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Posts in Category: Moving Bottom Bracket bikes

Penny trike 

Friday, October 22, 2010 9:33:04 AM Categories: Moving Bottom Bracket bikes penny farthing trikes
Meticulous care with the lathe - meticulous - and so I was only four thou out when I'd finished making the bearing housings. Four thou for heaven's sake! Again! Heigh ho, so what's new? I'm a rubbish machinist. But I own scissors, and Coke cans are to be had from the wayside. Neatly shimmed, the bearings sort of fit, after a fashion.

The frame angle is a Lowing Joint which is my favourite. The Lowing Joint is named after Dr Lowing who, in a series of complicated emails from the far side of the world, told me how to do this partic'lar weld which he calls a 'Double-D Joint'. When I finally understood I was so impressed that I renamed it, and the Lowing Joint it has now become in the great lexicon of recumbenteers, along with tadpole, which I rather disapprove of, and sitzhöhe, which I like.
 The rear axle got welded to a sleeve clamp so I can vary the wheelbase, and the vile handlebar got itself off that BMX which started the whole project off. No other handlebar would allow knee clearance, and I certainly wasn't about to waste time making one.

I had thought - being realistic - we would now have a completely ludicrous machine for riding round and round the house at a variety of speeds on varying numbers of wheels, destroying the lawn and various boy's (sic.) trousers. But the surprise was how much there was to learn from it.
 
The seat position puts all the body weight on the muscles doing the work and it's painfully uncomfortable but the seat needed to be well back to avoid putting the weight above a single wheel. Lifting oneself forward and up does make the thing dreadfully unstable because it isn't a bike. Ever ridden one of those Newton conversion trikes? Single back wheel from a conventional bike, but with two front wheels and Ackerman steering. I once rode one through the village along Warner Street, where there was a murder at number 12 and where Johnnie Johnson (1) was born at number 21. At the war memorial I got off and pushed it home. It was a Truly Horrible Machine. Effectively you're riding a bike because you're sat above the single of three wheels, and you're not allowed to balance because the second front wheel won't let you. Ghastly. I mentioned this to my brother-in-law who possesses a disabled child, and who is keen to get through money as fast as he can, and who was about to buy his daughter exactly this layout of trike for six hundred quid. I spoke of the shortcomings. He bought it anyway and whenever the child came to stay with us, she tipped herself off it into the road. (You paid for it, incidentally, not him. He applied for a government grant.)

When the wheelbase is long the trike isn't very stable, but is rideable. With a short wheelbase the weight is on the back wheels so the front wheel spins like a drag racer. But oddly enough, you don't immediately feel you need a wider range of gears. Your psyche seems to say, 'Ho, 26er, eh? I'm happy with that,' and you trundle along at double walking speed on the dirt roads of the orchard. But you soon realise the need both for a brake, and for footpegs for when you've wound it up to speed and don't want your knees to buzz like a Japanese motorcycle. And it has the remarkable sophistication of a reverse gear. And if you forget to tighten the clamps on the back axle it's a lean-steer trike. - Well, a lean-wobble trike.

Immediately, of course, thoughts of miniature penny farthings are provoked, either with a 29er front wheel which I can afford, or a 36er which I can't. 36er unicycles are to be had in New Zealand; I saw someone riding through the middle of no-where on one with a huge rucksack on his back. But Mr English, notified of the experiment, immediately discovered that 36er penny farthings are being made in Taiwan http://www.taiyingsystems.com/penny_farthing.php so now I fancy making a penny penny, which means a mountain bike wheel on the back too. Since this would be a FWD MTB fixie I imagine all the locals will get very enthusiastic about it. Or not. As the case may be.

1. Johnnie Johnson was Britain's highest scoring fighter ace of WWII. He shot down my wife's mother's fiancée. Probably.

Schroder's Cat 

Monday, July 26, 2010 9:27:17 AM Categories: injury Moving Bottom Bracket bikes New Zealand Nigel Schroder Roll-down tests
 
Here, for no very good reason that I can think of, is a picture of the Maruia Falls. I had to steal this from harlequin.co.nz because the one I took got lost somewhere in the dusty innards of my computer. The Maruia Falls are très pretty but that isn't why we send all our visitors there. It's because in 1928 they weren't. In 1928 they were just a plain common-or-garden scenic river. Still Glides the Stream and Shall Forever Glide (1), until the 17th June 1929 that is, when, after a few days of the locals hearing what they thought were aberrant deer stalkers in the hills, there was a mighty cataclysm and the Mairua River suddenly broke in half and dropped  nine feet ten-and-a-ninth inches. (That would be three metres, Mr Hague, though frankly I feel your espousal of these narsty - ew - French measurements borders on the philistine.) This is an altogether more satisfying earthquake than the ones where a picture goes slightly askew in a housing estate on the outskirts of Peterborough, even if a clutch of people have to get buried in landslides for it to happen. We haven't had an earthquake for a while and therefore I suppose we ought to expect one. Pleasingly the estate agents have all bought houses for themselves on the Richmond Hills which command a view over Nelson bay, not thinking about the fact that the Richmond Hills only exist because occasionally they shoot upwards three metres at a time.
 
Below the Richmond Hills are the Saxton Playing Fields crammed of a Saturday morning with all the Nelson schools' sports clubs, and it falling to my duty to endure a van-load of the truly mindless conversation of my daughter's hockey team, I thought I would skip spectating for an hour and drop in unannounced on James or Nigel or Sam, who all live conveniently nearby waiting, no doubt, for a hearty terrestrial shaking to land a selection of startled estate agents in their midst.
 
To James McLeod's. James's neighbour was washing his car and had mistakenly thought the entire neighbourhood wanted to hear his choice of what purports to be Music but in fact James, unable to bear the din, had gone out. James is of Scottish descent and, I hope, about to take up the bagpipes by way of retribution.
 
To Sam McEachern's. There stood his blue recumbent on the verandah with its new seat upholstery but there was no sign of Sam nor indeed of any of his neighbours, so perhaps he had spent the morning giving James some preparatory bagpipe lessons.
 
To Nigel Schroder's. No neighbour, no Music, but no Nigel either. And there stood Nigel's new low racer, gleaming in his shed, so obv. they weren't all off secretly riding up the Richmond Hills together.
 
Nigel's new machine is a front wheel drive with a swinging bottom bracket. I knew he'd finished it because he sent me film http://www.youtube.com/watch?v=FG5okNSvpTY of him riding it and he seems to be more in control of it that I ever was of the one I made, which after it whacked me in the side of the head got punished with a hacksaw.
 
However in the evening I had a doleful email:
 
Well the roll down - at Marsden Valley, the same place we did the last test - didn't quite go as well as planned. The old bike had topped out at 55kph and on the first run the new bike was faster at 58kph but I had to use the brakes a little to regain control as it started to wobble .
On the second run things went a little wrong. I crashed at about 50-55kph.
Fell from the bike and slid down the road a little then into a creek hitting some very large rocks on the way. My helmet was completely destroyed. James drove me home, then we went to the hospital where I spent the next 7 hours being checked. X-rays and a CT scan. Luckily nothing was broken. Feeling very sorry for myself today. As for the bike it's ok but it's the last time I'll ride it as a moving bottom bracket, so I think it'll get a rebuild and I'll go back to having a boom and a twist chain FWD. The moving bottom bracket was just too unpredictable. The speedo had a 55kph max after the crash and I hadn't got to the fastest section of the run.
Nigel
 
My daughter Susan gaily said 'If he keeps the broken bits he can call it Schroder's Cat, cos it can be a crashed and an uncrashed bike at the same time,' which stunningly obscure joke can only be understood by quantum physicists one of whom I am not.
 
Anyway as - surprisingly - there was no gravel rash we can't twin him with Bob Knight, and as there were no broken bones we can't twin him with Geoff Bird. But there were bruises everywhere and he's very sore so we can twin him with oh, just about everybody else in the recumbent-building fraternity, I should imagine.
 
1. Wordsworth who is famous, or Arthur Streeton who ought to be famouser.
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