This post - June 25th to 26th
~ 70 km, 1000 m - biked with the whole family
Follows: Norway Part IV - Jotunheimen National Park and Valdresflye Plateaux
See also: Our European Bike tour - people and gear
I've started to develop some very itchy hives on my hands... it's not clear to me if I've become allergic to our sunscreen, or if it was the fibreglass, but I took some antihistamines and stopped wearing sunscreen as a precaution. I picked up some cheap cotton gloves and rigged up a neck flap for my helmet instead.
The climb up from Fagernes was gruelling in the hot sun, but we treated ourselves to a whole watermelon and tub of ice cream at the top. Maybe it wasn't so bad that the grocery stores in the valley were closed yesterday. Then we found ourselves on another gorgeous high plateaux, where we picked up the Mjølkevegen cycling route toward Gol. It's worth mentioning how amazing the Norwegian drivers are when it comes to cyclists. You could have a loaded semi behind you as you slowly crawl up a winding hill, and the driver will wait patiently a respectable distance back since there isn't enough room to safely pass. Only once there is a spot for you to pull over, or a clear view ahead, will the driver pass you with a friendly smile and wave. It suppose helps that we're mostly on back roads - everybody who is in a rush takes the tunnels under the mountains, not the old roads over them - but the drivers are all still very friendly and professional.
On the plateaux we found great biking for F as well, since the roads were mostly flat or gently rolling, and there was little traffic. We camped only one night on the plateaux, but Fenya had a great time biking where she wanted on the little side trails while I ran after her. Nova entertained everybody by making a poop so big that the potty couldn't contain it and the pile reached her bum. The next morning the mosquitos were horrendous, which inspired our fastest camp teardown yet - 1.5 hours (previous best time was 2 hours). Once we got biking it was fine, though. Fenya did a lot of biking on the plateaux.
The descent to Gol was a set of steep mountain switchbacks, and on a major road. I have overheated my brakes in the past, while towing F in the chariot bike touring on the Gulf Islands where the road was too windy to go quickly. Let me tell you - it was pretty scary. First you realize you can't slow down anymore, then you smell the burning and know why - but you are still on the hill. Anyway, to avoid brake overheating I usually do descents pretty fast. This may seem counterintuitive, but going slowly really is the easiest way to overheat your brakes, and I've got to dissipate the energy for > 400 lbs worth of stuff - the more of that energy that goes into the wind the better. Line and I actually had a long discussion about it - specifically whether or not it did actually reduce the chances of brake overheating to go fast - and I eventually googled these proceedings (PDF warning) from the tent, which confirmed my suspicions. They put a bicycle disk brake setup in a small wind tunnel and measured the power dissipation as well as brake temperature, in addition to some numerical modelling. Looking at their results you can see that cooling is more-or-less linear (if you go 3x as fast, the air helps carry heat away from the rotor 3x as fast - this makes sense since the rotor is mostly cooled by the air, not conductive cooling to the rest of the bike or radiative cooling). We know that the heat you need to dissipate also scales linearly with speed (if you are loosing elevation 3x as fast that's 3x as much energy you've got to be shedding somewhere). So, overall for a given descent grade, your brakes would be at the same equilibrium temperature, regardless of speed, if it wasn't for aerodynamic resistance. But aerodynamic resistance (drag from the air) increases with velocity (google it!), so the faster you go the more energy is soaked up by the air and the cooler your brakes. This makes sense since in the limiting case (you don't brake at all) you just reach terminal velocity and are kept at that speed by the wind alone. Also, if you are just slowing down for corners, your brakes may never even reach equilibrium temperature (an alternative is to stop and let your brakes cool, possibly assisting with water, which is a strategy we also employed).
Anyway... that's why I was going really fast (with both kids - F sitting on the back and N in the chariot) when I got the first flat tire of the trip. Full speed, on some busy narrow mountain switchbacks. At first the bike started to kick back and forth. I yelled to F that this was not a good time to rock back and forth and she should keep still. She retorted that the bike was doing it, not her... when the bike started to fishtail and the rear end (and chariot) started trying to overtake the front I knew she was right - the rear tire was totally flat. I told her to hang on tight. The driver behind me (god bless Norwegian drivers in general, and them specifically) noticed something was up and gave me plenty of space. Fortunately I have a reasonable amount of experience biking around on ice with a studded tire only on the front... I was able to slow down gradually and steer/lean to keep the mass of the bicycle behind the front tire and stay rubber-side down. It was the scariest moment of the trip by far, but soon enough I was stopped on the side of the road, had unloaded the stuff, and was changing out the tube.
There was surprisingly little damage to the tire/rim, but the tube was split down the middle and looked like it had been cut with a knife. In a variety of other locations it also looked like it had been cut, but not all the way through. I initially suspected it was a tube manufacturing defect, but (later in the trip, after a few more flats) figured out it was actually a rim tape defect. Under the weight of the bicycle the rim tape squirmed around and folded on itself, creating a small ridges that would slowly slice their way through the tube. After figuring this out I replaced the thin plastic rim tape on both wheels with heavy cloth tape (Velox - the best stuff) and the problem disappeared.
At the campground in Gol we had a buffet of pre-cooked grocery store food. Fish cakes are scary cheap in this country. From Gol we saved ourselves kilometres of valley biking along busy roads by taking the train to Haugastøl and the next leg of our journey. That train is really set up for cyclists, with a separate car just for bikes - complete with an attendant that you just pass your bicycle on up to.
Next: Bike touring in Norway part VI: Rallarvegen
Interesting about the rim tape! We a potentially similar issue on our trip to Greece, with a new Haul a Day as well. I pumped up the tires and pretty much immediately had a flat tire, and then shortly after replacing the tube had another "explosive" flat tire. Both of these flats occurred while the bike was standing. The first was very close to the valve, and the other ripped a slit in the tube. Both were abnormal in that they seemed to not result from a sharp object piercing the tube. I resolved to use the tires at a lower pressure, assuming it had something to do with the spokes or rim tape. I wasn't able to find an obvious cause though - tape coming off or holes in it. It's plausible that I missed some folds in the rim tape though. I had better replace it, to be safe.
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