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.




  

5 comments:

  1. Humm so now, i must to cut two principal tubes with max 4 (8 total)degrees, no more 7.5 (15 total) right?

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  2. So, crank will be more low? Better for make a body (velomobile, aerodynamic )

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  4. You are right about lighter steering but the bike is ,twitchier, and won't track as well.

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    1. It's a balance between light steering and how well it tracks. You may also need to increase the kingpin angle for the trike to self correct in a straight line. I just finished with a new geometry steering. Less caster, and more kingpin angle. It's an improvement. But you are right that with more caster the trike will steer heavier and thus be better on the straights. In fact I recommend people looking for the easiest construction to use the Raptor design without any kingpin angle and caster modification and then link the front brakes! It will handle fine. Only the rear wheel will lean in corners 'the wrong way'. But that isn't a real problem.

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