Tadpole trike steering damper

ynot

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Mar 5, 2022
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Riding my fresh cargo trike yesterday it occurred to me that a steering damper would reduce the twitchies, any product recommendations please?

My trike basically is a normal bike, with the front forks exchanged for a 1 meter wide freight platform, each front wheel off center by a foot and a half. So if one wheel hits any sort of obstacle (small rock, or bump) the front wheels try to turn towards the obstacle. Since the trike's front wheels are powered with jump bike motors, the reverse happens if one of the front wheels loses traction because of a patch of gravel or sand. Have to hang on pretty tight, dare not scratch my ear or anything over about 5KM/hr.

The platform is pretty heavy with about 60 lbs of Nissan Leaf battery modules and the weight of the hub motors, not to mention a couple of grandkids that like to ride so need something a little above toy level for a damper.

Since the trike was built in Mexico stuff like bearings, dropouts and cranks are not bike standard fitting so thinking a cylinder type that I can fasten to the platform and the "bike" frame would be best.
The website of the manufacturer has a great pic , minus hub motors and floor battery box.
https://www.manufacturastrejo.com/en/
 
Those Mexican cargo trikes are intended for use at walking speed. Adding a steering damper won't fix that. It will still be a deathtrap at bicycle speed.

s-l400.jpg


You can reduce (by a little) its tendency to jackknife by adding a pair of extension springs from the cargo platform to the bike frame, one on each side. These will bias the steering to center without locking it out.

If I were you, I'd run those Jump bike motors on 12 volts with applicable controllers so as not to invite disaster. Center steering is treacherous. You mention you have Leaf modules, which are 2S if I remember correctly? Run your motors on 4S in that case, so your grandkids don't see Gramps tossed on his head. https://www.ebay.com/itm/304556370198
 
Chalo, you see any number of them in Mexico that have had the rear "bike" replaced with a smallish motorcyle, a 125 or 250cc bike touring along with the whole damn family on board, or six or so 20 liter drinking water jugs or propane bottles being delivered.
Was thinking of springs or bungies until I found out that people are using dampers on scooters and ebikes.
It does not feel risky at the kind of speeds I ride at, seldom more than about 15KPH. Gonna try a damper so was looking for recommendations.
The trike is becoming my preferred ride, except for the twitchy steering it feels quite solid.
Thanks for your comment, You are one of the most helpful people on this great site.
 
ynot said:
Was thinking of springs or bungies until I found out that people are using dampers on scooters and ebikes.

There's no reason in principle that you can't use both. A steering damper from a heavy motorcycle or an ATV would probably be in the right range to slow steering without restricting it too much.

Do keep in mind that whatever resistance you get to unwanted steering movement, you'll get the same resistance to corrective movements that bring you back to the desired heading.
 
Apparently the good dampers resist rapid road shock movement but do not resist slower handlebar steering input. (according to the sales pitches)
 
That looks almost like a Worksman trike.
We had one for several years, what a handful to use.
Only careful, well trained people were allowed to ride it.
A steering damper might make it a little more useful but I wouldn't expect too much.
The issue is leverage ... the distance from the steering pivot to the tire contact patch is much longer than any other vehicle.
So the steering damper needs to be strong ... like from a truck.

https://www.worksmancycles.com/stpt.html
 
PaPaSteve said:
That looks almost like a Worksman trike.
We had one for several years, what a handful to use.
Only careful, well trained people were allowed to ride it.

Mexican cargo trikes are WAY more venomous than Worksman front loaders. Like Dutch bakfiets trikes, Worksman trikes steer from a pivot placed directly under the load bed. It's kind of hokey, but it's still front steering.

Mexican cargo trikes steer from an axis in front of the driver but behind the load bed. This is mechanically simple to implement, but it definitely wants you to suffer and die. Imagine driving a car, or pushing a shopping cart, that steered by a hinge right in the middle. Those are four wheelers. Trikes aren't as forgiving.

Mexican trikes are designed for moving goods slowly in crowded city environments, mostly as portable vending stations. Going slowly enough to avoid catapulting yourself is acceptable for such applications.
 
Love me........ love my trike.
Wholy cow, you guys are scaring me to death.
Sitting in the hot tub and pondering, am gonna ask Chalo and others if the simple fact that the trike is being pulled along by the hub motors in the front wheels, makes it into a very different animal than if it was being pushed by the rear wheel?
Do the trikes you are comparing mine to have any models with front wheel drives?

Gonna try a steering damper, I ride like your granny, and am still learning how the trike likes to ride. What I am finding is that I have to hang on tight to the handlebar, but otherwise it feels ok. Maybe I should take off the rear bike part and get a newer bike and weld it to the freight part & turn it around making it a rear drive delta trike. Went to a ton of work bringing it back from Mexico after seeing them used as pushbikes and the motorized ones.
 
Chalo said:
PaPaSteve said:
That looks almost like a Worksman trike.
We had one for several years, what a handful to use.
Only careful, well trained people were allowed to ride it.

Mexican cargo trikes are WAY more venomous than Worksman front loaders. Like Dutch bakfiets trikes, Worksman trikes steer from a pivot placed directly under the load bed. It's kind of hokey, but it's still front steering.

Mexican cargo trikes steer from an axis in front of the driver but behind the load bed. This is mechanically simple to implement, but it definitely wants you to suffer and die. Imagine driving a car, or pushing a shopping cart, that steered by a hinge right in the middle. Those are four wheelers. Trikes aren't as forgiving.

Mexican trikes are designed for moving goods slowly in crowded city environments, mostly as portable vending stations. Going slowly enough to avoid catapulting yourself is acceptable for such applications.

Sitting in the hot tub and pondering, am gonna ask Chalo and others if the simple fact that the trike is being pulled along by the hub motors in the front wheels, makes it into a very different animal than if it was being pushed by the rear wheel?
Do the trikes you are comparing mine to have any models with front wheel drives?

Kind of double posting because this is very important to me, have a lot of energy invested in this trike and really do not want to walk away from it.
Thanks for your input.
 
Oh it's different alright. Could be good or bad depending.

Pulling in front would tend to keep the thing straighter, but pulling unequally (due to separate throttling or just different traction conditions) would be either actively stabilizing or actively destabilizing. Seems to me that having right and left throttle would allow you to learn to torque steer, and iron out twitchiness problems with differential torque. Or it might just be too complex to process in real time. I would have to try it and see.
 
Chalo said:
Oh it's different alright. Could be good or bad depending.

Pulling in front would tend to keep the thing straighter, but pulling unequally (due to separate throttling or just different traction conditions) would be either actively stabilizing or actively destabilizing. Seems to me that having right and left throttle would allow you to learn to torque steer, and iron out twitchiness problems with differential torque. Or it might just be too complex to process in real time. I would have to try it and see.

Yup, good point. In fact something I'd like to try myself eventually.

Point is, with arrangement like this, when loaded, you get what amounts to rear steering, which is not stable.

Loading the REAR (by using a motorcycle instead of a bike) in fact will help considerably!
Entire arrangement does sound like a handling nightmare unless you use torque vectoring exclusively at higher speeds - that it should handle kinda like a trike with a trailer.

You may want to use DD motors and use combination of torque and regen braking, and you want good controllers (think VESCs) and throttles and current/torque motor control is absolutely cruicial, don't bother unless you are willing to shell out money for such a setup... it is not THAT expencive mind, if you use something like vesc 75100.
 
In fact, the more I think about it, the more I like the idea - with such a setup (two DD motors and rear bicycle transmission) you get what amounts to all wheel steering and torque vectoring - so you have ability to turn on a dime and high speed stability - again, in theory, that would depend on actual implmentation a lot, and hanlding is going to change considerably depending on load.

Like I said, I've had a similar idea, but instead of two throttles I wanted to use two ADC brake handles, and use pedal torque from pedal generator as actual throttle (because recumbent form-factor with rear steering and front non-steered wheels)

Than, by combining three signals on arduino (or any other MCU), by differential braking, you at first move *driving* torque from one wheel to an other, than progressively brake inside wheel and move generated amps to outside wheel. This should be easy on the battery and you'll be able to have pretty efficient torque vectoring even at low power.
Press both brake handles to simply brake.

Don't have enough spare funds for such expriments now, unfortunately, but if you'll try that yourself I'd be very intersted in results :)
 
Steering done via a central pivot such as on your trike is termed "wagon steering"
Wagon steering is prone to "bump steer" whereas when one wheel hits a bump it causes an unwanted steering movement.
This simple system works okay on a wagon because the steering lever (drawbar) is much longer then the axle.
Usually the wagon is pulled, slowly, by a heavy animal.

Making it into a delta by turning the thing around and attaching a regular bicycle would make it easier to control.
Although ... keep in mind ... one wheel drive will still create some thrust vectoring.

We've have enjoyed several large pedal electric cargo contraptions.
Including one that came from China that looked like this :

delivery-bicycle-S0CJ97.jpg
 
Chalo said:
Oh it's different alright. Could be good or bad depending.

Pulling in front would tend to keep the thing straighter, but pulling unequally (due to separate throttling or just different traction conditions) would be either actively stabilizing or actively destabilizing. Seems to me that having right and left throttle would allow you to learn to torque steer, and iron out twitchiness problems with differential torque. Or it might just be too complex to process in real time. I would have to try it and see.
IMO with a rear wheel drive we would have the tail trying to wag the dog, in this case with the front wheel drive the dog is wagging the tail.
I have the motors on separate identical KT controllers wired to a single thumb throttle, trying to learn to steer with two throttles would be a nightmare and dangerous methinks.
I agree that if the bike was being pushed the front wheels could overpower the rider and go to lock on the steering and trip over the front wheel. Pulling the trike tries to straighten. The only forces I am dealing with appear to be bumps and traction, it does not appear to be a positive feedback wobble, it does feel like it is trying to straighten itself out.
Thanks for hanging in there
 
I have used motorcycle steering dampers attached from tie-rod to fixed frame location on a couple of tadpole trikes - these are "sport" trikes rather than cargo trikes.

On an old trike I had, I used one in hopes it would fix twitchiness in the steering, but that was not really the case, as that particular model had odd steering geometry.

More recently I attached a similar unit to another trike that was "wiggling" or oscillating the steering after I hit bumps etc, and came on after mounting a mid-drive motor to the boom, switching the weight forward. For this purpose, the damper works perfectly, as it allows slow-velocity movements with little resistance, but will not allow higher speed movements. It has little impact on steering feel, since steering inputs are generally small, or slow, or both.

That oscillation or shimmy issue is well served with these - not sure if you can solve other handling issues with them though. It's interesting that some cars, like air-cooled vw's, had hydraulic dampers attached to the tie rods similarly.
 
ccihon said:
I have used motorcycle steering dampers attached from tie-rod to fixed frame location on a couple of tadpole trikes - these are "sport" trikes rather than cargo trikes.

More recently I attached a similar unit to another trike that was "wiggling" or oscillating the steering after I hit bumps etc, and came on after mounting a mid-drive motor to the boom, switching the weight forward. For this purpose, the damper works perfectly, as it allows slow-velocity movements with little resistance, but will not allow higher speed movements. It has little impact on steering feel, since steering inputs are generally small, or slow, or both.

Thanks for that, do you by any chance have a brand or source for the damper you used.
We seem to have negative feedback on the steering as it tries to pull in a straight line.
 
Sure - Details and pics in this thread:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=112937&p=1676277&hilit=steering+damper#p1676277
 
ccihon said:
Sure - Details and pics in this thread:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=112937&p=1676277&hilit=steering+damper#p1676277

Ordered one before you posted, looks pretty similar and priced about the same.
We are entered in the city parade with some ebikes and scooters & will have the grand kids in the front with an umbrella up.
The stabilizer is due in on Friday so hope I can have it installed for Saturday.
Cheers & thanks for the info.
 
Chalo said:
Oh it's different alright. Could be good or bad depending.

Thought you might like to see a video of our ebike section of the local parade, my trike is there with its cargo, our bikes show up after a few minutes, so hang in there.

https://www.facebook.com/groups/606522906789818/permalink/1192606508181452/

The steering damper is helping quite a bit with the handling, now the major steering events are uneven braking on the front wheels, so have ordered hydraulic calipers to even that out.
Also the fact that the two motors on a shared throttle pull a little differently from time to time, may wind up putting two thumb throttles linked with a plate so that they act as one.
 
ynot said:
https://www.facebook.com/groups/606522906789818/permalink/1192606508181452/

It looks pretty okay in that short flyby, though that's much faster than I'd go with kids aboard. However, my experience with center steering suggests that in a jackknife crash, you'll get catapulted but they'll just fall over.

Here's my own primary experiment with center steering. Many test pilots were flung off of it:
Screenshot_20220719-104356.png

The steering damper is helping quite a bit with the handling, now the major steering events are uneven braking on the front wheels, so have ordered hydraulic calipers to even that out.

Well, when the first one oils its rotor, you'll have imbalanced braking every time. So be mentally prepared for it.
 
Glad to hear the damper is helping at least somewhat. On most tadpole trikes etc, there are two separate brakes and separate levers for each side - in my case I am using cable-operated disks. On trikes like these where the steering is accomplished in a car-like fashion, using tie rod and pivot points at the hub, the geometry is generally good enough that even with uneven braking force, the handling is predictable. I can even brake using one lever side only, and easily maintain a straight line.

Are there any cargo trikes available where the load is not pivoting with the frame, like the center-steered ones, but rather centered atop a stationary frame and the front wheels pivot underneath, as on a tadpole? I know a big concern may be the relatively higher center of gravity if the stoker is seated at bike height.
 
ccihon said:
Are there any cargo trikes available where the load is not pivoting with the frame, like the center-steered ones, but rather centered atop a stationary frame and the front wheels pivot underneath, as on a tadpole? I know a big concern may be the relatively higher center of gravity if the stoker is seated at bike height.
Are you looking specifically for a tadpole, or will a delta trike work? What is your budget range?



Can you build your own trike, given a basic known-working design / layout?
 
ccihon said:
Are there any cargo trikes available where the load is not pivoting with the frame, like the center-steered ones, but rather centered atop a stationary frame and the front wheels pivot underneath, as on a tadpole?

Nihola trikes from Denmark have Ackermann steering.

https://nihola.com/

I don't know of any that use a center pivoting solid axle under a stationary load.
 
Chalo said:
Here's my own primary experiment with center steering. Many test pilots were flung off of it:

Isn't that supposed to have a five-way safety harness :?:
 
Chalo said:
ynot said:
https://www.facebook.com/groups/606522906789818/permalink/1192606508181452/

It looks pretty okay in that short flyby, though that's much faster than I'd go with kids aboard. However, my experience with center steering suggests that in a jackknife crash, you'll get catapulted but they'll just fall over.

Here's my own primary experiment with center steering. Many test pilots were flung off of it:
Screenshot_20220719-104356.png
Well, when the first one oils its rotor, you'll have imbalanced braking every time. So be mentally prepared for it.

Good tip Chalo, will beware. I notice that your trike does not have any limit on the steering, my trike has about 30 degrees each side, limits the turn radius a bit with very strong blocks welded to the frame, which helps protect against the dreaded jackknife.
Would like to replace the rear coaster brake with a friction brake which would take much of the load off the front brakes, gotta find a new wheel tho'.
 
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