More Ideas 4 Building Consideration

[Freth]

Brad has probably already seen this ... but today was the first time that I've run across this trike in another forum. It has the the tubes going out to the wheels at a 90 degree angle ... for those of you considering that ... altho that may be too much thinking for me to get all the angles right ...

http://www.kmxus.com/models/tornado/
:thinking2:

[trikeman]

Brad has probably already seen this ... but today was the first time that I've run across this trike in another forum. It has the the tubes going out to the wheels at a 90 degree angle ... for those of you considering that ... altho that may be too much thinking for me to get all the angles right ...

http://www.kmxus.com/models/tornado/
:thinking2:

Freth, as SJ and I have discussed several times, its easier to get the angles right when the crossarms are at 90 degrees. Brad puts the cross arms at an angle to the frame to allow for more heel clearance for short riders (it also looks cool). That makes it necessary to cut a compound angle either on the head tube mounting, or the cross arms.

Studying the plans for the Warrior, I think achieving the result is easier with the Warrior than the StreetFox, although either way just requires a bit of patience and perhaps a few cuss words.

[TheKid]

Brad puts the cross arms at an angle to the frame to allow for more heel clearance for short riders (it also looks cool). That makes it necessary to cut a compound angle either on the head tube mounting, or the cross arms.


You'll also notice, on trikes with the type of design in the link, the BB is way up above the crossbars, so heel clearance isn't an issue. It's also way above the seat, which makes it harder to ride for some of Artie's victims.

[Freth]

I think if you angle the BB up and then horizontal forward ... as long as you have enough clearance to avoid heel strike ... it doesn't stick it so high in the air.

Some cuss words, a little pulled hair (if you have any left), propping the rear forks and main tube to get an idea of angles ... then a forward angle to go up to horizontal pedal height -- all that shouldn't be too hard. It's just how to angle and mangle the cross arms that would have me stewing ... There are some ideas there.

I'll mull them over for awhile ... then after I finish the Warrior ... if I think I need another trike (does one ever have enough?) ... I might consider it. Maybe my wife will ride one? Or a grandson?

[trikeman]

Freth - if you really chicken out (or don't want to do it again), and want to go with 90 degree arms, there are only two angles you need to get right. About 15 degrees seems to work OK for both of them. Take a look at 25Hz's bikes and you will see that he builds his kingpins and crossarms with a built in 15 degree tilt for the center point. Then, he runs his front frame tubes up at a 15 degree angle, so that when he welds the cross tube on at 90 degrees he automatically gets 15 degree caster. For 90 degree arms its not any more complicated than that - No rocket science here. It seems to work for him. Its all explained here (skip the part on Ackerman, since that is another story):

http://www.eland.org.uk/steer_intro.html

Brads designs are a bit more refined and require compound angles mostly due to the forward angle on the crossarms for heel clearance.