Howard, I appreciate you taking the time to put that up there. As WhiteKnight said, a guy can learn something new everyday. This is the first I knew about the raked triple trees on the tour models, which now makes the trail figures make sense to me. Your diagrams help put it all together.

In your opinion, why do you think Harley builds them that way?

What is the effect on the wheelbase when your triple trees are installed, as compared to the factory's? (I'm thinking that the wheelbase isincreased by an amount equal to the reduced trail?)

Also,I assumethe bike now sits slightly higher, due to changing the actual fork angle of 30 1/2 degrees (26 + 4 1/2) to the 26 degrees?

 

Q: In your opinion, why do you think Harley builds them that way?
A: I do not know, my guess is: “Setting the forks behind the steering stem with raked triple trees allows for a shorter wheelbase with this large trail” A shorter wheelbase provides for tighter turning circles. Try to turn around one of these raked out choppers with extended fork tubes, a trail of 10” and 20” over forks and a 45 degree head stock. You get the idea.

Q: What is the effect on the wheelbase when your triple trees are installed, as compared to the factory's? (I'm thinking that the wheelbase isincreased by an amount equal to the reduced trail?)
A: This is a 2 part question.
[ul][*]When trail is reduced for a given application, providing your wheel is in front of the steering stem, the wheelbase is decreased. In my application only, I put the fork tubes in front of the headstock and adjust the offset to be 4” aprox. with 26 degrees of rake. This is for a better handling motorcycle on corners and a more comfortable ride due to the fork angle.[*]Our trees locate the forks in front of the steering stem. The rake is decreased and the offset is increased to adjust for our desired trail of 4”. With stock tires and wheels, the bike with 13” air shocks and a total sag of ½”, the bike is 1 1/8” longer in wheelbase. The bike is set totally level. If lowered the bike in its leveled state, the wheelbase is near the stock 63.5 in. by fraction of an inch.[/ul] NOTE* Please do not confuse squirrelly forks with reduced rake. There was a study done on zero degree rake and proper trail. The bike performed as a stock bike but looked very weird/funny extending the offset with much extended triple trees to get the correct trail. Works the same but looks terrible.

Q: Also,I assumethe bike now sits slightly higher, due to changing the actual fork angle of 30 1/2 degrees (26 + 4 1/2) to the 26 degrees?
A: As far as height goes, you would be correct if we did not include a way to adjust the length of the forks. Our triple trees have the ability to raise and lower the fork tubes by adjusting the clamping on the fork tubes.
We are in the race business and it is important to raise and lower the front forks for a given situation. Race bikes do not sit level all of the time. This angle depends on the track or road conditions as well as the bike it self along with the rider. Find the optimum handling characteristics and you can go faster, and ride smoother. We only have one way of thinking and everything is geared for race and/or handling applications. The byproduct is a much, much smoother ride over anything you have ever ridden as well as safety in handling because your tire is in contact with the ground more of the time.



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Jack a Touring bike up by the frame and the front wheel will go to center. Jack up any other model of H-D by the frame and watch the front wheel fall left or right.

The forks behind the neck cause you to push the bike into a SLOW speed turn...with the other models you are literally holding the forks back from going to lock in a SLOW speed turn.