FWD and rear steer Trike

I am working on an easy trike concept for my first build. I like the simplicty of the drive straight onto the front wheel / wheels . However this makes steering on the front difficult.

So , How well do trikes ride with rear wheel steer. ????

Am thinking under seat steer and maybe incorporate saddle leaning if high speed instability with rear steer is a problem.
I have in mind the Tadpole concept, so this complicates drive onto 2 front wheels. Is a solid front axle such a big problem?. tight turns would suffer [ maybe a simple differential could be fitted- I reckon I could rig something up - did I say simple concept.????]

Or can the steering be from a hinge in frame behind the front two wheels? You know bendy in the middle

.... any thoughts appreciated.
Cheers, Glenn

 

I have a FWD/RWS 2-wheel bike that I built. One thing that I can tell you is that you have to slow the steering down a bunch. You may be able to design a tadpole FWD using the Python bike design as a base. Unless you use a differential for the drive wheels you will have problems with turning and stability. There was a FWD/RWS tadpole trike, the Sidewinder out of Lompoc, California but they closed down about a year ago. There trikes were only stable up to about 15-20 mph. I feel that there problem was centered on the design of the rear steering section. They also used cable steering but could be redesigned with linkage. You may be able to pick one of these up for cheap and go from there. Check out there web site:
http://www.sidewindercycle.com/sportzoutofstock

 

thanks for the info, bit concerning the instability of the trike you mentioned.
How is your 2 wheel - rear steer , stability wise.?
Glenn.

 

had a good look over my friend's two trikes this arvo.
[ one is a Flying Furniture and the other a New Zealand made ]
I am starting to think that maybe I should not be so scared of the Tadpole front steering set up.... but I still dont like that long chain.....
Glenn.

 

I just made some changes to the steering to make it more stable. So far the changes are an improvement. A RWS bike has a learning curve that is different than a "normal" bike. I have some balance issues so I'm not as stable on ANY bike other than something with 3 or 4 wheels than an average rider. One of my trikes is a KMX and I will say that the "headtube' angle is not the best. It measures 14-degrees with 406/559 wheels and is a bit twitchy. I have thought about going to a 507 or 406 rear wheel to increase the angle. IMO, something closer to 18-degrees with indirect steering would be ideal. Tadpoles do have a long chain and more friction but with "proper" designs, the number of idlers can be reduced. IMO, the KMX is too short of wheelbase at 41". I like a tadpole that has a shorter boom providing less flex, a longer wheelbase that moves your hands farther from the wheels giving a better ride and more stability.

 

thank you for those frame tuning tips.
It is those sorts of techniques that I need to learn, if building my own Trike since I am hoping to put an engine on, and it may travel at 35 km/h.... needs to be stable at 25 MPH.
- Am thinking that simpler building ideas may not give a stable enough trike for what I want in the end.
Cheers, Glenn.

 

I hope this is alright to add some info.
I went searching for rear wheel steer and found a good one...

A VERY TALENTED , designer / artist / future thinker named
Dennis Renner.

Designed this rear wheel steer for a 2 wheel recumbent.
I watched his video and it appears very stable.
This link is to his detailed pics to assist home builders - not for production .

http://picasaweb.google.com/1147554...id=UCkBp5oXh00eszCtlN7fAA#5501232390765609378

Thanks to Dennis Renner for sharing this very valued info.
Glenn.

 

A while back, there was a trike from Russia that was a FWD tadpole. Here is a link to a sight you might find interesting:

http://www.aha.ru/~ykpro/

 

drop me a line and I'll send a couple pics of the rws/fwd delta trike I have as well as my leaning tadpole. There is a movie of me riding the leaning tadpole on recumbentjournal.com

 

In reply to Patti , nice Russian Tadpole. Interesting having differential and universal joints and steering all on the front axle. This makes the rear very simple - which is great for installing rear electric motor. But the complications of the front set up is daunting, Nice Trike though. Thanks.

 

in reply to Bill , How stable are each of these designs at speed ? They both sound good. I expect leaning helps tremendously but then the drive system gets complicated. I was thinking - seat leaning with the rear wheel steer - which moves the largest weight component .... ME
Of course after riding for a couple of months that weight wont be so great
Cheers, Glenn.

 

Oh sorry , I thought there was a back link from his Pics site... Here it is, thanks to You Tube. Funny intro " No Rear Wheel steer cant be done " !!! then he rides off on his

 

The Delta is very stable until you get to the nonlinear part of the steer lean around 18mph. At that point steering and leaning are not proportional and you have to lean more in response to the lean. If you get to the accidental tipping point it is catastrophic. The trike will flip. It is painful. I know.

The ARC-Maurer enables modulated lean with the steering so it is incredibly stable at any speed. It is a great design and takes only about 5 minutes to get used to. You can bank and turn much sharper with it than any fixed geometry tadpole. It is not RWS.

 

I was reading another Cycling Forum. A very thorough discussion about RWS and the engineering problems/ stability / Centre of Mass when turning / self centreing / issues ...
etc.
I am new to designing a vehicle, some experienced peoples have been trying for a long time to make RWS ideal , and stable, and safe - but the more I delve into it the more I am seeing this is not something for me to attempt.
Cheers. Glenn.