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#41
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On 21 Oct, 05:27, "Dre" wrote:
With practise, there is nothing stopping you from hopping over gates, fences etc. *Unfortunately my technique still needs work and I can only clear a beer carton and a half standing on the ends (approx half a meter high) Actually Rob van der Plas recommended that racing cyclists jump milk/ beer crates. So about 10" high and 20" long. The idea, I think, so you could clear a fallen rider for which you were otherwise unable to avoid. Plenty of off road riding on a road type bike seemed to work well enough for the training aspect for when required on the road. I never actually got a full torso in front of me, so I dont know if I could have jumped. |
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#42
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On 21 Oct, 23:37, RonSonic wrote:
On Wed, 21 Oct 2009 12:57:35 -0700 (PDT), thirty-six wrote: On 21 Oct, 05:27, "Dre" wrote: With practise, there is nothing stopping you from hopping over gates, fences etc. *Unfortunately my technique still needs work and I can only clear a beer carton and a half standing on the ends (approx half a meter high) Actually Rob van der Plas recommended that racing cyclists jump milk/ beer crates. * So about 10" high and 20" long. * The idea, I think, so you could clear a fallen rider for which you were otherwise unable to avoid. *Plenty of off road riding on a road type bike seemed to work well enough for the training aspect for when required on the road. *I never actually got a full torso in front of me, so I dont know if I could have jumped. I failed to keep a link of it, but there is some great footage of a pro bike race, a small group of riders out on a break, two of them jump and are off by themselves. Now one is trying to drop the other and they fought it out for miles. Finally one starts his attack just before a huge intersection, sort of an ovoid roundabout, bunny hops onto the huge traffic island at a dead sprint, keeps pounding across the island flies off the other side and made good his separation. It was a thing of beauty. The hop onto the island was perfect, it didn't look like he was even an inch higher than the curb, both wheels came down together and in perfect balance. Flying off the other side, again perfectly smooth no wasted motion and the bike just gently put back on the road. Hopping while clipped in is much easier. Apparently BMX and trials guys can make the bikes stick to their feet or something. They have gheko in their blood. The shortcutting of race route by jumping kerbs is not unknown to me. I was most impressed when a local pro managed it on the final bend to win the finishing sprint on a stage in the Tour of Britain. He went on to win the tour. Thing is with a circuit race or criterium, you have to leave it until the final sprint or everyone gets the idea. Unfortunately, my breath didn't seem to hold out for long enough, enough. |
#43
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On Oct 21, 3:57*pm, thirty-six wrote:
Actually Rob van der Plas recommended that racing cyclists jump milk/ beer crates. * So about 10" high and 20" long. * The idea, I think, so you could clear a fallen rider for which you were otherwise unable to avoid. *Plenty of off road riding on a road type bike seemed to work well enough for the training aspect for when required on the road. *I never actually got a full torso in front of me, so I dont know if I could have jumped. My best jump was over a dog that suddenly ran out directly in front of me on a narrow country lane. I had a riding buddy on each elbow and nowhere to go but up. And it wasn't a perfect jump; the rear wheel caught the dog and broke its shoulder. Wasn't even a very big dog. But back in those days I was getting lots of practice. My commuting route had a bad set of RR tracks that I'd fly over most days. I'm more staid now. BTW, the way I've always visualized what I'm doing is this: Using my hands and feet, I propel my body upward, then pull the bike up after myself, by the handlebars and toe clips. Keep that handlebar straight for the landing. - Frank Krygowski |
#44
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On Oct 21, 6:37*pm, RonSonic wrote:
Hopping while clipped in is much easier. Apparently BMX and trials guys can make the bikes stick to their feet or something. I can do it a bit without clips, but not nearly as easily or as high. It happens so fast it's nearly unconscious, but I think the physics goes like this: Rider jumps up, and pulls handlebars up after himself. Mass center of the bike rises while the rear wheel is still on the ground. Then the rider pushes down on the bars, to rotate the bike about its mass center so it's horizontal. The end effect is two wheels off the ground. I've seen that explanation given for the similar trick of jumping a skateboard, except that the start of that sequence is kicking down on the back of the board as the rider jumps up, so it "wheelies" on its rear wheel. But the explanations don't cover the smoothness and skill with which some guys perform these moves. People are capable of amazing things. - Frank Krygowski |
#45
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On Oct 21, 8:00 pm, Frank Krygowski wrote:
On Oct 21, 6:37 pm, RonSonic wrote: Hopping while clipped in is much easier. Apparently BMX and trials guys can make the bikes stick to their feet or something. I can do it a bit without clips, but not nearly as easily or as high. It happens so fast it's nearly unconscious, but I think the physics goes like this: Rider jumps up, and pulls handlebars up after himself. Mass center of the bike rises while the rear wheel is still on the ground. Then the rider pushes down on the bars, to rotate the bike about its mass center so it's horizontal. The end effect is two wheels off the ground. Good analysis, I think. I've never practiced it. I think maybe there's a forward thrust / rotation of the bars component. Obviously the rider cannot "pull up" on unattached pedals (it's definitely all in the handlebars), but does use the inertia of his body to lift the bike off the ground. I've seen that explanation given for the similar trick of jumping a skateboard, except that the start of that sequence is kicking down on the back of the board as the rider jumps up, so it "wheelies" on its rear wheel. But the explanations don't cover the smoothness and skill with which some guys perform these moves. People are capable of amazing things. Remarks like "it's nearly unconscious" and "explanations don't cover" are atypical coming from you. I'm impressed :-) |
#46
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On Oct 21, 11:49*pm, Dan O wrote:
On Oct 21, 8:00 pm, Frank Krygowski wrote: On Oct 21, 6:37 pm, RonSonic wrote: Hopping while clipped in is much easier. Apparently BMX and trials guys can make the bikes stick to their feet or something. I can do it a bit without clips, but not nearly as easily or as high. It happens so fast it's nearly unconscious, but I think the physics goes like this: *Rider jumps up, and pulls handlebars up after himself. *Mass center of the bike rises while the rear wheel is still on the ground. *Then the rider pushes down on the bars, to rotate the bike about its mass center so it's horizontal. *The end effect is two wheels off the ground. Good analysis, I think. *I've never practiced it. *I think maybe there's a forward thrust / rotation of the bars component. *Obviously the rider cannot "pull up" on unattached pedals (it's definitely all in the handlebars), but does use the inertia of his body to lift the bike off the ground. As a former BMX racer, current BMX dirt jumper, skate park and street rider and someone with a lean toward trials style on the MTB, I'll chime in here. I can hop higher on my BMX, no clips, than I can on anything I have with clips. The way I do it is entirely weight transfer and momentum through the handlebars. It goes something like lean back, into a manual (wheelie) that you know would loop out. When the bike passes the balance point, throw all your weight forward (which is now 45 degrees from the ground at a minimum, likely higher, exactly where depends on the bike). The basics can be practiced in a much more mild way. Lean back and pull up on the bars to get your manual (wheelie) and then shove the bars forward with all your weight and momentum. It feels more natural to throw the weight forward in relation to the ground rather than the angle of your bike, that's fine for starting out. The only limiting factor is it will not allow you to hop higher than you can manual. Be sure you are transferring your body weight and momentum into the bars and over the front wheel and not just pushing with your arms with your weight still back on the pedals. The reason we're able to control the rear of the bike so well when doing this on a BMX with platforms is there is basically no weight on the pedals at this point, we've thrown all our weight and momentum into the direction we wish the bike to go. The pins on the platform provide sufficient bite into our sneakers for small adjustments. Another way to practice is to find a small rise, say 4", that is not sharp enough to pinch your rear wheel. Ride up to it and manual your front wheel on, then throw your weight forward into the bars and lean forward, lifting your rear wheel up onto the rise. Once you can do this, it's just a matter of speeding it up to hop up the same rise. Then you can work on height. BTW, practice on things/times/places that won't get you really hurt or damage your bike (i.e. if you think you are hopping 5", don't try to hop a 4" curb at an angle in front of traffic). You're never going quite as high as you think you are. The only way to know is to clear obstacles. You can start with 2x4's on their side, if you're not getting the 3.5" you'll knock it over. Then 2x6 (for 5.5"), etc. Once you can clear a section of 2x12 (11.5") consistently you're ready to start looking at larger obstacles. My current challenge is a downed trash can, it was easy-peasy in my real BMX days but these days I tend to clip the things. snip |
#47
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Will a 29er work for college campus commute?
On Oct 17, 8:03*pm, Dan O wrote:
On Oct 17, 11:36 am, wrote: I live abt 3 miles away from university I attend. I want to buy a bike that I can commute with Problem is I want the fastness and low rolling resistance of a mt bike but the ability to jump curbs and cut across grass a mt bike give There are MANY curbs between me and school..... and many curbs and obstacles on campus. Will a 29er be the best of both worlds? *Will it allow me to feel "fast" on the streets to school.... yet allow jumping curbs and such? A 29er will have the cool factor you'll probably desire on campus. Fast is all about gearing, my 20" MTB is faster than my SS 29er. I can also hop it WAY higher. In fact, while I can clear any curbs I come across on my 29er, that's about it. On my BMX I can get over a downed trash can, although these days I'm likely to clip it with my rear wheel on the way over (no big deal, doesn't even slow me down, just annoying since I used to be able to hop so much higher when I was more in practice). For that ride, personally, I'd want a BMX. Huge toy/fun factor. Throw some pegs on whatever side you rotate towards, and you'll find places to throw stalls and grinds in along the way. Next thing you know you'll be looking for jumps. If you want a 29er, however, it'd work fine for this application. Just make sure you can hop one high enough to clear a curb, or get ready to spend some time practicing. It's a lot of bike to will into the air. IIRC, MTB Dan (who I expect is very good at the sort of riding you describe) said his 29er was much harder to bunny hop and stuff like that. This is true, this describes a typical city ride for me, which could be done on my BMX, my 29er, a 26" MTB, whatever's around. Only bikes I don't do this stuff on are the road bikes with the very skinny tires and drop bars. My 29er is certainly much harder to bunny hop than a smaller bike, but that's true all the way up the line. Try a scooter, or a 16" kids bike. You'll be amazed how easy it comes up, since it's so small. The bigger the bike the harder it gets. Do I need a front shock or will balloon-like tires work? I find my rigid 29er to be fine. Suspension is not going to help your cause hopping things, and 29ers are plenty comfy for bombing around. |
#48
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Let's do the bunny-hop, was Will a 29er work for collegecampus commute?
On Oct 21, 12:36*pm, Dan O wrote:
On Oct 20, 6:49 pm, Andre Jute wrote: On Oct 21, 1:49 am, "Dre" wrote: "(PeteCresswell)" wrote in message .. . Per Andre Jute: Is the implication here that if I blow up my Big Apples a bit higher than the 2 bar (approx 30psi) they are now, I can go kerb-hopping? I'd think so. * I mean, you have to be a *little* bit cool about it - throwing your weight forward and off the pedals as the tire hits the curb, but the only pinch flat I've ever had on the 55/55's was when the rear tire was down around 20 psi - so low it was squirming on corners. -- PeteCresswell This is where bunny hops come in *real* handy. *I have no problems hitting a curb at full speed because I bunny hop up onto it. *Both wheels clear the curb so no pinch flats ever Cheers Dre What do you have to do to make the bike bunny-hop? Give it to me in steps, if you please, leaving nothing out. It helps to have a lightweight bike. Meh... weight is overrated in this respect. My 20" BMX is my heaviest bike. It's also the smallest. It's also the one I can hop highest, by orders of magnitude. |
#49
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Will a 29er work for college campus commute?
" wrote:
For that ride, personally, I'd want a BMX. Funny you bring BMX up as there are a TON of them on campus and ridden by younger students. BUT.... I'm a full size adult student! Where do I get a BMX frame and bike that fits a 200 lb adult??! |
#50
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Will a 29er work for college campus commute?
On Oct 22, 11:38*am, wrote:
" wrote: For that ride, personally, I'd want a BMX. Funny you bring BMX up as there are a TON of them on campus and ridden by younger students. BUT.... I'm a full size adult student! Where do I get a BMX frame and bike that fits a 200 lb adult??! www.danscomp.com The only measurement that matters is top tube length, the rest is just to work the geometry. I'm 5'10, 180lbs. I can ride a standard L or XL 20" BMX with no problem. Oddly enough, when I was at my best I was about 200lbs, since it was before I took up mountain and road biking. I've been abusing the same 20" BMX for the past 12+ years. 48 spoke Peregrine Superpro wheels & sealed hubs by the same, DK General Lee frame, Profile cranks, the rest is really just what you like. I have not bought major BMX components since the 90's as there is simply no need, my old stuff is still bulletproof. I have ridden with some younger kids, and the "new thing" is to use a much smaller chain ring and freewheel (which requires a different size hub, standard now but very rare or nonexistent when I built my bike). I assume this is done to increase clearance, a 45T chain ring on a 20" bike doesn't leave a lot of clearance. The gear ratio's stay the same. Also, when I was racing back in the day some of the "older guys" (probably the age I am now) ran 24" BMX bikes. We called them cruisers, but they were really just BMX bikes built around 24" wheels. 20" is plenty big enough though, as my best friend who is 6'4" and can out ride anyone I know on a 20" on any given day would be happy to demonstrate. I wouldn't worry about being 200lbs, as long as you get something designed for abuse. I'd look for a dirt jumper over a racer or skate park bike. You can still do all the skate park stuff (I do on mine) and they're rugged as can be and built in such a way that it's comfortable to ride pretty darn quick. Once concern with a BMX is they are not the 20" bikes of yesteryear, i.e. "RAD", with the S shaped seat posts and high seats where it was comfortable to sit and ride. On any mid 90's forward BMX you stand while riding, and the seat is really low. |
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