported on-tour repairs include tying the adapters in place with dental floss or gluing them with SeamGrip. An alternative is to wrap about a half-roll of electrical tape around the rack so a sizing insert is unneeded. According to reports, swearing and cursing are an essential component of the repair process.
2) There have also been reports and photos on the 'Net showing broken stabilizer fins snapping where the more flexible fin meets the solid, cylindrical base. This is due to the existence of a stress riser caused by an abrupt change in section width where the flexible fin meets the inflexible base.
3) Cold does seem to be a large correlate in frank (outright) breakage of Ortlieb hooks. I have read several reports of the hooks snapping in the cold.
4) The major factor in non-cold breakage is users failing to fully seat the hooks and engage the spring-loaded clasping (retention) arm below each hook. What this means is one hook is carrying the full load, and at an angle, leading to twisting and greatly increased loads and therefore breakage.
5) Second-order vibrations and impacts also play a role; more about that later in this post.
Frighteningly, a few people on the 'Net apparently use their Ortliebs without the adapter inserts, though they are needed for their sub-16mm racks. This can lead to failure (and a lot of rattling!).
It also helps to periodically check the tightness of the machine screws Ortlieb uses to mount their rails. The gasketed entry points for the bolts are also a source of unexpected leakage in otherwise waterproof Ortlieb bags, as waterproofness depends on a gasketed trapping of the pannier fabric between the nut and bolt where holes pierce the bags. In general, loose bolts in any location are also more prone to shearing.
Ortlieb pannier hook and mounting rails failures seem to be less frequent with the later QL-2 mounts, but they may simply be too new to have developed much of a failure track record. No-tools hook adjustment and replacement are nice features of the new mounts.
Belt 'n' Suspenders (carry spares if you're worried; I do!)I decided to carry one complete spare set of hooks, pre-installed on the QL-2 rail of each rear pannier. Placed there, they take no room in my bags and add an extra impediment to a quick snatch-theft. The idea is to have a spare set of hooks that can be used in any place on any of my bags in the unlikely event of a hook broken due to crash damage or materials fatigue. I doubt I will need them, but they weigh little and are unnoticed in riding, sitting quietly at the ready if needed.
I also have two stabilizer fins fitted to each rear pannier. Though the second fin adds stability, only one is really needed, and so is available for replacement on any bag.
Perhaps this would ease your mind a bit about the possibility of breakage and how to manage if it occurs.
Of course, this does nothing about the possibility of a broken rail, but one can't carry spares for everything. I carry zip-ties of various strengths and gauges (be sure to avoid the whitish ones; they have little UV resistance), and figure I can always rig a semi-permanent mount to the rack with those if necessary, perhaps even boring through the fabric and stiffener to do so (yes, the bag would no longer be waterproof, but there's always bin liners and such, which is how I managed before...and I would still be mobile, which is critical in come of the places I go).
Tie 'em down! (the unrecognized value of compression straps)I have wished on occasion the Ortlieb back-stiffeners were a bit stiffer, particularly with regard to how they affect hook rotational torsion. My tests* have shown a prime cause of Ortlieb hook-wear on racks (scuffing through powdercoat and into the steel rack tubing) comes from this rotational wear. To see the effect in action, load a bag, clip it onto the rack, then boost it from the bottom with your hand to simulate riding over a rough road. You'll notice the flexible stiffener allows the rail-mounted hooks to rotate around the rack tube.
The solution is to use a compression strap (around the bags and rack) to keep the bags and contents in place hard against the rack and limit movement. It does wonders for virtually eliminating the second-order vibrational impacts the contents, bags, racks (and ultimately the bike) would otherwise be subject to. Hit a bump and you feel the jolt. If the bags aren't fully constrained, that same bump will cause the bag contents (and the bags that carry them) to loft and fall in response, creating a second-order impact).
It is not enough to simply compress the load in the bags. The bags and contents must be tied solidly to the racks. This is key to reducing the possibility of breakage.
Tie the bags and contents solidly to the racks, and you've cut that by half or more, as the contents cannot move, the bags can't loft or move against the rack, and everything has an easier, happier life,
including the hooks that suspend it all. That's a lot of useful function from one webbing strap, Fastex buckle, and keeper per bag. At times I feel a bit like the lone voice in the wilderness on this, but if one really wishes to reduce the possibility/incidence of pannier rack and bag hook breakage, tie 'em down with compression straps. The advantages increase as the road surface gets worse. It is a cheap, effective, lightweight solution and adds a small additional burden to the snatch-and-grab thief, especially if the buckle is rotated to sit below the bag where it isn't immediately visible. If the web strap is secured with a Fastex or quick-release buckle, it is a trivial impediment in regular use.
Hope this helps,
Dan.
* My test rig was made from an old bicycle rear-frame (seat tube, BB and rear triangle) with a rear rack mounted on it. The square-taper BB was fastened to .25in steel strap bent in a "]" shape and anchored solidly to the workbench. The rear axle was fastened to an off-center mount attached to an electric motor with an offset plate. When the motor ran, the rearframe hopped up-and-down cyclically, pivoting at the BB. The panniers and load mounted to the rack also bounced up-and-down, and I could closely examine what was going on, unlike when I am riding.
Ortlieb hooks/rails do rotate thanks to flexible back-plate stiffeners and vertical bag movement, and compression straps do help. A lot. Enough, I think, to make it a non-problem.
