Tuesday, December 17, 2013

Forward progress in snow

When we were thinking about buying Nihola #1 two years ago in Denmark, we had really basic questions that we never got a good answer for before we tried for ourselves, such as the possibility of cycling up hills.  Turn out hills are harmless, so now we've moved on to snowy, icy hills.  Is that possible?  (I can imagine that the risk of not being able to get up hills in the winter would be a huge barrier to someone who didn't already own two cargo bikes before arriving at the hills in question.)

I have Nihola-ed around in Oslo since last February so I know a bit of the answer already, but unlike then, I now need to get my kid up 70m of steep elevation climb in the morning, descend 175m (in a bit over 3km), pedal 7km farther to work, then repeat going the other way.  Its actually a bit of a question if this is going to work all winter.

It snowed maybe 10-15cm (4-6in) on sunday and monday a week ago.  The first thing I did was to go out there with the summer tires on, and no weight on board.  (We were trying to go get a pizza.)  Turns out a Nihola configured in this way can hardly move on flat fresh-snow-covered ground, but getting a 20kg kid to sit on the cargo rack enables respectable hill climbing.  (Putting weight in the box has no potential to improve forward traction.)

So that brings me to the first lesson of driving a Nihola on ice and snow.  Put weight on the back tire, lots of it.  Everything that you are carrying should go back there, with the possible exception of kids.  I would agree if someone were to declare its pretty stupid to have a big empty box in front, while everything is hanging off the rear rack with bungies, but at least the big empty box keeps the machine from falling over.  (There is actually one kind of trike available in Copenhagen, Sorte Jernhest, which is front wheel drive with rear steering.  So anyone who is really bothered by empty cargo boxes and full cargo racks can go buy one of those and find peace.  Best of luck on the snowy, icy hills.)

The second thing to do is lower the pressure in the rear tire.  How much depends on lots of things, but in a difficult situation it can go really low, just enough to keep the rim off the ground maybe 1cm when loaded.  That is only advisable at low speeds.

The final magic is to fit a tire with helpful tractive properties.  I am under the impression that aggressive tread (knobby) is a good idea on a Nihola because the three-wheel balance enables some digging, and studs are essential if anything is to be accomplished by the tire once it digs through the snow cover.  For climbing on ice, the more studs the better, but studs really aren't going to do much on a hill unless you have first added some weight on the back tire, and set an appropriately low pressure.

Friday, December 6, 2013

A little day tour in late November

Winter is late in Oslo.  Its December and I haven't gotten out the studded tires for the Niholas.  But perhaps that is not so impressive; a Nihola has three wheels so a bit of ice is not likely to cause anything surprising to happen.  The other weekend, we even took a little day tour (maybe 25km on significant hills) in lovely sun with a bit of snow and ice on the ground.

Out on a little tour in November with a bike, a Nihola, and two kids
There are a few things to note in order to minimize problems with this.  First, there should be a good load on the rear tire, in this case, several liters of water and hot tea, kilos of tools and random junk, and sometimes a running bike.  It also pays to keep the tire pressure a little on the low side.

Oh, and the kids can get really cold sitting there so bring all sorts of warmth accessories.  We brought an old blanket, a foam mattress for the floor, and left the roof at home.

Anyway, its kind of interesting to spin a tire on a trike.  Its more of a curiosity than it would be in a car, because you're sitting right there looking at the tire and the road, everything is fairly quiet, and you can really feel the interaction of inertia, tire and ice.  Often enough I am going along and start slipping (with the back tire), make it a bit farther, then start sliding backwards and either use the front brake to stop the backwards slide, or just slide into an area of traction.  The idea is then to plot a new course for the back tire, avoiding the ice.  It isn't necessarily helpful to get off and push, because probably you can't do any better on foot than on the pedals.  However it can sometimes be useful to move the rear sideways, onto a better surface.  While this is all going on, you can have a calm chat with the kids.  Lets all sing the praises of three wheels.

But that is kind of off topic.  On this little tour we took, I found only a small area that was icy.  There was also one good climb where I was happy to use the 15 gear-inches ratio, and which also was on snow, ice and gravel.  I could feel the tire slip here and there, but things went well enough.  So the studded tires are sitting in the basement, for now.

Adjusting the front brakes

We got our yellow/orange Nihola around the 1st of May 2012.  I don't know how far we've driven it, but it didn't start getting intensive use until the middle of September 2013, when it was fitted with an Olso-appropriate gearing system.  Since then, the front brakes have seen serious use most days of the week.  I think few Niholas ascend or descend a hill so steep, in their entire service lives, as the hill that ours does each working day.  As the weeks passed, it became clear the brakes were getting a lot weaker.  Almost certainly, the cause was the cables stretching (but the drum brakes can also wear).  So, the question is, how does a person tighten the front brakes on a Nihola?

The brake lever has no adjustment.  Down by the wheels, each brake has what appears to be a standard Sturmey-Archer drum brake cable adjustment mechanism, but its hard to access and nearly impossible to adjust.  Its also partly covered by a rubber part presumably designed to keep water out, which is itself hard to get out of the way.

The cable adjustment mechanism of the left wheel, wedged against a significant piece of metal
On a normal bike, those would be the only two options.  On a Nihola, however, an adjustment can also be made right above where the single cable from the brake lever is split into left and right cables for the brakes.  Two 10mm wrenches take care of the problem (although its not as nice looking once the little rubber cap is too high to cover the threads).

Center brake cable adjustment on a Nihola, with rubber cap moved well out of the way

More about Reelights on Niholas

I thought I should add a bit to the topic of Reelights on a Nihola.  I had noticed that the rear blinker (SL620) wasn't flashing at walking speeds (which is also pedaling speed on a particular hill I drive up most mornings) so I added a third magnet, and that solved the problem.  It seems to flash at just about any speed, it seems to quickly charge up its capacitor (for flashing when stopped), and I can't think of any downside except that I had to find a third magnet.

Reelight magnet and generator on a Nihola.
Magnet placement is actually a little bit important.  My wheels are 36 spoke, so two magnets can not be spaced evenly (unless mounted off-centered on the spokes).  Three magnets can be mounted at even intervals (while all being mounted centered), which is what I did on the Nihola.  However unequal spacing can actually be a good thing with a flashing Reelight, because the light often flashes right when the magnet passes the generator, and if the magnets arrive at uneven intervals, the light flashes less evenly.  But it gets better than that, because the light also appears to try to flash according to a timer.  The precise way that power-pulses and the timer interact is hard to determine, but I mounted three magnets on my wife's commuting bike as well, at highly unequal intervals, and it seems to give a nice semi-random flashing pattern at biking speed.  (And it also flashes at walking speed.)

Three magnets at a good speed, I'm guessing 25 km/hr, gives almost continuous illumination on a Reelight SL620.  It still flickers and does random-looking things, but a human eye wouldn't perceive it as getting dark.

Anyway a final bit about mounting the generator on a Nihola.  The steel frame in the rear is fairly thin, and proves somewhat less than ideal grip to the Reelight generator.  Its not a big deal, but a few times I've had to adjust it to keep it from rubbing on the magnets.