Tomm Posted November 23, 2005 Report Share Posted November 23, 2005 And I feel insulted that you think I'm not inteligent or qualified enough to know what I'm talking about. :P No not at all, I know you are one of the people that knows what they are talking about. I just didn't explain it very well. Quote Link to comment Share on other sites More sharing options...
Haz Posted November 23, 2005 Report Share Posted November 23, 2005 Here's a crappy paint drawing; On a second class lever, shorter X is, the closer the load is to the fulcrum, which makes it easier to lift. On a bike it's the same, except for the fact the bars start higher, same principle. On a second class lever, the longer Y is, the further the effort is from the fulcrum, which on other levers, would decrease the amount of effort needed, on a second class, it's all about the load and where it's placed. So if you use X, the farther the effort is from the load, the easier it is to lift. On a bike, you get a transverse affect. Because by moving the effort forward and up, instead of along in a straight line, you move the load along with the effort, so it becomes more spread out, with load now directly opposing the effort on the bars. If it makes sense? Quote Link to comment Share on other sites More sharing options...
MSM Posted November 24, 2005 Report Share Posted November 24, 2005 The problem with the longer stems make for better leverage argument is that the longer stem will move more of the riders weight forward, which increases the load that you are trying to lift. A shorter stem will move the riders weight further back, thus helping to lighten the load you are trying to lift and thus reducing the physical weight shift required in order to obtain the same effect. The extra leverage that a longer stem might afford you is, maybe 40mm increase on something that will already be well over 1000mm (i.e. distance between handlebar grips and rear wheel axle). Move the riders weight back by the same distance, and you are making a real difference to the distribution of a mass that is likely to be more than 5 times the weight of the bike. This will make a big difference to the effort required to lift the front. Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted November 24, 2005 Report Share Posted November 24, 2005 No not at all, I know you are one of the people that knows what they are talking about. I just didn't explain it very well. Bloody hell, I feel respected. :P :P The problem with the longer stems make for better leverage argument is that the longer stem will move more of the riders weight forward, which increases the load that you are trying to lift. A shorter stem will move the riders weight further back, thus helping to lighten the load you are trying to lift and thus reducing the physical weight shift required in order to obtain the same effect. The extra leverage that a longer stem might afford you is, maybe 40mm increase on something that will already be well over 1000mm (i.e. distance between handlebar grips and rear wheel axle). Move the riders weight back by the same distance, and you are making a real difference to the distribution of a mass that is likely to be more than 5 times the weight of the bike. This will make a big difference to the effort required to lift the front. Suddenly it all makes sense, ta for that. Quote Link to comment Share on other sites More sharing options...
omgnoseat Posted July 9, 2010 Report Share Posted July 9, 2010 Very old topic but I cannot be bothered to make a new one. I'm planning on getting a new frame with a different geometry than the one I'm using right now. Current frame geo: Wheelbase: 1005mm Chainstay: 362mm Bottom bracket height: 60mm head angle: 72. It's pretty much a bunnyhop machine with the stem i'm using, and I like that way. I just want a little more rear wheel balance. New frame geo: Wheelbase: 1010mm Chainstay: 350mm Bottom bracket height: 60mm head angle: 71.5 The major change is the chainstay. How much will it effect the bunnyhopness, will the front be alot heavier to pull up? All the "bunnyhop" frames seem to have at least 360mm chainstay. What would be the whole change actually, since I'm not too sure on the effect of shorter chainstays. Any idea on this? Thanks. Quote Link to comment Share on other sites More sharing options...
forteh Posted July 9, 2010 Report Share Posted July 9, 2010 Very old topic but I cannot be bothered to make a new one. I'm planning on getting a new frame with a different geometry than the one I'm using right now. Current frame geo: Wheelbase: 1005mm Chainstay: 362mm Bottom bracket height: 60mm head angle: 72. It's pretty much a bunnyhop machine with the stem i'm using, and I like that way. I just want a little more rear wheel balance. New frame geo: Wheelbase: 1010mm Chainstay: 350mm Bottom bracket height: 60mm head angle: 71.5 The major change is the chainstay. How much will it effect the bunnyhopness, will the front be alot heavier to pull up? All the "bunnyhop" frames seem to have at least 360mm chainstay. What would be the whole change actually, since I'm not too sure on the effect of shorter chainstays. Any idea on this? Thanks. Uber bump LOL! Shorter chainstays will pull up faster but you will be more likely to loop out because your balance point above the rear axle is smaller. Longer chainstays are harder to pull up but more stable on the balance point, helps for sustaining manuals Quote Link to comment Share on other sites More sharing options...
Revolver Posted July 9, 2010 Report Share Posted July 9, 2010 If you want to make your bike pull up easier without buying anything new, tilting the bars back can make quite a difference. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted July 9, 2010 Report Share Posted July 9, 2010 Short and high front end, high BB, short chainstay. Edit: Wow, SUPER bump! hehe Quote Link to comment Share on other sites More sharing options...
FINDUS Posted July 9, 2010 Report Share Posted July 9, 2010 Short and high front end, high BB, short chainstay. +1 would practice also be needed, once you get used to the bike setup you have its easy regardless of setup. i find going from one bike to the next they all feel so diffrent, hard diffrent even though the owner of the bike thinks its the best setup. or this might just be the drink still talking! Quote Link to comment Share on other sites More sharing options...
Mark W Posted July 9, 2010 Report Share Posted July 9, 2010 Longer chainstays are harder to pull up but more stable on the balance point, helps for sustaining manuals Fails for doing spins or tricks out of manuals though... Quote Link to comment Share on other sites More sharing options...
omgnoseat Posted July 9, 2010 Report Share Posted July 9, 2010 (edited) Alright thanks alot guys . Yeah it´s a bit of a bump haha. So if I understand correctly shorter chainstays actually decrease stabillity whilst on the rear wheel? Edited July 9, 2010 by omgnoseat Quote Link to comment Share on other sites More sharing options...
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