A sedate tandem, yesterday

My tandem is now finished and I have ridden it and that is all you ever do with a tandem. Ride it once and hang it up to dry.

Since Bob Knight has a tandem and someone I happen to know was going to a medical course near Rangiora at the weekend, I hitched a ride and took with me various items of mutual interest - a Peugeot frame with no visible means of fixing a seat post in it, a micro steam turbine car, some handlebars with an OD of 24mm - that sort of thing. Why does a reputable handlebar manufacturer suddenly take to churning out 24mm handlebars? Ever tried getting a brake lever onto a 24mm tube? Maybe the designer was having an off day.
'Excuse me sir, but Mr Smith has telephoned to say he has a cold and can't come to work today.'
'What does Mr Smith do?'
'He designs the outside diameter of our handlebars.'
'Right. Okay. Um. Yes. Er. We mustn't panic. - Tell you what - telephone the Breville Kettle Company and see if they can design the outside diameter until Mr Smith gets better.'

The person who happened to be visiting the Knights went tootling off to Amberley to study what to do when someone falls off the roof of a car while mooning and this left me at liberty. Mrs Bob Knight had a prior engagement with her girlie friends and their birthdays and this left Mr Knight at liberty.
Mr Knight knew of three adjacent shops in Christchurch which he felt could be of interest. Mr Knight's views and mine are at variance in a number of matters - his bicycles have to be perfect concours specimens whereas I'm content if the chain doesn't fall off - but we are as one in the matter of shopping. So we abandoned Mrs Knight in a small dinghy with a compass and a map of the Pacific and headed for Pak'n'Save, an emporium where, should you desire genetically modified peanuts, you can probably get a couple of tons for sixpence. Pak'n'Save is a vast hideous yellow box supermarket-like thingy next to the bike shop but we were under no need of the facilities other than gracing their forecourt with Bob's car. I shall not discuss Pak'n'Save any further lest I receive a Cease and Desist letter from their lawyers, and I shall not mention that New Zealand also has a vast hideous red box store called The Warehouse where, as the schoolchildren sing to the tune of their advert, 'everything's open and broken'. Don't want The Warehouse's lawyers sending me a Cease and Desist letter either. (I have been reading a book called Tescopoly by Andrew Simms.)(And another book called The Walmart Effect by Charles Fishman.) The Warehouse is New Zealand's largest retailer, and if you buy a heater there you keep the receipt because it will, actually, break as the guarantee runs out and they won't have any truck whatsoever with you when it does. This happened to us. Unluckily for The Warehouse it was two weeks before the guarantee was up, and unluckilyer for them, I managed to find the receipt. It broke again a month later though. We never go near The Warehouse now and I strongly recommend you don't either. The workers there hate it. I've actually seen one playing football with the goods he was supposed to be stacking, kicking them to his mate up a ladder.

The bike shop was magnificent but it was cheaper to buy new handlebars than to buy special brake levers. 24mm. Huh! The model shop next door was superb too and had the brass tubing that one requires if one is the father of a fourteen-year-old bent on steam engine manufacture, but the tool shop next to that switched off its lights because it was 12.30 and the assistants wanted to spend Saturday afternoon pulling one another's trousers down. (I understand this is the aim of the game of rugby football.) But I managed to get five Eclipse hacksaw blades for ten dollars, which is four quid in civilized money. - Well it is at the moment, though I gather what Gordon's done means it isn't likely to be civilized money for too much longer.

An-y-way, in the afternoon - which is what we were building up to - we got the Knight tandem down from its hook. Mr & Mrs Knight possess an Ibis made in California and my legs-and-arms approximate to the lengths of Mrs Knight's legs-and-arms so I could sit on the back and enjoy myself.
A 22 mph tandem which I did not build

I haven't ridden tandems before but now I've built one I needed to find out how they're supposed to go. One has to have total trust in the chap up front, and sit clipped in while he stands at junctions, and one has to pedal like absolute stink when setting off because the pilot is busy trying to balance and steer and locate his cleat, and this pedalling is done from a standstill at the command of the pilot, and one has to stop pedalling on command too, and one has to refrain from steering. All of these things don't come naturally. However my bad neck which has prevented me riding drop handlebars for a while was now no obstacle because I didn't have to see where I was going but could peer straight down throughout the ride and admire the chainset, and because I do not wish to offend Mr Knight on a public forum such as this web log, I shall not disclose that his left rear crank had fourteen specks of road dust on it.

Approx halfway along the ride someone shot an airgun at my helmet. I heard the pellet whizz past in the air. I said the usual word, then:
' - what the (usual word) was that?'
And then I received a direct hit on my helmet. I said the usual word again, and nearly bringing the tandem down, twisted round to see who was shooting at me. A large bird was flying away with a vicious grin on its beak.
'Hah!' said Mr Knight, delighted. 'Magpie attack!'

It seems that the Australian magpie, which is a handsome crow with a white back and the most magical musical song, has for the two nesting months of September and October a habit of attacking cyclists' heads from behind. These aerial attacks are so startling - I now vouch for it - that people have fallen off, and indeed one wealthy cyclist paid for hunters to shoot every magpie they could find in a certain mountain pass where he fell off and broke his bones.

On the Sunday we did another ride sans magpies managing 22 miles in one hour which is as good as I can manage on a closed oval racetrack on a racing recumbent. I was reminded of the first BHPV event I ever went to which was in, oh, about 1986, where the Crane cousins thrashed everyone including the Vectors, riding a caged tandem.

A 44 mph tandem, 1986. Dick and Nick Crane, Milton Keynes. The shoulder in the yellow jersey attached to the chap who doesn't know which way to arrange his hat is that of one Richard Ballantine Esq.

Home, and I took my recumbent on my daily ride, and slowing on the cyclepath to spy out all its broken beer bottles (I swept up four) I was overtaken by a roadie who cleared first his left nostril in front of me and then his right, which I considered really quite impolite because the spray went all over my face.

So I paid for hunters to shoot him.

However they have to get the right roadie.
Because I had to send a note through to the Police asking them to contact a local truck driver and ask him if he'd very kindly stop driving deliberately close to me, and the Police replied and said three of their officers have had the same problem with the same truck driver. You see, half the local roadies are also Police officers, a fact which isn't as widely known as you might have thought, though when one particular pair of exuberant youths repeatedly carved up a training peloton, they found out on the Monday morning when a uniformed senior officer pulled up outside their house and discovered a bag of cannabis in the offending car.
Wednesday, September 16, 2009 11:45:34 AM Categories: New Zealand stupidity tandem

Stupidity Quotient 

There is this New Thing, and I have Invented It.
It is called the Stupidity Quotient. It is a bit like the Intelligence Quotient, only the opposite. I have an abundantly high one. Mine's about 174. I examined all the bits and pieces and decided that I would need a super-narrow chain and rushed pell-mell to see Josh, who was out. Josh is a boy of 19 and he tells me stuff I don't know about MTBs, which subject he studies diligently. He works in the bike shop, except when he doesn't, and then I prove my high SQ to myself by spending money on things I don't understand. I got them home and was baffled by these new-fangled pin thingies. Therefore I emailed Mr Knight:
My tandem has some cranks and nearly some chains and I got two cheapy seats and I am getting exciteder than my wife is getting. I got two 10-speed narrow chains but they look like as if it will be impossible to split them once joined. Any experience in this matter? - R
Mr Knight emailed back:
Are they new chains? And Shimano ones with the push in pins? If so, you can break them again but you must use a new pin every time you rejoin them; the pins are dead cheap and easily available. However, I do not like the Shimano system and steer clear of them for this reason. I use SRAM chains because they come with a neat little joining do hicky which can be opened repeatedly. - Bob
Having a high Stupidity Qotient I had got on with the job without knowing what I was doing, and therefore was in the embarrassing posish. of having to email back:
The chains have been abandoned. Stuck back in their boxes. Yes, they have little pins, but I am a marvellous angel with chains, removing them and waxing them monthly, and having to buy new pins is against the waxing religion. Each cost me $32 and they will now be stored for when the world collapses, which it definitely won't do because the New Zealand Treasury have forecast a modest recovery. I used three chains from bikes obtained from the dump. I measure all chains coming from the dump, and every now and then one measures exactly 12 inches for a foots-worth of chain and I clean and wax it for making tandems. I had three. And I was much pleased to find they fitted past the crank on the synch side. - R
As a matter of fact I am not the only one with a high SQ: whoever designed a handlebar clamp for a BMX and made the inner bit 7/8 of an inch instead of the otherwise standard one-inch has a high SQ, though I am yet more stupid for not having examined it beforehand to see if this was going to be the case. One should never underestimate the stupidity quotient of any person charged with designing bicycle components. If they can dream up a slightly incompatible part, then I assure you they will. The other day came a phone call from a friend whose son had broken spokes in his back wheel and could he come round to remove the cluster. Which he did. Without the wheel. Which he had forgotten. Which was a nuisance.
'Tell you what, lend me your tool and I'll go and fix it at home.'
I now have a firm policy, friend or not. No tool gets lent by me to any other creature, human or inhuman, friend or foe, Rotarian or interesting person. There is a reason for this, and since every single reader of this blog is utterly certain to know what the reason is, we needn't discuss it further. He went away, and returned with wheel and son, son being under an injunction to watch & learn from proceedings or he (father) would not help with the repair. I examined the wheel. It had the one cluster for which I have no removing tool.
'Can't help you,' I said, fingering my Suntour tool which would nearly fit and which, unattended, he would probably have coaxed into place with a hammer. - It was a millimetre too tight. - And the son's wheel was an old piece of - er - was worth a good deal less than a Suntour block remover.
'Can't help you unless I weld the block solid, and then you won't be able to use it again.'
'He needs it for school tomorrow. I'll just phone home and see if I've got a spare block.'
He had, so I welded it and took it off with a chain whip, and then, because he had wandered off inside discussing the local hospital with my wife, I started to sort through the spokes he had brought. There were 36 of the right length, neatly labelled '700c 36 3-cross small flange' inexplicably in my handwriting on a card attached to them with a rubber band, and there were 16 assorted other spokes of which half had no thread and the remainder were the wrong length. I fitted four spokes, reducing the bundle of 700c spokes to 32. While I was tightening them, the father wandered back.
'I'll do that, if you like,' he very kindly offered.
And then he collected his son, who had been watching from a different room several doors away, and my Stupidity Quotient is so high that when he said the words 'thank' and 'you', they sounded to me exactly like 'Well we'll be off then'.
Monday, September 7, 2009 10:29:53 AM Categories: stupidity

Tandem welding 

I have braced my tandem. I have looked at every single photo of every tandem I can find, and tried to get my feeble brain to imagine what the stresses might be, and have examined my wife's Raleigh Lady Clubman, and have concluded that a mixte frame has so much going for it that it's worth a try. I have also heard by e from Mr Knight of Rangiora, a tandemist until he had children when his tandem was retired. I expect when his children grow a little more and leave home he will get his tandem down and shortly afterwards Mrs Knight will divorce him. Anyway here follow his remarks:
Now then young man, I've just perused your tandem piccies and I am mighty impressed by how straight and aligned the top tubes and seat tubes are. This is most unlike you. Did you have help? I hope that you intend to brace that big open hole where the direct lateral tube isn't. The Direct Lateral Design is the best tandem design; you know this is true because my tandem is one and everything bike that I own is the best. Also I strongly recommend keeping the drive all on the right hand side if possible, otherwise you need to venture into tandem chainsets which may look like normal chainsets except that of the four cranks, three are reverse pedal threaded to normal. Both fronts and the left rear. Tandem chainsets are expensive. However a triple or quad rear chainset and a sync chain on the right will work well. Sacrifice high gears for low ones. You need low gears, lots of them. You will be slower on a tandem, best get this out in the open at the start. Lots of people buy a tandem and think they will be really fast, twice the output, same frontal area and all that. Unfortunately, it doesn't work out like that, tandems tend to average your separate speeds. If you are faster than Heidi, then she will go a bit quicker than normal and you will go slower than normal. Uphill you will be slower, much slower. Downhill you will be much much faster. And on the flat you will be about the same or maybe a bit quicker. I have lots of tips for riding tandems; we will discuss them shortly at great length. After you have examined my Campagnolo toolkit.

I have just read this to my wife, who immediately has just said ' Oh *uck, that's no good. I thought we'd have an easy life. You'd better get in training then.' (She says *uck quite often, as a matter of fact, but I never tell anyone because several of the people we know are Rotarians.)
Anyway Mr Knight is almost unkind in implying criticism of my brilliant welding and alignment and whatnot, and the only reason he isn't entirely unkind is because it is a factual remark. My welding is crap and so is my alignment, usually. And no I didn't get any help and the way it came out right was this: Pure Luck. The jig to weld was two bits of angle iron clamped very hard to the BB shells, the frames held together with a length of rubber inner tube. And my experience has always been that this is as inadequate as any other method I've ever dreamt up, and I fully expected to have to bend the thing afterwards - erm - that is to say, Cold Set it -and was astonished that this hasn't been necessary.
Note, however, that I do not afford this Blog the courtesy of close-ups of the welds. "Hmm, MIG welds aren't very pretty, are they,' is what Mr English observed once when he had spent too long examining one of my machines.
So now I have got out all my old chainrings and spiders and bless my soul, my head aches with trying to find two that will synch in such a manner as to please Mr Knight and earn his respect and regard and ravioli. (No, ravioli isn't the word I wanted. I suddenly felt in a thingy mood, where you try to use the same letter - wosscalled - alliterative.)

Friday, September 4, 2009 10:51:45 AM Categories: tandem

Career advice 

I have just read the following comment on the Internette:
I make my living as a consultant applying semantic technology to knowledge intensive enterprises to unlock and analyze dynamic data to transform into actionable information for better decision-making and to make knowledge workers more productive and organizations more profitable.
Fantastic. Just fantastic. I want to meet his school career advisor.
Meantime, anyone tell me where I left the Vernier? Can't find it. Put it down and now it's looooorrrrst.


Thursday, September 3, 2009 11:03:54 AM Categories: engineering problems


I think my wife wants a divorce. She has given me permission to build a tandem. - Actually she didn't give me per.. - I just got some mountain bikes and got on with it.

The way you make a tandem is this. First you re-read Martin van den Nieuwelaar's article in the Feb 2008 newsletter of KiwiHPV, and then you re-read Sheldon Brown, and then you re-read John Allen and then you head for the dump at Mariri.

With a name like Martin van den Nieuwelaar you are required to live in Christchurch which is reassuringly flat. You're 1.8 metres tall, and the person who's (probably) thinking about divorce is a 1.6 metres tall fully trained German violin maker which I still find difficult to believe. What are the chances of finding a fully trained female German violin-maker in a country with a population the size of Birmingham? - As a matter of fact I bought an old Stradivarius in a junk shop here, signed with the date - 1776 - written in by hand, a trifle baffling since any reputable forger would know Stradivarius died in 1737. - What's odd is it does have a nice tone. - What's odder is it's a 15/16 size, so if anyone's a particularly small violinist in need of - anyway, this isn't getting us very far.

Martin told us his and Hanna's heights in his article about making a tandem, it being relevant, but my wife nicks all my bikes so I knew I would be able to get away with two frames about the same size. And luckily enough the dump had just been freshly filled. The Police had evidently run out of room in their garden shed. Some of the thirty bikes still had Found Property Label, Police, For Use With Form 263 tied to the handlebar, which label has (economically) printed on the obverse Exhibit and Miscellaneous Property Label (for use with Pol. 268). Next time I get prosecuted for something juicy and the Exhibit is presented to the Jury I shall cunningly turn the label over and say I found it. Whatever it is. Gun, bike, lead piping. - Matter of fact Colonel Mus- well, John actually - found a large adjustable spanner on a bike ride a month or so back, and recognising the ute off which it had freshly fallen, hied him along to the relevant farmer who didn't even thank him. $45 the spanner was worth. (I'll advise him to use it in the kitchen. Farmhouses in New Zealand don't have a billiard room.)

A perfectly good gentleman's mountain bicycle

Most of making a tandem comprises worry. You worry about meaty front forks. You worry about cutting the wrong bits of rear stay off. You worry about whether 36 spoke MTB wheels will be up to it, and you worry about the geometry going wrong because you've cut a bit of tubing either too long and you can't be bothered to file it exactly to size or that you've cut it too short and the finished thing will look like a hog.

Most of my time is spent saving fivepence by splicing bits of tube together. I do this because whenever I see a sawn-up bike frame I think about how long it would take me to mine the ore, smelt it, and come up with a perfect piece of tubing. Making tubing by hand is astonishingly laborious. When the first gas pipes were laid in England, gunmakers were the only people who knew how to turn a lump of iron into an air-tight pipe (clue: Damascus barrels), and it is reported that the first gas-pipe was musket-barrels welded end to end. When once you know a thing like this you can't ever bring yourself to cut into a 20 foot length that you keep for just such purposes.
Oval tube prior to splicing.

Preparing the donor frames mostly comprises removing bottom brackets. I advance the Middleton Theory, which is that there is a mischievous elf who goes around with a spanner tightening pedals, stripping the thread in cranks and hammer-forging the right-hand cup into the BB shell and when he's done with all that, he pours dilute zinc chloride into handlebar stems. Come to think of it, John found his spanner. Hah! Where's the Araldite? Two can play at this game. He'll be amazed at how irritating it is to find a washer epoxied all the way into the lock of his ute.

Two perfectly good gentlemen's mountain bicycles, shortly after coming into my care.

(I have retired from politics, by the way. I learnt yesterday that 'not being in Parliament is not a handicap at all' which tells the British HPV membership all they need to know about Winston Peters the last foreign minister who - ahem - lost his seat, along with those of his entire political party, at the last general election. - New Zealanders do not need to be told about Winston Peters. They already know.)
Wednesday, September 2, 2009 10:04:30 AM Categories: tandem


I have decided to enter politics. The chief requirement appears to be an inverse relationship between a need to sound important and an ability to do anything useful. Accordingly breakfast is now dedicated to studying the morning radio where just before the last election a comparatively new MP told the nation that over some policy or other

'I think it is almost certain that we probably will.'

Hurrah! Three caveats in just ten words. I thought he'd go far. And in the event he became Prime Minister.

I can't tell you what he thought he was almost certain probably to do because I was rushing to the fridge to write it down on an old envelope before the words slipped from my memory. We have a large pile of old envelopes on the fridge. They are my lecture notes. The common theme appears to be pointless repetition:

'I recognise that there are a lot of unsung heroes that don't get recognition' (Chris Hipkins MP)
'to apply punitive punishment' (Clayton Cosgrove MP)
'there's always constant pressure' (John Key MP)

and if you need to cover yourself, you repeat words you've just made up for the purpose:
'either expressedly or impliedly' (David Cunliffe MP)

Sometimes we only get to the fridge in time to jot down an important-sounding word -
perhaps in context -
'keep the optionality'
or in its original sentence -
'I wouldn't use the word incompetent - there was a management-skill gap'
- without managing to note who said it or why.

But with everyone becoming interested in economics and what politicians can't do about it, the most self-important phrases, used by bank economists as well as portentous politicians -
'Uncertainty is certain to grip the market'
- concern finances. And I do assure you I'm trying to learn how to use 'leverage' though unfortunately whenever I hear it my mind blanks over and I don't take in anything else in the sentence.

Which, of course, is the whole point of it. Economists who say 'leverage' wear dark suits and a blue tie, and they say 'leverage' because they know it will make me feel insignificant and ignorant and I won't hear what the suit is about to do with my money. He himself doesn't know what he means by 'leverage', and this is how he knows that he'll humiliate my understanding. Sometimes he says 'leverage' to mean that his bank owes another bank two hundred billion dollars, and sometimes he says 'leverage' when he would like to sell a lot of dried milk product (sic.) to China.

Prior to my usefully entering politics I only ever thought of saying 'leverage' when trying to lift the corner of the wardrobe up with a garden spade so my wife can peer underneath with a torch to see if a dead mouse has crept there and is stinking the room out. There is a dead mouse - it might be a rat or a fish or a possum - we haven't found it yet - and it started off over by the door but is now somewhere near my computer. It's unusually mobile among dead mice. If it turns out to be a dead bank economist I expect it will tell the radio that it was leveraging its position geographically-wise.

I can't actually lever the wardrobe up with just a spade: I need a block of wood as a fulcrum. But I'm wary of saying 'fulcrum' lest the minds of people in sharp business suits blank off at the untoward appearance of a word from a junior school physics book. Politicians and businessmen and economists and important bank officials don't like to hear basic physics. Try them on the rather worrying fact that even the conservative International Energy Agency is now saying that world oil production will start to decline within the next ten years. They prefer to dismiss physicists or geologists as fanciful fools who don't have an MBA and are thereby out of touch with reality.

I myself am a fanciful fool, fondly believing that recumbents are the silver bullet to the world's - well, everything, actually. I am just about to go for a ride up the valley; and:
Fact: it will take me 55 minutes because I am going on my recumbent.
Fact: if I were on my Würthrich racing bike, on which Walter Hänni won the Austrian championships a few years ago (forgive the name-dropping. I'm appealing to the sportive fraternity) it would take me an hour.
Fact: if I were on a perfectly good gentleman's mountain bicycle it would take me an hour and twenty minutes. ("A perfectly good gentleman's mountain bicycle" is how the policeman described it when, abandoned for several days at the side of the road, I took one into Quorn police station. As a matter of fact it wasn't perfectly good, it was crap, and I later cut it up with a hacksaw and used the BB on recumbent number 17.)
Fanciful conclusion: Recumbents are faultless.

Mr Knight is a fanciful fool too, fondly imagining that council staff down in Canterbury might responsibly view their employment. This email just in:

Rode in on Wednesday with a Nor'Wester on my back in record time. The ride home was also in record time but the not the good kind of record. The bridge was shut again. The council runs a [not very good (Ed.)] cycle shuttle that carries you and your bicycle around the 300m bridge by way of a 5km detour. It is only suitable for [not very good (Ed.)] bicycles and is manned by council [not very kindly or intelligent employees (Ed.)] who earn $12.50 an hour (he told me) and take delight in deliberately damaging $20K bicycles carried in his rack (he told me). My Coppi now has a small dent in the 0.4mm top tube. I repeatedly beat the council employee with his own [not very good (Ed.)] rack and then dumped his body under the dangling pile of the closed bridge so that his life would serve at least a minor purpose. [In my view he is a not highly respected person (Ed.).] I intend to cycle in tomorrow and if the bridge is shut, I'll [expressed with some emphasis (Ed.)] well ride down the motorway again.

Truth is that speed depends on infrastructure, not on my skills as a recumbent builder, and infrastructure depends on the oil not running out. Infrastructure of course is the politician's word for tarmac, but inflation has extended its use to anything else we fancy. - Before there was infrastructure there were roadmen who lived in little huts and, on foot and equipped with a shovel, looked after a stretch of about eight miles of unsealed dirt road, filling potholes with stones and swearing at the early motorists if they went above 20 miles an hour and shot the stones out of the repaired potholes with their tyres. (Been reading. This was from page 150 'High Noon for Coaches', a much better book than its title implies. It describes the early days of colonial transport in New Zealand.) If Rangiora is no better served with infrastructure over the rivers to Christchurch, Mr Knight would be wiser riding a crap perfectly good gentleman's mountain bicycle which would handle council employees' malevolence with more aplomb than his hitherto pristine hand-built Italian light-weight Coppi does.

If there wasn't tarmac from here to Rocky River and back on the other side I too would be quicker on a perfectly good gentleman's mountain bicycle which manages unsealed roads rather better than my recumbent does. A road is defined by a piece of paper held in the Tasman District Council Offices, the road having been drawn in by an early surveyor often with nothing more than optimism, and I have actually walked quite legally through someone's garden on a 'paper road' as they are called. Owing to rising sea levels, there is one paper road here that goes a mile out to sea and then turns right. Accustomed to their wild, dense and deceptively dangerous native bush New Zealanders will quite commonly expect me to use the word 'road' to mean a place where trees aren't, except if I were on the radio when they'd expect me to say it's a commoditized optionality expressedly or impliedly utilized on an invitational basis as a transportation facility.

(However when I become the Prime Minister I shall cover my tracks by adding that this is what I think it is almost certain it probably constantly always is.)
Sunday, August 30, 2009 1:57:07 AM Categories: New Zealand

Pedalling dimensions 

It is raining. When New Zealand rains, it does so on a Saturday and it does so Very Hard. There is an inch of standing water on the path, which, to indicate just how hard, will take only half an hour to drain off when the rain stops. Outdoor activity is limited to rugby football and pig-hunting, which have so much in common that I am at a loss to explore their differences. Therefore I have time to clarify my last post, which because my brain is walnut-sized, did not prove especially helpful:

The aim of determining optimum bottom bracket height is either to minimise frontal area or to maximise comfort. The former defers to speed and excitement, the latter to age and wisdom.

Filming a cycle of the pedals of a recumbent cyclist from the side, you find that the highest and lowest points of frontal area are not necessarily your torso. They are quite likely to be the knees and the heels. If a freeze-frame tracing is made showing the entire cycle of the crankset, this can be seen graphically:

Therefore one approach is to place the BB at the height where the knees rise above the shoulder by the same amount that the heels dip below the sitzhohe. (We have discussed sitzhohe.) For me this is 9 inches above the sitzhohe; it does not mean it is 9 inches for everyone else.

Another approach is to remove the head, which gives a reduced frontal area of 0.41 square feet, though since a crash helmet would not then be required, the benefit would be larger. Anyone who performs the experiment is invited to tell us all what speed gain results. An additional benefit is reduced mass, which, without disassembly, can be estimated by filling a bucket with water, weighing it, displacing a volume of water equal to the volume of one's head, and re-weighing the bucket. Experimental error lies in the neglect of the volume of air contained behind the nose but it's about 6 lbs.

A third approach is to raise the bottom bracket a little more so that the highest point is the knee-toe line, and then, in my case at least, the lowest point becomes, conveniently, the heel-sitzhohe line. In our present example, the BB then becomes 9.5 inches above the sitzhohe, and the frontal area (neglecting the head area which is also reduced by this procedure, though not by as much as decapitation) is reduced by about 5%.  One can see where one is going by peeping between one's knees and toes.

This is all very well until a fairing is made, whereupon one sacrifices a bit of frontal area for the considerable benefit of being able to see where one is going.

Further figures are available from the Inimitable One:

Saturday, August 15, 2009 3:21:36 AM Categories: Bottom bracket height

Technical terms 

Our German Girl has vanished, so there have been divers happenings relating to recumbency in the Southern Hemisphere over the weekend. Our German Girl is an exchange student who has appeared courtesy of the world's various Rotary Clubs; she isn't actually Ours; we sort of share her with various other families whom the Rotary Club deem unlikely to be child molesters. - We are not, ourselves, Rotarians, because we do not wear business suits nor feel the urge to meet every Tuesday evening with people who do wear business suits and I'd better go no further lest a Rotarian happen on this Blog and take offence. - Not that there's much chance of it. Rotarians are such folk as not, I find, greatly to interest themselves in recumbent bicycles, though if it so happens that one of them does I shall, on application, supply him with my brown paper bag. It must be jolly embarrassing to have the entire HPV world discover that you're a closet Rotarian. - Anyway I know for a fact that they don't because they wouldn't release a German Girl into the custody of someone who cycles up and down the valley with a bra on his head. (Actually our financial advisor reads this blog, though I happen to know that she's only a Rotarian in order to get the latest goss on which local lawyer is having an illicit affair with which other local lawyer but unfortunately she does not share the details with us or I would derive immense pleasure from revealing all here, though this would almost certainly terminate the entries because I don't suppose they have Internet facilities in New Zealand gaols.)(And of course our financial advisor wears a brown paper bag anyway, and has done ever since the sub-prime thingy.)

Our German Girl is the daughter of an actual Brain Surgeon. I mention it because it is so unlikely. How many brain surgeons d'you know? No, neither do we. But anyway further details about her can be skipped because she doesn't ride recumbents, which state of affairs you may depend will be remedied within the next few months.

With no German Girl to entertain the weekend was clear for Sam the Scotsman to pop over for some learned discussion on the topic of tandems and whatnot. Sam, Sam, pick up tha musket. (Obscure and irrelevant. Ed.) It will/won't be recalled that Sam has a broken trike and wishes to turn this into a recumbent tandem of sorts, using approx nil of the trike parts because approx nil of them are strong enough. Accordingly he has been busy popping in on the local bike shops assembling a collection of various 406 forks and wheels, and we now have a merry heap of components scattered about the workshop floor. And since our researches are of no avail to the world if we do not share them I advance the following info, some of which will be erroneous, some duplicate, and perhaps, just perhaps, some of it useful to someone in Afghanistania (1). Provided, of course, Afghanistanians' recreational interests do not centre on wearing a business suit of a Tuesday evening.

Imprimis. That Larrington man has a useful site full of recumbent tandems:
and if you can read Foreign, so has a Foreigner from Abroad:

Item. For $NZ87.50 you can buy a 48 spoke, 406 wheel on a 14mm axle, and you can winch the cones in and out respectively to make stub axles.

Item. The 14mm axles with sealed bearings have a shoulder on the axle itself, so you can't turn them into stub axles.

Item. You need whacking great big cone spanners for 14mm axles.

Item. I have lost my vernier calliper.

Item. I have found it. Why don't I put it back every time? Am I stupid? - Don't answer that one.

Item. Right, specifically you need 19.05mm cone spanners, 3mm thick. 19.05mm is 3/4 of an inch. Sit up at the back and pay attention.

Item. You can screw a cheap derailleur block onto a 406 rear wheel with a 14mm axle ($NZ99.95), but only by removing the RH cone lock nut and using a slightly munted axle nut, the munting performed neatly on the lathe, of course, and a spacer to lock the cone. It then becomes a pig of a job to remove said block, because the hole in the middle of the block-removing tool (don't I know any technical terminology?) is smaller than 14mm, so the entire axle has to be dismantled and extracted out of the RH side, which requires final careful tapping with a hammer to dislodge the protective dustcap that sits on the RH cone by friction. What a rubbish sentence. We need more specific technical terms than just 'leg-suck'. Did you ever do Airfix kits when you were 12? 'Locate the locating peg in the locating hole' was never entirely informative, and you always ended up gluing the undercarriage of your Fieseler Storch the wrong way round. - And while we're about it, did you ever try to use a Haynes manual to find out where to look for the fuel pump on a Mini that was always going wrong? Those diddly photographs had me crawling about underneath on the wrong side and the wrong end of the car with a torch, jabbing myself occasionally in the eye with a bit of oily dangly plastic pipe the purpose of which I never discovered. My father-in-law had a sensible approach to our Mini van, hacksawing a chunk out of the radiator grille to get at the oil filter which you could only otherwise reach if you had a second elbow half-way up your forearm.

Item. Where were we? Ah - more technical terms. -

Item. If you happen to enjoy the same seat position that I do, then the optimum height of the bottom bracket is 9 inches above the sitzhohe. - Sitzhohe is now the correct technical term for the lowest point on your seat. It has been the correct technical term for the last thirty seconds when I nicked it from Germany, and it would have an umlaut somewhere to make it look even more correct and technical except my keyboard doesn't have umlauts to hand and sitzhoehe looks clumsy. It is a better technical term than 'bent', which I see is still persistently used by those who know no better. There needs to be a Royal Commission, like the Academie Francais (no accent or cedilla key, either), to which American Persons can make supplication for new words. - er - Where were we again? - yes, the BB needs to be 9 inches higher than the sitzhohe and then with a 170mm crank, heel-clip at 4 inches will equal knee-rise at 4 inches.

Item. I just invented heel-clip and knee-rise too. Heel-clip is how much your heel drops below the sitzhohe (I'm enjoying this) during the rotation of the cranks, and knee-rise is how much above your shoulder the knee goes, both of 'em messing up your frontal area. We'd better settle for BB even though it isn't a bracket and isn't at the bottom of the machine any more.

Item. However N=1 which means to say this experiment was conducted on the only legs available, viz., mine, so if you chance to differ in any anatomical way from me, then I may be talking gibberish. I often am.

Item. If your pelvic girdle is approx the same as mine, any large upright member such as (shut up, Carol) the front part of a Z-frame cannot be closer than 8.5 inches from the seat angle.

Item. Seat angle is a technical term, too. It's the bit - well, it's usually the sitzhohe, except where the seat has a webbing base when the sitzhohe may sink below the seat angle. And (by experiment) the seat angle is usu. the body's centre of balance, if you're lying back comfortably so that the BB is indeed 9 inches above the sitzhohe.

Item. Heel strike (someone else's term. Where your heel hits the front wheel) is guaranteed if the BB is within 17 inches of the front axle. This for a 'nornery Q-factor (Hurrah! 'nother tech. term) and 'ornery 170mm cranks and a 'nornery 406 wheel with the 1 3/8 Primo tyre that Sam gave me the other day and it was a Jolly Good Thing he did because my Stelvio had delaminated.

Item. The seat base needs to point at the centre of the BB.

Item. The steering head tube is 1.5 inches shorter than the pivot tube thing of the fork itself. Hey, what does Archibald Sharp call it? - Here we are, p 297 - the steering-tube. Mind, he also refers to the 'top adjustment cone of the ball-head' and we'd all like to know what a ball-head is. (Shut up, Carol.)

Item. The cantilever bosses on forks for a 26 inch MTB wheel are just 5mm too high for those funny cross-over U brakes that they fit to BMX bikes. Wonder if we can make them fit? The pivot appears to be 46mm from the centre of the lowest brake-block mount, and it really needs to be 50mm.

Item. No matter how carefully you measure seat angles and seat distances, it is impossible to draw them accurately to scale. Impossible. Totally impossible. Y'know those all-in-one carbon fibre frames incl. the seat? They use human sacrifice on a moonlit night with incantations round a cauldron to get it right. There is no other way.

Item. This list is now so boring I need either to Get a Life or to join Rotary. I shall draw a drawing full of technical terms instead.

1. Its new name, on no less an authority than the New Zealand Prime Minister. He said 'Afghanistanian Government' on the morning radio. He actually said it. I wrote it down at once. And since we're off-topic, why do New Zealand broadcasters refer to Her Majesty as 'Queen Elizabeth the Second'? Did New Zealand have a Queen Elizabeth the First that I haven't been told about?
Wednesday, August 12, 2009 11:59:29 PM Categories: engineering problems

Memento mori 

A while now since they 'built' a cycle path opposite our house. It was actually an excuse for funding, because one of my privy councillors informed me that they could only get funding for the sewer if they built a cycle path on top of it, and they could only get funding for a cyclepath if they built a sewer below. - Don't ask me. I didn't make the Rules. - But Mr Knight, a volunteer fireman, informs me that the fine on the Canterbury Plain for lighting an un-licensed fire is $400, while the licence costs $1500. So the Rules are occasionally a little puzzling.
First they dug and laid the sewer, then they deposited an entire truckload of crushed glass on the road outside our drive, then they left matters for a fortnight, and finally they returned and shovelled most of the glass into the mud and laid tarmac over the top, scattering the whole with gravel.
We had six punctures in the first week. One of the Rules is that 'if there is an adequate cycle path provided, cyclists must use it.' There is some discussion around the word 'adequate.'
At the timber yard one of the chaps who lives down our lane sympathised, saying he wouldn't ride a bike - if he did ride a bike - on that cycle lane, but - mind - he'd drive his car as close as he could right next to anyone using the road on a bike if the cycle lane was any good.
Sprang Gordon Wallator from the office to the fray:
'Doesn't matter what their reason for riding on the road is - it's not your business to endanger their lives just because they choose to avoid a crappy path full of puddles and broken glass!'
I liked Gordon. He was a Canadian, nice guy, wiry and lean, white hair and specs, a mountain biker. He would chat enthusiastically about our tobacco sheds, which are large and capacious and the sort of thing Canadians don't have in Canada, so they get all carried away when they come across them in New Zealand and dream up things you can convert them into. He retired last Friday, aged 65, from the timber yard. On Sunday he died.
Yesterday the flags over the timber yard were flying at half mast.
Wednesday, August 5, 2009 11:05:11 AM Categories: cycle path

Behold! a bra. 

At the considerable risk of Larrington reverting to a view of what I am bonkers in, behold, I shall now state that I have taken to wearing a bra.

This is not the sort of admission one normally makes unless one is the late Julia (formerly Jim) Wiggins, who rode a Kingcycle and shot Turkish recurve bows and erected a camera obscura from the roof of her (formerly his) Berkeley 3-wheel car and took to wearing high heels and progressively other items of effeminata, and I daresay young Carol Hague will now wake up rather abruptly because she's always alert, I find, to mild eccentricities such as public transvestitism. Jim Wiggins was an eccentric right from the beginning, incorrectly imagining the members of the Society of Archer-Antiquaries would prefer to see the Annual Shoot projected, up-side down, in his passenger seat. In fact he discovered that most of us found it altogether more convenient to stand outside in the August sunshine and watch the real thing, upright. Jim rather cunningly tricked the doctors at the private hospital in Leicester into thinking he wasn't on heart medication, whereupon they performed his desired operation and turned him into a her, but unfortunately his heart, deprived of its drugs, couldn't cope and he - I mean, she - died, admittedly content in her new identity, a fortnight later. (His Kingcycle, should anyone start getting all acquisitive, had already been stolen.)

I have taken to wearing a bra as a combined result of retail mismanagement and my wife's mendacity. I used to have one of those - er - wossname - Trek thingies that you stick on your head, a sort of hat with the skullcap missing that makes you think a Jewish person from Golders Green visited the shop with a pair of scissors just before you got there and nicked the crown for his Saturday's devotions. - Headband. - A headband, that's the word I was groping for. I got cold ears so bought a Trek headband and my wife thought it so excellent a garment that she immediately nicked it. I went and bought another headband. She lost the first and nicked the second. She denies losing the first because she is a Big Liar, and she denies nicking the second because she is Another Big Liar.
It still being cold I went to the bike shop and behold! no headbands. The sports shop yielded big thick furry headbands such as won't go under helmets, and in New Zealand helmets are mandatory by law. (This is because the politicians here believe head injuries among cyclists are frequent. Head injuries among motorists are statistically more frequent but motorists do not have to wear helmets because politicians drive cars and wouldn't be seen dead in a car with a bicycle crash helmet on. Hey! A humorous joke has just occurred to me involving the phrase 'wouldn't be seen dead' but I will not trouble the Internette with it because I'm kind.) I went to see Jim and behold! even more No Headbands. Jim runs the bike shop in Richmond and also runs Cycling Nelson which is all about racing and whatnot, and in defiance of the UCI he encourages recumbents at all Cycling Nelson events, which is a bit of a bugg - a bit of a nuisance because now there's no excuse to avoid training.

So then it went through my mind that since sawn-off socks, extracted from the bin after my wife has been through John's washing, make convenient ankle warmers, perhaps there was a garment that might make a convenient ear-warmer.
I went to a certain bedroom in search of a suitable garment. Behold! there was only a single pixel of carpet to be seen. On the floor of this bedroom, and to avoid embarrassment I shall not say whose bedroom it was, I found the following:
1. A piano score of Joseph and the Amazing Technicolor (sic.) Dreamcoat.
2. A pile of clothing.
3. A school bag.
4. Another pile of clothing.
5. Spillage from a bag of clothing. (Hasn't she got a wardrobe?)
6. Another schoolbag.
7. A Harry Potter DVD.
8. A French folder.
9. A tin containing 22 cassette tapes.
10. A maths textbook.
11. Another pile of clothing.
12. A paperback: Popular Card Games.
13. 2 loudspeakers.
14. Another French folder.
15. An office chair with a basket of washing on top.
16. A plastic bag, containing clothing.
17. A graph of a parabola.
18. A hardback: Pride and Prejudice.
19. A bag of miscellaneous paper shapes.
20. A chessboard with two brown sandals in the middle of it.
22. Half a history essay.
23. A plastic bag of university prospectuses.
24. A digital camera.
25. An English exercise book.
26. A physics exercise book.
27. A lunchbox, containing last week's wrappers.
28. Another loudspeaker.
29. A pencil, pen and calculator.
30. A DVD player.
31. A loudspeaker attached to the bedpost with the string from a kitbag, the kitbag still in situ.
32. A straw hat and a resuscitation doll.
33. A Fawlty Towers DVD.
34. A used chocolate cake plate.
And - handy to have teenage daughters in the family - I found a - well, a garment. Which garment, after suitable modification with scissors and thread, does not betray its origins when I cycle up the Mot Valley with it wrapped round m'lug'oles.

An anyonymised cyclist wearing 1. a brown paper bag and 2. a bra round his ears. To be legal he is required to wear a crash helmet. Brown paper bags are not an acceptable substitute in NZ law.
You may depend that I have no intention of disclosing any of this to anyone at all. Altogether too many BHPC members would howl jubilant derision. But at least there is a reduced likelihood that my wife will nick it.


Thursday, July 30, 2009 10:35:16 AM Categories: bike clothing
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