BO15 WAHA-SEDB-3 (TRIKE-TOR...2nd Place)

[MazdaFlyer]

With all of the bracing along with the 'tractor body' it is beginning to look quite heavy.
You might need to start thinking about an electric rear hub motor! You would have plenty of space to hide batteries and electronics.

Yah a motor would be good but pricey, gearing is cheaper. Tractor vehicles aren’t meant for speed.

I’m rooting for this build!

Thanks, starting rethink jumping into this trial and error contraption.

You're doing great with figuring out the steering/suspension on this thing!

Glad you think so, thanks! Getting tricky to balance parts available, some are too heavy duty some are too delicate. Hopefully getting closer. Raining today so driveway shop is closed.

OK, I tried the multi quote reply process with the forum software on an iPad. Seems to work, but a little more cumbersome. Liking my app method better.

 

[The Renaissance Man]

Tractor vehicles aren’t meant for speed.

 

[sandman]

 

[MazdaFlyer]

Experimented with the steering today after it dried up some from 1.80” of rain again. 8” total over the last week.
The present setup works fine except for one issue. My cognitive thinking a little lame today. Notice the issue?

I think one solution is to flip the axle beam 180 degrees and add a center pivot at the beam. That should sync the wheels with the steering. I could be wrong...?

 

[Psychographic]

Try flipping the bracket to face the back first and see if that works. The tie rods don't necessarily have to be straight across.

If you designed that from my suggestions, I apologize, it should have been rear steer. I was concentrating on the mounts more than the steering.

 

[MazdaFlyer]

Try flipping the bracket to face the back first and see if that works. The tie rods don't necessarily have to be straight across.

If you designed that from my suggestions, I apologize, it should have been rear steer. I was concentrating on the mounts more than the steering.

The steering is reversed with the current mock-up. This is my own mistake done in a hurry. Kinda of a right brain left brain solution. Your sketches were fine and didn’t really revolve around the steering.
Thinking I’ll borrow the concept in the attached photo. At least that is the next approach.

 

[The Renaissance Man]

That made me think of a little wooden go kart that my father made for us kids with a rope winding steering wheel that was backwards by mistake. lol It was fun to try to ride it before he fixed it.

 

[MazdaFlyer]

Try flipping the bracket to face the back first and see if that works. The tie rods don't necessarily have to be straight across.

If you designed that from my suggestions, I apologize, it should have been rear steer. I was concentrating on the mounts more than the steering.

On the steering I was flying my own flight pattern and crashed, so no problem. I do appreciate your bracket flipping suggestion. It didn’t sink in at first but then I came up with this.

 

[macncheese]

Late to the party on this one but its looking good! Your designs are very much "low trail." The current trend in curing speed wobble in low trail bikes is with a headset with friction washers built in to add resistance in the steering system. The added resistance might also help control your steering input. You may be able to just attach a torsion spring with one end to the frame and the other to the stem/fork?

 

[MazdaFlyer]

Reversed and reinforced the fork steering bracket. Cut the tie rod links to fit new pivot location. The bracket consists of a Simpson Strong Tie Tee and a piece of the angle. Tie rods connected with Heim couplers. Still need to tweak the alignment. It works setting static on driveway though.

A short video of operation.

It might be a little smoother if I shorten the fork to raise the pivot.
I don’t trust the two lag bolts holding the cross beam to the frame. Think I need to add a couple of Ubolts or add a strap and a couple of 4” bolts at least to do a test ride. More trial and error.

 

[kingfish254]

When you have it all of the way right or left, are the wheels at the same exact angle?

 

[Psychographic]

Good to see you getting it straightened out. What's making that creaking sound, is anything binding?

 

[handyandy1100]

Pretty cool. Maybe a Model T style wishbone going back to where the turnbuckles are currently attached?

Sent from my Pixel 2 XL using Tapatalk

 

[MazdaFlyer]

When you have it all of the way right or left, are the wheels at the same exact angle?

Good question, seemed to be pretty close to parallel. I’ll have to check it.

Good to see you getting it straightened out. What's making that creaking sound, is anything binding?

Thanks! Another good question...I didn’t originally notice the sound, my phone was turned down. May be some binding at outer tie rod ends. Another reason to raise the fork pivot. The Heim ends work like a ball joint but there is a max tilt to them. They are tilted down at present. Some of the noise may be tires also.

Pretty cool. Maybe a Model T style wishbone going back to where the turnbuckles are currently attached?
Sent from my Pixel 2 XL using Tapatalk

Thanks! @Psychographic had shared some design ideas he had to simplify my framework. One of his elements would mimic the wishbone idea. That would also help stabilize the axle cross beam.
I still have the gas struts that I haven’t taken out of their package yet.

 

[MazdaFlyer]

Late to the party on this one but its looking good! Your designs are very much "low trail." The current trend in curing speed wobble in low trail bikes is with a headset with friction washers built in to add resistance in the steering system. The added resistance might also help control your steering input. You may be able to just attach a torsion spring with one end to the frame and the other to the stem/fork?

Hey thanks for taking a look. I hadn’t heard the term “low trail” used before. I a previous direct steer solid axle version I had used a couple of springs in tension or compression. I had also tightened up the head set. They calmed the steering down some but then I got the steering knuckles.
So currently trying to work out the bugs in the steering. I’ll most likely experiment with your ideas particularly the springs. I still have the two I started with and a couple of gas struts.
I have a two wheel city bike with a spring attached to the fork and downtube. I think it was added mainly to keep the front wheel straight when parked with a dual legged kickstand. But it also has steering resistance when riding.

 

[Psychographic]

You can get cone shaped washers for your rod ends that will give you more room for angles without them binding.

I had suggested you use an "I" shaped bracket for your steering rather than a "T" shape to get the Ackerman steering effect. When I say "I" shaped, imagine a sideways "H" (The font I'm typing with doesn't have the crossbars on the top and bottom of the letter), if you mount your rod ends on the ends it should give you the Ackerman steering effect you want.

It's crude but you should get the idea,

 

[kingfish254]

I think one of the issues you'll face with your steering is that no matter what connections you have coming from the forks, they will be moving not only in an X-Y flat axis, but there is always going to be a Z vertical axis component because of the rake of the fork/steertube. And that Z won't be linear either or even applied equally to the left and right arms. There is a lot of tricky geometry going on here.

 

[Psychographic]

I think one of the issues you'll face with your steering is that no matter what connections you have coming from the forks, they will be moving not only in an X-Y flat axis, but there is always going to be a Z vertical axis component because of the rake of the fork/steertube. And that Z won't be linear either or even applied equally to the left and right arms. There is a lot of tricky geometry going on here.

Would bending the arms of the spindles to match the fork help, or does the kingpin need to match?

A little caster would help make it a bit less twitchy also.

 

[MazdaFlyer]

I think one of the issues you'll face with your steering is that no matter what connections you have coming from the forks, they will be moving not only in an X-Y flat axis, but there is always going to be a Z vertical axis component because of the rake of the fork/steertube. And that Z won't be linear either or even applied equally to the left and right arms. There is a lot of tricky geometry going on here.

Making my brain hurt...indeed tricky. The fork legs are parallel withe the head tube. The current tie rod attachment point is at center of fork and set back a few inches so the pivot should form an arc radiated from the head tube center “Z”. The current tie rods slope down from steering arms to the central pivot connection.
Per KF, “And that Z won't be linear either or even applied equally to the left and right arms.” That seems to be the key point. The location of the pivot or tie rod connections in relationship to the fork center is also pertinent.

Would bending the arms of the spindles to match the fork help, or does the kingpin need to match?
A little caster would help make it a bit less twitchy also.

To gain caster I’d probably consider adding a spacer at top of the Knuckle mounting brackets to add positive caster by giving them a backwards tilt. The spindles have some positive camber built in.
The knuckle assemblies are stout bending would be an issue in itself.

At this point I’d just like to get this thing straight line rideable, with maybe a larger than normal turning radius, U-turning is starting to be a secondary issue. I may try the “H” shaped bracket idea before I shorten the fork.
Pretty easy to turn by picking up the rear seat.

 

[kingfish254]

Making my brain hurt...indeed tricky. The fork legs are parallel withe the head tube. The current tie rod attachment point is at center of fork and set back a few inches so the pivot should form an arc radiated from the head tube center “Z”. The current tie rods slope down from steering arms to the central pivot connection.
Per KF, “And that Z won't be linear either or even applied equally to the left and right arms.” That seems to be the key point. The location of the pivot or tie rod connections in relationship to the fork center is also pertinent.

If you think of the circle that your pivot point would draw. While it is perpindicular to the steertube, it is at an angle to the plane that your wheel pivots are at. So you need something that translates that angular action to action that is either parallel or perpendicular to the need wheel action.

Have you thought about using some sort of universal joint. That is basically what is used in an automobile steering column.