British
Human
Power
Club

 

Posts in Category: High Racer

High Racer Frame 

Wednesday, October 5, 2011 9:27:00 AM Categories: High Racer

Well now a spy down in Rangiora informed me last night that Mr Knight has been filing his knees, so I have had to pull m'finger out with John's high racer.

The first stage of making a High Racer is to plan everything carefully beforehand and draw it neatly and think about every bit of clearance, and then go and look on the Bike Heap for the necessary parts.

The second stage, when you come back to the drawing board, is to rip the design up and screw all the bits into a ball and hurl them across the room and start again because everything in the Bike Heap's an inch bigger than you wanted it.

The third stage is to retrieve all the bits and put them on your light box and make a sketch of the first stage, with all the alterations added.

Of course if you are a proper engineer you do not do this at all, but you and I are not proper engineers. We are rank amateurs, and leave the professional stuff to Mr Bird and Mr Burrows and Mr OtherpeoplebeginningwithB.

My Bike Heap these days dangles from hooks screwed into the rafters of the shed, a magnificent advance in amateur bicycle manufacture which I commend to anyone who possesses a shed with rafters. Unf. most of the bikes have either been sawn up already or are made of 531 tubing. The Donor Bike selected did not match my drawing, and pencils are easier than welders and paper is cheaper than steel. The next donor bike said Chromoly on the stickers but it also said Milazo and since Milazo is a cheap brand sold by the Warehouse, a New Zealand equivalent of Walmart, I knew it would be mild steel so I sawed it up cheerfully and was a bit startled to find thin-wall seamless tube all over the workshop floor so perhaps it was chromoly after all. Perhaps Milazo was a reputable company before the Warehouse buyers got to it and forced the quality down.

The rear swing-arm pivot will go through the old bottom bracket, and rather than soften and machine the cups to fit, the Dremel was applied. Only a smidgen needed removing since I wanted a 3/4 tube through it, with nylon bushes inserted and a 12mm OD tube as the actual pivot.

Preparing the hole for welding in the head tube

The mainframe is 2" OD 18g mild steel, and I used a 38mm hole cutter in the drill press to bore a hole for the 40.5mm OD head tube. This would appear to be of mildly inadequate size, but I am a Rubbish Welder as well as a rubbish everything else, so the idea is to insert a hacksaw blade through the hole and saw little radial nicks before hammering everything outwards like a mediaeval crown to enlarge the hole. It makes the welding easier, but rather more importantly allows you to delicately adjust (whack away with a hammer) the exact angle of the head tube, which needs, according to my envelope, a backward slope of one degree. This is one case where it pays to have a hacksaw cut on the pull-stroke. - I offer this gem of wisdom as my contribution to the field of engineering, and require tribute in consequence. - No autographs, sorry. This is the Internet.

John's High Racer 

Wednesday, October 5, 2011 8:40:00 AM Categories: Bob Knight's fairing High Racer

Saturday, September 3, 2011

John's High Racer

Mr Knight has taken to blogging his Geared Facile and this country is deeply unhappy unless there is some kind of competition going on. Two thirds of New Zealanders don't really give a toss about rugby, we have just learnt, but they still like their competition and are prepared to do almost anything to enhance it. Rural Herculeses (sic) hold sheep-shearing and wood-chopping competitions. Urban damsels hold World of Wearable Art competitions. (No, they really do. Google it.) Even the voters don't like their politicians getting complacent and I have just surprised myself reading that
46% of National voters would consider voting Labour
33% of National voters would consider voting ACT (the far right party)
26% of National voters would consider voting Green (the 'streme left)
62% of Labour voters would consider voting Green
37% of Labour voters would consider voting National
15% of Labour voters would consider voting ACT
(National = the Conservative party. Labour = the Labour party. ACT isn't really the far right party but nobody really knows what it is. It used to be led by a bonkers loony called - um - I forget his name but he actively disbelieved in global warming, but anyway he isn't the leader any more because he tried to get the former leader of the National Party, one Don Brash, a man chiefly noted for his imitation of teeth, to join him, and Don Brash surprised him by accepting on the condition that he, Don Brash, replaced him, the one whose name I've clean forgotten, as Leader, and now he, Don Brash, has sacked all their MPs. - Well, actually I suppose that's a fair definition of a far right party.)

Anyway back to the topick in hand: Mr Knight is blogging his Geared F., and I'm feeling all Left Out, and John now wants a recumbent because he only has a racing bike and a mountain bike and a funny 29er penny farthing and a unicycle and a few other things we've welded up over the last few years, poor deprived fellow.


John before he outgrew everything (Photo: Mike Toohey)

So I'm going to build him one and I shall now blog it and Mr Knight shall lag behind because he is a Perfectionist and uses air-gauged tubing and polishes each molecule of paint wherewith he eventually adorns each of his machines, whereas I wade in with a welder and a hammer and Just Get On With It. The score stands like this:

Me: approx several recumbents.

Mr Knight: approx 0 Geared Faciles.

We ignore for the purposes of this competition sundry 1904 Royal Enfields & Red Racing Bicycles & tricycles & Weird Garden Toys & horse-manure trailers & hand wagons & other useless junk wherewith we have each cluttered our sheds.

So I am the Def. Favourite, and will def. win, & Mr Knight will have to eat humble pie and grovel before me when I have finished and he still hasn't burnished the 54th spoke nipple to his exacting satisfaction.


Mrs Knight's 1904 Royal Enfield after she had indulged in some over-vigorous pedalling


Mrs Knight's 1904 Royal Enfield after Mr Knight attended to Routine Maintenance

Right, here's the brief. He (John, that is) wants it as simple as possible, so it has to be short wheelbase and handlebars over the knees. He dislikes being run over & killed so he wants it to be reasonably high. He wants to be fast so the BB has to be about 5 or 6 inches above the Seat Angle. He wants low rolling resistance so we'll go for dual 700c wheels. - Tyres, in the Colonies, can be a bit of a problem unless you go for what's commonly available. - He can manage a high seat because he's now substantially taller than me. (Yes you can say 'taller than me' because 'taller than I' is pedantick and cumbersome.)

In addition he shall be given rear suspension because I don't want him beating his brain to death with a million road bumps, and carrier racks because a recumbent that can only carry a-person-and-his-Lycra isn't a vehicle, it's a racing machine and only a racing machine and nothing but a r. machine. - Here speaks the wisdom of the years. It's the compensation for grey hair and baldness. -

 

Okay, where do we start? - Wheelbase of 45 inches because I know it's stable, trail of 1.75 inches ditto, frame of 2 inch 18g mild steel tubing because it's not as expensive as chromoly, fork with 1.75 inches of rake (they generally do) and 15 inches from axle to base of head tube. Pivot of rear swing arm in the middle of the putative chain run so it doesn't interfere. The seat will as ever be the biggest problem because we'll need to fiddle with it to get the lumbar and neck support right but we'll start with the base pointing at the middle of BB because I know that works, and we'll give him 37.5 inches from the seat angle to the BB because his legs are 3 inches longer than mine, and we'll allow some adjustment for growth because he's only sixteen. Coo! What would it be to be sixteen again. You'd have sex to look forward to, instead of only remember.

Copyright 2006 Blog Author