Swize Posted November 21, 2005 Report Share Posted November 21, 2005 As the title really what actually makes the frount end of a bike easyer to pull up? Well is it having a long stem or a short stem, high riser bars or low riser bars, Short chain stays or long chainstays, does a light end make a diffrence? When i say pull up ime meaning manules and shizzle not backhops and that. Ive not a clue so can anyone tell me :D Sam :turned: (Y) Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted November 21, 2005 Report Share Posted November 21, 2005 short stem high bars short stays light front helps higher bb also helps-usually down to longer forks Quote Link to comment Share on other sites More sharing options...
Davetrials Posted November 21, 2005 Report Share Posted November 21, 2005 short stem high bars short stays light front helps higher bb also helps-usually down to longer forks High front end thats it. lol Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted November 21, 2005 Report Share Posted November 21, 2005 shush dave :turned: Quote Link to comment Share on other sites More sharing options...
sUm Posted November 22, 2005 Report Share Posted November 22, 2005 Well, think of it from a simple physics standpoint. The longer a lever is, the more leverage you can get. Now think of your chainstays as a lever that's holding the front end of your bike down. The longer they are, the more force is keeping you front end down. Same thing with your stem, except this is where the upward force comes from to counteract the downward force being applied by your chainstays. In this sense you can think of your stem as an extension of your whole frame. The longer this frame + stem combo is, the more leverage you have on your hub to raise the front end. If that was confusing, basically the following combination will make your front end easy to pull up: long stem, short chainstays. I suppose long forks would also make this easier, as you have less distance to actually pull the bike up since your front end is starting from higher :turned: . Quote Link to comment Share on other sites More sharing options...
shovel Posted November 22, 2005 Report Share Posted November 22, 2005 short wheelbase, high front end, light front end, doesn't really matter about length of stays as my martin hawyes used to be soo easy to bunnyhop about 40"+ and the stays weren't that short but yeah all of the above will give you more of a streety flicky feeling bike Quote Link to comment Share on other sites More sharing options...
Waynio Posted November 22, 2005 Report Share Posted November 22, 2005 ye personally i dont think stays are a factor in this i think its all to d owith front end set-up, i had an old megamo radical and that bunnyhopped so much nicer than most other frames i have had and i think john shrewsbury will tell you the same as he still has his. id go on bar and stem set-up but the other thing you cant forget is, to bunnyhop you must have confidence, if your thinking you aint going to be able to bunnyhop it then its not going to happen, so if your thinking that its your bar and stem combo then your putting your self down straight away, be happy with what you have you should be able to bunnyhop it with crap set up aswell as good set up all that you will notice is that it will feel nicer to bunnyhop if the bar and stem set up is near perfect. Waynio........................ Quote Link to comment Share on other sites More sharing options...
Simpson Posted November 22, 2005 Report Share Posted November 22, 2005 Taking off your front wheel! :turned: Quote Link to comment Share on other sites More sharing options...
poopipe Posted November 22, 2005 Report Share Posted November 22, 2005 carry loads of change in your back pockets ? Quote Link to comment Share on other sites More sharing options...
mat hudson Posted November 22, 2005 Report Share Posted November 22, 2005 shorter higher stem. shorter top tube. lighter forks, bars, wheel etc Quote Link to comment Share on other sites More sharing options...
Tomm Posted November 22, 2005 Report Share Posted November 22, 2005 Well, think of it from a simple physics standpoint. The longer a lever is, the more leverage you can get. Now think of your chainstays as a lever that's holding the front end of your bike down. The longer they are, the more force is keeping you front end down. Same thing with your stem, except this is where the upward force comes from to counteract the downward force being applied by your chainstays. In this sense you can think of your stem as an extension of your whole frame. The longer this frame + stem combo is, the more leverage you have on your hub to raise the front end. If that was confusing, basically the following combination will make your front end easy to pull up: long stem, short chainstays. I suppose long forks would also make this easier, as you have less distance to actually pull the bike up since your front end is starting from higher :P . That doesn't make any sense, long bikes aren't easier to pull up at all. As plenty of people have said, short stem, high stem. High BB has something to do with it, I think it's to do with pivots and arcs around the back axle, but I don't know how to explain. But basically BB drop makes it harder to pull up. Most people with high BB frames say that they are nice to bunny hop. And not just 'cos they have a short reach. I think :P Quote Link to comment Share on other sites More sharing options...
sUm Posted November 22, 2005 Report Share Posted November 22, 2005 (edited) That doesn't make any sense, long bikes aren't easier to pull up at all. As plenty of people have said, short stem, high stem. High BB has something to do with it, I think it's to do with pivots and arcs around the back axle, but I don't know how to explain. But basically BB drop makes it harder to pull up. Most people with high BB frames say that they are nice to bunny hop. And not just 'cos they have a short reach. I think :P I disagree, the only possible reason that a long frame could be hard to pull up would be if you have a very low stem and/or a very short fork, thus putting more of your weight forward over the bike. If this were the case then the length would certainly be working against you. edit: you have to remember to take things into perspective, just because you change one aspect of your geometry it won't necessarily drastically change anything. It is a combination of many aspects that will change how different forces will affect your bike. Edited November 22, 2005 by sUm Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted November 22, 2005 Report Share Posted November 22, 2005 Well, as I understand it short stays make the front end of a bike come up more easily, however too short and it gets silly hard to bunny hop without looping out. A long frame would in theory make it easier to hop as you would have more leverage, but with a long frame one needs more exagerated movements to get the same effect, this is due to the fact that the lever is longer so the displacement on it has to be larger, this means it will take longer to lift the front end. In conclusion a short bike with shortish stays is best. This is because the bunnyhop is a fast explosive move, you need to make fast movements without the worry of looping out, but you also want the front end to come up reasonably quickly so a long bike to act as a large lever is out of the question. High bb frames eh, well I have a wee theory on them, as you see if one makes the chainstays angle one gets shorter "effective" chainstay length (red line), I think. Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted November 22, 2005 Report Share Posted November 22, 2005 High BB and a low stem would fire up the front, but why? BB rise sucks for a start. Just go and practice. I can lift up the front of my bike with 5kg sus forks on and a low BB. It's technique. Quote Link to comment Share on other sites More sharing options...
skandy32 Posted November 22, 2005 Report Share Posted November 22, 2005 When i say pull up ime meaning manules and shizzle not backhops and that. Ive not a clue so can anyone tell me :$ Sam :P :) along with all the other suggestions of altering your bike, just practise yanking the bars up. If a rider can manual - they could probly do it on any bike, its more abotu technique than bike i think. I can manual a 7inch rear travel DH bike with triple clamps no problem aswell as a trials bike. yeah - so just give the bars a big yank to get it up, and if your manualing, once its up it'll stay up easy with practise Quote Link to comment Share on other sites More sharing options...
Tomm Posted November 22, 2005 Report Share Posted November 22, 2005 Too much thinking? Sorry it's not very clear :P Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted November 22, 2005 Report Share Posted November 22, 2005 Nah, cos point X has nowt to do with how hard it takes to turn, the only resistance to your turning moment is your wieght and the friction in the bearings of your hub, assuming brake is off of course. Quote Link to comment Share on other sites More sharing options...
skandy32 Posted November 22, 2005 Report Share Posted November 22, 2005 Too much thinking? ha yeah - far too much thought gone into that! lol :P Quote Link to comment Share on other sites More sharing options...
Tomm Posted November 23, 2005 Report Share Posted November 23, 2005 Nah, cos point X has nowt to do with how hard it takes to turn, the only resistance to your turning moment is your wieght and the friction in the bearings of your hub, assuming brake is off of course. You're not seeing it the same way I am. God knows if my theory holds any weight, but it relies upon the idea that: 1. Your body weight is (mainly) on the BB 2. The force of pulling back comes (at least partly) from the BB 3. You pivot around the back axle I want the engineering boyos to come and tell me what I've done wrong. Or at least do a better job of explaining it. Quote Link to comment Share on other sites More sharing options...
modrider666 Posted November 23, 2005 Report Share Posted November 23, 2005 hmm i cant pull the front of my bike up very well. Ive got an echo team 05 short with a zoo stem and bars with no stem stackers. so i am buying an echo stem because they are alot longer and will hopefully sort the problem out. cheers Peter Quote Link to comment Share on other sites More sharing options...
Tomm Posted November 23, 2005 Report Share Posted November 23, 2005 so i am buying an echo stem because they are alot longer and will hopefully sort the problem out. Really bad idea, a longer stem will only make it harder to pull up. Due to some people in this thread talking crap :P Quote Link to comment Share on other sites More sharing options...
Corish Posted November 23, 2005 Report Share Posted November 23, 2005 (edited) short stem high bars short stays light front helps higher bb also helps-usually down to longer forks Short stem? Personally I think your wrong at a guess. Longer stem will create more 'Leverage' therefore easy to pull up. Not 100% sure on it though, you could still be right :P correct me if im wrong though. Edited November 23, 2005 by Corish Quote Link to comment Share on other sites More sharing options...
Davetrials Posted November 23, 2005 Report Share Posted November 23, 2005 i did write somthing but it made no sense short stems less leverage=easier to pull. Quote Link to comment Share on other sites More sharing options...
Tomm Posted November 23, 2005 Report Share Posted November 23, 2005 Short stem? Personally I think your wrong at a guess. Longer stem will create more 'Leverage' therefore easy to pull up. Not 100% sure on it though, you could still be right :) correct me if im wrong though. :P Jesus. Anyway, no, longer stems are NOT better for bunny hops. As anyone would know if they've ever even in tried more than one bike. Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted November 23, 2005 Report Share Posted November 23, 2005 You're not seeing it the same way I am. God knows if my theory holds any weight, but it relies upon the idea that: 1. Your body weight is (mainly) on the BB 2. The force of pulling back comes (at least partly) from the BB 3. You pivot around the back axle I want the engineering boyos to come and tell me what I've done wrong. Or at least do a better job of explaining it. It doesn't matter where your body weight is in bb height in theory, do a force diagram the pivot is the axle of the back wheel, the force down is you on bb, if you shift the bb up 2 inches it still needs the same force to displace you the same distance (ignoring the negligible change in gravitationla force). I've just realised the only reason high bb frames are easier to pull up is cos you're already closer to the balance point. This rubbishes my previous theory oddly enough. And I feel insulted that you think I'm not inteligent or qualified enough to know what I'm talking about. :$ :P Jesus. Anyway, no, longer stems are NOT better for bunny hops. As anyone would know if they've ever even in tried more than one bike. He speaks the truth, the shorter the stem the easier the fron pops up as you can shift your body weight further back. :) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.