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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/12/2010 :  12:41:26  Show Profile  Reply with Quote
What is the best head angle for a FWD low racer?
I want to be able to race on the road at speeds between 35-60kph.
20" front wheel(driven) and 26" back.
I was also thinking about using pistol grip handle bars will this work on a FWD.
Cheers Nigel

MoSTHPV
Starting Member

USA
17 Posts

Posted - 02/12/2010 :  14:52:07  Show Profile  Reply with Quote
What sort of wheelbase are you running, and how high is your center of gravity?

If it's a high seat, then probably somewhere around 18-20° from vertical.

Learn to Design; Design to Build; Build to Ride; Ride to Win - Missouri S&T HPV
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randy
recumbent guru

721 Posts

Posted - 02/12/2010 :  16:07:36  Show Profile  Reply with Quote
I've had good results from an ~80 degree headtube and zero rake fork for both FWD and RWD.
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Jeff Wills
human power supergeek

USA
1206 Posts

Posted - 02/12/2010 :  16:23:11  Show Profile  Visit Jeff Wills's Homepage  Reply with Quote
quote:
Originally posted by randy

I've had good results from an ~80 degree headtube and zero rake fork for both FWD and RWD.



Assuming the 20" wheel is actually a 406mm rim diameter (18" actual diameter) and zero offset (aka rake) an 80° head angle yields trail of about 1.6". This may make steering feel a little light at speed. 2 inches of trail is supposed to give acceptable steering feel for most people. For that, about 1/2" of rearward offset is needed.

Play around with the "Actual Trail Calculator":
http://www.recumbents.com/wisil/trail.asp
if you're trying to build a bike around existing parts.

FWIW: an 80° head angle and some rearward offset is what I eyeballed on the Velox Solium:
http://www.ohpv.org/events/albums/bm2004/velox/pages/velox5.htm
That bike is what I'd try to emulate. It was very stable at parking lot speeds and did almost 60mph at Battle Mountain.

__________________
Jeff Wills
All my bikes:
http://home.comcast.net/~jeff_wills/Gallery/index.html
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/12/2010 :  19:43:19  Show Profile  Reply with Quote
quote:
Originally posted by MoSTHPV

What sort of wheelbase are you running, and how high is your center of gravity?

If it's a high seat, then probably somewhere around 18-20° from vertical.

Learn to Design; Design to Build; Build to Ride; Ride to Win - Missouri S&T HPV


I want it to have a low seat hight.(ei) as low as I can without hitting the derailleur.I'm thinking about 7" from the ground.

quote:
Originally posted by Jeff Wills

Assuming the 20" wheel is actually a 406mm rim diameter (18" actual diameter) and zero offset (aka rake) an 80° head angle yields trail of about 1.6". This may make steering feel a little light at speed. 2 inches of trail is supposed to give acceptable steering feel for most people. For that, about 1/2" of rearward offset is needed.

Yes it is a 406mm rim.

I want something like the "rapto" low racer,but lower.
[url]http://www.raptobike.com/lowracer.php/url]

I also want to add a fairing to it at a later date.

Edited by - nigel schroder on 02/12/2010 19:44:59
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Larry Lem
human power expert

South Sandwich Islands
2284 Posts

Posted - 02/12/2010 :  20:13:36  Show Profile  Reply with Quote
I'd aim for 65-70 degrees for the head tube. Less than 65 causes a lot of fork flop and makes it harder to start. 75-80 degrees makes it incredibly easy to start, but usually a little less stable at speeds above 40 mph.

You'll end up optimizing your own handlebar and grip position, maybe trying to tuck your elbows as much as you can up and into your body instead of hanging out or hanging low in the wind.

Larry Lem
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sean costin
human power supergeek

Lesotho
1976 Posts

Posted - 02/13/2010 :  13:32:29  Show Profile  Reply with Quote
If I was going to build a FWD lowracer again, I'd build one of these.

http://www.python-lowracer.de

Sean
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Upright Mike
human power expert

USA
3440 Posts

Posted - 02/13/2010 :  14:07:53  Show Profile  Visit Upright Mike's Homepage  Reply with Quote
Here is John Morciglio's latest, very cool FWD, swing-arm lowracer.
I'm not sure what fork angle he used, but he optimized where his handlebars are attached to minimize torque steer.
I got to see this beauty in person. Its a work of art.
Also its very light - John measured about 21 lbs before adding the tailbox.



Edited by - Upright Mike on 02/13/2010 14:10:36
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/13/2010 :  15:33:01  Show Profile  Reply with Quote
quote:
Originally posted by sean costin

If I was going to build a FWD lowracer again, I'd build one of these.

http://www.python-lowracer.de

Sean



Hi Sean can you tell me why? (pro's ,con's)
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/13/2010 :  15:37:11  Show Profile  Reply with Quote
What do you guys think of the "Zorkrabikes"
Kouign Amann special

http://www.zockrabikes.com/index.php?option=com_content&view=article&id=1&Itemid=8

Like John Morciglio's but lower,might work well for road racing

Edited by - nigel schroder on 02/13/2010 15:43:37
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warren
human power expert

4853 Posts

Posted - 02/14/2010 :  12:38:40  Show Profile  Visit warren's Homepage  Reply with Quote
I agree with Larry, for high speed you want more trail. I have been using 3" of trail on my FWD streamliner with a straight fork and that works well (406mm wheel).

My FWD lowracer (406 mm wheel) has 2" of trail, and it's a bit darty, so I'd add more trail if I did it again.

-Warren.
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sean costin
human power supergeek

Lesotho
1976 Posts

Posted - 02/14/2010 :  13:46:05  Show Profile  Reply with Quote
Nigel

If you have a high BB (relative to the seat, There is a great deal of pedaling torque that effects your ability to steer. I was never satisfied with the handling on my Crash o Matic. It appears that the Python resolves this issue by moving the pivot back. It looks like many people have successfully made these bikes, So that's why I said I would build one. I'm not sure about your specific needs, so it is hard to say if it fits your requirements. I look at it and see potential to be the fastest recumbent unfaired hour bike.

A bike like John Morciglio's is another interesting route to take and by looking at the height of the BB relative to the seat I can tell it would be easy to ride.


Sean


quote:
Originally posted by nigel schroder

quote:
Originally posted by sean costin

If I was going to build a FWD lowracer again, I'd build one of these.

http://www.python-lowracer.de

Sean



Hi Sean can you tell me why? (pro's ,con's)

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Larry Lem
human power expert

South Sandwich Islands
2284 Posts

Posted - 02/15/2010 :  06:58:31  Show Profile  Reply with Quote
Reading that the Kouign Amann special only weighs 7.3 kg, 16 lb and seeing the no hands video has me very curious. My own attempt at this as one of my first recumbent experiments failed horribly, so I haven't been interested since then.

Is it only seat to bb height that moving bottom bracket bikes to be unaffected by pedal steer? What was obvious to Sean that made him think this? I can see that much personal experimentation will be needed when I get to it this summer.

As min bb height is usually set by avoiding heel-to-ground interference during hard turns, that would put the seat at least 13" above ground (not 7").

Larry Lem
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/15/2010 :  18:09:43  Show Profile  Reply with Quote
Here's a drawing of the Kouign Amann
http://i1003.photobucket.com/albums/af156/nigelmelanie/low%20racer/dimens11.jpg
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sean costin
human power supergeek

Lesotho
1976 Posts

Posted - 02/15/2010 :  19:26:55  Show Profile  Reply with Quote
Nigel,
The World Famous Crash-O-Matic 5000 is for sale. I don't have the Hed disk anymore, but I think I can provide you a nice complete bike for the trade of a new wireless Powertap hub. The bike breaks up nicely for shipping. I think I had the weight down to 11 Kg, but the front end is rock solid. Tandem fork blades were used. If you are interested you can email me at costin@wowway.com.

Sean
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 02/15/2010 :  20:25:45  Show Profile  Reply with Quote
quote:
Originally posted by sean costin

Nigel,
The World Famous Crash-O-Matic 5000 is for sale. I don't have the Hed disk anymore, but I think I can provide you a nice complete bike for the trade of a new wireless Powertap hub. The bike breaks up nicely for shipping. I think I had the weight down to 11 Kg, but the front end is rock solid. Tandem fork blades were used. If you are interested you can email me at costin@wowway.com.

Sean



Thanks for the offer but one of my favourite things about recumbents is building them.
I just can't make up my mind on what I want.
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DocBB
Starting Member

France
18 Posts

Posted - 03/01/2010 :  07:53:47  Show Profile  Reply with Quote
You might want to look at the chart here http://velorizontal.bbfr.net/le-coin-du-constructeur-amateur-f10/tractions-directes-vers-un-modle-de-rfrence-t6856.htm
in french but you may use google translation option when opening the link.
http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fvelorizontal.bbfr.net%2Fle-coin-du-constructeur-amateur-f10%2Ftractions-directes-vers-un-modle-de-rfrence-t6856.htm br /
and have a look at this one



as you can see : no steering bar
wheels 20”
pivot direction: 57°, drives out positive : 8cm wheel base: 1,05m Mass 11,5kg

for more precisions on masses
http://velorizontal.bbfr.net/le-coin-du-constructeur-amateur-f10/masse-du-stradi-carbone-de-ghp06-t6400.htm?
http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fvelorizontal.bbfr.net%2Fle-coin-du-constructeur-amateur-f10%2Fmasse-du-stradi-carbone-de-ghp06-t6400.htm%3F

and what he is thinking of his bike :

I immediately used without hands, and I soon realized it was better than Python. In Python, sit on the seat prevents only the "wheel flop", and does not provide stability of the trajectory. The wheel flop is penalizing the direct traction during the learning period: therefore, avoid at all costs.

Start position, hands down for balance, and feet on the pedals, start at low speed, and in case of imbalance immediately put 2 feet on the ground before the occurrence Quene wheel flop. Then leave a hand on the ground on each side, feet on the pedals. Once out of the bike path that was set, 2 feet on the ground, and leave etc.etc.
At no time, at least initially, the hands do not go for a handlebar assumed wrongly saving. If learning is completed, not a single fall, and growing confidence in the machine. Ca is very fast.
Result: faster learning than a Python stability downhill, not whimsical behavior of the beast.

Total satisfaction!


see also another compulsive constructor of FWD MBB Who unfortunately died last summer
http://les-velos-de-laurent.skynetblogs.be/

Edited by - DocBB on 03/01/2010 18:49:28
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DocBB
Starting Member

France
18 Posts

Posted - 03/01/2010 :  09:16:12  Show Profile  Reply with Quote
if you want to race search for "speculoos recumbent" and you will find some ones like this one : a real racer "la vipère noire"



In addition, the views of Marc Lesourd who has wanted to play guinea pig in this story.

Introduction:
----------------
Firstly, this bike would not exist without the ingenuity of its creator, the now famous Laurent Dechenne. After years of experimentation with the concepts pioneers
like the Flevo and Python, Laurent led a bicycle balancing stability, rigidity, simplicity and maneuverability. Without special training, but without a larva be human, he succeeded in good performance riding his prototype. In particular, this was the case during the HPV World Championships in Aalborg (DK) in 2005.
At that time I seriously considered changing the frame to replace my Cobrabikes Royal, one traction before "traditional". Rightly considering that I still spend my meager savings on an alien craft, Laurent offered me a deal: he would build me a bike for free on condition that I use in competition to prove the validity of the concept. Originally the contract stipulated that I was to win races, but that provision was quickly abandoned. A few months later, Laurent delivered the bike in person, and after some minor adjustments and procrastination of my own, I made my 1st laps. I must say that I never had the opportunity to test one of the Laurent's bikes before because of my legs too short.

Features:
---------------
- FWD Direct
- Front wheel 20 "ETRO 451, rear 26" ETRO 650
- Cassette 11-32 (11-23 for flat terrain) with trays 42-61
- Handlebar U
- Weight 13kg
- Easily separates into 2 parts for transport
- MADE FROM bicycles right of recovery, including a ATV child for the front
- Nickname "speculoos" in reference to the delicious crispy Belgian biscuit


Steering:
----------
Learning was harder than expected. "Thread" the bike proved already acrobatic, but less difficult than being disentangled! The steering seemed very heavy. At the that turning the handlebars too, I had to stop and restart line. Press power on the pedals was only a fantasy for me. But I didn't gave up , and after a few days of practice freewheel, I was on the road. Incidentally, there is a video on the site Johnathan (jnz) showing my 2nd real test inconclusive. I was already able to reach 40 mph and stay within the paved path of 1 m 2 wide ... or less! But climb even what the less Bosselet was still almost impossible. The torque generated by my legs was too powerful to be controlled by my arms. Besides they are my shoulder and arm ached after an outing and certainly not my legs.
The next step was to make my commute on 20km of "my" bike path along the Isere. Although through my pedal automatic control of the craft had improved, I still uttered from time to time when a "@$%^&&&!!" deviated from my path way impromptu to the river in low-cons.
And then suddenly, some time later, one day mastering the bike was perfect. More zigzags, no more hesitation, just the intense pleasure. And yes, steering was legere and become obedient. I think this aa do with tiny adjustments pedalage that the body is almost instinctively. By analyzing a bit, it seems that I pedal slightly off the axis outwards, ROVISIONS end of pedal stroke (extension). It is why the auto-pedals is necessary to have absolute control of the craft. When I sometimes pedal "dress shoes" I have more difficulty controlling the bike at low speed.

Performance:
--------------
The bike is very rigid and the efficiency of transmission is remarkable compared to bicycles wiyh indirect drive. This is also reflected by silence during pedaling: No more pulleys squeak. In Zurich in 2006, I traveled 45km in an hour. Too bad my skills in sprint does not allow me to demonstrate the effectiveness of cycling in the short races.
The craft climbs very well, it's best from the rest because my playground is the main Alps. I tested the 18% slowly but certainly no crash. I anticipate to install an advanced aerodynamic back this year .
Other detail which is important: I can ride without hands on handlebars. In winter, I sometimes ride at high speed, both hands warmly hidden in my jacket thanks to the high stability of the bike

Disadvantages:
-----------
- The bar above the shoulder can be a nuisance in the city or the stops are frequent
- The grip of the front wheel on wet or dirty and could a problem, although thanks to the center of gravity low on my bike this is not a main issue.
- Could be lighter carbon or titanium

Conclusion:
-----------
I love this bike, so easy to drive, so effective ... so that I sold my car and I did this my speculoos only means of locomotion. Distance driven annually ~ 12000 km shared commute, competitions,
shopping trips and sometimes equipped with 1 single wheel trailer.

Marc Lesourd


this seems the good geometry after an think-tank discussion
traduction:
Also IMHO, I proscribe the 406 for reporting an issue.
With the 451, it is necessary to draw a 65x11 to move quickly in the flat descendants. And 65, it starts to cause problems to find ...
Personally, if I started to make a speculoos and that I was your size, I'd live for a 559, as it is still in standard sizes of plates and gears ...
559 700, for example, or 2 x 559


translation:
I pass in front 622 rear 559; better rolling and comfort on surfaces rotten. (given that the initial goal is not pure speed, but to make the distance with comfort correct)
So the seat and pedals back respectively 35cm and 50cm, the groundwork was 39 cm, the limit for me and 44-45 of my size ...

The seat angle returns to 20 ° to 25 ° adjustable, it can reduce the need for 3-4cm.
I received the seat and made a path xy to reuse the profile across ...

Wheelbase of 1.40m is loooooong ...

the guys are gone vertical in front, to regain flexibility, as I was advised here and elsewhere ...


elswhere it was said that to much rigidity in the fronf leaded to some frame destruction issues



Edited by - DocBB on 03/01/2010 18:29:08
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DocBB
Starting Member

France
18 Posts

Posted - 03/01/2010 :  10:47:42  Show Profile  Reply with Quote
Now maybe you do not want to drive INTO the frame, the there are some others models , easy to ride "no hands" very good in climbing
see how its easy to climb (15% !!) , no hands :and guess why the name is "albatros" !

http://www.youtube.com/v/_hwVaPentjQ&hl=fr_FR&fs=1&



some comments (fast google translation)

I had the chance to make a few kilometers above (first time on a straight pull), it is very handy and fun to drive, and rather easy for a beginner. The design of steering and its removal is very intelligent and the drop style road bar is very reassuring and comfortable, a true marvel, homemade and more, what talent! In addition, it is particularly well-balanced and elegant...

Side wheel size, I am indeed much smaller than jean lou (1m75 for me), or with some adjustments that it could fit in 622, though 571 or 559 would give more room. In contrast, for low, 451 is already almost too small for my crotch ...


some pictures
http://beauxdebris.free.fr/Albatros/
and here berfore painting
http://beauxdebris.free.fr/Photos/20080512/
and here a plan in .dxf format
http://beauxdebris.free.fr/velocouche/albatros/albatros622_v2.dxf

the mesured trail is 150mm, the angle 55°
seat height is 40 cm and BB height 58 cm
tubing in A37 steel 50x1, 28x1, 16x1 (mm)

some angle reinforcement by a pentagone throught the main frame tube in 15/10mm
Weight ready to go (with first-aid tools under seat) 13kg and the frame only with derailleurs weigths 4,5 Kg
56% of the weight is on front wheel with the the driver on it
the bar is a 46 cm drop style road bar with cutted ends
Shimano 9 speed with Campa levers and an "adapter" (see #23 pict)

An evolution for his wife

a plan
http://www.beauxdebris.fr/velo/plans/Luciole_final.dxf

you can also find another one very similar here
http://pitchounenbent.blogspot.com/2009_12_01_archive.html
with a plan

some videos of another one : see how the bb is low and the seat up (better for climbing)
http://www.dailymotion.com/video/xcbop0_tarakona-fwd-bent

anyway remember that if you choose this kind of design everything is a matter of compromise: indeed, there is no upper limit to the diameter of the wheel, but the more the front wheel is large,
the more the seat is high and / or the BB is high, which may cause unwanted interaction with steering.


hope it helps

Edited by - DocBB on 03/01/2010 18:43:26
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Dana Barlow
recumbent enthusiast

322 Posts

Posted - 03/01/2010 :  21:05:04  Show Profile  Visit Dana Barlow's Homepage  Reply with Quote
"pedal steer" as force "A"=power in put at 90* to head tube ,can be then comepaired to "0" pedal steer on same in-line with head tube[not posible but to get point across],so as your power line =[hip to foot line] comes off of 90* to head tube were it is max. bad,like as exsample 30* off you get 1/3 less pedal steer for same power in put.

Dose that help any one with some under standing of just "pedal steer" when pedals are ahead of head tube.? This explans why you get less when lowering the BB. but if BB moves with the fork it is even higher force going into steering from extra arm you added to power input[= less control]and you wast lots of power trying to counter leg power with your arms. Making that very poor design work.
We actuly also get some other types of dinamic balance force from pedaling that also is a interplay with steering, from the out of balance from side to side of leg/foot load efecting steering.
I designed a way to counter most of that efect back in the 80's that I called "Barlow Spinners"
But that is another story compleatly.
Most of these designs I'm seeing are just bad,but we humans can learn to ride nearly anything and after a time can even think we're doing good with a design that should of been junked.
But then there's fun of making it work kind of anyway,even though it's not good engineering at all.


Dana
Team Strange
"Strange One","Too Strange","Strange Try"
Miami Fla.

Edited by - Dana Barlow on 03/02/2010 11:51:38
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 03/01/2010 :  22:55:51  Show Profile  Reply with Quote
Hi Marc

You said
( this seems the good geometry after an think-tank discussion
traduction:
Also IMHO, I proscribe the 406 for reporting an issue.
With the 451, it is necessary to draw a 65x11 to move quickly in the flat descendants. And 65, it starts to cause problems to find ...
Personally, if I started to make a speculoos and that I was your size, I'd live for a 559, as it is still in standard sizes of plates and gears ...
559 700, for example, or 2 x 559)

Apart from the gearing issues what else could be a problem with the 406 wheel?


The reason I ask is because I am not very tall and have short legs for my hight ,I don't think I'd have the reach for bigger wheels.

Do you have any more pictures or drawing of "speculoos recumbents" I prefer the one's with out the over shoulder frame.

Most of the racing that I will be doing will be open road with very few corners and racing against DF riders.

Also how are the new handle bars working out?
http://i1003.photobucket.com/albums/af156/nigelmelanie/low%20racer/KALD.jpg

Cheers Nigel

Edited by - nigel schroder on 03/02/2010 00:52:55
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DocBB
Starting Member

France
18 Posts

Posted - 03/02/2010 :  01:44:16  Show Profile  Reply with Quote
quote:
Originally posted by nigel schroder

Apart from the gearing issues what else could be a problem with the 406 wheel?
The reason I ask is because I am not very tall and have short legs for my hight ,I don't think I'd have the reach for bigger wheels.
Do you have any more pictures or drawing of "speculoos recumbents" I prefer the one's with out the over shoulder frame.
Most of the racing that I will be doing will be open road with very few corners and racing against DF riders.
Also how are the new handle bars working out?
http://i1003.photobucket.com/albums/af156/nigelmelanie/low%20racer/KALD.jpg

Cheers Nigel



Hello,

the plan which i published is the generally accepted as "the good" one
but you can modify it : the rear frame is almost always the same in the "open" option
you have 2 samples of the plans (ope option) in .DXF format and one here (clic in the blog's picture and it will be displayed in fullscreen)
http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fpitchounenbent.blogspot.com%2F2009_12_01_archive.html



so just modify it according to the dimensions of your wheels

for the front part
the head angle is better between 50° and 60° with the constrain that the nearest of 60° the Lower the BB in order to avoid pedal-steering
the safe range for the BB height is from 0 cm (60°) to +20cm (55°) (Zero is the seat heigt at its lower point)
but you have to check the seat inclination : the more you're sitting (45°) the the lower would be the BB
conversely the more you're leaning the highest could be the BB (up to +20 cm)
if you are climbing a lot of hills better be sitting a little more than leaning
another issue is the inseam: mesure the distance between BB and the lowest part of the seat : it should be the same that your inseam or 1 to max 2 cm less ; never have this distance bigger than your inseam
the last think : with a metal frame, it is better to have only two guys in the front frame in order to keep some flexibility : some have reported frame failure due to too much rigidity

the little one fully carbon would just fit you more a cruiser/racer than racer/cruiser
wheels 20”
pivot direction: 57°
Trail positive 8 cm
seat height : help yourself
wheel base: 1,05m
Mass 11,5kg


Things (+/-) are quite simple
If you draw a map with an head angle 50/55 ° a trail-8 / 12 cm
little or no difference between the seat height and pedal height.
Advanced-seated as much as possible near the steering column
Staying within these data should lead you to build a bike with a correct behavior.
And with the dimensions of the wheels and your legs ones you determine the seat height.

The easiest and fastest way is to draw step by step :

-front wheel (first choose the size)
-determines the trail, and the head angle Which fixes the steering column
-which places the seat
-whic will determine the position of the pedal
-then you place your rear wheel

here is another interesting tutorial for designing
http://www.jetrike.com/ergonomics.htm

"et voilà"

Edited by - DocBB on 03/02/2010 04:06:35
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DocBB
Starting Member

France
18 Posts

Posted - 03/02/2010 :  01:55:03  Show Profile  Reply with Quote
quote:
Originally posted by nigel schroder

Also how are the new handle bars working out?
http://i1003.photobucket.com/albums/af156/nigelmelanie/low%20racer/KALD.jpg

Cheers Nigel



This a prototype, still searching for the good shape of the bar
you can choose the U bar but it has some issue with hitting your tibias (ouch!)
the better choice seems to be the 46 cm drop style road bar with cutted ends
But Ghislain (the carbonic one) prones no bar at all , but he is an ex-pythonnist, only an "handle-break and gear handles". he argues that there is no problem except in strong wind gusts

and this one seem to enthousiats the cruze bikers 60 cm wide

from http://www.wtb.com/products/components/handlebar/mountainroaddropbar/

Edited by - DocBB on 03/02/2010 09:17:50
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 03/02/2010 :  21:32:19  Show Profile  Reply with Quote
quote:
Originally posted by Dana Barlow

"pedal steer" as force "A"=power in put at 90* to head tube ,can be then comepaired to "0" pedal steer on same in-line with head tube[not posible but to get point across],so as your power line =[hip to foot line] comes off of 90* to head tube were it is max. bad,like as exsample 30* off you get 1/3 less pedal steer for same power in put.

Dose that help any one with some under standing of just "pedal steer" when pedals are ahead of head tube.? This explans why you get less when lowering the BB. but if BB moves with the fork it is even higher force going into steering from extra arm you added to power input[= less control]and you wast lots of power trying to counter leg power with your arms. Making that very poor design work.
We actuly also get some other types of dinamic balance force from pedaling that also is a interplay with steering, from the out of balance from side to side of leg/foot load efecting steering.
I designed a way to counter most of that efect back in the 80's that I called "Barlow Spinners"
But that is another story compleatly.
Most of these designs I'm seeing are just bad,but we humans can learn to ride nearly anything and after a time can even think we're doing good with a design that should of been junked.
But then there's fun of making it work kind of anyway,even though it's not good engineering at all.


Dana
Team Strange
"Strange One","Too Strange","Strange Try"
Miami Fla.



Are you saying that moving BB are no good?
or could you not ride one?

Isn't it funny that the women's 12 hour record was set on one of these badly designed bikes
http://www.cruzbike.com/content/world-cruzbike-12-hour-recumbent-record-holder

Edited by - nigel schroder on 03/02/2010 22:28:17
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nigel schroder
recumbent enthusiast

New Zealand
190 Posts

Posted - 03/03/2010 :  01:48:52  Show Profile  Reply with Quote
I can't get this to open
a plan
http://www.beauxdebris.fr/velo/plans/Luciole_final.dxf
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DocBB
Starting Member

France
18 Posts

Posted - 03/03/2010 :  06:05:10  Show Profile  Reply with Quote
quote:
Originally posted by nigel schroder

I can't get this to open
a plan
http://www.beauxdebris.fr/velo/plans/Luciole_final.dxf



Its a common CAD format; you may use QCAD (free) to open it on WIN, MACosX or Linux

http://ribbonsoft.com/qcad.html

this is the 2X 700 version of the bike

http://beauxdebris.free.fr/velocouche/albatros/albatros622_v2.dxf
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