British
Human
Power
Club

Possum bars 




Mr Knight who is a Low Creature and a toe-rag and a scumbag and a Foolish Person asked what to bring to New Zealand and instantly I replied 'a lathe' and being a L.C., t-r., s. and F.P. he ignored me and on arrival discovered how vastly clever I am because having grown up with one he really wanted a Myford Super Seven but such as appeared for sale were what engineers call Knackered.
New Zealand has a low population of lathes.
 
 
Yet being a guardian angel I magicked a Super Seven out of the ether in gloriously perfect condition. (In passing, Norm Milne of Stoke, the gentle old man who had cared for this lathe - old lathes never die - had preserved it in lanolin for fifty years from the salty Nelson air. Norm was a star of Nelson Model Engineering Club.) For the record it cost $NZ 1600, which since that's only about six or seven hundred quid is the finest bargain ever known among lathe owners. As I say, Norm Milne was a gentleman.
 
 
 
The following e-exchanges now took place. (We can record them accurately. Mr Knight lives six hours away. All discourse is by e.)
 

It now occurs to me that I will need a higher range of gears. I *think* my current setup is 53/12 on the rear 559 MTB rim. In all races so far this gear has proved sufficiently high and always gets used. Ideas? - Bob

Biggest one I've got is an unused 58 from a downhill bike. - R

Ha, so what BCD is the 58 chainring? 4 or 5 arm?I suspect that it is either 110mm, standard MTB or 130, shitmano road. The spitfire fund needs to know. - Bob

Il y a five holes sur il. Each hole est 65mm from le next hole. Stamped sur one side it says 'DH 58T BCD 110'. In other matters, my mother-in-law is a horrible old witch. But she's going on Friday. Either we shall be very, very sad to see her go or we shan't, and I'm not going to tell you which. I am going swimming now and will be bitterly disappointed if I tread on a stingray and get killed before she goes. R


Bugger fuck, because my crankset is a shitmano road at 130 BCD. I'll have to buy one and I didn't think 58 was big enough anyway and I bought a 55W glue gun and *lots* of glue sticks today for purposes of sticking corriboardcorrexcoreflutekoretake. Axshully that last one doesn't belong there, it's the Maori word for slacker, I have no comment on that. I made some little jigs last night to try to discover the bounds of whirring feet, but feet whirr differently backwards to forwards and I will need to make some adjustable do dads and go for a short ride to establish this. I also need to make the ratracer tiller steering since the widest point at the moment is the handlebars on full lock (which isn't much). This is turning into an ordeal already. I've just looked at Simon Sandersons pictures of his new streamliner. *Anything* we make is shite in comparison:
Warning: much time wasting could be spent looking at that link. - Bob


Therefore Mr K set up said lathe and promptly made some possum bars and a 64-tooth chainwheel.

 
The bars were to be welded up by Gavin Keats who is an aircraft engineer and who has built his own aluminium velomobile. This resulted in:

Now then young man, I feel I have been remiss in replying these past few days but I am busier than Talley's PR dept (1). I will try and recap.
1) Gavin Keats is going to weld up the bits for the tiller next Wednesday, that means I can install it very soon and see how bad the handling is, if bad I will ditch it and return to the original bars. In programming terms this is known as a ternary statement and in this case would be written like this:
_handlebars = ((_tiller == ridable ? _tiller : _original);
you didn't need to know that but I'm at work and that's where my head is right now.
2) I have started to make a 64 tooth chainring, this prompted by the shocking price of 'real' chainrings on t'internet. Cheapest I saw was 300 NZ lira dollars. No way. Going ok so far, I *love* my dividing head. I'm slightly concerned that the grade of aluminiumiunmium I have used is too soft, but then it only has to last an hour.
3) I have ordered my Coreflute Correx Corriboard Fluteboard from a plastic shop here in town and will pick it up at lunchtime, I've got 2 sheets of 3mm for skinning the thing and 1 sheet of 8mm + another of 5mm for the structure, think model aeroplane. That's how I did the tailfairing on the Windcheetah. I will experiment with hot glue later and see if I need to use dental floss and tape again. In programming terms this is also a ternary statement, an alternative way of expressing the statement is:
if (_hotGlue + Corriboard == strong){ _construction = _hotglue;}else{ _construction = _dentalFloss + _tape;}
but you didn't need to know that either.
That is all. - Bob

1. Talley's are a local firm who made the national news when it was revealed that people were perturbed to open packets of Talley's Frozen Peas and find then half-full of Black Nightshade berries.


Later, I had the following:

Possum[1] bars are *quite* hard to get used to at first. I rode on the lawn at first and crashed a lot, then began to get the hang of it a little, so this morning I took the Ratracer over the ghastly Ashley bridge and up to Carrs road which more or less goes straight for 19km right into the wop wops. It does wiggle a little and also goes up and down rather a lot as roads do, but because it goes nowhere it is very quiet. Anyway because I was new to the bars and occupying more of the lane than I really should I was taking it relatively easy at first. I averaged 38.2 kph for the 40km with a max of 62kph ( that's ~23.8mph and 38.7mph resp. in old money). The bars are decidedly twitchy and I'm having to learn to ride all over again it seems; however by the end I was able to pedal reasonably hard around gentle bends, but tighter bends had my sphincter all puckered up in an unseemly manner. This will probably ease. The 64T chainring was a great success and I was able to use top gear for extended periods over 50kph with no trouble as long as the road was straightish. I also seem to have a death grip on the bars at the moment; the handling improved when I forced myself to relax when I became aware of it.

Bob

[1] not hamster bars, possum bars. Relatively recently introduced and hard to control.




 

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