Steering wobble on StreetFox

Joined
Oct 14, 2020
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I have speed wobble on the Streetfox: front wheels shaking at speeds over ~ 15kmh or so.
The wobble can be serious in higher speed, comes when driving with one hand or holding softly, and the cure is holding the steer with both hands and very firmly.

Doing research, i found that generally the relevant geometry factors are:
-head tube angle,
-rake,
-trail.

It is stated for tadpole trikes that:
"A tadpole trike is typically close to the same wheelbase as an upright cycle, so the head tube angle, rake and trail are very close to the same "generic" measurement",
but the picture for this shows rake = 0.
Am i missing something?

:unsure:

 
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Joined
May 31, 2013
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South Benfleet, Essex, England, UK
It is usually the tracking and each wheel fighting with the other to go a different way.
If things are just too sensitive the options are usually:
  • Stiffen up all steering elements (put rubber washers in the steering joints).
  • Crank down on the headset bearings so they get all "notchy" - this means they need replacing more frequently.
Or, go back and check you got all the build settings correct.

What happens to the front wheels if you lift the back wheel off the ground and walk backwards?

The standard Streetfox steering is a great ackerman approximation, but the best scheme is that designed through Peter Eland's spreadsheet tool.
 
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Joined
Oct 14, 2020
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Thanks Danny.

By stiffen up, you mean make the steering joints less sensitive to motion? Harder to turn?
And the headset bearings, to make them more tight?

I followed the instructions in the plan absolutely for the build settings.
No compromise on safety!

When i lift the back wheel and walk backwards, the vehicle follows me well with the front wheels straight ahead.

Still wondering about that rake...
 
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By stiffen up, you mean make the steering joints less sensitive to motion? Harder to turn?
And the headset bearings, to make them more tight?
Yes to both.
All it does is reduce the "Shimmy" and makes hte trike more rideable, the root cause remains.
 
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.. and is there toe in or toe out ?

at lower speeds does it track straight when pedaling with no hands on the steering ?

Paul
 
Joined
Oct 14, 2020
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Thanks for your contribution.
Problem understood. - Yes, it was a matter of tracking.

I experimented extensively with the tracking, and found the right spot.
Some days ago i made a change to the front hubs, which brought the wheels closer to the frame.
I did not imagine the lateral consequence of affecting the tracking!
(And of course this explains why the problem appeared suddenly.)

and is there toe in or toe out ?
at lower speeds does it track straight when pedaling with no hands on the steering ?
-Now for normal driving, it is toe-out.
-I can not be sure for a special reason": i did not weld the suspension pivot well positioned by mistake (did not hope that i would succeed by that time!) and this makes the vehicle always go a bit left if with no hands. But besides of this, i think that it goes OK straight ahead.

One last question.
Please, i would appreciate if someone clarifies the matter with the rake, as i explained above.
It is stated for tadpole trikes that:
"A tadpole trike is typically close to the same wheelbase as an upright cycle, so the head tube angle, rake and trail are very close to the same "generic" measurement",
but the picture for this shows rake = 0.
Am i missing something?
 
Joined
Feb 7, 2008
Messages
3,393
Location
Nottinghamshire England
From the picture angle it is not possible to see the rake ?

rake trail tutorial

Is that your trike in the picture ?

USS steering is considered better than ASS , most quality tadpoles have USS steering , I thing it is possible to convert the Streetfox ?

Paul

ps by the way I am no ' tadpole ' expert :whistle: never built one and never will , not sure why the ' experts ' have not been along yet ?

pps although I may yet build a quad ...
 
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Joined
Jun 15, 2012
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Lithuania
I experimented extensively with the tracking, and found the right spot.
Can you please provide more details with regards on how you found the right spot and what you did to fix the issue? I am having the same wobble issue and cannot find the root cause.
 
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Try this ?


Other's are probably available ?

Paul
 
Joined
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Messages
3,289
Location
South Benfleet, Essex, England, UK
Try this ?


Other's are probably available ?

Paul
Yup, that's how I did mine on Loki.
I made my own adjuster rods too out of tube, thumbscrews and dome nuts. Very effective.
 
Joined
Oct 14, 2020
Messages
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Can you please provide more details with regards on how you found the right spot and what you did to fix the issue? I am having the same wobble issue and cannot find the root cause.
I actually tested the trike repeatedly after turning the adjustment screw little by little - only half turn. My initial guide was the video above. If this information is not enough for you, do some patience because I am away from home and the smartphone is not good with details...
 
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