Tandem

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 Niewelaar's article in the Feb 2008 newsletter of KiwiHPV, and then you re-read Sheldon Brown http://sheldonbrown.com/tandem-build.html, and then you re-read John Allen http://www.bikexprt.com/bicycle/tandem.htmand then you head for the dump at Mariri.

With a name like Martin van den Niewelaar 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 http://www.violin.co.nz/links.shtml 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.)

Roads

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 -
'Commoditized' 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 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.)

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:

http://www.bhpc.org.uk/forum/forum_posts.asp?TID=3150&title=bb-height

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, http://www.youtube.com/watch?v=iiyFGeQPPms 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: http://www.legslarry.beerdrinkers.co.uk/tech/SpeedAndPower.htm

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:

http://www.legslarry.beerdrinkers.co.uk/misc/TwosCompany.htm

and if you can read Foreign, so has a Foreigner from Abroad:

http://generationsfutures.chez-alice.fr/velo/tandem_dos_a_dos.htm

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. http://www.discountcyclesdirect.co.uk/popup_image.php?pID=6985

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?

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.