The Creature!

[Night Train]

FWD tadpole trike?
I take it all back. There is someone in the world madder than NT
Kudos for making it, but...erm...why?
As if tadpoles didn't have enough in the way of stuff going out to the front wheels, so lets stick some driveshafts in and engineer a teeny-weeny differential!

Actually, I thought it was mad when I was designing one back in '96 with a view to it being three wheel drive.
However, having had a go on Bikepete's Russian trike I am a convert, they are fantastic.

There isn't a diff either, it has freewheels in the hubs, that means no wheel spin unlike with a diff. But if you want a diff you can get a conveniently sized one out of a powered lawn mower....

 

[TheDoctor]

Freewheels in the hubs? Interesting.
So, when it turns, the inside wheel is always driven, and the outside one freewheels?
That makes sense. And you don't have to control a chain that runs the entire length of the frame.
That's actually quite clever.

 

[Tigerbiten]

Freewheels in the hubs? Interesting.
So, when it turns, the inside wheel is always driven, and the outside one freewheels?
That makes sense. And you don't have to control a chain that runs the entire length of the frame.
That's actually quite clever.

Better still it leaves the back-wheel free for a motor .........

 

[TheDoctor]

I have a rear wheel with a SA drum brake and a 6 speed that I might use.
I was thinking of the SA 8 speed hub being amidships where the guide rollers would go. That would give me the triple chainring, driving the 8 speed, driving the 6 speed.
It all depends on how I decide to set it up.

A triple driving an 8 speed hub driving a 6 speed block?

That's gross!!

 

[byegad]

A triple driving an 8 speed hub driving a 8 speed block?

That's gross!!

That's only 64 gears. My AZUB-4 had 81. The range was 1000% and you never had a gap in the gearing so you could fine tune your cadence, but it could take some time with three different changers!

 

[TheDoctor]

3 times 8 times 6 makes 144.
That's why it's gross...

 

[Night Train]

Front wheel drive is still a possibility. Takes a bit of engineering, though, to keep the weight down.

 

[byegad]

3 times 8 times 6 makes 144.
That's why it's gross...

I missed the triple and thought it said 8 to 8. I plead insanity extreme old age and being blind.

 

[Night Train]

OK, I have a plan.

The Creature will be front wheel drive. I am looking at a range of UJs from car steering columns trying to find which are nice machined and balanced ones and are also common and cheap.
I have also designed a new brake back plate concept that produced twin leading shoes for some proper stopping power.

The plan is to avoid having any cables or chain, from front to back, so that the frame can be split after the seat is removed. This will allow easier 'folding' and can keep any parking brake and electric drive components at the back half of the frame and the spinny pedally bits all at the front.

 

[Chonker]

http://uk.rs-online.com/web/p/universal-joints-gaiters/4923957/

Any good? RS have a pretty good selection

 

[Night Train]

http://uk.rs-online.com/web/p/universal-joints-gaiters/4923957/

Any good? RS have a pretty good selection

Cheers, I had a look at RS but they are a bit small, not strong enough and not got enough working angle before they bind.

I was thinking more like this http://www.ebay.co.uk/itm/170841692127?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649 or this http://www.ebay.co.uk/itm/370630651838?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649.

I have figured that I also need a steel flip flop hub to cut up to be able to fit two freewheels into shafts in such a way that the right hand shaft doesn't unscrew itself!
Still need to find a good cheap hub gear to drive them. A SA 8 speed would be good.

 

[Chonker]

Wont these freewheels mean you are sending power to the unloaded wheel during cornering? Can you not send the power to just one of the front wheels and save the weight of a freewheel/driveshaft? When I had my trice Q I felt that the weight was distributed pretty evenly between the 3 wheels, it made traction tricky sometimes on loose surfaces but I still managed to get up the mountain bike track at redbridge.

 

[starhawk]

If you do it electric you don't need that many gears, I haven't moved the chain from my largest front sprocket since I converted the bike to an e-trike
Who the heck made that weld? I can do it better, and I only had a week-long welding course

 

[Night Train]

I want to drive either both front wheels or just the back one. Not keen on asymmetric drive, ie one side wheel.
Having had a go on a Russian trike with a similar front wheel freewheel set up it was fine. Powering the unloading wheel isn't a problem as it will just slip as it unloads sending power to the loaded wheel. It also corners really tightly.

The overall idea is to have the trike split with all the complicated stuff at the front.

The plan for the first back end is to have it simple with just a parking brake.
It can then be removed and replaced with an electric rear end with cargo capacity.
The final option is to have a rear driven tandem attachment so the stoker has their (her) own pedals, gears and brake all self contained.

It seemed like a good idea when I found the Stein trike split for transport.

The tandem idea is long standing. Arch and I have talked about it for a while and I figured on a front wheel drive trike where the rear wheel was removed and a sort of Xtra-Cycle type addition is added that has stoker's seat, pedals and wheel.
This gives me the opportunity to get on with it.
I will need some sort of rigid seat frame on the front half to maintain frame rigidity though.

 

[Night Train]

I think I have found the UJs and drive shafts.
Universal Joints.
Splined Drive Shafts.

If I get two shafts and cut them I can have two long inner shafts, and two short outer shafts, from each UJ.
The UJ can be machined to carry a 40mm bore bearing as close to the axis of the joint as possible, with a smaller bearing on the shaft between the UJ and the wheel hub. That puts two bearings on the steering assembly for the shaft to run on.