Adding rake with triple trees versus frame?
- Thread starter farnie
- Start date
Farnie said:
no you can only change trail by having angled yokes
rake is the angle of the steer tube
this gets into a whole lot of geometry,geology and science/maths making a bike have a look and still turn decently is what it boils down to
the geology part is when you get it wrong and take samples of that rock wall at that one corner
rockcitycafe
I make things.
there were or still are examples of custom parts that do that, but I personally think it's an awful idea because you're effectively moving the front wheel forward without moving the steering axis forward with it, move it enough and you'll have negative trail.
This is the poor mans way to achieve a raked out look. I have a pic of myself on the back of my uncles CB750 back in 1976 and he had raked trees on it.
Likely done with little to no regard to handling.
Dirt track riders sometimes have adjustable trees. Not really sure how they work.
But bottom line is do some rake and trail homework before you change the geometry of your bike.
Likely done with little to no regard to handling.
Dirt track riders sometimes have adjustable trees. Not really sure how they work.
But bottom line is do some rake and trail homework before you change the geometry of your bike.
AlphaDogChoppers
Science is true whether you believe in it or not.
Two ways to add rake. One is to change the actual steering stem angle. That generally means cutting and welding the frame. For some bikes, (notably Harleys,) you can get bearing sets with offset outer races that change the angle 3 degrees without frame modification.
The other way is raked triple trees.
These two methods have totally opposite effects on steering geometry. Raking the frame adds trail to the geometry. This can lead to heavy, cumbersome handling. The bike becomes less nimble. It wants to go in straight lines and requires extra input from the rider to make it turn. It can also cause a low speed, "flopover" effect, where by pure gravitty effects, the front end wants to go to full lock one way or the other just from the weight of the bike. As the bike moves faster, this effect goes away.
Raking the trees reduces trail. This makes the bike highly maneuverable and nimble. It corners easily, but may lack straight line stability, even to the point of inducing "tank slappers."
Ideally, if you want to increase rake, do some of it with the frame, and some with the trees. This gives you a balanced approach to get the stance that you want without excessive negative impact on handling characteristics.
Here is a rake and trail calculator. Play around with it and you will get a feel for what you can do to keep your bike within an acceptable range of characteristics.
http://207.57.8.251/tools/rake_trail.html
The other way is raked triple trees.
These two methods have totally opposite effects on steering geometry. Raking the frame adds trail to the geometry. This can lead to heavy, cumbersome handling. The bike becomes less nimble. It wants to go in straight lines and requires extra input from the rider to make it turn. It can also cause a low speed, "flopover" effect, where by pure gravitty effects, the front end wants to go to full lock one way or the other just from the weight of the bike. As the bike moves faster, this effect goes away.
Raking the trees reduces trail. This makes the bike highly maneuverable and nimble. It corners easily, but may lack straight line stability, even to the point of inducing "tank slappers."
Ideally, if you want to increase rake, do some of it with the frame, and some with the trees. This gives you a balanced approach to get the stance that you want without excessive negative impact on handling characteristics.
Here is a rake and trail calculator. Play around with it and you will get a feel for what you can do to keep your bike within an acceptable range of characteristics.
http://207.57.8.251/tools/rake_trail.html
AlphaDogChoppers
Science is true whether you believe in it or not.
Here is a better calculator. The Web site just happened to be off-line for a few minutes when I was making my previous post.
https://www.rbracing-rsr.com/advchoppercalc.html
https://www.rbracing-rsr.com/advchoppercalc.html