Sunday, November 29, 2015

less caster angle

My new steering geometry.

A pro trike builder advised me to reduce the caster angle. What I did is place new braces for the bottom rod-end bearing with a sort of bulge. He is probably right. Steering feels nice and light now and the rear wheel is not leaning as it used to do.

Of course there are other ways to modify your trike for a reduced caster angle then the braces I made. Keep in mind the bottom bracket has to be at 30cm for heel clearance. On a higher trike the main tube can be horizontal. But the lower the trike will be, the more angle you need to reach the acquired BB height. Therefor the correction of the caster angle must be done in the kingpins itself.

I will add some more pictures later.

Notice the approx 12 degree caster in the previous design isn't that bad for handling. But a bit less angle will improve overall performance. That is the idea.

Couple of pictures from other builders.

Friday, October 4, 2013

Thanks to txusic we have a great Sketchup of the trike.

Here's the file
(7.36MB It's on my Google drive)

Here you can download the Sketchup viewer.

The seat is a little different from what I have but no reason not to look at both designs and pick your favorite or design a seat yourself. 

Tuesday, April 2, 2013

Less caster angle?

I spent an afternoon at LTE recumbent bike shop. The owner Boudewijn, from the Tripod and Tracer trikes, suggested I did less caster on the Tribolt. The tilting effect will be less as a result.

Maybe he is right. Maybe not. Point is he always links the front brakes on his trikes. Then you don't need centerpoint steering.

When I built the first copy of the Raptor I had no steering axis inclination. The handling was perfect. With 14 degrees caster. After I added my design steering the brake-steer was as god as gone, or at least very manageable. But it didn't improve anything else.

So I will do some experiments with less caster and less kingpin angle and compensate with the wheel axle further behind the kingpin.

The last word is not spoken yet about the steering. It's complicated. My L-profile setup works fine. But perhaps it can be improved by other angles, more or less Ackermann compensation and axle placement.

If you do link the front brakes, please consider the simple straight Raptor method with no steering axis inclination whatsoever. Death easy construction. I found 14 degrees working great. Less then 10 degrees and you may encounter problems with the bottom bracket height and your heels touching the road. Check before you drill.