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Miscellaneous bicycle wisdom

The bicycle stuff that you might not find elsewhere on the net.
riding in mountains steel myth calibrating the calculator punctures repairs packing for a flight
clipless weight myth digital maps 26" vs 700C stiff sole myth

Why is riding in mountains slower than on flat ground?

It may be obvious to most of you, but it wasn't to me. After all, there are always two sides of a mountain. While you are slower going up, you are much faster going down. The average should be equal to riding on flat. Hmmm, this calls to some math.

Let's say we are riding up and down a symetrical hill of road length 2S. We cycle up with average velocity v1 and go down with average velocity v2. The up and down parts have equal length S. What is our overall average speed v?

The enticing answer is (v1+v2)/2, but, as you may presume, the world is not that simple. Combining the formulae: v1=S/t1, v2=S/t2, t=t1+t2, v=2S/t, we have: v=2S/t=2S/(t1+t2)=2S/(S/v1+S/v2)=2/(v2/v1v2+v1/v1v2)=2v1v2/(v1+v2).

So the answer is: v=2v1v2/(v1+v2) and it's independant on length S. For example, if you climb with 10 km/h and descend with neck breaking 70 km/h, your overall speed is not 40 km/h as you might have wished, but only 17,5 km/h, as you will find out looking incredibly at your computer at the end of the downhill. The only reasonable way to increase the overall speed is to climb faster. If you climbed just 50% faster, with 15 km/h instead of 10 km/h, then the overall speed increases to respectable 24,7 km/h. If, instead of climbing half faster you descended twice faster, i.e. 100% faster, at the world record breaking 140 km/h, your overall speed would still be miserable 18,7 km/h.
The point of this story: instead of risking your neck at speeds where there is no margin of error, beter have a lighter pack which will enable you to climb a little faster.

We'll make some more use of mathemathics. We first express climbing speed as a percentage f of descending speed, v1=f v2. The average overall speed is then v=v2 2f/(1+f), as compared to intuitive (and wrong) average speed (v1+v2)/2=v2(1+f)/2. The difference, together with the ratios of climbing/descending speeds from the above example (10/70, 15/70 and 10/140), is indicated in the graph.

Steel frame is softer than aluminium one?

Modulus of elasticty, brittleness, strength, stiffness, elastic limit, are standard terms of the theory of elasticity. They are, however, more often than not misinterpreted when used in "technical" debates about bicycles. Many times they are abused as a "scientific evidence" of some natural feel like: "steel is softer then aluminium". Softness, by the way, is not a standard quantity in the theory of elasticity. It can be interpreted as a reciprocal quantity to stiffness. The measure of stiffnes of a material is its modulus of elasticity, or Young modulus, E, which is defined as a ratio of stress vs. strain. In that sense the common bicycle myth that steel is softer than aluminium is a total nonsense. It is not true that steel has relatively low modulus of elasticity, i.e. is a "soft material". In fact its modulus of elasticity (Young modulus) is the highest of all commonly used engineering materials: it is 210 GPa, which is 3 times greater than aluminium (with 69 GPa), 1.75 times greater than titanium (120 Gpa) and at least 1.4 greater than carbon fiber (150 GPa). You can find these figures in a table on Wikipedia page: http://en.wikipedia.org/wiki/Young%27s_modulus. Steel is the stiffest material to make a frame of, unless you are considering a tungsten or a diamond one.

It is perfectly OK with me if someone feels a steel frame to be softer than aluminium. But please don't try to prove this by misinterpretation of some half-understood theory.

P.S. I am not a "steel-hater". Steel is the best engineering material for most applications because of its strength, stiffness, ductility, fatigue strength, weldability and price - but certainly not because of it's softness.

Calibrating the bicycle calculator

I noticed that my bicycle computer is rarely as accurate as are road markers - usualy it shows few percents more. I was pretty sure this is caused by a wavy bicycle path - until I did some calculations. Let's look at this more closely.

Question: What distance will be recorded on a bicycle computer on a straight, flat 1 km path if you cycled in a zig-zag fashion, swerving away from the middle line for 10%, lets say a=1 m every L=10 m (i.e. 1 m to the left after 10 m, 0 m after 20 m, 1 m to the right after 30 m, etc)?

Lets denote a pecent of off-center deviation as f=a/L. Then, instead of every straight L meters you are doing L1=SQRT(L^2+a^2)=SQRT(L^2+f^2L^2)=L*SQRT(1+f^2) meters. Your path is longer for k=L1/L=SQRT(1+f^2) (in percents). So, for f=10% off-center deviation your path is longer for k=0.499 %. In 1 straight km you are doing 1.00499 km or 4.99 meters more.

The point of this is to show that inaccuracy of the calculator due to the oscilating path of the wheel is negligible (0.5 % for off-center deviations as high as 10%). Manual instructions for calculator set-up are typically innacurate up to +3%.

All you never wanted to know about punctures

To unacquainted rider punctures come as incomprehensible random events which generally follow Murphy law of happening at the worst possible moment. We will however try to put a trifle of rationality in it, hoping at the same time that vicious Puncture God doesn't take this as a heresy.

First of all - as heretical as it may sound - every puncture has its cause. This is the founding axiom of puncture science and the most important concept for puncture-free experience. If you have a puncture for which you don't know the cause, you will have lots more of them - and rightly so, since you didn't make an effort to understand it.
The causes of punctures can be separated into two types:
  1. external puncture is caused by an external object first protruding through the tyre and then puncturing the tube.
  2. internal puncture is one that is not external.
Within these types there are variations. We further subdivide punctures as to get a list of every possible puncture cause known to man, woman or child. The following causes are ordered from most likely to least likely cause, based on my experience.
  1. external punctures
    1. external object embeds into the tyre and punctures the tube after several wheel revolutions.
    2. external object protrudes through the badly worn tyre, punctures the tube and falls off.
    3. external object is pushed through tyre and the tube deliberately.
    4. external object protrudes through tyre and the tube within one wheel revolution.
  2. internal punctures
    1. "pinch flat" or "snake bites" when a tyre presses against the tube, mostly when hitting a rock or a pothole.
    2. tube punctures near the valve facing the rim.
    3. tube protrudes through the valve hole and blows out.
    4. tube rubs against an object caught between the tube and the tyre (eg. piece of sand, shreds of rim tape, etc.).
    5. tube punctured with a tool when installing it on a rim
    6. tube protrudes through the fault in the tyre and blows out.
    7. tube is pinched between the tyre bead and the rim and blows out or punctures.
    8. deliberately deflated tube (this is not a puncture, but looks like one).
    9. tube patch peels off
    10. tube patch cracked
    11. spoke is too long and punctures the tube from the inside
    12. tube rubs against a fault inside the rim, or against the rim tape.
    13. tube rubs against a fault on the inside of the tyre.
More often then not you can tell if the puncure is external or internal, or even its subcategory, by a little forensic study. Use the following procedure:
  1. Before removing the tube from the wheel mark one matching point on both the tyre and the tube. This step is not necessary if you've installed the tyre and the tube correctly (see points 13, 14 and 15 below for installation).
  2. Before removing the tyre look if there are pieces of sand, etc. inside it.
  3. Look if the puncture is at the inside of the tube (the surface facing the rim). If it is, it's an internal puncture.
  4. Examine the rim and/or the tyre at the point that matches with the point of the puncture in the tube. You are likely to find the cause of the puncture at this point. If you don't find it there, go all around the tyre and/or the rim looking for one.
  5. Some punctures (a.2, a.3, b.1, b.2, b.3, b.6, b.7) have no physical evidence of the cause, but some can be identified by the position or appearance.
  6. Type a.2 punctures usualy occur on a very worn tyre thread (eg. so that tyre fabric beneath is showing or if there are a lot of cuts and cracks in the thread). The thread is so thin that the item that punctured the tube (a sharp piece of stone, glass) will not embed in the tyre and will fall off. Changing the tyre is the best remedy.
  7. Snake bites (b.1) are often in a form of double holes about 4 mm apart.
  8. b.2 and b.3 type punctures are at the base of the valve. b.2 punctures are frequently caused by high-pressured tube pressing against the nipple head on single walled rims. (See the solution below).
  9. Some punctures (b.2, b.3, b.6, maybe b.7) can happen when the bike is not in use (e.g. overnight).
  10. A minuscule, slow leaking puncture on the side of the tube is representative of a needle pinch (a.3)
  11. Blowout type of punctures (b.2, b.3, b.6) deflate the tube immediately. b.3 and b.8 leave large holes.
  12. External punctures of type a.1 are often slow leaking.
  13. Rubbing-type punctures (b.4, b.12, b.13) are also slow leaking, at least in the first stage when the tube develops small sracks in the rubbing area. Eventualy these cracks join into a bigger hole.
  14. If you can't identify the cause, record the circumstances for further analysis. If a puncture is particularly mysterious, send the details to me, I am collecting such data.
The good news about the punctures is that most of the type b punctures are avoidable. With little care, most of the type (a.1) punctures are avoidable too. Replacing the excessively worn tyre usualy gets rid of the (a.2) punctures. So only with the type (a.3) are we in the mercy of Puncture God, which in this case frequently takes the form of a common man. My advice to puncture-free experience is the following:
  1. Pump your tyres to high pressure. Check and keep the pressure high at all times. Recommended pressure on the tyre sidewall is high enough. If pressure range is indicated, go closer to the higher value. I don't believe in benefits of reduced pressure (e.g. higher traction, softer ride).
  2. Always find out the cause of the puncture and remove it.
  3. Check both tyres regularly for embedded bits of glass, wire, etc. Do this before or after every ride at home and at the start/end of the day on a tour. I always keep a safety pin on my jersey to pick out the bits from the tyre.
  4. Do the above check immediately if you ride through pile of glass, etc.
  5. Do the above check immediately if you hear the sound comming from the wheel at each wheel revolution.
  6. Do the above check always after a puncture unless you are absolutely certain it's an internal puncture.
  7. Don't use any tapes between the tyre and the tube - at least not as a permanent solution.
  8. Use rim tape.
  9. Change the tyre when its sidewall is cracked. As a temporary solution make a tyre boot (duck-tape worked for me).
  10. Change the tyre when its thread wears so much that the tyre fabric beneath is showing. As a temporary measure put a piece of duct tape over these parts.
  11. Few things are important when patching tubes: clean the tube with sand paper before applying rubber cement; let the cement dry before applying the patch!!; press on the patch for 3 minutes; remove the plastic cover from the patch after few hours.
  12. Inflate the tube slightly before puting it inside the tyre.
  13. As a protection against b.2 and b.3 punctures, cut a patch of an old tube and slide it down the valve, so that it covers the valve base (about 2 cm of tube left and right from the valve). Cut a notch on one side of this patch, let's say on the left side.
  14. Most tyres are marked by the manufacturer and brand names only on one side. Install your tyre so that the valve hole is at the middle of this mark and that the mark is on the QR side of the wheel (or on the opposite side, according to the drive direction marked on the tyre).
  15. Put the tube inside the tyre so that the notch mentioned in #12 is to the left when you are facing the tyre mark mentioned in #13. This fixes the relative positions of the rim/tube/tyre combination and hepls in finding the cause of the puncture.
  16. Refrain from using any tools for mounting the tyre on the rim. If this can't be done, it's time to think about different tyre.
  17. With the tube partially inflated go around the tyre and check that the tyre bead doesn't pinch the tube against the rim.

Repair tips

Some of us like to have our bikes in perfect order, no ticking, skipping, squealing. Here are some things that I learned over the years, by experience or from the net.
  1. Tyre wear at one spot can be the result of a bent or untrue rim. When the bent part of the rim hits the brakes, the part of the tyre which is at the contact with the ground at that instant skips. As this is always the same point of the tyre (unless you are rotating it regularly on the rim) it will eventually wear out and blow. The thing happened to me in Kyrgyzstan, the explanation is Sheldon Brown's.
  2. Broken brake cable usualy doesn't happen unexpectedly. The individual wires in the cable break first with a warning sound that can be heard, and which usualy happens after a sudden squeeze of the brakes. Check out the cables when such warning comes.
  3. When breaking the chain the pin should not be extruded completely. If this happens however, you can hammer it back by holding it with some narrow tool. Needle plies are the best, but a piece of wood with the hole in it might do as well. The stiff link is loosed simply by bending the side plates of the adjacent links.
  4. If you feel a bump every wheel revolution and the rim is true, it's most probably a tyre bead that is unevenly engaged in the rim or is even pinching the tube. It may also be due to the damaged tyre sidewall.
  5. If the chain stucks in the deraileur seemingly unrelated to the revolution of the cranks, check out the side plates of the chain - they may be broken.
  6. Ticking in the handlebar most likely comes from a stem/stearer connection. Grease every part of this connection, including bolts, and tighten.
  7. Ticking in seatpost. Check if your seat tube has a metal shim between the tube and the seatpost. Grease all the surfaces that come into contact (shim/seatpost, shim/seat tube).
  8. Squeal in the rear derailleur during shifting. Oil the axis of pulley wheels.
  9. Ticking in the crankset area. Could be number of things. Check out the simple things first: oil the pedals; tigten cranck bolts; see if cranck is not hitting the front derailleur cable; make sure the sound is not coming from your shoes.
  10. Cracking sounds unrelated with pedal or wheel revolution. When the spokes are too loose they can slip at the points where they cross each other. Happens both when seated or not, holding handlebar or not. Can't happen on radially laced wheels.
  11. Squeel when turning the handlebar. Break/shifting cables are fretting in cable stops - oil the cable stops. Cables may fret one against other - tie them with tape.
  12. Rattling when going over rough surface. It can be caused by anything that is attached to the bike (bags, lock, pump, water bottle, ...) or anything loose in the bags. If it happens on "naked" bike: check the headset for looseness; check that the shifting or braking cables are not hitting each other.
  13. Unusual sounds. Deal with them by eliminatig possible causes one at the time. Is the sound present only while turning pedals? Only while seated? Only while riding a bike (i.e. not when turning the wheel by hand)? Only when holding the handlebar? Only when peddaling forward? Only with bags attached? With each crank revolution? With each wheel revolution? Sounds may not necesarily come from the bicycle - check the panniers, racks, shoes, things in your pockets.
  14. Derraileur adjustment is most easily done when the bike is turned upside down. Just check visually that the pulley wheel runs in the middle of the cog.
  15. Rim wear can be drastically reduced by using quality brake pads. The sand particles will embed quickly in most of the ordinary pads. This will act as sand paper, chipping off bit of rim material, which will in turn embed into the pad rubber, resulting in even more wear. Use best pads you can get: Kool-Stop pads are the best.
  16. Brake squeal is reduced by proper toe-in of the brake pads and sand-papering the rim.
  17. Cleaning the chain on the road. Find a piece of rug by the side of the road. Start by cleaning the pulley wheels. Then clean the front chainrings. Then start cleaning each chain link: shift the chain to the big front ring and clean the links as they go around the front ring teeth. The chain is not flexing there so you can clean it using one hand only. (This is one operation where I would not agree with Jobst Brandt and prefer to do it with the bike upside-down.) Then oil the chain: dip the end of a toothpick into oil and put one drop of oil in the roller/sideplate gap of each chain link. Wipe excessive oil.
  18. Carbon forks have a bad reputation for touring. I don't know why. I cover mine with electric tape or with bubble wrap as a protection from scratches. So far, it worked rather good.
  19. Low pressure is bad. Among other things it can result in cracked tyre sidewall.
  20. Tips about reducing probability of punctures are given above.
  21. If you don't have the appropriate tool try to improvise. Imagine what the procedure would be like if you had the tool. Think about the principle of that tool. You may find a simple substitute that has the same principle.

The clipless myth

To start right from the middle: I don't like clipless system. The fact that I broke my arm in a low-speed fall because I failed to unclip may have to do something with this position, but it's not the only reason.

Efficiency. I heard claims that clipless system greatly improves cycling efficiency - there were numbers as high as 20%. I was skeptical, so I did my own measurements in a real-world road-cycling circumstances. I was more then disappointed. I measured average speed on two loops of fixed length (60 km and 85 km) with and without clipless system, all the other factors being the same (i.e. the same bike and clothes). The average difference (averaged over 2 and 6 rides) in average speed was less then 0,5%. On one of the sections it was in favor of clipless system, on the other section it was in favor of plain pedals and shoes. The difference was smaller than the difference in individual rides within one system. Thus, my measurements doesn't show any statistically significant advantage of any of the system.

Safety. All clipless advocates confess that falling off is part of the learning process. What they do not tell is that you will damage your bike in that process and that an injury is a real possibility. My quick search through the net revealed only 4 voluntarily reported injuries caused by clipless system. When talking to the people after my accident I got the impression that they are much more common - even my physiotherapist had broken the arm. There seems to be a high degree of self-censorship, self-guilt (e.g. "it's MY fault that I couldn't unclip") and the dread of being scoffed at by the "pro"'s.

The feel. Nothing is life is all bad or all good. I liked some aspects of clipless system, especially "the feel" and "the look". I suspect that these are the main reasons for its popularity. As for me, I am not going to risk another 2 or 3 months of rehabilitation, just to stay within the "cycling mainstream". The proper cycling technique and a positive feel that your foot is not slipping on a pedal can be trained and learned, without any disadvantages of restrained feet.

Every so often I read and hear people comlaining about some additional aspects related to the clipless system: pain in feet, ankles or knees due to restricted movement, water seeping in through the holes in the soles, cold sensation due to heat transfer through the cleats, sorenes in the feet due to pressure in the cleat area, awkward walking, the need for a second footware on a tour. The general consensus, however, is that the benefits of the clipless system override any disadvantages. But what exactly are these benefits? Have they ever been proven in an authoritative research? I know of only one reasearch regarding this issue (link here) and according to it the benefits are so slim, that I can only conclude that clipless system is just another market gimmic with huge turnover, exploiting people's urge to copy their idols.

Does weight matter?

The basic phisycal equations for the forces on a bicycle rider show that weight has almost proportional effect on the power required for cycling. That is: the required power is greater by the same percent as the percent weight increase of the rider+bike+luggage combination. Interestingly, this fact is the basis for the conclusion that weight doesn't really matter that much: if I weigh 75 kg, my bike 15 kg and my touring luggage 20 kg (a total of 110 kg), then even if I manage to reduce my luggage by 50% (10 kg less - a very difficult task indeed), it would still mean just 9% gain in power. Why then bother with it at all? Well, there are several reasons why light weight might be prefered. I can think of the following:

- The fatigue life.
- The simplicity.
- The effort.
- The lifestyle.
- The elegance.

The fatigue life. Weight has large influence on the material of the bike and other equipment. Metals fatigue roughly with 3rd power of stress - and stress is proportional to weight. 5% decrease in weight, for example, results in 16 % increase in fatigue life of the equipment. 20 % decrease in weight = 73 % increase in fatigue life. By reducing the weight one then considerably reduces the likelyhood of equipment breakage. This is the primary benefit and the one that made me go the light way. The stories about cracked rims and broken racks are almost without exception told by 4-panniered heavy-duty tourers. By the way, it seems logical that the weight has similar effect to the body fatigue. The body can heal, of course, but it requires energy to do so.
The simplicity. Simplicity is freedom. And freedom means simplicity. They are the same thing. With each thing less you are more carefree. I remember one occasion when I bought a wooden carving in Zimbabwe. From the moment when I purchased an, otherwise outstanding sculpure, I was in a constant worry. How will I transport it on a bike? How will I protect it from the rain? What if they stole it from my tent? How will I take it on the plane trip back home? Will they accept it as hand luggage? And if not how will I package it? These worries made for some miserable nights until the return trip and a 2 kg statue on the the rear rack resulted in a couple of broken spokes (on otherwise already weakened back wheel).
The effort. As said above, you need more power to cycle with heavier setup. 9 % more power may seem negligible with respect to the comfort that you're supposedly throwing away. It is a matter of preference: is it important to you to make 10 or 15 km more each day? Or you can cycle the same distance, feel much less tired and have more time in enjoing your rest. Far more effort (in terms of percentage) is saved when you have to carry or push your bike: in this situation your body weight doesn't enter the equation and the effort is proportional just to luggage (and bike) weight. In fact, body weight should not have the same impact as luggage and bike weight. Heavier people are usualy stronger and can produce more power. It is somewhat misleading or "unfair" to compare lugguage weight of differently strong people. But if we take out the body weight from the above equations, then reducing the luggage weight by 50% makes a 29% gain in power, instead of 9%. The real percent gain is somewhere in between.
The lifestyle Cyclists like to think of themselves as ecologicaly superior to motorists. By the same line of reasoning lightweight touring is superior to loaded touring. A couple of years involved in reducing the luggage weight had changed my view on many things, unrelated to cycling. I became aware of many redundancies in our everyday procedures and behaviour.
The elegance Obviously this is a subjective thing, but a light setup on an elegant bike, preferably set in some spectacular natural environment, is a real pleasure to my eye.

Digital maps

Do you like to hang on at the end of the day, with a map spread in front of you, tracing on it the route you've just cycled and contemplating the part that lies before you? It's one of the best feelings isn't it? Well, that's just about all there is good about a map! From a point of view of a light-weight unsentimental cycling warrior - a map is a waste of space. The first urge after this realisation is to cut the map, leaving only the part where you wish to travel. But, there is a much more thorough approach: digitizing a map.

The idea behind it is rather simple. You can view a map as a colection of points of interest and connections between them. This info can be stored in "digital" form, using alphanumeric characters, in much smaller space then the map itself. The point of it is to store all the information on a small plastified card which is accessible "on the fly", say from a cycling jersey's pocket, without any unfolding, searching, folding and storing. Larger itineraries can be stored on several cards with only one used at any time. Such digital info may not be visualy as clear as a map, but all the info will be there. In fact your card will have much more info then a map, since there will usually be enough space on the card to store info on water points, food, accomodation, camping spots, altitute, passes, check points, usefull phrases, important telephone numbers, repair tips, ...

There are many ways to make a digitization. I will explain how I do it currently by an example of digitizing Himalaya itineraries in Pakistan, India, China and Nepal.
  1. Let me start with some definitions. A crossroad is a point where more then two roads meet. A point of interest is either a crossroad or any other feature (e.g. a town, a camping spot) that is on the road and is not a crossroad. A connection is a part of the road between two points of interests, A and B, with the condition that it has no other crossroads on it. Any network of roads can be described as a collection of connections.
  2. The first step is to draw a diagram of the selected routes, showing all possible connections and major points of interests. In the diagram the points of interests are presented as numbers, 0,1,2,...
  3. We represent a point of interest as a name and its number immediately following it. The points of interests are, for example: Islamabad0, Kashi1, Ali2, turn off to north4, Saga3, etc. The points of interests are fully defined by their numbers, the name is not necessary and may be used for clarity.
  4. We represent a connection by its ending points of interest, separated by a dash: Islamabad0-Kashi1, Ali2-Saga3, Ali2-turn off to north4. The connection is fully defined by ending points' numbers, the name may be used for clarity: 0-1, 2-Saga3, Ali2-4, Saga3-t.o.north4.
  5. We first list all the possible connections, using their numbers and names when they are introduced for the first time. As an additional information we add distances of the connections in parenhteses. All the distances will be in kilometers. Example: Islamabad0-Kashi1(1182); 1-Ali2(1323); 2-Saga3(752); 3-t.o.north4(62); 2-4(978). 3-HWY318t.o.5(167); 5-Kathmandu7(231); 5-Tingri.t.o.6(73); 6-EBC8(67). 6-Shegar.t.o.9(48); 8-9(96); 9-Lhatze10(133). 4-10(257);
  6. In the second part we add detailed information about the individual connections. We can do that for all of the connections or just the selected ones. The detailed info for one connection looks like this:
    1-2: #315: 200/TL:Yarkand. 65/Yecheng,TR. #219: 25,1500/armyB. 31,1840/V. 15/F. 41,3150. 14/F. 5/armyB. 30,3000/Kudi(426). 18,3280/armyB,F. 27,4300/RRS. 11,s217,4825. 24,3675/Mazar,TL. 13/F. 35,3860/RRS. 3/F. 17,s309,4795. 15/rrs. 16/RRS. 24,3560/Xaidulla(629). 41,3700/t.o.KKH. 20,s425,4180/Kosbel. 12,3800/Kangxiwar,RRS. 50,4000/Dahongliutan. 25,4500/RRS. 22,s534,5080,Aksai Chin. 9,4900/tent,f. 34,4735/Tianshuihai. 93,s670,5125. 2,5005/Tielong. 16,s688,5185. 12,5000,Lungmo tso. 15,s715,5090/NP. 5,5140. 10,5090/Sumxi. 10,s740,5400/!. 88,4275/Domar(1093). 17,s845,4520. 8,4300/LP. 40,4170/house,f. 2,4150/Nyak tso. 23/H,boats,fish. 15,4150/Rutok Xian,TR. 27,4240/tent. 2,4250/houses. 3,4250/t.o.Rabang. 2,4250/petrogl. 53,s1020,4715/Lame. 32,4350/cp. 6,4200/Ali2.
    The meaning of it is as follows:
    1-2:                   info on connection 1-2 (Kashi-Ali) follows.
    #315:                  road number 315.
    200/TL:Yarkand.        after 200 km turn left for Yarkand.
    65/Yecheng,TR.         65 km to Yecheng, after that turn right.
    #219:                  road number 219.
    25,1500/armyB.         25 km to army base, it's at the altitude 1500 m.
    31,1840/V.             31 km to a village, its altitude is 1840 m.
    15/F.                  15 km to guaranteed food.
    41,3150.               after 41 km there is a pass, at 3150 m a.s.l. Passes are represented in bold.
    14/f.                  after 14 km there is probable food
    5/armyB.               5 km to army base.
    30,3000/Kudi(426),CP.  30 km to Kudi. Kudi is at 3000 m altitude and 426 km from the starting point of this connection (e.g. from Kashi).
                           There is also a Checkpoint.
    18,3280/armyB,F.       18 km to army base at altitude 3280 m and guaranteed food.
    27,4300/RRS.           27 km to Road Repair Station, at 4300 m.
    11,s217,4825.          11 km to a pass at 4825 a.s.l. There is a stone kilometer marker "217" at the top.
    24,3675/Mazar,TL.      24 km to Mazar, at 3675 m. Mazar is underlined, which means you can get everything there (water, food, accomodation).
                           After Mazar turn left.
    The extent of the detail for individual connections can be different. For difficult routes like the above one, you need detail on food points and altitude. For an easy connection only a connection length may be needed, all other info may not be necessary or might be found while cycling the road itself. The info on all of the usual connections in Hymalaya region can be stored on a card with dimensions 13x8 cm - for a person with good eyesight, that is. The front page of this card would look like this:
    The opposite side would have info on connections in India and Nepal (between Lahore, Amritsar, Srinagar, Leh, Delhi and Kathmandu). There would be enough space left on that side for personal info and few grace-saving chinese phrases.

26" vs 700c

The question which wheel is more efficient - 26" or 700C - has already attracted much intellectual energy, probably enough to power a small city for a year. I hope that my little addition to this wasteful practice won't turn you off, especially as you know that up to now the answer to this crucial question was still ambiguous.

The first stumble-stone is in the question itself. There are a lot of different 26" wheels, as much as 700C's, and certainly you will find a pair to show that either 26" or 700c is the correct answer. We can answer the question unambiguously only if we make some further assumptions - and restrictions. In the following we will consider only the difference which comes from the size - all other things being equal. That means both wheels have the same hubs, spokes (apart from length), rims with tyres (apart from different diameter) and tyre pressure. Both wheels also carry the same weight. Secondly, we consider the efficiency in the following sense: a rider is coasting on a bicycle on flat hard surface (asphalt) with no energy input, so that the bicycle will, from the initial velocity, come to a stop due to various resistances, the wheel which stops later is more efficient.

The resistances are: resistance from tyres rolling on ground (also known as rolling resistance), air resistance, and resistance in the hub bearings.

Let's concentrate first on rolling resistance (RR). The cause of the RR is the flexion (deformation) of the tyre. The bigger the flex, the bigger the RR. Both 26" and 700c have the same contact patch A. I conclude this simply because Ap=W and since both tyres have same pressure p and bear the same weight W, the area is also the same. Since the width of the tyre w is the same then from A=wc, c (the length of the contact patch) must be the same for both wheels. But, 26" flexes more. To see this, look at the segment of a circle with a chord of length c. You can see it as flattened part of the tyre in contact with the ground. The area of this segment is equivalent to the amount of the flex. Given the fixed chord length c, bigger circle has smaller segment - or smaller flex. And opposite, smaller circle (26") has bigger area=flex. In other words, rolling resistance of 26" is greater.

The formulas at the Wikipedia page can be used to calculate segment area (equivalent of RR) for any combination of W,w,p,R. I did this for a typical touring situation: W=50 kg, w=35 mm, p=4 kg/cm2 and both wheels (diameters ISO 559 and 622) and I get 10% bigger RR for the 26" (ISO 559). Surprisingly, the result (1.10034) is practically the same as the ratio of wheel diameters (with tyres on): (622+2w)/(559+2w)=1.10016.
BTW, using the same equations we can prove the often stated argument that wider tyres of same diameter and pressure have smaller RR then thinner ones.

Now, let's look at the resistance in the bearings. It is also in favor of 700c wheels, since on a fixed road distance bigger wheels rotate less times. The bearing resistance of a 26" wheel is then bigger for the factor depending on wheel diameters (with tyres on) - the same factor as above: (622+2w)/(559+2w) =1.10016.

The air resistance is proportional to the frontal area. Considering just the wheels, the front area of 700C is greater by the same ratio of the wheel diameters: (622+2w)/(559+2w). But we are considering a rider and a whole bicycle (not just the wheels), so this disadvantage is smaller. If the percent of the wheel frontal area to the whole riding frontal area is f, I estimate f=7%, then the advantage of 26" due to smaller air resistance is by a factor 1.0065.

Our finding is than, that 700C wheels have smaller rolling and bearing resistances, both of about 10%, but have a greater air resistance of about 0.7% because of greater frontal area. It is not difficult now to predict when the 26" wheel will be more efficient. It will be when air resistance force is 0.1/0.07=14,3 times greater then combined rolling resistance + bearing resistance force. The air resistance force increases (nonlinearly) with speed, so we expect that 26" will me more efficient above a certain speed. Using this calculator, starting with the default data, setting slope 0% and weight 100 kg, and playing a bit with the speed, we can see that above 70 km/h the air force is greater than rolling resistance force for a factor 14.3.
So, the conclusion: 26" are more efficient than 700C only at extreme (downhill) speeds.

P.s. Just before 700c (or "bigger is better") enthusiasts start screaming of joy and ordering rounds of beers, let me remind you that situations such as "just size - all other things being equal" don't exist in the real world. Depending on tyre width, tyre pattern, weight, pressure and possibly year of your birthday, 26" might well be preferred.

Stiff sole myth

Another in the long line of cycling myths goes approximately like this: "When buying shoes for cycling make sure you get the ones with the stiffest sole you can find." The argument seems to be that the energy is lost by the flexion of the sole, so the one that flexes the least is the best. I must admit that this is a very convincing myth. I myself had fallen for it until very recently.

But firstly, a clarification of the terms. If by "cycling shoes" we mean special shoes that are fixed to a pedal (SPD or similar clipless system) than this is not a myth but a reality. In this case the force on the pedal is transmitted through small area and if the sole were not strong (=stiff) it would quickly be ruined. However, I think that the stiff-sole-myth had been around before the clipless system hype, so it doesn't descend directly from it (btw, for the reasons explained above the clipless system is not an option for me).

A recent experience convinced me that stiff sole used with ordinary pedals (no clips or straps) might be unfavorable. One Saturday I rode 150 km with two friends in a relatively fast pace. During and after the ride I felt great, the bike fit was perfect, I had no pains whatever. I felt as if I was at the peak of fitness. Next Sunday I rode 80 km "recovery" ride, same bike, same clothes, different shoes. To my surprise on that ride nothing seemed right: I had back pains and the saddle felt uncomfortable. On Saturday I had trainers with soft rubber sole, on Sunday I had shoes for in-door football (which, btw, were up to now my touring shoes) with stiff sole which became sleek and slippery during three years of use. So I am quite convinced that my uneasiness on Sunday was caused by the constant corrections of the position of my feet because the soles of the shoes were slipping on the pedals. If the soles were a bit more flexible they would grip the pedal preventing the slip.

My conclusion is therefore that the non-slipping contact between the pedal and the sole is much more important then the stiffness of the sole; and this is better attained if the sole is somewhat softer.

Packing the bicycle for a flight

There are several schools of thought on how to pack a bicycle for a flight. Some like to leave it unpacked so that the baggage handlers will see it's a bike and will treat it gently. Others are convinced that only a hard shell case with steel bracing will do the job. Most of the cyclists take the middle way and put the bicycle in a cardboard box. So let us first start with:
Recipe for packing a bicycle in a bike box
- 1 road bicycle, size 622 (or 700c) wheels, frame of the size L (or 58), drop bar.
- 1 cardboard box of dimensions 138x78x20 cm.
- several pieces of cardboard (a middle sized cardboard box will do).
- 1 spacer for the fork (or cardboard).
- 1 roll of packaging tape.
- 2 meters of duckt tape.
- 2 or 4 plastic bottles.
- Allen keys 4, 5 and 6 mm.
- 15 mm pedal spanner.
- scissors.
- 1 large beer.

  1. Put the beer in the fridge.
  2. Tape the bottom of the box with packaging tape, from inside and outside.
  3. Reinforce the carrying openings of the box with cardboard from the inside.
  4. Put the chain on the largest rear cog and largest front ring.
  5. Put one plastic water bottle in a bottle cage.
  6. Unscrew the pedals.
  7. Fix one crank arm by taping it to the seat tube with duckt tape. The other crank arm should point down below the front rings to protect them.
  8. Remove the seat and fasten back the seat clamp.
  9. Deflate the tires slightly. The rear one a bit more then the front one.
  10. Lower the rear wheel a bit below the dropout and move the wheel toward the seat tube. Tighten the rear Quick Release.
  11. Cut the bottom of plastic bottles and protect the rear axle and the rear derailleur with it. If you have only 2 bottles, cut them in quarters.
  12. Unscrew the stem-steerer bolts and turn the handlebar for 90 degrees in line with the bike.
  13. Fasten the stem-steerer bolts back.
  14. Turn the bike upside down.
  15. Remove the front wheel and remove the front quick release axle.
  16. Put a spacer in fork dropouts. You can use a rolled piece of cardboard.
  17. Protect the front wheel axle with plastic bottles.
  18. Put the bicycle (without the front wheel) in a box.
  19. Unscrew the stem-handlebar bolts and remove the handlebar.
  20. Screw the stem-handlebar bolts back in.
  21. Put the front wheel in the box so that it fits somewhere between the fork and the seat tube.
  22. Put the handlebar in the box.
  23. Put additional pieces of cardboard between the wheel axles and box sides, and between the front wheel and bicycle frame.
  24. From a couple of pieces of cardboard a bit wider then the box width make rolls and put them in the box as spacers.
  25. Put the saddle, the pedals and front QR axle into the box and fix them to the bike or the rack.
  26. If you have anything else to put in a box, do it now.
  27. Shake the box and look for any loose parts. Everything should fit tightly without moving.
  28. Close the box and seal it with packaging tape.
  29. Have a beer.
Time required: 2 hours.
If you have smaller bike or wheels (MTB especially) and flat handlebar you can use a smaller box. If the box is too small, you'll have to take the rear wheel off too: in this case the procedure might be considerably different.
Other options
Of course, the cardboard box is not the only way to pack the bike for a flight. Other options are:
  1. Leave the bike unpacked, just turn the handlebar, lower the seat, deflate the tires and remove the pedals. There is an ongoing debate whether by doing so your chances of getting your bike damaged are increased or decreased.
  2. Dismantle the bike and put it in a hard shell travel case. This would certainly be the preferred method if you have somewhere to leave the case upon your arrival.
  3. After the procedure as in 1, put a minimal protection made of pieces of cardboard or pieces ob plastic bottles on the sensitive parts: shifters and derailleur. Something like this
  4. .
  5. After the procedure as in 1, wrap the bike in plastic. You can use a roll of food wrapping plastic. A roll of 30cm x 60m should do. The result looks like this.
Which procedure to use might depend on the policy of the airline company and whether you are starting the tour or flying back. I prefer to start the tour by packing the bike in a box as explained and my preferred option for a return trip is to wrap the bike in food-wrapping plastic. This allows me to cycle to the airport with minimal packaging material and without hassles of finding a box or transportation, preparing the bike and wrapping is quite easy and fast (half an hour) and attracts lot of interested attention at the airport. It also complies with rules of some companies that the bike has to be packaged (to avoid damage to other baggage).

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