Sunday, November 22, 2015

Another winter

So another winter is starting is Oslo, in Lommedalen its a moonscape of tracks frozen into ice, sprinkled with gravel.  Really rough stuff.  On the roads, conditions range from bare pavement to black ice to thick rough ice.  The Nihola remains a good tool for hauling kids to and from birthdays, school and daycare.  I haven't put on any winter tires yet, but the tires are a bit soft and do the job well.

Oslo seems to have a growing cargo bike movement. But Norwegians as a rule are very serious about being hardcore, transforming stretchpants into every day attire, and when it comes to cargo bikes, they prefer two wheels. I assume to be sporty. I did see one of those turn-tilting trikes (Butchers & Bicycles) around. I don't understand it myself, but I presume because corning fast is very important. Nice bikes I'm sure, I'd buy a Bullitt myself except before that I'd get some other bikes. Priorities...

I think all the cargo cycles I've seen are electrified, sensible on hills of course, and important if you are to achieve high cornering speeds up hill.  However all the electric two-wheelers are vulnerable when traction fails, even for a short distance.  Trikes, including those with electric motors, suffer a much smaller penalty when they come into a situation where the drive wheel spins.  Its also pretty harmless to corner at a speed where the steering tires slide.  Icy ridges are amusing, not scary.  I think people in Oslo under-valuing this.  (Edit in spring: cargo bikes were invisible all winter.)

So I can screw around on icy ridges and steep hills with no winter tires.  I can use 100% of the available traction, no need for a safety margin (except for braking distance).  The winter tire (the back tire) can wait for winter to really arrive, and I can still get all the way to the center of Oslo safely.  Those two 20" winter front tires probably will go unused for the 3rd Oslo winter.  Long live the trikes.

(There is still the trouble that Niholas have poor front brakes, so I can't really say they are a obvious choice in Oslo.)

Friday, August 14, 2015

Small tour with 7 & 4 year olds

A person might wonder how long a Nihola can be used for child-hauling.  In part, this has a lot to do with what other options you have.  Here in Oslo, its pretty well impossible to take the kids on a bike tour because of the abundance of hills to climb, in addition to the rather hazardous state of the bike path network.  So, I had the day off work, two kids, very nice weather... and I wanted to buy some Lego plates from a toy store in Røa, 12km away by car.  Needed those Lego plates, and who really wants to drive to get them anyway?

So the main problem is what to do with a 20" wheel bike, a running/balance bike and two kids (7+4) when the hills get steep, or they otherwise want a rest.

One self-propelled kid

Zero self-propelled kids

Not entirely pleasant, but it works.  This is what makes a ~24km round trip on hills work.

Wednesday, May 6, 2015

Shimano BR-IM80-F, BR-IM50-F, BR-IM45-F

Its been most of a year since I wrote anything.  Life goes on.  I've been doing lots of commuting on an official Danish-name-sticker bike, straight bar, fenders, cargo rack, lights, gear hub, etc.  Its got a Shimano roller brake in front, attached to a dynamo hub.  This is lovely except that it isn't much good for stopping.

I noticed some years ago that more impressive-looking roller brakes were available.  My bike had a BR-IM50-F.  I wanted one such as a BR-IM80-F, but I could find none for sale.  None online, none in bike shops.  Generally they were not even available on bikes in Denmark or Norway.  I had bike shop owners argue with me about whether one would even fit my bike.  I had people say it was all the same, no point in switching.  I had noticed that sold lots of them, but they didn't really do small part orders.  Then, I actually went to Amsterdam.  I even had to go to the workcycles shop twice to get through to a mechanic without too much waiting.

So, now I had a BR-IM80-F in my hands.  In my carry-on at the airport even, by accident.  That got a raised eyebrow.

Anyway once home, I performed the swap.  Possibly the easiest part swap this side of a pedal with greased threads.  Take off the wheel, apply a 17mm (I think) deep socket, change the shift cable to a new-style cable (had one laying around), done.

So did it improve braking performance?  No.  Not in any noticeable way.

Here I have laid out a BR-IM50-F, BR-IM80-F and BR-IM45-F with their business sides exposed.  The two newer ones appear to be identical except for the cooling surface, and the older one is just damned dirty, also possibly a little worn.

So hopefully by writing this down in the sight of a search engine, others can be informed.  These roller brakes are generally not so useful on hills, and getting a "bigger" one doesn't help.  I have another bike which, like the one I just modified, has only the potential to mount hub brakes.  On that bike I mounted a Sturmey Archer XL-FD (a 9cm drum brake hub), which fits perfectly, brake arm and all, and its stronger though perhaps a little more temperamental.  (Niholas use the 7cm version of that drum brake.)  Going the Sturmey Archer route does appear to require building your own wheel though, not a big supply of pre-fab wheels built on drum brake hubs.