Triple Tree Offset Handling
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Road Master
Joined: Oct 2017
Posts: 815
Likes: 292
From: Uptown Bay Area, Cali
Triple Tree Offset Handling
After doing research on the stock triple trees, and getting the offsets, rake, and trail figured out, I can see how the extra offset triple trees, like those by Kraus, help to reduce the trail. Howard, at Motorcycle Metal, makes his trees with a 2.6 inch offset with his inverted forks. Is there negative effects to how the bike handles when making the offset large enough to get the trail down to 3.5 to 4.0 inches?
Thanks,
Dave
Thanks,
Dave
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
After doing research on the stock triple trees, and getting the offsets, rake, and trail figured out, I can see how the extra offset triple trees, like those by Kraus, help to reduce the trail. Howard, at Motorcycle Metal, makes his trees with a 2.6 inch offset with his inverted forks. Is there negative effects to how the bike handles when making the offset large enough to get the trail down to 3.5 to 4.0 inches?
Thanks,
Dave
Thanks,
Dave
Thread Starter
|
Road Master
Joined: Oct 2017
Posts: 815
Likes: 292
From: Uptown Bay Area, Cali
Howard,
I am glad you saw this and replied. I thought I had saw a post of yours before how they copied you. The American Dream, right?
Back to thread, would a rider be able to tell the difference between these two set-ups:
Dyna frame with 28 degree neck, 2.6 offset trees with 0 degrees rake, 26.5 diameter tires, trail 4.09".
Dyna frame with 26 degree neck, 2.3 offset trees with 0 degree rake, 26.5 diameter tires, trail 3.9".
To answer some questions before they are asked:
The back of the bike is raised to reduce the neck angle from 29 degrees to 28 on the first example and using your trees.
3 degree rake cups installed reverse to reduce the neck rake angle from 29 degrees in the second example with stock FXDB Street Bob trees. I don't know if this would cause tire and/or fender interference with the frame.
Both set-ups are close to 4" trail, albeit by different methods.
I had a phone conversion with you a couple of weeks ago, and I am thoroughly researching all suspension mods until I don't want to do anymore, and then pull the plug only once.
Thanks,
Dave
I am glad you saw this and replied. I thought I had saw a post of yours before how they copied you. The American Dream, right?
Back to thread, would a rider be able to tell the difference between these two set-ups:
Dyna frame with 28 degree neck, 2.6 offset trees with 0 degrees rake, 26.5 diameter tires, trail 4.09".
Dyna frame with 26 degree neck, 2.3 offset trees with 0 degree rake, 26.5 diameter tires, trail 3.9".
To answer some questions before they are asked:
The back of the bike is raised to reduce the neck angle from 29 degrees to 28 on the first example and using your trees.
3 degree rake cups installed reverse to reduce the neck rake angle from 29 degrees in the second example with stock FXDB Street Bob trees. I don't know if this would cause tire and/or fender interference with the frame.
Both set-ups are close to 4" trail, albeit by different methods.
I had a phone conversion with you a couple of weeks ago, and I am thoroughly researching all suspension mods until I don't want to do anymore, and then pull the plug only once.
Thanks,
Dave
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
Howard,
I am glad you saw this and replied. I thought I had saw a post of yours before how they copied you. The American Dream, right?
Back to thread, would a rider be able to tell the difference between these two set-ups:
Dyna frame with 28 degree neck, 2.6 offset trees with 0 degrees rake, 26.5 diameter tires, trail 4.09".
Dyna frame with 26 degree neck, 2.3 offset trees with 0 degree rake, 26.5 diameter tires, trail 3.9".
To answer some questions before they are asked:
The back of the bike is raised to reduce the neck angle from 29 degrees to 28 on the first example and using your trees.
3 degree rake cups installed reverse to reduce the neck rake angle from 29 degrees in the second example with stock FXDB Street Bob trees. I don't know if this would cause tire and/or fender interference with the frame.
Both set-ups are close to 4" trail, albeit by different methods.
I had a phone conversion with you a couple of weeks ago, and I am thoroughly researching all suspension mods until I don't want to do anymore, and then pull the plug only once.
Thanks,
Dave
I am glad you saw this and replied. I thought I had saw a post of yours before how they copied you. The American Dream, right?
Back to thread, would a rider be able to tell the difference between these two set-ups:
Dyna frame with 28 degree neck, 2.6 offset trees with 0 degrees rake, 26.5 diameter tires, trail 4.09".
Dyna frame with 26 degree neck, 2.3 offset trees with 0 degree rake, 26.5 diameter tires, trail 3.9".
To answer some questions before they are asked:
The back of the bike is raised to reduce the neck angle from 29 degrees to 28 on the first example and using your trees.
3 degree rake cups installed reverse to reduce the neck rake angle from 29 degrees in the second example with stock FXDB Street Bob trees. I don't know if this would cause tire and/or fender interference with the frame.
Both set-ups are close to 4" trail, albeit by different methods.
I had a phone conversion with you a couple of weeks ago, and I am thoroughly researching all suspension mods until I don't want to do anymore, and then pull the plug only once.
Thanks,
Dave
1) >>> Dyna frame with 26 degree neck, 2.3 offset trees with 0 degree rake, 26.5 diameter tires, trail 3.9".
<<< With your use of offset cups, a Dyna frame could be 28.5 degrees which is what I measured on my bike accurately. Than add the cups which would change the rake to 28.5 degrees (-) 3 degrees = 25.5 degrees.
That trail would be 3.77" according to your calculations minus the neck rake correction.
There is no problem with fender or wheel to frame problem as you are raking the forks out but the axle distance is raked in.
Now comes the correct answer on how you came up with getting minus one degree of rake from the steering head by lengthening the shock. Please provide the actual distance/measurement. A full degree is a very large number and very hard to do.
I hope your questions are answered.
Thread Starter
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Road Master
Joined: Oct 2017
Posts: 815
Likes: 292
From: Uptown Bay Area, Cali
Howard,
Thank you for your insight on this subject. I reversed engineered some of the FXDB specs on put them on AutoCAD, and correct me if I am wrong, but if you put 14.5" shocks in the back, WG forks in the front, it would not take much raising the forks on the trees to lose a degree in the neck. I looked on the internet to see if there are any blueprint specs for the frame, and I didn't find any.
My main question is there any benefit deraking the neck and having less offset in the trees OR leaving the neck alone and putting more offset in the trees to get the same amount of trail. On paper, it is six one way and half a dozen the other, but is there other handling benefits/issues that occur?
Thanks,
Dave
Thank you for your insight on this subject. I reversed engineered some of the FXDB specs on put them on AutoCAD, and correct me if I am wrong, but if you put 14.5" shocks in the back, WG forks in the front, it would not take much raising the forks on the trees to lose a degree in the neck. I looked on the internet to see if there are any blueprint specs for the frame, and I didn't find any.
My main question is there any benefit deraking the neck and having less offset in the trees OR leaving the neck alone and putting more offset in the trees to get the same amount of trail. On paper, it is six one way and half a dozen the other, but is there other handling benefits/issues that occur?
Thanks,
Dave
Thread Starter
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Road Master
Joined: Oct 2017
Posts: 815
Likes: 292
From: Uptown Bay Area, Cali
Howard,
To add, do you have a drawing of the actual dimensions of a Dyna frame? I know I will go **** if I start to take measurements, i.e., finding a flat true surface to measure from, getting out the Starrett Surface Gauge...you get the point. LOL
Thanks,
Dave
To add, do you have a drawing of the actual dimensions of a Dyna frame? I know I will go **** if I start to take measurements, i.e., finding a flat true surface to measure from, getting out the Starrett Surface Gauge...you get the point. LOL
Thanks,
Dave
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
Dave, the bad thing about these chat sites is it does not let me know what you are thinking. I did not know that you are thinking of adding 2.6" longer fork tubes and 14 1/2" long shocks. My over-site for not knowing this plan. While you are figuring your frame you may also figure on a chain tensioner while you are at it. Take a look at a XR1200.
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