A red Newton

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Ivan Haynes, the owner of this Newton trike has not only provided some superbly sharp images but also shared some YouTube videos.

WARNING! Please note that the image enlargements in this chapter are from 300kB up to 600kB. If you are on a slow internet connection please be advised that clicking on any image may result in a considerable delay. If you have to pay for your downloads then this is one more reason to avoid the enlargements. I normally set a size limit of 300kB per image in my blogs but wanted to do justice to the photography on these excellent images: 

General view showing unisex top tube arrangement and twin front wheels in the so-called "tadpole" configuration. As opposed to "delta" which has two rear wheels. The tetrahedral arrangement of front frame tubes ensures stiffness at the front end. The steeply sloping, top tube is continued as a further pair of stays to the rear wheel drop-outs. Very strong and stiff but with a weight penalty. In fact, this Newton is no lightweight according to its owner.

The emphasis on weight at the front might make it more difficult to bump it up over a pavement edge. But at least the wheels don't run into the backs of your legs when you walk it around.  (as does a delta)

View from behind the cockpit. The rider can clearly see where the front wheels are going. Making it easier to avoid potholes compared with a delta. The front axle bracing is well seen from this viewpoint.

 

Right side, front axle in close-up. Showing the Welsh head badge and Newton signature. Brake equaliser bell-cranks are seen on the extended head tube. The steering rods are clearly seen with ball joints at either end. These take care of the strange angles as the wheels move from lock to lock in both directions. Ackermann steering with the king pins pointing down at the centre of the tyre contact patch to avoid bump steer. Earlier tadpole makers used upright kingpins with disastrous results on high speed stability on rough surfaces.

The tadpole has a much wider turning circle than a delta. Not a problem in normal riding but a possible inconvenience in tight spaces. The delta can turn in its own length if necessary. With the Newton I'm thinking about the bars fixed at the ends of cycle paths. They form a very tight chicane to stop motorcycles and scooters from entering and causing high speed mayhem.

Rear view of front hub and widely splayed bracing tubes to ensure the axle stays aligned on the front of the supporting bicycle frame. The king pin housing employs bicycle head tube bearings neatly capped off. This should ensure very long life and no early redundancy due to lack of spare parts. This can be a serious factor with proprietary cycle parts. Many of the recumbent machines on the market at the moment will become so much scrap metal if their manufacturers should fold. Their designs incorporate unique parts made and used only by their makers. The Newton has wisely chosen the well trodden path of standard parts. So should have no real limit on its lifetime if treated reasonably kindly.

Front wheel and hub seen from the front of the machine. The slim rims need no braking surfaces. The wheels are quick release thanks to a sprung pin through the hollow axle. These large flange, Sturmey-Archer, drum brake hubs are popular on wheelchairs. I have a pair of these wheels in the 24" size just waiting for me to finish a project to build a similar tadpole trike. At present progress I may be too old and doddery to ride it when it is finished! 

The finish is a little "untidy" on some of the joints. Particularly in the bottom bracket area. This uses a lugged, bottom bracket shell. Goodness knows where this came from originally. Perhaps a rear tandem bottom bracket?  

A single rear brake probably provides a steadying influence on long descents. I have no idea if the S-A drum brakes are prone to heat fade as are car drum brakes. One owner complained about the lack of braking power with drum brakes. Newton now employ disk brakes on their trikes and conversions but as some extra expense.

The bottom bracket are showing duplicate tubes for the front axle braces. I suppose one should call them front axle stays. Their lateral dimensions must ensure that the rider's toes do not collide with them in normal use.

Ivan Haynes, the owner, tells me that it is relatively easy to lift the front wheels individually while riding or standing still. Even to corner as if on a bicycle if so desired. The front wheels are also rather easily locked under hard braking. While on a delta it is almost impossible to lock the single front wheel even braking hard on black ice. Though it is much easier to do so on loose gravel.

Now a couple of videos of the Ivan showing the truly remarkable stability of the tadpole arrangement. Or is it just his acrobatic skills? It would take considerable practice on a delta to be able to lift a wheel and keep it in the air. I have tried lifting a wheel to ride on two but do not enjoy the feeling at all. It feels very unsafe and unstable and rather unkind to the wheels. Ivan, the owner of the Newton, makes it look very easy indeed. He himself emphasises how stable the Newton is compared with his own delta trike.


http://www.youtube.com/watch?v=Pjzl5eNYJds

http://www.youtube.com/watch?v=xleBHImj1QU

Back click from YouTube to return here.

Note: These videos are not publicly listed on YouTube. So are only available via a direct link.

I am most grateful to Ivan for sharing these excellent images and links to his videos.

Ivan's review of his Newton follows: Note: I have split some of his original paragraphs into smaller sections dealing with specific points about the Newton trike. His words remain unchanged. Just as they were communicated to me in a private email. He has given me permission to post it here.

"My experience with an upright tadpole trike, having bought one last year and ridden one for the first time last year is that it is much easier to ride than an upright delta. Over the years I have tried many experienced (two wheel) cyclists on a delta and found they cannot ride it, but now if I try them with the tadpole first, they can then “progress” onto a delta after a few minutes. It is much more stable through bends, seems to require less lean from the rider (hanging off) and you can get away with braking into corners.
 
So far I haven’t really noticed any pull to one side even though the brakes are not quite even. That might be because the front brakes are not very sharp, but it is still very easy to lock up one of the front wheels under braking. Normally on a good surface you will know how hard it is to lock up the front wheel of a bike or delta trike. On the tadpole they lock up surprisingly easily however good the surface and grip is.
 
When cornering it is very easy to go round a corner with either the inside wheel or outside wheel lifted. In fact you can lean the machine over into a corner just like a bicycle. This is a bit trickier on a delta. Either of the front wheels can be lifted very easily indeed, again much easier than on a delta as there is much less rider weight on the front wheels than the back wheels of the delta. When riding along the road a front wheel will often come up “of its own accord” or from going over a bump.
 
Some downsides of the tadpole are as follows; Weight, it is quite a heavy machine, I must weigh it so that I can let you know what it actually does weigh. With all the extra work for steering the front wheels, it is quite heavy at the front and overall I would say is heavier than an equivalent delta.
 
Steering lock is also a limiting factor. This is not something that matters or would be noticed in normal road riding, but it has very limited steering lock. You know how you can almost spin on the spot with a delta, the turning circle is much larger with the tadpole. The frame design is shaped so that the front wheels can turn, but eventually they will meet and the tyre will rub on the frame (inside wheel). When riding, before it hits the frame if you turn too sharply, the wheel will make contact with your foot as there is huge toe overlap. This as said before is not an issue with normal road riding, unless you want to do a u turn on a narrow road.
 
Another issue with the Newton trike is build quality. I don’t like to speak badly of a builder and I have only got the experience of my machine, I have not seen other Newtons up close, but the frame is a little rough in its construction. It seems to be arc welded rather than fully brazed and some tubes are joined (in the middle) in their length. Overall though it is still a nice machine, just a few touches here and there could make it really nice."




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