ALUMINIUM VERSES POLYMER CASES
You are a few days into an adventure you have been planning for months. All your gear has been checked, packed and repacked. You are heading down a rough path to a campsite when a vehicle coming the other way forces you into the side of the path and down goes you and your bike. You and your bike are ok but those very expensive aluminium panniers are now bent and the lid will not close? What can you do? Hit the lid with a rock to straighten the bend? That is not going to work. Sadly, you are going home. A small tumble from the bike should not ruin your adventure just because your aluminium luggage deformed.
If you spend much time on the internet reading the comments and debates on adventure motorcycle luggage you will quickly realize that there are two teams of riders – Team Soft Luggage and Team Hard Luggage. As I have mentioned in previous articles, I think there is a strong argument for both – but it is all based on the ride. You would think that as a manufacturer of hard luggage I would be opposed to soft luggage but if you look at the picture on the About Us page ( About us – Caribou Cases Europe ) you will see I have a set of Giant Loop soft bags on my bike as they were perfect for the tight trails we were riding. I think the only times I did not enjoy using them was the daily packing and unpacking process – and the smell!. It’s tough to be organized with those bags but packing cubes are your friend as they can keep the dank musty smell off your clothes and gear.
Inside Team Hard Luggage there is also a debate: Aluminium verses Polymer. Here I am obviously strongly on the polymer side. What pushed me in that direction? I was head of product development for polymer equipment protector case company Pelican Products (known as Peli over here in Europe) for 27 years ( Pelican | Cases, Flashlights, Coolers, and Travel Gear | Pelican) and I learned a lot about what works and does not work out in the real world.
At Pelican we designed, built and shipped literally millions of polymer protector cases around the globe. Probably the largest customers for our cases were the military and take it from me, they are a demanding customer because when they deploy to various parts of the globe, their equipment needs to arrive in perfect working condition or frankly, people get hurt. The cases need to be capable of protecting their contents in the harshest of environments and transported via military vehicles – these are tough conditions, and the military is the most aggressive of customers.
Over the years, the military has evolved from using simple wooden crates, to aluminium containers to polymer cases. Why is that? It basically comes down to the containers ability to handle impacts without permanently distorting and therefore losing the critical lid seal that protects the contents. We had to prove our products by testing to NATO, Stanag, Mil-Spec and IATA standards. So why polymer verses aluminium?
Some engineering basics: Aluminium, while strong and lightweight, has a relatively low elastic strain limit – typically around 2%. This means that when yield stress exceeds this threshold, even briefly, the material yields and deforms permanently. Of course, you can try and bash it back in place, but it is not easy and rarely goes back into the original form. In a typical 2mm thick aluminium pannier, a moderate impact (if you can call a big GS tipping over onto a pannier “moderate”) will result in a visible dent or a lid that no longer closes, and seals properly. In contrast, structural foam polypropylene (like used in Peli cases) has a much higher strain-to-failure threshold, often exceeding 10-20%, allowing it to flex under impact and then return to its original shape. You can test this for yourself with an aluminium can and a plastic drinking bottle. But you knew that anyway.
The real-world issue with an aluminium motorcycle case is when it is subjected to an impact. I think a few battle scars look sort of cool but aesthetics aside, the big issue is that it becomes very hard to close lid and the seal typically no longer does its job. We all encounter rain on our rides but the last thing you want to experience is arriving at your campsite or hotel to find your clothes and gear soaked. And what are you going to do it the folded metal latch no longer works?
Some will read this and say “yes, but plastic cases often crack!” Indeed, some do. Early plastic cases were made from ABS. It is a good plastic but at Pelican we could demonstrate to customers that our polypropylene was far superior to ABS when subject to impacts because the former is quite brittle. Polypropylene has much better flexibility characteristics than ABS and will therefore survive a tumble better than a case made from ABS. It’s no coincidence that literally ALL the military equipment protector cases are now made from Polypropylene and Polyethylene – because they are the toughest materials for the application.
The above picture was taken by Caribou customer Eric Lawrence. He had recently fitted a set of 35L side cases (35L Side case – fit most of the major suppliers) to his Suzuki V-Strom and unfortunately experienced a crash at a relatively high speed. As you can see from the picture, the polymer case did not deform even though the bike hit the ground hard and slid down the road. As Eric said “try that with your fancy aluminium cases!”
Another aspect of aluminium cases that I really do not like is the construction method. There are too many rivets employed for my liking, especially attaching the mounting and locking hardware to the shell. Motorcycles vibrate across a wide range of frequencies and rivets can work lose and even shear. Of course, you can drill out the old rivets and install new ones but that rarely happens at a convenient time. Rivets also have a nasty habit of allowing water to run down the centre. At Caribou we attach our mounts and hardware using stainless-steel fasteners with nylock nuts. This provides a very secure attachment method that can be checked in the field. It also allows parts to be replaced in the event of a serious crash where the case needs to be replaced – which we do for free as our products are guaranteed for life.
The team and I designed literally hundreds of different equipment protector cases. Each one had to undergo rigorous testing to ensure that they passed IP67 ingress protection standards (1 metre submerged for 30 minutes) and countless drop and impact tests. Passing the tests was satisfying but not as much as hearing the survival stories of customers cases. I’ll share those another day. In summary
So, as you can see, I am firmly on Team Polymer Case. Also, on Team Polymer are most of the world’s military, outdoor photographers, film crews and Hollywood super villains. You will be in good company should you decide to choose Caribou Cases Europe.