Elka's and bump steer?
Jul 15, 2003 | 05:51 PM
#4
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Elka's and bump steer?
elsanco is absolutly correct, Bumpsteer is a product of front end geometry, although a good set of shock's will without doubt help in the damping of the front end therefore limiting the travel of the a-arms which will give you a better ride, Putt
Jul 16, 2003 | 09:38 AM
#5
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Elka's and bump steer?
Thanks for the replies guys. Any chance you could elaborate on your comment elsancho? or point me to where I could read more about it, I'd like to learn as much as I can about this.
Jul 16, 2003 | 07:19 PM
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Elka's and bump steer?
ill try to explain this as best as i can...if you have a compass( the kind you use to make circles) place it on a piece of paper and make a half circle from the 1 o'clock position to the 6 o' clock position (any given size radius will do).the arc you just made represents the line of movement of your spindle as it moves up and down ( as seen if you were looking at your bike from head on). your spindle will make this arc motion beacuse it is attached to the a-arms. so to relate this to teh compass: the bushing of teh a-arm, or teh part that connects to teh frame, is like the sharp point of teh compass. and the pencil of teh compass represents teh spindle. but we dont stop there. take your compass and make a slightly larger radius( spread teh compass out. not too far, but just enough to create a slightly larger circle). now place the point of the compass just slightly below and to the left of the original focus, or center point. Again create a half circle from teh 1 oclosk position to teh 6 o clock position, as you did in teh 1st circle. on your paper you should now have 2 arcs which are non-concentric or rather different sizes. this second arc we made represents the tie rods, which are at one end connected to teh steering stem( point of compass) and the other end connected to teh spindle( pencil end of compass). take a ruler or straight edge and place it on the paper from left to right. slide the ruler up and down keeping it in a straight line from left to right. as you slide it up and down take note of teh distances between the 2 arcs. it changes. this is what is happening when your suspension moves up and down. the tie rods dont travel the same radius as teh a-arms and thus createing bumpsteer.. when you hit a bump teh suspension travels and the tie rod ends up pushing or pulling( depending on the geometry of teh front end) the steering knuckle of teh spindle and change teh stering angle...........now to explain what puttnutt said: since suspension travel is a culprit to bumpsteer, if you limit the amount of travel (lets say with a new set of shocks which are a bit stiffer)you limit the effect of bumpsteer.... i hope this helps.
anthony
anthony
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Jul 16, 2003 | 07:40 PM
#8
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Elka's and bump steer?
Originally posted by: elsancho
ill try to explain this as best as i can...if you have a compass( the kind you use to make circles) place it on a piece of paper and make a half circle from the 1 o'clock position to the 6 o' clock position (any given size radius will do).the arc you just made represents the line of movement of your spindle as it moves up and down ( as seen if you were looking at your bike from head on). your spindle will make this arc motion beacuse it is attached to the a-arms. so to relate this to teh compass: the bushing of teh a-arm, or teh part that connects to teh frame, is like the sharp point of teh compass. and the pencil of teh compass represents teh spindle. but we dont stop there. take your compass and make a slightly larger radius( spread teh compass out. not too far, but just enough to create a slightly larger circle). now place the point of the compass just slightly below and to the left of the original focus, or center point. Again create a half circle from teh 1 oclosk position to teh 6 o clock position, as you did in teh 1st circle. on your paper you should now have 2 arcs which are non-concentric or rather different sizes. this second arc we made represents the tie rods, which are at one end connected to teh steering stem( point of compass) and the other end connected to teh spindle( pencil end of compass). take a ruler or straight edge and place it on the paper from left to right. slide the ruler up and down keeping it in a straight line from left to right. as you slide it up and down take note of teh distances between the 2 arcs. it changes. this is what is happening when your suspension moves up and down. the tie rods dont travel the same radius as teh a-arms and thus createing bumpsteer.. when you hit a bump teh suspension travels and the tie rod ends up pushing or pulling( depending on the geometry of teh front end) the steering knuckle of teh spindle and change teh stering angle...........now to explain what puttnutt said: since suspension travel is a culprit to bumpsteer, if you limit the amount of travel (lets say with a new set of shocks which are a bit stiffer)you limit the effect of bumpsteer.... i hope this helps.
anthony
ill try to explain this as best as i can...if you have a compass( the kind you use to make circles) place it on a piece of paper and make a half circle from the 1 o'clock position to the 6 o' clock position (any given size radius will do).the arc you just made represents the line of movement of your spindle as it moves up and down ( as seen if you were looking at your bike from head on). your spindle will make this arc motion beacuse it is attached to the a-arms. so to relate this to teh compass: the bushing of teh a-arm, or teh part that connects to teh frame, is like the sharp point of teh compass. and the pencil of teh compass represents teh spindle. but we dont stop there. take your compass and make a slightly larger radius( spread teh compass out. not too far, but just enough to create a slightly larger circle). now place the point of the compass just slightly below and to the left of the original focus, or center point. Again create a half circle from teh 1 oclosk position to teh 6 o clock position, as you did in teh 1st circle. on your paper you should now have 2 arcs which are non-concentric or rather different sizes. this second arc we made represents the tie rods, which are at one end connected to teh steering stem( point of compass) and the other end connected to teh spindle( pencil end of compass). take a ruler or straight edge and place it on the paper from left to right. slide the ruler up and down keeping it in a straight line from left to right. as you slide it up and down take note of teh distances between the 2 arcs. it changes. this is what is happening when your suspension moves up and down. the tie rods dont travel the same radius as teh a-arms and thus createing bumpsteer.. when you hit a bump teh suspension travels and the tie rod ends up pushing or pulling( depending on the geometry of teh front end) the steering knuckle of teh spindle and change teh stering angle...........now to explain what puttnutt said: since suspension travel is a culprit to bumpsteer, if you limit the amount of travel (lets say with a new set of shocks which are a bit stiffer)you limit the effect of bumpsteer.... i hope this helps.
anthony
ummm holy crap are you a mechanical engineer? hehe