Category Archives: construction/design
There is lots of information about building a tadpole trike available online besides what I have written myself. I am not really adding anything new here. Rather I am simply posting this one article with links to all that I have written about the subject before making it a bit easier to find it.
Here is one of them: https://tadpolerider2.wordpress.com/2015/01/30/gotta-do-your-homework/
Here is another one: https://tadpolerider2.wordpress.com/2014/05/11/tadpole-trike-construction-the-science-of-tadpole-trike-steering/
Here another one: https://tadpolerider2.wordpress.com/2014/05/11/home-built-recumbent-trike-detailed-plans-and-construction-steps/
And here are a bunch more postings on my blog about custom built trikes: https://tadpolerider2.wordpress.com/category/homemade-tadpole-trikes/
Evolve Trikes … interesting concept, but they are sure having problems getting into production and to market. Years and years seem to be passing by and still they are waiting for things to come together. It just doesn’t seem to be happening. Yep, they seem to be having trouble evolving to market.
Since it’s inception they have made some changes in its design. The main boast is that it folds faster and smaller than any other trike.
When I look at the design construction of trikes I am always concerned about how ell they are made and whether or not they are likely to fail. Mind you I am not an engineer, but I do have well over 50 years experience at welding and fabricating. In welding my “specialty” was repair welding. That means I worked on a whole lot of things that failed and required repair. In making the repair it was usually easy and obvious to see why the item failed. And in repairing it I always made it much stronger so that it didn’t fail again. Looking at many trikes I see areas of concern in many of them. They just look weak and apt to fail. Many folding trikes concern me for this reason. This one not only is no exception, but it is even more of a concern as it just looks weak. Any trike can have a failure, but some seem to have far more than others. Again, looking at the way they are constructed I can see why. A simple basic rule is that the more complex something is the more likely it will have issues over something with less complexity.
Here it is disassembled and folded up into a suitcase. The video below shows how it is done.
I don’t know what the weight limit is for the Evolve trike, but I think that it would be best for those who weigh very little. A heavy rider would stress those areas which are already suspect of failure.
I personally don’t think I would buy one of these trikes as it just has the appearance that problems would develop due to failure in one or more parts of the frame.
The folding hinge is quite often a concern and this one is no exception. When I look at something like this the thought that comes to mind is “designed to fail” due to being underbuilt. Mind you, this is far from the only tadpole trike which in my opinion looks underbuilt.
Another factor is wear and sloppiness developing in these areas. Things get loose and movement takes place where there should be no movement.
I know that the Evolve people are not going to like what I have said here and perhaps some of you may not either. I have to say what I think about these things. I hope I am wrong and this trike would hold up well. But my gut feeling is otherwise. I like the concept. I am just concerned about the quality of the build. Manufacturers underbuilding products brought a lot of repair work my way over the years. I would not want a trike that requires repair and reinforcing it to make it stronger. That would be my concern here. This may be okay for someone who rides very little and needs a small folding trike, but I could not recommend it for anyone who does serious riding. I don’t care how good of a warranty it may come with and how good the company may be in taking care of customers … when you are many miles from home and have a major failure leaving you stranded it is not fun. Nope, I will stick with my non folding Catrike which I am confident in … that it won’t fail me. I like to … KEEP ON TRIKIN! …. and ….
ENJOY THE RIDE!
Now I am not out to attack rear wheel steering per se, but I am reporting what I have read about it as well as my opinion about the design. I am in full agreement with what I have read about rear wheel steering. And what I read about it is exactly what I think it would be like. At slow speed it works okay. At super slow speed it could be a lot of fun and helpful. But I am not interested in always going slow so if there is a handling and safety problem with rear wheel steering it is not for me. This issue comes up because I just recently made the discovery that the tadpole trike maker, Sidewinder, is still in business. I thought they went out of business due to a lot of complaints and concerns about their trikes being unsafe above a certain speed due to stability issues. One thing for sure, there aren’t many Sidewinder trikes around. I have never seen one nor talked to anyone who has. It is reported that some of the most sophisticated fighter jets made can’t be flown without the aid of computerization. They will crash without it. That is about my take on rear wheel steering and riding above certain speeds. Something beyond human input and control is needed in order for it to be safe. There are lots of stuff online to be read about this subject. Here are a few of them:
Look at it this way … if rear wheel steering were safe and practical car, truck, bus, motorcycle, etc. manufacturers would employ it. They don’t. I rest my case. We all want to be safe and …
ENJOY THE RIDE!
I think this is rather ingenious … the trike leans (tilts) when the wheels are turned. I wish it showed close detail of how it works.
I have written an article about this model previously. You can read it HERE.
I am sure many of us have been asked that question by others. I sometimes reply “with the handlebars” and usually show them where the handlebars are at since they don’t seem to be able to figure it out for themselves. That is the short and simple answer to the question, but wait … there is more to it that that. I mean … SELF STEER, WE STEER, PEDAL STEER, BRAKE STEER, BODY STEER — THEY ALL STEER. Did you follow all of that? I am sure some of you did, but for the rest I will explain further. Let’s look at them one at a time.
I already mentioned the WE STEER and don’t think it needs any further explanation. We simply turn the handlebars and thus we steer the trike. The only thing I think I will add here is that if we hold onto the handlebars too tightly and are pedaling hard we can effect the steering thru the handlebars by simply moving them back and forth. We often won’t even realize we are doing this. Of course, direct steering vs. indirect steering will also make a difference. Usually direct steering is more sensitive to slight movement, especially at speed.
SELF STEER (self centering) – is simply the way the trike is designed. If designed and built correctly the front wheels should more less center themselves and go straight ahead on a flat smooth level surface. This is desirable.
PEDAL STEER – is when the trike tends to turn one way and then the other as we pedal along. This is the result of the boom flexing and effecting the forward line (path) of the trike as it moves along. This is something undesirable, but unfortunately it happens. Some trikes are far worse than others. That is because some trikes have a whole lot more flexing going on than others. Again, a well designed and built trike will have very little pedal steer. Pushing hard on the pedals results in a worse case of pedal steer. Shifting into a higher gear will decrease pedal steer. It is important not to grip the handlebars tightly as when pedaling we tend to input slight movement into the handlebars. Using just the fingertips can help us lesson our grip. Shorter crankarms will help reduce pedal steer. The more upright a person is sitting the more likely it is to experience pedal steer. Riding sitting as stationary in the seat as possible while pedaling and not swaying your upper body side to side in the seat will help reduce pedal steer. Just leaning to one side or the other will cause the trike to steer in the opposite direction. Again, depending upon the trike design some trikes are more sensitive to this input and will move about accordingly. So pedaling from the hips and not involving the upper body will eliminate most pedal steer. The further out the boom is extended (accommodating a tall person) the more likely it is to have an increase in pedal steer. “Mashing” (hard pushing) the pedals usually results in increasing pedal steer. It is far better to “spin” than to mash. The straighter we can push on the pedals the better. This may mean pulling our knees together inward somewhat and adjusting the position of our feet on the pedals as well. Pedal steer can be pretty much eliminated if we work on it.
Here is what Catrike says in the owners manual about some of this …
<> Riding tips: If you don’t have experience with recumbent tricycles, you may find that for the first few rides you experience noticeable pedal steer (pushing hard on the pedals makes the trike swerve) and brake steer (grabbing one brake harder than the other causes the trike to swerve). These two phenomena become much less noticeable as you gain experience. Pedal steer is minimized or eliminated by pedaling smoothly at a fairly high cadence, rather than mashing hard. Brake steer is minimized by braking smoothly and evenly…if the trike lurches under braking you’re overdoing it (it’s like driving your car…you don’t stand on the brakes every time you slow the car; rather, you learn to modulate the pressure so that the car does not lurch). The smoothest, most enjoyable ride comes when you learn not to over control the trike. The steering is very responsive, and does not require much input at all to make the trike change direction. The less you try to steer, the smoother the ride will be.
BRAKE STEER – occurs when only one brake is applied and the trike steers in the direction of the applied brake. This can be helpful when done properly by someone experienced and skillful. However, it can be quite dangerous as well, especially when it is done by someone not so experienced and skillful. It can be quite scary and lead to tragedy.
Here is what Catrike says in the owners manual about some of this …
<> Brake Steering: Our frames are designed for a diminished brake steer effect. However keep in mind that the trike is not a heavy vehicle such as a car. It does not have hydraulic, electronics or self correcting mechanisms either. It is instead, a very light recreational vehicle with a mechanical steering linkage that carries a rider sometimes over 8 times its weight. Therefore the weight & dynamics of the driver can exert total control over the capabilities of the vehicle. It does demand that the rider develops proper riding skills, such as smooth pedaling, smooth steering and smooth breaking and that it is always conscious when riding. The Catrike has front brakes only, since in a breaking situation 90% of the weight is transferred to the front of the trike. The front brakes are also independent, meaning that you can break the right wheel only, or the left wheel only. Therefore, especially in high speed or down hill situations, it is mandatory that you pull both brakes at the same time and with the same intensity. If you elect however, to brake only with one brake, this could cause the trike to steer out of your path and cause serious injury or death.
The bottom line here is we need to be careful in applying the brakes, especially at higher speeds.
BODY STEER – which seems to have varying effect depending upon the particular trike and how it is designed and built and perhaps setup. Body steer is simply a matter of leaning to one side or the other while seated and riding along. Leaning to the right should result in the trike steering to the left. Leaning to the left should result in the trike steering to the right. Oftentimes I would have to say it doesn’t have much effect.
(I purposely left out lean steer trikes since they are not very common.)
So when someone asks you how you steer that thing you can share with them all of this I have discussed here. Of course, they will probably be sorry they asked. 😉 It probably would be better to just tell them that you steer it with the handlebars and then you can just …
KEEP ON TRIKIN’
Lastly, HERE is a poem of sorts someone made up about pedal steer. I would give them credit for it if I knew who wrote it, but alas I don’t so all I can do is share the website where it is posted. It is rather lengthy, but interesting:
As the internet has flourished,
It’s the place where brains are nourished –
Questions answered, good advice, and all for free.
But at times we find confusion,
Petty spats with no conclusion;
On some issues, people simply disagree.
Pedal steer’s one red hot topic,
Where the biased and myopic
State their strong opinions – kooky to sublime.
Teams of tadpole testers wrote us,
“It’s a problem you will notice..”
Others tell us, “You’ll forget it; give it time.”
Some folks try to understand it,
And why builders haven’t banned it,
Simply making good decisions in design.
Are some tadpoles worse than others?
Men might ostracize their brothers,
Disagreeing… So what is the bottom line?
One authority is certain:
“CASTER! That’s the culprit.” (Flirtin’
With a partial loss of credibility)
Other pundits shun that war word;
Sure the rider’s too far forward,
They insist the key is fore-to-aft CG.
One guy says, “That boom’s too flexy.
Sure, light weight is super sexy;
Still a tadpole works much better if it’s stiff.
Folding frame or soft composite –
That’s the sort of stuff to cause it.
Solid alloy steel would fix that in a jif!”
Some posts tell us, “Make tracks wider.”
Others claim that all a rider
Needs to do is just relax his stonelike grip.
Scores of would-be trike designers,
Second guessers, geeks and whiners
Offer their beliefs or freely share a tip.
Though I rarely speak in bellows,
I – like all these other fellows –
Can’t (or should I say I won’t?) resist the urge
To assist in education
Of the unwashed population,
Helping logic, truth and reason to emerge.
No, you know of course I’m poking
Fun at technogeeks; I’m joking.
Still there is some truth in what I have to say.
I’ve spent years in engineering,
Analyzing, probing, peering
Into why contraptions act some quirky way.
When I started out three-wheeling,
I encountered that odd feeling
As the trike began to waggle – gee then haw.
But did I, appalled or frightened,
Shout, “This wrongness must be rightened!”
In a single word, the simple answer’s ‘NAW’.
I feel sure – at least I’m hopin’ –
That if you’ll keep your mind open,
Though you doubt at first, you’ll have a change of heart.
Gather ’round, all those who’ll listen;
I’ll share points some may be missin’,
Going back to basic biking as a start.
Hey… remember starting biking?
It was not much to your liking
When the danged thing rocked from side to side – then CRASH!
Still all cyclists gained reflexes –
Smart and dumb folks, both the sexes –
So that they weren’t dumped each day they dared to dash.
You have seen one-wheeled abortions,
Watched their riders do contortions,
Smiling, though they jerked around to stay upright.
Unicyclists, pedals pumping,
Pirouetting, even jumping,
Balance as they ride, aloft, eight feet in height.
BOTTOM LINE (IMHO time):
Folks, it’s not exactly SHOWTIME
When someone can ride a tadpole straight and true.
Even if, when you first try it,
You may think, “Bull. I don’t buy it,”
Settle down and give it one more chance (or two).
Tadpoles yaw when someone meddles,
Blithely stomping on their pedals,
But it’s not at all essential (as on bikes)
That new riders learn rare talents,
Skills or even basic balance
To prevent unplanned rollovers on their trikes.
With their stable three-point footing,
Tadpoles yaw, but they’re not putting
Even handicapped (or clumsy) folks at risk.
Riding tadpoles is so easy,
Thoughts of skill can be… well, breezy –
Or at least until one’s cornering gets brisk.
Some folks find some trikes instinctive;
Others get a strong (distinctive)
Feeling when they pedal other trikes, they swerve –
Back and forth, like some cheap floozy,
Strutting through some joint, so boozy
As she waddles by, her path’s an ess-shaped curve.
But so what? Folks, pedal steering
Isn’t something to be fearing.
In most cases the sensation’s pretty small.
Subtle shifts you make in spinning,
From the first as you’re beginning,
Well may mean that you won’t notice it at all.
At its worst, it’s one reminder
Trikes – compared to bikes – are kinder.
Hey, at least you won’t keep falling while you learn
How to make those small corrections
That will counter odd deflections
As your pedals, cranks and wheels begin to turn.
Pedal steering is SUBJECTIVE.
Any rational detective
Should catch on and tell the victim he’s to blame…
Well, at least in part, I’m thinking,
Though I’m grinning now and winking,
And although of course all tadpoles aren’t the same.
I believe most tadpole riders,
Once they’ve stroked their three-wheeled gliders
Long enough and far enough to earn their stripes,
Learn the simple compensations
For whatever deviations
Pedal steering makes in tadpoles of all types.
Tadpoles don’t demand much training.
Just go riding; stop complaining.
Very soon you’ll note your style has reached its peak.
Is it automatic? Brainless?
If it’s mental, folks, it’s painless
To develop what’s required for good technique.
So… I’ve stated MY opinion,
Which some TROLL (and faithful minion)
Will insist and swear is wrong as wrong can be.
Hey, if TROLLS begin agreeing,
I’ll be very swiftly fleeing
To another point of view… Is that just me?
I recently came across some images of a custom made trike and upon taking a closer look at it discovered it was made by a man who calls his trike fabricating business “Trikewars”. His name is Warren and he is located in the Philippines just north of the capital city of Manila.
I am not going to try to post much here as he has a Facebook page you can visit with lots of photos of the trikes showing all thru the construction process. You might find that, in and of itself, interesting. I certainly did.
As a weldor/fabricator myself I can appreciate what is involved to produce something like this, especially when he has a very limited shop setup as far as tools, machinery and equipment. Even the work area is quite small. That in itself makes the job challenging.
From what I understand factory manufactured trikes are fairly rare in the Philippines and very expensive to buy … about twice the cost of what they are here in the United States. That being the case, it is good to know that there exists at least one person in the nation who is custom building tadpole trikes which are much more affordable. That being said, understand that the Philippines is a country where most of it’s citizenry is quite poor so even at a greatly reduced cost over factory manufactured trikes these custom made trikes are still quite expensive for most Filipinos and most would never be able to afford one. I have heard that the economy has been improving and for several of the peoples in the Philippines life has improved and some of the people have had more disposable income. I am glad to see that these trikes are being offered and I wish him well. Hopefully more and more tadpole trikes will “make the scene” there in the Philippines. And may they all …
KEEP ON TRIKIN’
Here is Warren’s contact information and maps showing his location:
Trikewars custom made trike & bike
369 Cadena de amor st. brgy. Saluysoy
1329 Meycauayan, Bulacan
+63 915 279 7130
You can find this map on his Facebook “About”page.
I am pretty sure most of us wouldn’t have a clue what we are looking at when viewing the image above. Maybe this will help …
These are “springs” made of aerospace titanium grade 5 metal and are Azub’s choice for a unique front suspension which they claim is superb … superior to anything else out there. Azub is known for quality in their products so I am sure they have a winner here. You can read about their design HERE.
This new model has been in the works for 3.5 years (I have also read 5 years so I don’t know which is correct) and will be available at the end of July of this year (2016) for those are signed up on Azub’s waiting list. It will be available in either a 20 inch or a 26 inch rear wheel. The cost of the trike is said to be “starting at $4992 or €4160”. You can check out Azub’s website for more on this model or any other model they offer.
Azub had it on display at the recent SPEZI event in Germany.
There is lots of articles about this model available online. HERE is one of them.
Azub boasts of “self stabilization” … something not achieved by most other trike makers. The leaf springs used on the front suspension offer 1.5748 inches (40 mm) of travel.
I am not sure of this because I haven’t found any information about the rear suspension of the Ti-Fly model, but I think it is the same as found on their Tri-Con model. Here is a picture of the rear suspension of the Ti_Fly …
This model does fold and, in fact, is capable of folding up extra small by removing the front boom and wheels. The trike has indirect steering. It has 4.33071 inches (110 mm) of ground clearance. The back of the seat adjusts between 34 – 52 degrees angle which is pretty generous. The overall width of the trike is 32.874 inches (835 mm). The track width is 29.7244 inches (755 mm). The wheel base (front to back axles) is 46.06299 inches (1170 mm). The seat height is 10.2362 inches (260 mm) at it’s lowest setting or 11.4173 inches (290 mm) at it’s highest setting. The maximum weight limit of rider and luggage is 275.578 pounds (125 kilograms).
It will interesting to see how these sell and if ever I actually see any of them out on the local trails. I haven’t seen my first Azub yet so I won’t be holding my breath awaiting it. That’s a whole lotta’ money to invest in a trike, but some folks do it. Most people I talk to think a thousand dollars is outrageous and quickly lose interest in pursuing getting a trike when they find out how much they cost. With or without full suspension or even rear suspension let’s all just try to …
KEEP ON TRIKIN’
It is called a walking bike in this YouTube video, but actually it is a walking recumbent quadricycle. It certainly is not a tadpole trike, but I thought you might enjoy seeing it since it is quite unique.
What’s your angle?
One of these is somewhat “recumbent” while the other one is not …
not at all.
I will probably get myself in trouble over this one. We’ll see. The question popped into my head just a few moments ago … when is a recumbent not a recumbent? Now I ask ya. Hey, it is a fair question. To start with I think we need to take a look at what the word recumbent means. The most literal meaning is “lying down”. So using the definition of recumbent we don’t have any factory made recumbent cycles … not really! The most laid back seat angle on tadpole trikes I know of is 25 degrees. Most are much more upright. My own trike, for instance, is at a 45 degree angle. And several are more upright than that. Yeah, I know … I am getting too technical … nit picking. I just find it interesting and somewhat amusing that so many tadpole trikes are referred to as recumbent when the seating position is nearly upright. At the same time I reckon I would have to go along with the fact that we have a problem … I mean … what else are we going to call them … especially without making things all the more confusing?
I rode another tadpole trike recently which had the seat angle extremely upright compared to mine. I didn’t care for it at all. I definitely did not feel “recumbent”. The office chair I am sitting in now as I type this is far more ‘laid back’ than that trike seat was. It was very uncomfortable compared to my trike. The seat was quite high and the pedals were quite low. It definitely did not seem like I was seated on a recumbent trike. It was more like a “cruiser” bicycle position. I guess it comes down to “different strokes for different folks” … and in case you hadn’t noticed a cruiser is not at all recumbent. Yep, we are all individuals with different likes and dislikes. So I reckon we will continue to see tadpole trikes that are not at all recumbent. One thing about it … riding one of these “non-recumbent” recumbent trikes one does not have to be concerned about losing stuff out of pants pockets. Another thing about riding a non-recumbent recumbent … it wouldn’t be as easy to fall asleep while riding it. 🙂
Whether you are really laid back, semi-bent or straight up … by all means …
KEEP ON TRIKIN’
I don’t know anything about how much money people might have or whether or not they are singing, but I know it is possible to travel along side by side on a tadpole trike. I have shown pictures of such trikes in the past on this blog. Recently I saw another such trike on Facebook which prompted me to write this article now. These trikes are a bit unusual as the tandem trikes are more commonly the same as tandem bikes … with one rider sitting behind the other.
I was going to post a picture of the side by side tandem here, but when I went back to Facebook looking for it it seems to have disappeared. I don’t know what is going on. Anyway, they really do exist although they are all custom built. No company known for making tadpole trikes yet offers them as far as I know. The closest thing to it is Utah Trikes. Here is one they made. It is a quadricycle however.
One thing for sure … you want to make sure that whoever you are riding with is someone you really get along good with and you better hope they bathed recently. 🙂
Another homemade side by side tandem tadpole trike …
Here is one under construction found on Atomic Zombie …
Obviously it would be easy to make these into a quad instead of a trike … and this too has been done.
And here is one with 6 seats …
Who knows what we will see next? One thing about it … although these might seem intriguing they would be very limited in practicality as they are too wide for riding many places, particularly on bike trails. The turning radius would probably also be a determining factor as to where they could be ridden. But hey, even if you don’t have a barrel of money you can travel along singing a song side by side. Sorry I couldn’t show you the picture of the tadpole trike I spoke of. It must have been deleted as I looked long and hard for it to no avail.
Belt Drive is not new. Several motorcycles have used belt drives for many years now.
Trek Bicycle has tinkered around with belt drive for their bicycles. I love belt drive on motorcycles and ponder over whether it would be as good on bicycles. In Trek’s own words … “a movement to bury the finger-pinching, pants-munching, rust-prone sprocket and chain, and usher in a new era of belt-driven bikes.” The only thing about it I can see that comes into play is multiple speeds. An internal gear rear hub would be needed as derailleur systems would not be possible with belt drive. At least I don’t see how it could be done. Along with an internal gear rear hub I think one would also need 2 or 3 speed internal hub built into the crankset. Of course, these items add considerable expense to the cycle. Still as times goes along the savings one would experience in chain and sprocket replacement would offset the initial expense. Hmmm, I wonder why we don’t see belt drive tadpole trikes?
On motorcycles the drive belts seem to be quite strong and hold up very well. They are made pretty tough … heavy duty … as they have to be to handle the high horsepower involved and the performance the motorcycles are capable of. Obviously a bicycle application does not involve any of this and so the belts are made much lighter duty. Never the less they are still pretty strong and under normal circumstances should hold up quite well. One of them I read about claimed it would last as long as 4 chains. This one pictured below is reported to have gotten cut while off road riding. The damage led to its total failure.
Of course, with a tadpole trike the drive belt would either have to be extremely long (not practical) or use at least two drive belts and some sort of a jack shaft in between.
I read that the belt tension is critical and that weather (temperature and possibly humidity) can cause problems with tension. Perhaps the cycle frame is changing with temperature changes and not the drive belt, but still the end result is the same. Anyway, the person reports that in the winter time the drive belt seems to lengthen slightly and thus require minor re-tensioning. Then when warmer weather returns the drive belt seems to shorten slightly so that the belt needs readjustment again.
Whether or not we will ever see drive belts used on tadpole trikes is something I guess we will just have to wait and see.
I recently came across this video showing the manufacturing process of Azub bicycle frames. The process for their tadpole trikes is quite similar so I offer this video demonstrating it to you. Here is their video description:
“At AZUB, we are very proud that an overwhelming majority of production process and assembly of our recumbents take place in the Czech Republic. The rest is done in the neighbouring Slovakia. From the first sketch, continuing with bending of tubes, welding until the last screw screwed up, we produce everything in the heart of Europe!
The production process of all parts of our frames is computerized using the CNC technology, be it for welding of parts for the seat fixation or bending of the frame tube itself. You can appreciate human craftsmanship when looking at the visual aspect of welding on AZUB bikes. Their quality and aesthetics are incomparably better than the ones of frames produced in Taiwan or in mainland China.
The assembly of our recumbents takes place at the AZUB headquarters. It is undertaken by experienced mechanics whove been building up recumbents for almost a decade. Each bike (except the ECO line) is carefully set up according to the height and weight of its future owner and tested prior to shipping. Therefore, when ordering an AZUB bike you can be sure that the bike you’re getting is perfect.”
*as mounted on a diamond frame bike where the leg is coming down from above*
Have you ever seen anything like it? I didn’t think so. This technology is out of Japan as I understand it. It is said to be 35% more efficient than a conventional crankset and therefore able to propel a cycle faster for the same applied effort and energy expended. Since I know next to nothing about it myself and anything I could write about it would be that which I read online I will simply post a link HERE to an article about this revolutionary design where you can read about it. It is called “SDV drive with oval pedal motion”. According to their description “the SDV drive is comprised of two sprockets and a chain extended around the sprockets, thus forming an oval track of the chain. A pedal is attached to the chain directly.”
Borrowing from the article I linked to above this sentence somewhat sums up everything: “We think the geometry of SDV makes riders use larger muscles, giving lower cadences than we expected.” It makes sense that this system would work better than a conventional crankset. Of course, the positioning of the two sprockets would be different between a diamond frame bike/trike and a recumbent bike/trike since the legs are coming onto the pedals from different positioning … down from above on a diamond frame and forward from behind on a recumbent. In the image below I have drawn yellow lines showing the difference in the positioning of the sprockets between a DF bike and a recumbent. Both cycles are travelling in the same direction.
I can’t find any online videos available to share here so if you want to see any you will have to download the files onto your computer like I did. I am unable to post them here in this blog like I do other videos. HERE is a link to a webpage where you can download the videos. The webpage is all messed up and difficult to figure out what is there as there is text on top of other text. You will have to click on the British flag in order to open up the next page and then click on Movie Theater to get to the video links. You can try using this LINK Using this link should start downloading the video unto your computer. It is a WMP (Windows Media Player) format. Personally I would not bother even looking at any of the other videos as they are either the same thing, but not as good of quality or not much to see.
HERE is a website page where you can read about the technical aspects of this drive. HERE is a .PDF file on this innovative design. It is quite technical so it probably isn’t of much interest to the average reader of this blog. And HERE is one of the better webpages I have found on this drive system.
It will be interesting to see what happens as time passes as to whether or not we start seeing this new technology put to common use. If I understand correctly this has been around since 2007 so it doesn’t look like it is getting rushed to market. Well, one thing for sure … with or without this innovative drive system my plan is to …
KEEP ON TRIKIN’
I think we all knew it would just be a matter of time before Catrike came out with a full suspension model. And just like they did with the rear suspension offered on the Road model creating something unique in design the same holds true of the new front suspension. Unfortunately in the pictures I have seen of this new model none of them show the front suspension very well. Hopefully that will change soon and I can include an image of it here. Meanwhile images are about all I can include as there just isn’t much information about this trike available at this time.
Basically from what I understand the Dumont is pretty much like the 559 with a 26 inch rear wheel and very similar rear suspension in appearance only as Catrike also redesigned the rear suspension to increase lateral stiffness with a new yoke, yoke pivot, axle and a fully triangulated swing arm.
The yoke redesign includes oversized 37mm ball bearings, triangular side tunnels, and underside opening. The result is a 53 percent increase in stiffness. The updated yoke pivot boss now has a 360 degree three axis profile and a 25mm through axle.”
Again my understanding is that in the design of the front suspension the all too common phenomena of “diving” when braking has been eliminated as well as the problem with turning and experiencing similar diving. The front suspension uses elastomers although they are different than those found on ICE trikes. The elastomers are made of a different material and are said to be superior to the material used on some other trikes such as ICE.
I have not seen a price yet, but it is a pretty sure bet that it will be the most expensive model to date. Suspension on a trike most definitely adds to the price.
It will be interesting to see just what further information is released about this model. I would rather imagine that there will be many people interested to purchasing this machine.
I have to admit if I were in the market for a folding trike I would really like one that folds up into a much smaller configuration like the Evolve or Trident Odyssey do. That being said, I am concerned about both of these models as far as how strong their frame components and hinge areas are. It just seems like making them so that they fold up so small would greatly take away from the strength of the frame. I hope I am wrong about this, but that is something that concerns me. One thing about Catrike … they are all about quality and great and thoughtful engineering.
This new model should be available in October of 2016. At least that is the most recent news release from Catrike.
You may have to wait in line awhile if you want one. That would be my guess, anyway.
HERE is BentRiderOnline’s recent article on this new model from Catrike. Here is a top view of the front suspension.
Until such time as Catrike releases some more images of this new model or someone manages to capture some showing this front suspension we are pretty much in the dark. I have searched online about three times now and there just isn’t anything more I can find. I have attempted to crop and enlarge this image of the front suspension, but as you can see it really doesn’t show all that much.
Catrike has a few images posted on their Facebook page. Hopefully they have another great model in their lineup. Knowing Catrike it is a pretty sure bet.
And HERE is a news release from Catrike.
Update — Recently I read that the price for the Dumont will be about $4500. I also read that the front suspension is not retroactive, that is, it can not be installed on other Catrike models.
And here is a video produced in Sept. 2016 …
When buying a used trike it is very possible that someone has shortened the boom … cut the end off so that it can go down into the outer tubing further. This is more common than you might think or expect. My own boom has been shortened as it would not go in far enough to adjust to my X-seam. Recently on Facebook Recumbent Trikes Group this picture was posted.
Upon taking a close look at it I figured out what happened to cause this. Can you spot it?
No doubt when the boom was extended out it was not noticed that it no longer was inserted back all the way inside the outer tubing … past where the slot is. This greatly reduced the strength of that area of the frame as both the inner and outer tubing need to be together to provide their combined strength. Without the smaller diameter inner tubing the larger diameter outer tubing lacked the strength needed to withstand the stress load placed on it. That is what led to the crack happening. And, of course, the weakest point is right where the crack occurred … at the end of the slot. Indeed, many people would not notice this if they didn’t know about it. That is why I am posting this article about this to help others to know about this and prevent it from happening to them. It is imperative that the boom goes back into the outer tubing far enough to provide this strength needed.
The good news is that Trident is covering this for the owner under warranty. If it would not be covered by the warranty this is a steel frame which can be repair welded rather than have to replace the entire frame. The boom, of course, will either need to be replaced or lengthened by a qualified weldor. It would do no good to repair weld the crack and reassemble it using the same boom as this would only happen again.
Others report that Trident trikes are known for using poor quality steel and having cracking problems. If this is true then it is sad as one should not have to deal with such a thing. Buying any product you should expect it be made of quality material. I assumed that these were chrome moly frames which would be stronger than mild steel, but apparently they are mild steel and therefore not as strong. That is mighty thin tubing to be using if it is indeed only made of mild steel.
I don’t know if this boom had been shortened. This particular trike was sold by a dealer and not purchased used by it’s current owner. It was a “demo” model. If the boom had not been shortened then there is a problem in that it is too short to reach where it needs to back into the outer tubing. Like I said, I don’t know the story on this particular boom. BTW, Trident offers a longer boom for riders with longer X-seam than what the standard boom handles.
Trident reports: “Standard Boom length on all Spikes gives you an X- Seam range of 36 1/4” – 43 3/8”. Long Booms are available at no charge (exchange for your standard boom) which will give you an X Seam Range of 36 1/4 – 47 1/4 “ In addition your standard boom can be cut down to accommodate X Seams as low as 32 ½” with the use of 152mm Crankarms.”
I do know this … shortened booms happen. Be on the lookout and don’t be a victim. This is not something you want to go thru. We all want to …
KEEP ON TRIKIN’
No, I am not talking about how business is going for Catrike even though it has really taken off and qualifies as a “boom”. Rather, I am talking about the boom of the tadpole trike … that part that sticks out in front and where the crankset and pedals are found. Here is a picture of my boom.
I am talking about booms here because they are a very important part of a tadpole trike. With the crankset and pedals being a part of the boom one of the inherent problems with tadpole trikes in their design and build is what is called “pedal steer”. Some trikes are worse than others and the amount of pedal steer can be considerable. Pedal steer occurs when (and because of) the boom flexing … actually bending side to side when the pedals are pushed on. This in turn results in the trike “turning” from one side to the other as it is being pedaled along. A well engineered and made trike has very little pedal steer. Some trikes have quite a lot of it. And the further out a boom is extended the worse the problem becomes. Along with the problem of pedal steer when the boom flexes there is also a loss of pedaling efficiency. Catrike has a patented design which greatly strengthens the boom and eliminates most pedal steer and helps with this loss of efficiency. The boom has an internal reinforcement to make the boom more rigid so it can’t flex like it would if it were just a hollow tube as other trike manufacturers’ booms are. Also Catrike booms have a groove in the top which does not allow the boom to rotate out of proper position … something very common with most tadpole trike booms. This groove has a matching “key” or “pin” which fits down into it to keep in from turning (rotating). I have seen some booms on other brands of trikes which were considerably rotated out of position.
Here is a look at the patented internal reinforcement and the patented groove …
Those three internal “webs” you see run the full length of the booms. In this image I have added the silver colored lines to show this since it is too dark inside to see it otherwise. I applaud this ingenuity. [ICE (‘Inspired‘ Cycle Engineering) eat your heart out! Your booms and frame members rotate all over the place … although I will give them credit for doing a pretty good job in the matter of pedal steer.]
Here is a closeup image of the groove and key. It is hard to find an image of it which shows it clearly. I worked on this one trying to improve it so you could see it better …
Here is what Utah Trikes wrote about the Catrike booms:
“The engineering of the Catrike is probably most evident in the boom now found on all models. I think it is safe to say that the Catrike boom design and implementation is second to none in the trike industry. Because the seat is part of the frame all adjustments for rider leg length are made by adjusting the boom. The advantage to this is that there is no cross bar to get in the way for shorter legs, but it also means that the boom can get pretty long when fully extended. A long piece of tubing can flex which robs pedaling power. Big Cat engineering came up with a novel approach to eliminate boom flex, and it’s all hidden inside the boom. To keep the boom strong while maintaining a low weight, Catrike creates their boom with a custom extruded tubing with an inner webbing whose cross section resembles the Mercedes logo. This inner bracing eliminates any flexing in the vertical plane (minimizing power losses), while also having a dramatic effect on removing pedal steer effect.
The Catrike boom is extremely easy to adjust and yet always stays in alignment. Most other trikes that have adjustable booms need to have two bolts to secure the boom position so that it will not rotate as the trike is being pedaled. The Catrike boom is indexed with a groove along the top which align with their proprietary boom clamp system. Because the boom cannot rotate quick release clamps with less pressure can be used to hold the boom in place without worrying the boom will twist. This makes adjusting the boom length on the fly very easy.
To finish the boom off, Catrike has taken the extra step of including an integrated accessory mount on the front derailleur post an all models excluding the Villager. Amazingly simple, but in the end will save you $20-40 when you decide to mount a computer or headlight to the front of your trike. Speaking of mounts, every Cat also comes with a computer sensor mount on the left wheel. It makes installing a wired, or wireless computer very easy.
Instruction to Set the boom length from Catrike owner’s manual:
Sit on the trike, wearing shoes like those you’ll have on when riding, and adjust the boom length. This is done by loosening the boom release enough to allow the boom to move, then putting your instep on one pedal and extending your leg fully (the boom will rotate…just move it back to vertical with your hand). You should be able to lock your knee, but not have to lock your knee. You can fine tune the position later. Re-tighten the boom release (or pinch bolts) enough to keep the boom from slipping.”
Trike manufacturers need to do all they can to eliminate such things as pedal steer and brake steer. I am glad to see Catrike taking this seriously. It helps riders to …
ENJOY THE RIDE!