Electric Tricycle design

JerryUtah

1 mW
Joined
Apr 22, 2022
Messages
13
Hello, Newbie here and with the Daywins MG 1703 Tricycle, just one of many similar Chinese brands now. I chose this 20 inch wheel 4 inch fat tire model (most brands have a 24 inch wheel) with the Bafang 750w motor in order to have the best acceleration. ( could the 20 inch be the cause?) I assembled it yesterday and tested it without power. It has the Shimano 7 gear cassette.
I had studied various videos of different brands for half a year as reviews by competent bike reviewers. NONE had mentioned steering problems so I thought I had no reason to reject this brand except there was no actual video review of the 1703. Here is the problem:
Upon pedalling gently without power within 5ft. it starts to turn on its own either left or right and heads for the ditch. It is simply impossible to merely correct it by turning the other way. It does this every time I try. I have to brake get off and walk it onto the driveway. If I had enough space it would keep turning in a circle!
I carefully followed the assembly video and today noticed I was 1/4 inch off on the bracket connecting the rear wheel assembly so I triangulated a measurement from the axle to the seat post frame but upon testing again the same unwanted turning happened. I'm now thinking its the rounded fat tire from side to side. I am thinking it is the tiller stem to fork which may be too vertical. Should have more rake? This, in conjunction with the bike being too short? ( 49 in wheelbase). I recall about 15 years ago I came across a vendor owner selling his own tricycle brand and when I attempted to pedal in the tent the same thing happened. It would not steer straight in a few feet and veered like this one. I told him then the rake needed to be greater on the short bike. Now, since NO ONE reviewing these bikes that I have seen recently have said one word about this I thought maybe there is no issue now.
I submit that it is not a mere matter of learning how to ride a trike. For the above reasons I believe it a design flaw. My bike is useless and I have told my vendor and the Daywins manufacture that I should be given a full refund with no shipping or restock 20% fee. I even ripped the box off to get the parts out. I told them I would not even give it away and have some one get hurt or killed on the road. Ungodly awful. I had planned to drive 5 miles to the grocery to eventually save on gas. I live in my trailer and my Ram v10 gets about 10mpg.
Your experience would be appreciated.
 
Trikes steer downhill. They just do; it's one of the reasons they suck. Astute front end geometry helps, but doesn't cure this trait, and almost no trikes have astute front end geometry. It's too much cheaper and easier to use bike parts, which are wrong for the job.

Fatbike tires exhibit a characteristic called "self steering" on bicycles, where they tend to roll further into a turn and not want to come up out of it. I expect the front tire of a trike is somewhat affected by this, but not to the same degree as a bike.

If you want the trike to behave better, well, you have the wrong trike. But using a fork that has much more offset-- like enough offset to reduce trail to about a half inch-- would reduce the trike's tendency to make for the gutter.

I think most trike purchases could be prevented if the prospective buyers would only test ride one first.
 
JerryUtah said:
Hello, Newbie here and with the Daywins MG 1703 Tricycle,
This one?
https://www.electricbikeparadise.com/products/daywins-mg1703-fat-tire-electric-trike


(most brands have a 24 inch wheel) with the Bafang 750w motor in order to have the best acceleration. ( could the 20 inch be the cause?)
Yes, in that the smaller the wheel, the higher the torque but the lower the speed, for the same input to it.


I had studied various videos of different brands for half a year as reviews by competent bike reviewers. NONE had mentioned steering problems so I thought I had no reason to reject this brand except there was no actual video review of the 1703. Here is the problem:
Upon pedalling gently without power within 5ft. it starts to turn on its own either left or right and heads for the ditch. It is simply impossible to merely correct it by turning the other way. It does this every time I try. I have to brake get off and walk it onto the driveway. If I had enough space it would keep turning in a circle!
Delta trikes in general will tend to steer downhill, and they handle differently than bikes do. (I haven't ridden tadpoles enough to say)

The fat tires probably don't help; if they are low pressure (squishy vs harder) they'll probably make the steering mushier which may not help. (takes more time to correct steering)

You say that it is not a matter of learning how to ride a trike, but they do handle differently, and the reactions learned from bicycle riding are different from those used to handle a trike like this. If you only rode bicycles (other than the test ride you describe where you found the same problem) before and not trikes, you may need to retrain yourself for the way the trike handles; if so then if you ride it enough, you should get used to the way it behaves and be able to better control it. How long that takes depends on your own learning times (for me it's longer than others, for instance).

My very first trike experience was using a trike kit on the back end of the long and low CrazyBike2,
https://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=336930#p336930
and I took it off after the first test rides, because it so badly changed the way CB2 handled that I nearly flipped myself over just turning around, and almost crashed into various parked cars on my street.

I can say that in general trikes like this don't ride well above 10-15mph, and are highly likely to tip and flip in any turn higher than walking speed (at best).

I suspect that reviews that don't mention the problem might simply be that they don't see it as a problem, or they may have enough experience riding trikes that they automatically correct for it and don't think about it. You'd have to ask each individual reviewer to find out.

When I built Delta Tripper (my first trike)
https://endless-sphere.com/forums/viewtopic.php?f=2&t=22720
it took me some getting used to before I could ride it without thinking about it. I crashed it a few times in the process. :oops: When I built SB Cruiser
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833
I could ride that pretty easily and naturally because I already "knew" how to ride a trike. Some of it's build characteristics made it easier to ride at higher speeds, and better at cornering without flipping, but anyone that has tried it out (only one of them had any bicycle experience and no tricycle experience at all) has had similar problems to what you had, though to a lesser degree because of it's length and weight/COG, etc, and what I had when I learned to ride DT.

I am thinking it is the tiller stem to fork which may be too vertical. Should have more rake? This, in conjunction with the bike being too short? ( 49 in wheelbase).

A short wheelbase doesn't help, but it isn't the single root cause. I built SB Cruiser much longer than Delta Tripper partly for that reason, and partly to haul more cargo.

A slacker steerer angle will change the way the steering works (will probably be less "twitchy" if that is a problem for yours, but it also depends on trail, too; just changing one may not change the behavior the way you want to. Chalo's advice is probably the best to follow for geometry changes, if you are willing to modify the trike to suit your needs.

SB Cruiser has a much slacker angle than Delta Tripper, but it also has a very long tiller where DT had a very short stem, and that also changes steering because it gives me more leverage against the front wheel.
 
Hi,
Thanks for input. I had a consultation with a mechanic this morning. First thing: I had assembled the tiller with the fork backwards! That changed and him describing how to drive by leaning outward and turning back has me acknowledge that it IS a matter of learning to ride a trike! He suggested to find a flat place to practice instead of the crowned dirt road at my camp. He's right. I'm camped with my trailer on BLM in Utah. But I really need to be able to go off road with this. Yes, that is the 1703. I put a 42 gal. bin on back the small basket is too small. I will be putting a 55lb. bagged inflatable raft in it to get to the lake with. I had a larger basket on my other bike and put it on the front. I have a small 35lb Healer that I hope will ride in front. With all that, a huge grade up from the lake about 3/4 miles on the Hwy. Hope for the best...
 
I came across a nice explanation of the drift downhill. The gist was that straight axle trikes like mine are without any camber or toe in adjustment. The recumbent style trikes have a tie rod to adjust resulting in better tracking on crowned roads. I decided to keep the 1703 and practice a lot before getting on the shoulder of a Hwy.
 
JerryUtah said:
I came across a nice explanation of the drift downhill. The gist was that straight axle trikes like mine are without any camber or toe in adjustment. The recumbent style trikes have a tie rod to adjust resulting in better tracking on crowned roads. I decided to keep the 1703 and practice a lot before getting on the shoulder of a Hwy.

In your case, there's only one steered wheel, so it can't be cambered or toed. The downhill-seeking effect comes from steering trail, which serves as a lever to steer the trike with when there's a sideways thrust on it (like when the trike is sitting on a slope).

By adding fork offset until steering trail is cancelled out, you deprive the system of this lever. But no manufacturers actually do that, because it would require using a fork that doesn't come from a bicycle (and which would therefore cost more).
 
Hi,
This is a warning to those considering buying one the trikes such as mine. I took it out today on my dirt road which is actually slanted somewhat but flat otherwise.
This bike CANNOT BE CONTROLLED ON SLANTED GROUND. End of practice! I'm going to sue for ALL my money. These trikes are NOT for any surface other than level and flat surfaces!
It does not matter if I lean completely over while fighting to steer in the other direction. This is completely unacceptable to even have to do that.
Also, if you do buy do not buy from brokers such as I did. Mobility etc. 20% restock, bike cannot be used, same box. (gone) So they won't likely even accept it. If so, I will be making my first youtube video of me burning it to the ground! $2,300 up in smoke.
 
I wish you were here in Phoenix; I'd love to ride that trike around and test it.

I'm sure that even if it is a little bit more difficult than other trikes to control, even that could be fixed pretty easily with a different fork, or a modification to the existing one, to change it's trail and steering characteristics.

Seems like a pretty strange thing to throw away all that money rather than investing a bit of time and perhaps a few dozen more dollars to improve it for your specific needs, but I guess I'm not a typical user of products.


JerryUtah said:
Hi,
This is a warning to those considering buying one the trikes such as mine. I took it out today on my dirt road which is actually slanted somewhat but flat otherwise.
This bike CANNOT BE CONTROLLED ON SLANTED GROUND. End of practice! I'm going to sue for ALL my money. These trikes are NOT for any surface other than level and flat surfaces!
It does not matter if I lean completely over while fighting to steer in the other direction. This is completely unacceptable to even have to do that.
Also, if you do buy do not buy from brokers such as I did. Mobility etc. 20% restock, bike cannot be used, same box. (gone) So they won't likely even accept it. If so, I will be making my first youtube video of me burning it to the ground! $2,300 up in smoke.
 
Most trike buyers think trikes are something they're not. If buyers demand something that can't work the way they imagine it will, it's not really the manufacturers' fault when they make what the buyers are asking for.

I encourage everyone who wants to choose a three wheeler over a two wheeler to try one first, in the conditions they plan to use it in. The two wheeler is almost always the better choice.

The trike you have can probably be improved dramatically with a "fat chopper" fork that has plenty of offset at the triple clamps, plus more offset at the dropouts.

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I reject any idea that I should modify the trike in an effort to make it work on uneven or slanted terrain. I have it boxed up now to ship back. The Rep for Daywins.com has acknowledged that it is difficult to control on slanted surfaces. The design of these trikes is such that they barely work on uneven or slanted surfaces. Period. All the various brands with similar frames likely behave the same. It simply is a faulty design. Also, I am perplexed that no reviewer I have watched on YouTube has mentioned one word about it but that does not mean I am wrong or merely inexperienced.
 
A plaintiff need only meet the requirements of one of the tests to prevail.

i. The consumer expectation test — failure to perform safely.

a. What is meant by consumer expectation.

A product is defective in design if it failed to perform as safely as an ordinary consumer would expect (or have a right to expect) when using the product in an intended or reasonably foreseeable manner.
( This is California product liability law)
 
If you have faulty ideas about how a trike works, that's not a problem with the trike. The problem is your understanding. The trike isn't defective; it's doing what a trike does, which isn't what you expected.

In this case, the only remedy is to try one before you buy, to dispel your misconceptions about it.
 
Yes, I did not expect it to behave this way nor was I told it would behave this way and no reviewer said it would behave this way and the manufacturer did not say it would behave this way.
Faulty ideas? Come on! So tell me why it behaves this way except that it is the way these trikes behave.
So therefore, the trike is faulty in design.
 
JerryUtah said:
So tell me why it behaves this way except that it is the way these trikes behave.
So therefore, the trike is faulty in design.

Steering trail is the lever a bike uses to return to a balanced state when it leans to one side or the other.

When a (delta) trike has steering trail, it doesn't work that way, because the trike doesn't lean with respect to the surface. Trail becomes the lever that turns the front wheel in the same direction as any lateral force that acts on the trike. Most commonly that's centrifugal force in a turn, or else a slope in the riding surface. A trike that has steering trail will tend to steer to the outside of a turn or in the downhill direction on any slope.

When a trike manufacturer uses a bicycle-like head angle and a bicycle fork (which almost all of them do), the result is a bicycle-like amount of steering trail. The same lever that makes a bike easy to ride makes a trike unruly and difficult.

All you have to do to counteract this bad trike behavior is use a fork that has enough offset to more or less cancel out its steering trail. I know of no manufacturer of granny trikes that does this, though. They use a bicycle fork because it's cheap, so the trikes point themselves downhill. You can say the design is faulty, but they're all like that, so is it really? If you've ridden one before, you know what to expect.
 
I barely understood what you said but I have guessed previously that I thought the fork was too vertical.
But I certainly should not be expected to correct anything and will not. All these companies are at fault for foisting off deficient designs and calling it good. Not! It is not up to me to make major design corrections.
Also, I had no opportunity to find a local dealer as I live in a remote area. Bikes are sold all over the world without personally testing. I relied on expert? reviews for months before buying and none said anything about it. But it is a REAL problem. I was bamboozled. These type of trikes should be banned.
Read again my post copied from California product liability law.
 
When I started riding ebikes I found a design fault that's probably injured thousands. When I stop, it falls over!

AussieRider
 
AussieRider said:
When I started riding ebikes I found a design fault that's probably injured thousands. When I stop, it falls over!

Yep, that's a problem with bikes.

Trikes are great at standing still. They fall over after they start moving.
 
Chalo said:
Trikes are great at standing still. They fall over after they start moving.

That generally requires for the center of gravity to shift outside of the triangle drawn by the center of each wheel. In my case, I have to turn with about 0.7G lateral acceleration to get up on two wheels. While not the best cornering performance in the world, it is very acceptable and usable, as long as I keep this limitation in mind. For any kind of normal riding @ 30-35 mph where I'm not pushing the trike to its limits, and as long as my rear tire never violently comes off the wheel, I will not have to worry about falling over while moving. There are all kinds of abnormal conditions where this could become an issue, such as being rear-ended by a car while at speed, or the rear wheel being sent airborne by an unavoided road obstacle only to land and regain traction in an undesired manner, but these sorts of caveats can apply to any platform/layout.

Mine is stable enough to ride in the snow or rain on crappy roads @ 30-35 mph with confidence that I'll retain control. While I wouldn't recommend doing this, I once took my hands off the steering bars @ 50 mph going down a hill prior to motorizing mine, and it remained straight and didn't veer off course.

Bottom line: get the right kind of trike for the application if you're going to use a trike. Most trikes are very poorly designed/built for ebike applications. Even mine leaves a lot to be desired, but I can live with it and am very happy to have it.

I'd recommend looking into a Hase Kettwiesel if you want a delta layout. Try before you buy if possible. If that's not an affordable option anytime soon, do what was recommended in the topic and get a different front fork, as that may correct your issue.
 
To toecutter,
I am the OP. My complaint has to do with the Daywins MG1703 and likely all brands similar with the 2 wheels in rear.
 
The Toecutter said:
Bottom line: get the right kind of trike for the application if you're going to use a trike. Most trikes are very poorly designed/built for ebike applications.

True. But most low slung recumbent trikes are poorly designed for bipedal humans to ride. So it's a wash.
 
OP here. It's not only a wash Chalo, it's a shame on the manufacturers for not printing a disclaimer on their descriptions of the trike so I would be forewarned:
While we make a very durable trike with fat off road tires please refrain from driving on uneven, slanted and crowned roads or paths as you will not likely be able to control its direction.
Toecutter: The MG1703 was seemingly the correct application for me. Cargo and fat tires. Big 18amp battery, 750w motor. Whether electric or not the concept of its design has it a failure. Along with all the others similar.
Who knew?
No one is talking. Any manufacturer that made a disclaimer like I gave above would not have many customers.
 
Most trike buyers have preconceived notions. You can't explain things to them, but you can sell them what they ask for.
 
I would have understood the disclaimer and have moved on to the most appropriate application: The Rokon 2x2!
 
AussieRider said:
When I started riding ebikes I found a design fault that's probably injured thousands. When I stop, it falls over!

Too bad you are in Australia. If you were in the US you could find a lawyer who'd be happy to run with that.
 
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