HPVS October 2002

hpvs@lists.lysator.liu.se

23 participants
33 discussions

Hallandsloppet, påminnelse.
by Pär Borgström 08 May '07

08 May '07

Hej bröder och systrar! Tänkte bara påminna om att det nu är dags att anmäla sig till årets Hallandslopp den 4 maj. Det kostar 120 kr att cykla 36 km och 200 kr att cykla 100 km. Barn under 12 år i målsmans sällskap betalar halv avgift. Är du intresserad av att cykla i grupp med några glada liggister kan du anmäla ditt intresse till mig senast onsdag 13 mars så tar vi detaljerna sedan. Vill du kolla mer och kanske anmäla dig själv direkt så går du in på www.hallandsloppet.com. Ta dig i … [View More]

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RE: [hpvs] Fwd: Liggcykelargument
by Fridqvist, P.A.S. 01 Nov '02

01 Nov '02

Jaha, så liggcyklister skulle kunna säga: "Liggcyklister gör det" (fniss) Sverker > -----Original Message----- > From: Peter Markusson [mailto:peter.markusson@telia.com] > > Tvingar du upp mannen i sadeln? > > Precis bakom pungen finns det ett litet nervcentra. Det > sitter inte så bra > > till för cyklister, konstaterar Berlingske Tidende. Enligt > forskarna kan > > lång tids cykling göra att nervcentrat inte mår så bra och > det kan leda > &… [View More]

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Stockholm lever!
by Jan-Inge Ljungberg 31 Oct '02

31 Oct '02

Hej kamrater liggister! Hittat på HPVS diskussionsforum! Trehjulingar No score for this post October 18 2002, 9:01 PM Har just flyttat till Stockholm... Har en Leitra och en A.S. Engineering S-327. Mekio Yoo (no login) 217.208.221.176 Börja leta på Stockholms gator! *:-.,_,.-:*'``'*:-.,_,.-:*'``'*:-.,_,.-:*'``'*:-.,_:-.,_,.-:* Jan-Inge Ljungberg webmaster(a)liggister.org www.liggister.org

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Mountaindrive
by Bernt Carlberg 29 Oct '02

29 Oct '02

När vi ändå håller på att diskutera tekniska hjälpmedel till cyklar undrar jag om det är någon som har någon erfarenhet av Schlumpf mountaindrive? http://www.schlumpf.ch/language.html Är det bara ett dyrare sätt att få samma sak som med två kedjedrev fram? Tyvärr saknar ju min Hurricane fäste för främre växelförare så jag får ändå köpa nytt frontrör mm. för att fördubbla antalet växlar. Så prisskillnaden för min del kanske inte blir så stor i slutändan. H.d.s.l. Bernt Gratis e-mail … [View More]

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trasig fälg + bygget
by Göran Thyberg 29 Oct '02

29 Oct '02

Hej visserligen ingen liggcykelfråga men ändå. En fälg med skada enligt nedan: http://medlem.spray.se/tuben7/galleries/021026/ Vad kan orsaka en sådan skada tror ni? Har jag kört på något som slagit sönder den eller är det ett utmattningsproblem? Den har gått ~400mil vara hälften på en trainer. Det är fråga om drivsidan på ett bakhjul med 32 oreducerade ekrar. Fälgen är specificerad som "Custom made for Bianchi by FIR". Mitt långsamma lowracerbygge går för övrigt framåt steg för steg. Nu … [View More]

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Fwd: Liggcykelargument
by Peter Markusson 29 Oct '02

29 Oct '02

Hej allihop! Vidarebefordrat brev: > Från: Seinegård Marieanne <Marieanne.Seinegard(a)gp.se> > Datum: tis 29 oktober 2002 kl 09.56.34 (Europe/Stockholm) > Till: "'peter.markusson(a)telia.com'" <peter.markusson(a)telia.com> > Ämne: Liggcykelargument > > Ett argument för liggcyklar hämtat från FL-Net:? > > Tvingar du upp mannen i sadeln? > Precis bakom pungen finns det ett litet nervcentra. Det sitter inte så bra > till för cyklister, konstaterar … [View More]

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RE: [hpvs] pedalling technique
by Fridqvist, P.A.S. 28 Oct '02

28 Oct '02

As always I cannot resist these technical discussions. Please forgive me... Richard Wizins wrote: > Maybe you are right Frederik, maybe not. I am personally not > convinced that > we can pedal very much more efficiently than most skilled > cyclists already do. This seems plausible. There is so much money in pro cycling that it would be unlikely that the pro teams haven't already done what's within the reach of scientific investigation to promote the highest possible … [View More]efficiency. This, of couse, dosen't exclude new scientific discoveries... > B. We have the issue of aerobic limitations. I.e. the > cardiovascular system > can not support an increase in power over any lenght of time > even if we have > the muscles to do it. This I agree is the limiting factor for power output for most cycling activities. > energy. One could argue that it "only" prevents us from > actually resting on > the pedals on the upstroke and thereby counteracting the push > on the other > pedal. There is no telling how much power we actually add - > it could well be > nil. Yes. The idea of Powercranks is to avoid spending some energy counteracting youself, i.e. pushing 'backwards' with one leg and 'forwards' with the other. Some energy would undeniably be saved if this can be avoided. It might be very little, though, maybe too little to bother. And maybe the action of actively lifting one leg instead of just letting it be lifted causes involvement of additional muscles, resulting in a nil gain or a loss. The human body is mechanically quite complicated (sic) and activating one muscle here generally requires another muscle there to be counteracting, to avoid the having body severely twisted... > Bikedrive on the other hand does address the problem of > erratic power. If > we accept that we have an spike of force on the down stroke > (or up stroke by > the way) which is in part lost on trying to overcome the bike's (and > rider's) moment of inertia (weight basically, in this case) we have an > interesting opportunity here. By storing part of the access > force (energy > actually) in the spring instead of "burning" it on a > fruitless attempt to > jump the bike forward we can use that energy during the > otherwise virtually > powerless 12-6 o'clock part of the cycle. Thereby we would add no new > energy, but we would waste less of what we have on fruitless short > accelerations (F=m*a). Well, storing energy as spring tension or as momentum would make no difference, would it? Only the momentum storage is more light-weight, and has no termal losses... BTW, the energy provided by each pedal stroke is small compared to the moving energy of the bike with rider, I think. I the energy of the moving bike was plotted, the pulsing caused by pedalling would be a tiny riddle on top of a comparatively steady line. > - My first impression of the Powercranks was a bit flawed. Their main > principle is preventing "resting" (pushing if you like) on > the pedal in the > up-stroke. Learning to use muscles to lift the foot will > increase effective > power (theoretically). If the power contribution in the > up-stroke remains > small (but not negative) it will do nothing to smooth the > power curve. This might work, but I'm sceptical. I am, too. But read the last lines below: [View Less]

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Re: pedalling technique
by Frederik Van De Walle 26 Oct '02

26 Oct '02

Hey all, I think that things have been discussed 'sufficiently' and it is now time to wait for Dick to try and test Bikedrive. So what follows is just some ideas and stuff I thought about when I followed the past discussion... that might be interesting for you. -Some guy named Harrison measured already in 1970 that the rowing motion can give higher power than pedalling when the exercise lasts longer than 30 seconds, as in, not in sprints. This is when inertia of the rowing movement is … [View More]maintained with a flywheel (in a test laboratory) but a bike at speed also has quite some inertia,... The explanation that for the fact that no HPV rowing records exist (well, actually, Derk Thijs had some records, for some time at least) is that the motion takes more space and so ultimately, aerodynamics suffer more. Ah yeah, also the power was greater with the butt fixed and the legs moving, instead of the whole body moving. It is quite obvious that THAT causes a lot of lost acceleration forces... -I actually once road an alternative drive that really worked. It was on an upright bike invented by a Belgian... inventor ;-) Anyway, he used a connecting rod system attached to the cranks that lengthened the crank length in the push position and drastically shortened it in the back stroke, so no need for clipless. Not only this, he also succeeded in having the time spent in the back stroke reduced and the time in the front stroke enlargened. As a result, it was a piece of cake to pedal HUGE gears, like 65-11 on 26 at a speed of 30 km/h was comfy. It really worked; yet sadly, his work is hardly acknowledged by anyone. Well, the construction is quite elaborate and cannot be implemented on a recumbent since the whole rod system would then point downward. Well, not in the form it was when I saw it anyway. Still to bad no one picks it up in the upright world. -If Bikedrive lessens peak force with 20%, it is because the resistance is 20% lower. Or because the local speed is about 20% higher (right?). OK, then you spend 20% more time in the dead points, transferring stored energy and inertia into the drive system. My question is, why not learn to pedal 20% faster and skip the dead points +40% faster? That is the whole trick of the 500W of professional record power, it is done at 110rpm. The change of inertia in the legs with a bikedrive system, +20% to -20%, 220 times per minute, must be quiet interesting at those rpm... and so the story goes on... forever ?? ;-) Just test it :-) Regards, Frederik _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 [View Less]

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RE: [hpvs] kul
by Fridqvist, P.A.S. 25 Oct '02

25 Oct '02

Jo, den var kul! Var kan man se den i verkligheten? Sverker

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kul
by Johan Fohlin 25 Oct '02

25 Oct '02

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HPVS October 2002