Some contradictory info on CBH website
Posted: Sun Mar 13, 2022 2:42 pm
I have some questions about some info that seems to contradict other info on the site and would just like a little clarification.
In the second part of the Springer Rocker Design article dated 5/4/2001 in the section on suspension geometry it states:
"control points #1 and #2 are always aligned along an imaginary horizontal line parallel to the ground regardless of the rake angle."
Control points being the rocker pivot points.
Then in the Good Mockups article it says
"The Rocker Angle"
We talked about the 120-degree rocker angle earlier and the reason Harley decided to keep the front and rear rocker pivots parallel with the ground line was because they determined it gave the best spring action back in the old days when rakes were in the 26 to 30-degree range and the sprung legs (fronts) were at a relatively shallow angle.
As time progressed and neck rakes started to increase builders found the the old parallel rockers did not produce good spring action so the rocker angle started to change by canting the front leg pivot hole upwards relative to the rear pivot point.
Sugar Bear was blasted in the media when he told a reporter that it was best to keep the rocker pivots parallel to the ground but his remark was taken out of context because what he was actually saying was that the starting point for rocker angle was parallel to the ground for a stock fork and this was how the jig should be set up. If you build every set of forks using the 120-degree angle the rocker pivot points will automatically be canted to the best position when the forks are installed on bikes having any conceivable rake angle as shown below.
Note that although the angle between the rear rocker pivot and the legs of the forks is always 120-degrees, the angle of the axle moves upwards as rake increases which is the way it should be for best suspension action. This also changes your axle height so the difference needs to be added to the length of the forks you order.
I'm a little confused, which way is the better way to set the rocker angle?
I read an interview with Sugar Bear a while ago where he did say that he set the rocker angle parallel with the ground mounted but in the full extension position and most of the writings I've found on the CBH sight say that is the way to set the rocker angle.
In everything I've seen on the sight UL/FL springers measured 19.5" from the top of the bottom tree to the rear leg pivot hole but in the Mockup for Forks section of the Good Mockups the measurements are 16.5" measured from those points and 19.5" measured from top of bottom tree to the rocker axle hole. Just wondering which of those is correct.
Lastly I could never figure out what was meant when I read that using dropped rockers "tricks the front end into thinking it is running a smaller front wheel" until I saw the diagram in the 2nd part of the Rockers article so thank you for that it clarified that point for me.
Not trying to stir up any shit I wanted some clarification.
In the second part of the Springer Rocker Design article dated 5/4/2001 in the section on suspension geometry it states:
"control points #1 and #2 are always aligned along an imaginary horizontal line parallel to the ground regardless of the rake angle."
Control points being the rocker pivot points.
Then in the Good Mockups article it says
"The Rocker Angle"
We talked about the 120-degree rocker angle earlier and the reason Harley decided to keep the front and rear rocker pivots parallel with the ground line was because they determined it gave the best spring action back in the old days when rakes were in the 26 to 30-degree range and the sprung legs (fronts) were at a relatively shallow angle.
As time progressed and neck rakes started to increase builders found the the old parallel rockers did not produce good spring action so the rocker angle started to change by canting the front leg pivot hole upwards relative to the rear pivot point.
Sugar Bear was blasted in the media when he told a reporter that it was best to keep the rocker pivots parallel to the ground but his remark was taken out of context because what he was actually saying was that the starting point for rocker angle was parallel to the ground for a stock fork and this was how the jig should be set up. If you build every set of forks using the 120-degree angle the rocker pivot points will automatically be canted to the best position when the forks are installed on bikes having any conceivable rake angle as shown below.
Note that although the angle between the rear rocker pivot and the legs of the forks is always 120-degrees, the angle of the axle moves upwards as rake increases which is the way it should be for best suspension action. This also changes your axle height so the difference needs to be added to the length of the forks you order.
I'm a little confused, which way is the better way to set the rocker angle?
I read an interview with Sugar Bear a while ago where he did say that he set the rocker angle parallel with the ground mounted but in the full extension position and most of the writings I've found on the CBH sight say that is the way to set the rocker angle.
In everything I've seen on the sight UL/FL springers measured 19.5" from the top of the bottom tree to the rear leg pivot hole but in the Mockup for Forks section of the Good Mockups the measurements are 16.5" measured from those points and 19.5" measured from top of bottom tree to the rocker axle hole. Just wondering which of those is correct.
Lastly I could never figure out what was meant when I read that using dropped rockers "tricks the front end into thinking it is running a smaller front wheel" until I saw the diagram in the 2nd part of the Rockers article so thank you for that it clarified that point for me.
Not trying to stir up any shit I wanted some clarification.