Trike technical help please

[Gareth]

I have recently purchased an abandoned recumberent trike project, and intended getting this on the road for next springtime. It is a Russian made frame, front wheel drive, front wheel steer tadpole trike by AS.

I am a very experienced and competent Mechanical Engineer, and skilled steel & stainless steel fabricator, with access to a well appointed machine shop.

To the best of my knowledge, I have now reached the point of bespoke design and manufacture to obtain exactly what I want. In fact, I am almost at the point of scrapping the frame that have I bought, and starting afresh. So I have a few technical questions that I would like to ask those in the "Know."

I want to keep the front wheel drive,and front wheel steering features, but have committed myself to using 26 inch front wheels complete with hub dynamos and disc brakes all round. I expected to make, and have hardened new stub axles so that I could fit the disc braked, and dynamo hub wheels and get rid of the drum braked hubs, but I am now questioning the side loads that steering will impose upon the standard size bearings and cones. I am also starting to question the freewheel differential steering of the driven front wheels. Basically all power is directed to the left hand wheel when turning, and the right hand wheel goes into freewheel mode.

I have seen several standard trikes i.e. one wheel up front, and two behind being used locally, and have seen racing trikes out on the A11. However, these all seem to be of a fixed rear axle design without a differential to accomodate the differences in linear travel that wheels make during a turn. Is there a commercially made, off the shelf, bolt on tricycle axle differential unit available?

 

[Gareth]

The frame I have is a recumberant trike, which was originally specified for 24 inch wheels, and if I have to make a whole new frame, recumberant is the way I shall go. I am also determined to use 26 inch wheels, basically because I have a love and passion for Continental Town & Country tyres. Which are now only available in 26 X 1.9 size.

When I do eventually have a completed recumberant trike, it will be used for weekend pleasure touring on A, B and some C class roads, along with a few green roads, and all at a nice sedate pace. I do not envisage, or want to do all terrain off-road stuff on it: For that I have a robust cheap hard tail ATB.

For my type of pleasure cycling, using professionally built wheels on mountain bike rims and spokes, I don't perceive a problem; especially if I have a centre mounted differential unit. The full size road racing trikes, and tandem trikes that I have seen out and about I assume to be on 700c rims and tyres or similar. These are cornering at speeds in excess of what I want to be pedaling at, and their wheels are holding up!

 

[mickle]

Few companies manufacture differentials and I think I am right in saying that no-one else makes a front wheel drive tadpole. And 26" wheels? Few if any builders use this size die to the limit on steering lock versus width. There are other very excellent tyres out there you know. I use Schwalbe on my Speedy and am delighted with their performance.
I hope you aren't flogging a dead horse...

Try Hase in Germany for a differential, it's an option on some of their lovely delta trikes.

 

[ufkacbln]

The original machines were made by AS engineering whose site is here They marketed the AS 237 and Zenit Lg Trikes

These machines were unique, but heavy and complex when compared with the other options such as the Windcheetah, Greenspeed or Peter Ross Trice.

Few were sold in the uk, Peter Eland of Velovision was an owner. His ownership report is Here

There are also notes from author of this site and lots of other information

From what I remember they were 406 or 451 al round - anything bigger is a problem on a trike:

If you really wantto get technical though there was a three wheel drive version!

Finally the British Human Power Club has an excellent resource in their book So you want to build an HPV

Hope this all helps

 

[ufkacbln]

PS if you are in Norfolk you have an eminent source of information at Rackheath near Norwich - Mike Burrows designer of the Windcheetah and pioneer of recumbent trikes!

He runs an engineering company, and and may be able to help.

 

[Arch]

<small voice> without wishing to sound rude, it's 'recumbent', not 'recumberant'... </small voice>

Anyway, have fun!

 

[Hilldodger]

Mike Burrows designer of the Windcheetah and pioneer of recumbent trikes

I didn't realise he was THAT old.

 

[ufkacbln]

Mike Burrows designer of the Windcheetah and pioneer of recumbent trikes

I didn't realise he was THAT old.

Almost as old as you?

 

[Hilldodger]

Cheeky

But MB wasn't building trikrs in either the 30's or late 70's

 

[ufkacbln]

Cheeky

But MB wasn't building trikes in either the 30's or late 70's

I know - I was "bigging it up" for the OP!

Howzabout Mike Burrows - significant contributor to the development of trikes in the eighties?

 

[byegad]

I feel that 26" wheels at the front are going to make cornering interesting, given fwd I don't see how the high centre of Gravity (or complicated drive lines if the seat is lower than 13") is going to work out in practice.
The reason most trikes use 20" or smaller front wheels is the resultant reduction in cornering stress. One look at the lean of a 700C rear wheel on a loaded trike was enough to convine me I was going for 20" all round!

 

[mickle]

Also. Fitting 26" wheels if it's designed for 24" ... I wonder what will happen to the steering centres relative to the tyre contact points. An increase in trail coupled with a shifting outwards of the steering centres methinks.

 

[bikepete]

If it's an older frame the kingpins are probably vertical viewed from the front, so just the trail to worry about. But surely best to stick with the original size.

I used to have one a while ago:

http://www.eland.org.uk/s327.html

It's just possible it's the same frame :-)

Anyway, please dont' scrap it! I could even be tempted to buy it back...

I should correct Cunobelin: the original manufacturer was AS Engineering (Alexei Soloviev) and the current website is

www.trikes.ru

They're not in production now AFAIK.

Also see

http://www.berkut-trikes.com/

as they did make some larger-wheeled models.

To actually answer the original question...

Yes, some upright trikes do use diffs instead of freewheels, but the problem of losing all traction if you lift a wheel means that most seem to favour the freewheel option.

There is a suitable diff unit available, as used on Greenspeed Anura trikes, and available from Greenspeed. As to 'bolt on', there'll certainly be some mods needed to fit it:

Not in the parts list but I'm fairly sure you can obtain one by emailing them as described at:

http://www.greenspeed.com.au/gsparts.html

Good luck!

Peter

 

[mickle]

Hi Pete!

 

[bikepete]

Hi Mick, I do occasionally de-lurk :-)