tadpole seat height

[jmygann]

How high can one have the seat on a tadpole( with non hub motor drive) and still be stable at 25 mph ?

14 - 18 inches ??

 

[spinningmagnets]

One tadpole site I looked at had a standard width that would roll through a full-sized door, and also the extra-wide, for more stability...how wide do you want the two front wheels?

 

[jmygann]

Under 48 inches ???


"The Villager’s 12.5” seat height allows you to get in and out with little effort; 5.5” ground clearance helps you negotiate speed bumps and curb transitions; stable 31” track

http://www.utahtrikes.com/TRIKE-CTVILLAGER.html




The Phoenix measures 42″ across at its widest point. 20" seat height ... maker says stay under 15 mph

http://www.cyclegenius.com/trx.html


EZ-3 SX Tadpole

unstable at speeds over ~10-15 MPH ??...The seat height at 14”
32" wide

http://www.sunbicycles.com/product_detail.php?short_code=EZ-3+SX+Tadpole&cl1=RECUMBENT



ExerTrike ES

58 inches wide .... You cannot tip it on flat ground, even if you tried!

http://www.exertrike.com/exertrike_ES.html


Would like something I don't have to climb or roll out of but be able to keep up with city traffic 25-30 mph even though the legal speed limit is 20 for elec assist bicycle

 

[Jeremy Harris]

Depends where you put all the weight (other than the rider). 48" track isn't far off that on some small compact cars, and they're stable at high speeds, primarily because all the other heavy stuff is fairly low down.

The critical bit is the relationship between the roll centre, the vertical centre of gravity and the available lateral grip from the tyres. Tadpole trikes aren't that much less stable in roll than four wheel vehicles, as light cars like the old Morgan three wheelers showed 70 or 80 years ago. I drove a tadpole trike layout kit car that probably had about a 50" - 60" front track and it was fine at speeds up to around 80mph or so (as fast as I took it).

One thing you might consider is altering the seating position so that you're more recumbent. You could then raise the seat base height and still maintain a low C of G by lowering your upper body. Combined with batteries in the base of the trike you might find that you can get good stability with a fairly high seat base.

Somewhere on the web (I can't find it at the moment) is an interesting series of article by a chap building a tadpole trike from scratch. He looked closely at things like the roll centre, stability in general and steering geometry. The link is probably worth Googling for, as the articles were very good.

Jeremy

 

[RWP]

Somewhere on the web (I can't find it at the moment) is an interesting series of article by a chap building a tadpole trike from scratch. He looked closely at things like the roll centre, stability in general and steering geometry. The link is probably worth Googling for, as the articles were very good.

Maybe this is the series of articles you were thinking of Jeremy:
http://www.speedpedal.com.au/cms/articles.html
You have to scroll down quite a bit to find a great series on a fully suspended home built recumbent trike.
There is a whole bunch of stuff on trike suspensions and other cool trike build info.

Hope this helps.

 

[Jeremy Harris]

Thanks for that, RWP. I hadn't seen that article, but it's the same chap, he's updated his project. Luckily the link you gave led on to the original series, here: http://autospeed.com.au/cms/A_2936/article.html It's a long read, but written in such a way that it makes it simpler to understand some of the more technical aspects of steering and suspension.

Looks like I now need to sit down and read his updated series of articles!

Jeremy

PS: The link above is to part one of the series. The following parts are also on the Autospeed site, just use the search engine on that site to find them (search on "Building a Human Powered Vehicle" and they will all show).

 

[jmygann]

The goal is a comfortable(gel seat) street legal (1000 watt electric assist) tadpole trike

One thought is to get a cycle genius (has SRAM DD) , lower the seat ? and reduce rear to 24", but still may not be "stable" at 25 mph

Like the looks of KMX Cobra but need higher seat ..may be possible ??

berserker looks about right ...

 

[RWP]

Maybe you noticed the http://berserkercycledesign.com/ above is a full suspension machine...with a hefty $5,000 + price

 

[jmygann]

That I don't need and can do without ... but

the seat height is 15 in so that is about what I would like

24 in wheels ..

I'm thinking 20 in front and 24 in rear ... Like the KMX Cobra .... but with a 14-16 in. seat height

 

[jmygann]

HP Velotechnik has unveiled on their site the new ErgoMesh HS seat for their Scorpion line of recumbent trikes. The HS stands for "high seat" (hochsitz) and certainly lives up to the moniker providing an 18" seat height on the Scorpion fx and just under 16" on an fs.

http://www.rbr.info/community/blog/14-travis/218-hp-velotechnik-to-debut-new-ergomesh-hs-at-eurobike.html

 

[spinningmagnets]

Ach du Lieber!

 

[jmygann]

Depends where you put all the weight (other than the rider). 48" track isn't far off that on some small compact cars, and they're stable at high speeds, primarily because all the other heavy stuff is fairly low down.

The critical bit is the relationship between the roll centre, the vertical centre of gravity and the available lateral grip from the tyres. Tadpole trikes aren't that much less stable in roll than four wheel vehicles, as light cars like the old Morgan three wheelers showed 70 or 80 years ago. I drove a tadpole trike layout kit car that probably had about a 50" - 60" front track and it was fine at speeds up to around 80mph or so (as fast as I took it).

One thing you might consider is altering the seating position so that you're more recumbent. You could then raise the seat base height and still maintain a low C of G by lowering your upper body. Combined with batteries in the base of the trike you might find that you can get good stability with a fairly high seat base.

Somewhere on the web (I can't find it at the moment) is an interesting series of article by a chap building a tadpole trike from scratch. He looked closely at things like the roll centre, stability in general and steering geometry. The link is probably worth Googling for, as the articles were very good.

Jeremy

I remeasured .... I am comfortable sitting / getting up/ pedaling at a minimum , (butt to ground) , height of 10.5 inches (no Lower)

so ....cattrike Villagr or ??

 

[MitchJi]

Hi,

Jmy: With the proper design you can have a pretty high seat (check the Air 150 links or the excerpts below):

Jeremy:

Looks like I now need to sit down and read his updated series of articles!

Jeremy

PS: The link above is to part one of the series. The following parts are also on the Autospeed site, just use the search engine on that site to find them (search on "Building a Human Powered Vehicle" and they will all show).

I think the following two articles on the Air 150 are more recent (newer improved design):

From Another Human Powered Vehicle! Part 16:
So now that I am pretty happy with the design....I am building another trike.

’ll also change the anti-roll bar design and make some changes to the rear suspension arm that will decrease weight. The front suspension arms will drop in wall thickness from 1.2 to 0.9mm - the current ones have never shown any visible deflection, even under hard braking.

The seat will be quite a lot wider and the motion ratio of the front suspension increased a little (ie the air springs will move inboard about 20mm). The combination of these two factors will move the springs closer to the edges of the seat, providing better stiffness.

The frame will additionally be stiffened to better resist flex under high pedal forces.

So the changes will be relatively subtle but I think will make for a better overall machine and one with which I will feel happier. In my estimation, the current trike is perhaps at 8/10 – and I’d like to make the next a personal 9.

From Air 150 Part 1:
In Another Human Powered Vehicle! Part 16 - The Conclusion I wrote that I was building another trike, one that incorporated a host of subtle changes over the design that had been covered in that series. And now, some 6 months later, here it is.

Rather than describe the day by day ups and downs of this build (and there were lots of problems as well as successes!), and also attempt to relate this trike to the one previously covered, I’ve decided to present this new design as a standalone pair of stories.

If you want detail on why, for example, airbag springs were used rather than (say) polyurethane elastomers, or why an odd-looking semi-leading arm front suspension design was used, refer to the previous series where the design decisions for each part of the trike were covered in detail.

http://www.autospeed.com/cms/A_109615/article.html

Air 150 Recumbent Trike, Part 1

What you can see here is, I believe, the best riding human powered vehicle in the world.

In its suspension design it incorporates apparent simplicity with a ride vastly better than a conventional non-suspended trike and very much better than any other suspension trike whose design I have seen. In addition, it has outstanding frame stiffness that results in much more power from the legs getting to the ground. It also performs well in skidpan testing, matching many commercial trikes. In bumpy cornering, I think it would be superior to nearly all trikes.

At a bare 23kg it is certainly no lightweight in the recumbent trike world, but it is also a very large machine, with a width of 94cm and a total length of 205cm. With the addition of the rear carrier and pannier mounts (adding 1kg) it can carry up to 40kg of gear with little trade-off in handling and an actual improvement in ride quality.

It is equally at home racing down a hill at 80 km/h as it is toddling along on a cycle path.

And of course it also has some deficiencies. We’ll look at the range of good and bad points later, but first, let’s look at the technical make-up of this machine.

http://www.autospeed.com/cms/A_109618/article.html

Air 150 Recumbent Trike, Part 2
6. Conclusion

So what are the good and bad points of the design? My summary (with ratings out of 10) is this:
* Seat – roomy, supportive and well-shaped seat; width allows elbows to be tucked against seat sides for stability; wide seat results in higher centre of gravity (because extra sag needs to be taken into account); comfort would be enhanced by a cushion under bum section - 8/10

* Ride quality - outstanding over large bumps, good over small bumps, not floaty, little pedal squat, improves with large loads, some rear suspension extension under brakes, a small front/rear symmetrical bob at high pedal cadence – 9/10

* Handling - predictable, precise, not upset by bumps, adequate although not outstanding maximum lateral acceleration, very predictable when on two wheels, not upset by large loads – 7.5/10

* Steering - precise but not nervous, no bump steer, good at both high and low speeds, can pedal-steer a bit at high speed in top gears when pedalling hard – 8/10

* Brakes - excellent fade resistance, progressive and easily modulated, twin independent discs require even pressure, can lift rear wheel under hard braking – 7/10

* Frame - very little boom bending, small amount boom twist, able to carry large loads, low weight for size of machine but heavy in absolute terms - 8/10

Clearly, from this scorecard I am pretty happy with the end result. For those who think the Air 150 too large (and so overweight), something like perhaps 15 per cent of the mass could be taken out by the use of smaller 16 inch wheels and a proportionally smaller width and length. If the rider was prepared to put up with boom flex typical of some commercial trikes, a little more weight again could be shaved off.

However (I guess as is self-evident since I made it to suit me and no one else!), I love its size and the resulting roominess. I think that ride/handling compromises can always be improved: there’s not a ride I go for on the machine where I don’t think: “Hmm, steering feel was a bit bereft then” or “Impact harshness over that bump too high” – but there’s also barely a ride where I don’t think: “Hell, the trike handled that bump well” or “Gee, the frame is stiff – I am climbing my 40 per cent gradient [no mistake!] driveway and I’m not even in bottom gear!”

But as the negatives above show, I certainly don’t think the machine is perfect...

Video (very impressive smoothing of a large drop with almost no after-bouncing):
[youtube]7RgSpdDD-3c[/youtube]

More recent trike ("Chalky" 7 part series):
http://www.autospeed.com/cms/search/index.html?keywords=chalky+&x=813&y=7
From Chalky Part 1:

So why now a third all-new design? Let’s briefly look at the first two designs.…

The Air 150, initially made as the prototype Air 130, was another
recumbent tadpole design, but one that addressed all these shortcomings. It
used Firestone rolling-lip airbag springs, a unique high roll centre, semileading
arm front suspension, and a trailing rear arm suspension design.

The frame was made from chrome moly steel tube and a high seating
position was used. The result was a practical and effective vehicle, with an
excellent ride quality and good handling. The downsides were that if it
was being freighted interstate for touring, it required a very large packing
crate. The high centre of gravity and soft suspension also meant that a very
strong anti-roll bar needed to be used, and large torsional loads were fed into
the frame.

When loaded with about 30kg of touring gear, the steering could also
become twitchy. However, the biggest negative remained its large size –
despite appearances, this was not ever a problem on the road but certainly
was when it needed to be freighted anywhere.

From Part Chalky 7:

…Both because of the more forwards weight bias and the more
upright seat (in which I felt more comfortable), I found I could throw the
machine around quite phenomenally. I haven’t yet measured max lateral acceleration but it’s
probably the highest of any recumbent trike I have ridden.

In fact, to get it up on two wheels and hold it there I found quite difficult.…

…Firstly, and most seriously, the roll stiffness was insufficient. At speed, and
especially with vigorous pedaling, the trike rolled from side to side. It also felt
‘tippy toed’, easily falling one way or the other from its vertical position, with
the roll only then resisted. So there was both a lack of roll linearity, and roll
stiffness that was simply too soft. Next, I thought the position of the
handlebars was wrong for long distance touring.

The front drum brakes were grabby, the rear mudguard rattled incessantly, the
ride quality over coarse surfaces was clearly poorer than on my previous 20
inch design, and I thought the front suspension would probably benefit from external damping.

On this ride, I’d give the trike maybe 7/10, tops.

So why hadn’t I found these problems before? Simply, on this ride I was alone, it went for a relatively
long time – and I got tired. And a tired rider spots things a fresh rider never even notices!

From Here....
Rather than continue this series next week, I think that at this time I will stop for a longer period.
Chalky has shown itself to be fundamentally a good design with:
* An excellent ability to be broken down into a small package
* Excellent comfort on most surfaces
* Very good handling
* Good steering
* Adequate frame stiffness

It needs further development in:
* Roll control
* Steering handlebar positioning
* ...and a few other minor areas

The earlier Air 150 might (?) be better a better basis as a platform for a high power Etrike. Heavier and stronger. Larger wheels for a little better high speed ride.

OTOH "Chalky" has a little better lateral grip due to the lower CG.

 

[jmygann]

thanks ,


Aerodynamics aside ...... is there a body/leg/back angle that is the most efficient at pedaling ?

 

[jmygann]

The main feature of the Rover is it's new seat. A full 4 inches higher than most other tadpole trikes on the market; it is the same height as a standard office chair. This makes getting in and out of it a breeze - even no-handed! This also puts the rider at almost eye level with most standard car drivers for better visibility and safety.

But how stable is it ?

http://www.terratrike.com/rover.php

 

[Rassy]

Jmygann, I raised the seat on my Terratrike Path about 4 inches to make more room for the mid-drive. Seeing the Rover specs gave me confidence that it would work okay. I am really happy with the result and haven't noticed any stability issues, but I also don't let the speed exceed about 25 MPH, mainly because with only individual front brakes it becomes too hard to prevent a little swerve when first applying the brakes at higher speeds. I normally lean into corners and that seems easier to do with the seat slightly higher relative to the pedals. The only time a wheel lifted off the ground was before I raised the seat.

Edit: Avatar updated.

 

[coln72]

As a part of a team that designs and builds racing trikes, obviously we are not making ease of access a priority, so the seat is going as low as possible. We found that dropping the seat approx. 2" saved 20 seconds per lap with no other changes to the bike due to better stability.

My current build has the seat approx. 4" off the ground but this may be made lower still. This trike has an electric motor and a petrol motor so packaging is fun.

 

[jmygann]

I figure 16-18" seat height would put one a the same eye level as a person in a car. Rover is 18" see video

But how wide to be stable up to 25 mph on curves ? 40+" ?? Maybe also lengthen to 50" wheel base ?


http://www.youtube.com/watch?v=npSPP9Wrork&feature=related

Lengthened Rover ..

 

[docnjoj]

I too have read all of Julian Edgars Autospeed articles and learned quite a bit. I am gradually raising the seat of my Steintrike (about 3" above the original mount) but in my case it must fit through the front door of our house. I will be trying 20" front wheels (up from true 16") and will see if I can get the additional height without losing too much cornering power. I suspect I will have to ease off the corners a bit, but the straight line stability so far has been unaffected by the seat raising. I never exceed 25 mph and usually average about 12 mph for our 15 mile rides.! At almost 66 years old and on blood thinners I really don't want a crash! My overall width must be 32" or less to get through the door.
otherDoc

 

[slacker]

thinking of selling my big dummy with bl-36 and getting rover with cargomonster and ebike kit ddhub with new black cased 48volt battery for my personal commuter.any thoughts pro or con would be greatly appreciated.anyone have similar set-up.reason for switching to tadpole is i have had 2 accidents this year and at my age,49,i do not heal as fast and living in st.paul,mn. its hard to stay up on 2 wheels in the winter.going to hit 30 degrees today so out i go to ride my downtube 9fs.all advice welcome.

 

[docnjoj]

The original Rover had either a 3 or 8 speed rear hub so you would have to use a Stokemonkey/Rassy type motor mounting. It may be that the extended model has a rear deraileur? Trikes are pretty safe but with vigorous cornering you can go over on them. My suspension helps but the narrow track (30 inches) means I need to slow in the corners.
otherDoc

 

[jmygann]

I have recently purchased a Rover .... the Cargo Monster on a Rover can be purchased at Utah trikes ...

http://www.utahtrikes.com/RECENTTRIKE-Rover_CargoMonster.html

Terrtrike only sells the 3 and 8 speed standard trike

i like the seat height ... can see where i am going and others can see me better.

see what others say ....http://www.terratrike.com/forum/viewforum.php?f=29&sid=6b44af99aa8101b84f0264b3ed0e2727

utah trikes have made mods to have a derailleur and plan on elec assists