Thursday, April 16, 2015

Redesigning the Hilleberg inner tent (review)

The cat likes the renewed tent too!
Opening is now through the middle, no more zips under tension
wriggling around corners etc. Just straight lines. We have

also lengthened the top mountain strap with an extender.
Tents or swags are part of long distance travelling. Unless you have the finances to stay in hotels for 3 years... which most of us don't have. But which tent do you take? A cheap throw-away or something more long lasting. As we didn't want to contribute even further to the waste-mountains on this world, we opted for a quality tent. As you can read in our review on Hilleberg tents, we were disappointed. But as we still want to get the most out of it, we made some changes to combat the flaws in the design. 

There is a lively debate on the net on Hilleberg's infamous zipper problem. Owners of the Swedish tentmaker's products report abnormal zipper wear which can render the expensive tents useless in as little as a few months. Hilleberg claims the zippers wearing quickly is simply the result of dust in the zip and states they have to be cleaned regularly with a toothbrush... They regard it as normal wear and tear. We have other ideas! Other brands of tents don't have the problem, yet they have zippers too.

If dirt and dust would be the cause then all tents should suffer the same problem. Yet I have never seen anyone cleaning their tent zippers with a toothbrush, have you? The problem also seems to be isolated to Hilleberg tents and more in particular to their tunnel type tents like our Keron. I have already written that in my opinion their quality has degraded over the years. So much so that we have now come to the point where we feel we can no longer justify spending this kind of money on a tent that has so many problems. If we had some cash to spare we would have bought new tents for the next part of the trip, as we wonder how much longer they will last, as it is we will simply have to make do with what we have.

When I grew up, tents were big heavy cotton constructions with enough poles to built the Sydney Harbour Bridge. They also came with enough pegs to anchor down a small family home. Pitching wasn't quick then. But once up, they provided a comfortable and dependable shelter. Apart from reduced weight and smaller packaging, all nylon tents are horrible things. They all have condensation problems, which even if it doesn't leak will make everything inside the tent wet. Stormy weather will have the thin fabrics flapping in the wind and keep you awake all night, while sunlight changes them into an oven. 

Even with the zipper open there is less chance of mosquitos flying in... and there's that cat again!
Tent constructions have changed over the years too. All but a handful of manufacturers have now abandoned the old fashioned A-frame tents and gone for more complicated constructions which involve bending poles, snapping on clips and hooking up to a bewildering array of straps and strategically placed and colour coded eyelets. In the old days we used to have two types of tents: small tents and family tents. Now we have mountaineering tents, backpacking tents, hiking tents, expedition tents and even motorcycling tents. The choice is endless and to make it even worse they come in two-, three- or four season variations too. 

We've lengthened the strips that attach the top of the inner tent to the outer, again to take pressure off the inner tent
No doubt there have been improvements made over the years but to be fair, things have gone completely over the top. Unfortunately most have gone form over function too. Sloping entrances for instance are just a dumb design. Have you ever seen a house with a sloping front door? No, and for good reason: it doesn't work. For starters opening the door would mean rain water entering the house. So why would that be any different in a tent? Yet quite a few tentmakers, including Hilleberg have entrances you can't open when it rains... Even the old A frame design didn't have that problem! 

Our Hilleberg Keron 4GT is a big tent. It's strong and lightweight and easy to pitch. But it's also a tent with the usual drawbacks hampering all tents made out of plastic sheet. It flaps in the wind, is baking hot in the sun, freezing cold at night and has moisture problems which cause sore throats and damp clothes in the morning even with all ventilation open. The Hilleberg has two more problems though. UV radiation can degrade the outer tent in less than a year to a state where you can simply push your finger through it. As we have seen with both the Staika and the Keron. The other problem is isolated to the Keron: zipper wear. 

Sewing thin slippery fabric like this is tricky...
The YKK zippers Hilleberg uses aren't overly big, but I don't think that is the cause of the problem. In my opinion it's the tent design, whereby one long zipper has to follow corners and is under continuous tension as it forms a stressed member of the tent. There is lot of tension on the zips as a dozen straps pull on them in all directions. It makes the zippers from new, without any dust on them, hard to close. The raw saw-like sound tells it all: this zipper is clearly unhappy with it's working conditions and will thus wear prematurely. There is another problem with the design too: exiting and entering the tent in mosquito areas is less than pleasant as opening the zip will cause the no-see-um mesh screen to fall open fully... causing all the flying terrorists to enter. You might laugh but when the flying squad carries malaria... it becomes less than funny. We have asked Hilleberg to change our inner tent zip design to the same setup as the Staika, as we were entering malaria and Dengue fever areas, but Hilleberg refused. 

Sewing at slow speed to avoid the needle getting hot and melting
the fabric
We were somewhat disappointed with their reply. As the solution to all of the above is basically simple: modify the tent so that the zipper only has to move in a straight line and remove any stress points on them. It would make it a better tent and end the Hilleberg zipper drama. As they refused we decided to try ourselves as what we had simply wasn't working. That's easier said than done though... We needed a wizard with a sewing machine, super strong thread and 3 long zippers... Mike's grandma came to the rescue as you can see in the photos. She's a bit camera shy but you get the idea anyway. Water-cooling the sewing needle, as Hilleberg does, wasn't an option for obvious practical reasons. Instead grandma sewed the whole thing together at very low speed. The 3 zippers came from the Staika which had fallen apart. The Staika's tent fabric was destroyed by UV radiation but the zippers in it where just a couple of months old. A tedious task of carefully removing all of Hillebergs' stitch work followed to salvage the long zips.

It was a bit of a hassle to feed the thin material through the sewing machine. Grandma hand sewn it first so that we could setup the tent and try it all. She then stitched it through on the machine. The result: the new main zip goes up and down in a straight line now, no corners, no friction, no stress. There is also no tension on it as the inner tent doesn't hang on it like in Hillebergs' own design. The zip opens from the bottom, meaning there isn't a gaping big hole for mosquitos to aim for. Normally it's enough to open the main zip and one of the smaller ones halfway. As they all operate without tension and in a straight line, they run well. Grandma also made a couple of extenders to reduce the tension from the top mounting points on the inner tent. You can see one of them in the second photo, right above the central zipper.

We had expected some unforeseen problems but all in all it's working even better than we had anticipated. All good then. But it shouldn't have been necessary. From a tentmaker which claims: 'Your Hilleberg tent must perform equally well across the entire spectrum... and must be fully functional in the most demanding conditions' we had expected better. It's somewhat ironic that my grandma can improve upon the design and made it into a better tent. It's also disappointing that Hilleberg didn't care that we were entering malaria and Dengue fever areas with a tent that was just completely unsuitable.