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#31
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Fastest speed on a coker?
showard wrote: *Actually, Harper's hub will result in *four* wear spots 90 degrees apart instead of two. * Speaking on behalf of myself and the other idiots I represent, I must ask "Why"? The uni appears to roll forward in a consistent manner, so why would there be four wear places? I understand why on a giraffe which gets idled a lot over the same part of the tire, but don't see why it would happen on a uni that doesn't get idled (much) and pretty much just does distance or speed riding. -- tomblackwood - Registered Nurtz My other brake is my face! ------------------------------------------------------------------------ tomblackwood's Profile: http://www.unicyclist.com/profile/3762 View this thread: http://www.unicyclist.com/thread/27287 |
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#32
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Fastest speed on a coker?
GizmoDuck wrote: *I wonder if drafting at 20km/h will save us a few minutes over 160km? * Based on my uni racing experience I can't recommend it. When done by bicyclists with lots of training and racing experience, drafting can still be fairly dangerous. Add the extra things that can go wrong on unicycles at high speeds, along with what I think would be a reduced aero benefit, and the return would seem to diminish quite a bit. For those not familar with the situation, these are things that can go wrong in a drafting situation: 1. Rider in front falls--guaranteed fall for rider in rear, plus landing on front riders' unicycle. 2. Touching tires front to back. If they touch pretty hard, it can throw off both riders--see #1. 3. Overlapping wheels--since our wheels generally don't go straight but have some wobble, this could be disasterous. If the wheels touch and the rider's center of mass is in the wrong place, it might be impossible to recover from the position. Coker riders are generally going slower than bike in a race, so the amount of advantage you get from drafting will be less. I don't know if the riders' bodies are any closer than bike bodies, but the fact that we generally sit up much straighter, and are less aerodynamic, may increase the amount of "benefit" you could get from drafting. But for me, I don't think it would be worth the risk. -- johnfoss - Now riding to work John Foss the Uni-Cyclone www.unicycling.com ________________ "Where's my kids?" -- Amy Drummond "Where's my unicycle?" -- Andy Cotter spoken one right after the other, mostly to themselves, at NAUCC 2003 ------------------------------------------------------------------------ johnfoss's Profile: http://www.unicyclist.com/profile/832 View this thread: http://www.unicyclist.com/thread/27287 |
#33
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Fastest speed on a coker?
johnfoss wrote: *Based on my uni racing experience I can't recommend it. When done by bicyclists with lots of training and racing experience, drafting can still be fairly dangerous. Add the extra things that can go wrong on unicycles at high speeds, along with what I think would be a reduced aero benefit, and the return would seem to diminish quite a bit. * The general rule on bikes is that you need to be going over 15 to 17 mph (24 to 27 kph) before drafting becomes worth it. Below those speeds you are not getting enough of a draft off the front rider to give you much benefit. At speeds above 20 mph (32 kph) drafting gives you a very noticable advantage on a bike. The thought of drafting another unicyclist at 17 mph is craziness. Too much risk of a very high speed UPD and a bad crash. Dangerous. However, drafting behind a bike at 17 mph would be a little less crazy, but still crazy. You'd need the bike to cooperate and maintain a very consistent speed. It would be an exercise in intense concentration on the part of the bicyclist to be able to maintain a very consistent speed and communicate with the unicyclist about speed, road conditions, etc. The bicyclist would also have to sit up to create as big of a windbreak as possible. Drafting at 17+ mph on a unicycle would be something to put on John Foss' Things Not To Do page. -- john_childs - Guinness Mojo john_childs (at) hotmail (dot) com ------------------------------------------------------------------------ john_childs's Profile: http://www.unicyclist.com/profile/449 View this thread: http://www.unicyclist.com/thread/27287 |
#34
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Fastest speed on a coker?
I've done A LOT of drafting on bikes, and John Childs is exactly right - it's generally not helpful below something like 17mph. Biking in a tight paceline at 25-30mph is a fantastic feeling and not all that crazy as long as everyone knows what they are doing. This is where your front tire is 1 to 6" from the rear tire ahead of you. (Sometimes even touching!) I've "drafted" on a unicycle going 10-12 mph (for photos), but it isn't really drafting - you're just riding behind the person in front. There is one case where drafting on a unicycle actually makes sense: in a headwind. If you are able to push say 8-10mph into a 15mph wind, you actually do get some benefit from drafting. The reason is that John's 15-17mph isn't the speed of the cyclist, it's the speed of the cyclist plus the headwind. So you're relative speed to the air here is 23-25mph. Be very careful doing this on a unicycle! ---Nathan -- nathan - BIG rides: Muni & Coker ------------------------------------------------------------------------ nathan's Profile: http://www.unicyclist.com/profile/251 View this thread: http://www.unicyclist.com/thread/27287 |
#35
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Fastest speed on a coker?
showard wrote: *... there's three possible places to anchor the arm dingus so if the hub is switched from 29" to 43.5" often, the tire should wear fairly even. * To add further complication, when the wheel is stationary and the torque arm (arm dingus) is rotated one full turn, the pedals rotate one half turn. In reality, then, there are six unique positions of the pedals with respect to the wheel in direct drive, or 29", mode, not three. And to further nitpick, the contraction "there's" is completely inappropriate here in that it should take a singular predicate nominative rather than the plural, "places". The irregular contraction "there'r" would be appropriate in this sentence. Now we're jacking this thread with two tangential topics. Cool. Finally, it is part of my belief system (as opposed to something I know) that Frank's hub gears up by 1 and 4/7 or 1.57 something. This could be something I made up knowing that the numerator and the denominator must be integers of reasonable values. -- harper - Old dog, no tricks -Greg Harper B L U E S H I F T "I managed to get my missus riding a couple of yards before she got pregnant with Jenny, but she hasn't tried riding since. " - Danny Colyer "Sa da tay! Sepotown!" - Pootie Tang ------------------------------------------------------------------------ harper's Profile: http://www.unicyclist.com/profile/426 View this thread: http://www.unicyclist.com/thread/27287 |
#36
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Fastest speed on a coker?
On Mon, 8 Sep 2003 19:43:43 -0500, harper
wrote: Finally, it is part of my belief system (as opposed to something I know) that Frank's hub gears up by 1 and 4/7 or 1.57 something. This could be something I made up knowing that the numerator and the denominator must be integers of reasonable values. Frank initially stated that his hub's gear ratio was 1.57. For that reason the machine has been (or is?) known as uni.57. However when I asked about the exact value (about 1.5 years ago I think) he said that it is actually 114/72, or 1.583333. Interestingly, if this hub were mounted on a Coker with its nominally 36" tyre, it gears up to exactly 57" (nominally, I must add again before Steve H picks that nit again). That machine could become known as Coker.57. Klaas Bil - Newsgroup Addict -- If the crank is moving then it really sounds as if it's loose. - onewheeldave trying to pinpoint the cause of a clicking crank |
#37
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Fastest speed on a coker?
GizmoDuck wrote:
*I wonder if drafting at 20km/h will save us a few minutes over 160km? * I'm sure that GizmoDuck is not serious. One good reason is drafting at 20 km/h (12.4 mph) is too slow for wind resistance to have much effect and thus drafting will have minimal effect as well. Wind resistance is proportional to the cube of wind speed. I vaguely recall that wind resistance is not a big factor until 20 mph (or was that 20 km/h . Sincerely, Ken Fuchs |
#38
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Fastest speed on a coker?
I feel obliged to point out that although I'm riding really fast on my Coker every single day I wear a helmet and wrist guards on EVERY ride. As far as the high-speed UPDs I have substantial training in Aikido and have developed enough skill in the art to actually roll out of my UPDs. Not roll on my unicycle but to take a roll. Frequently my falls occur at about 20 mph. Usually the first thing that happens after I UPD is to tap my foot off of the ground and launch myself through the air for a huge forward roll. I realize the risks of what I'm attempting and try to prepare myself for the worst. Whether I'm racing on BMX tracks with my unicycle, leaping on obstacles at the skate park or simply racing along as fast as possible I make sure that my safety gear and skills are all ready to protect me. Don't try something extreme just because it has been accomplished before. Mike Peterson Eugene, OR Come visit Mike's Home for Wayward MiB agents at: http://gladstone.uoregon.edu/~mpeters1 |
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