That I like this idea may come as a surprise...

Very interesting design, I like it when things are examined from a design perspective.
What I hate those is the language used
"The unreliability of derailleurs" Er.... those things that have hardly changed for the last 50 years, which itself is a sign of a proper design, one that has stood the test of time.
The vid then talks about drag factors when in use while at the same time showing the rider freewheeling downhill and not turning the pedals. That to me seems a bit disjointed.
Next thing I question is the upper..is that a jockey wheel or a chainring ?, either way its the ring that has a hell of a lot of the main driving forces on it and that it seems to me look a little floppy to be able to stand up to years of use.
The presentation vid is 4:30 mins long, most of that is of him riding a trail. One thing is clear though int he vid which is the way the chain bounces all over the place, I mean its rattling about and that is something that was addressed by the addition of a clutch, so rather than keep the chain from bouncing about, this design has it acting crazily, I dont see that staying on rings without the need for redesigns and the later edition of keepers etc.
He also talks about changes to the frame itself, which I dont see manufacturers going for. I like the placement of it tucked inside the frame but I think this is more of a concept set up than anything thats going to replace Sram or Shimano any time in the future.
Dont get me wrong, new design is always interesting,I love the creativity of us Humans, but I think this is just a step too far.
 
Getting mixed reviews on the main site as well.

https://www.retrobike.co.uk/threads/whaaat-take-something-simple-and…….437590/#post-3192578



I’m like Epicyclo, I like to see innovation, even if a agree with Dyna that it’s unlikely to go far in production. Can see a lot of small downhill manufacturers liking it though.


Dyna, yes derailleurs have been around a long time and are the current best solution, but doesn’t mean they can’t be improved. I like the fact that it doesn’t need special wheels and runs on a normal cassette and cranks. The top pulley is simply to guide the chain and is vital to keep the chain force in the correct plane to allow the suspension to work properly. His is much bigger than most designs but from other reviews it does seem to be a wear/friction point. Chain will stay on fine. Yes it’s bouncing by the stays but the upper and lower guides keep it tensioned over the chainring which is the important part. Even with clutch mechs you’d be amazed how much the chain moves on rough terrain.


Unlike Dyna, I’m not sure it goes far enough. Imagine the possibilities if it was fully sealed and ran through an oil bath? Oh god, I think I’m turning into Brian.
 
Agree with all said above but don't see why it must be for high pivot only. If the system could be developed for all bikes especially hardtail which I have always preferred then it would tick more boxes. Also agree fully enclosed chain would be great especially for our climate. 😎
 
The reason I don't like derailleurs for an offroad bike can be best explained by this photo.


There we have a single speed bike with a bit of heather having worked its way into the rear disk mechanism and completely jammed it up.

The irony was I'd fitted a front drum specifically to avoid that sort of problem, but thought the rear disk was well out of the way.

If I have that sort of problem with protected part like that, just imagine the carnage I could inflict on a derailleur while riding through heather.

I might add just as my road rides rarely are, my singletrack rides rarely see much single track, deer track or no track being more attractive.
(Jamie might like to comment. :) )
 
Geof Cleland Apps last incarnation of his off road bike before he gave up trying to flog his ideas to the masses would be perfect for your mad adventures Brian. Roller hub brakes, hub gears and fully enclosed drive chain with loads of clearance and full mudguards and bash plate.
I wonder what a fusion of your ideas and his could have produced🤔
 
I wonder what a fusion of your ideas and his could have produced🤔


Bankruptcy!!

Read a bit about Geoff and reckon he was onto something for his certain type of riding. Unfortunately he was about the only person interested in that type of riding. He saw mtb as the cycle equivalent of the Scottish Six day trial, when in fact most riders were look for motocross.
 
True but Brian rides the kind of terrain Geof does and Brian's fat bikes are several steps away from what Surly envisaged.
 
True but Brian rides the kind of terrain Geof does and Brian's fat bikes are several steps away from what Surly envisaged.
The problem is Geoff is a skilled trails rider and what suits him would not be capable of the same performance in other hands. On the other hand, I'm more likely to drag or carry my bike through the stuff he can ride.

I could ride a lot of the stuff I walk, but because I'm out on my own I'm risk averse.

What we share is an aversion to having delicate bits getting ripped off the bike or allowing precision mechanical parts be exposed to muck.

This quote sums it up from Kevin Cameron of the USA magazine 'Cycle' (of the motorised variety) sums it up:

"This new form will have to be a complete concept - not just a mass of little improvements. It is hard to prove the advantages of wings by attaching them to a toad; they really do work best on a bird. To leap from the toad to the bird is generally too radical a step for conservative business corporations. They have invested too much money in producing better toads.

The novel concepts, therefore, come from nutty individuals, many of whom seem to like change for its own sake. Because of this they can make mistakes that make even their good ideas appear laughable; consequently, these ideas must wait until traditional thinking is completely bankrupt. Then they are widely adopted and labeled 'progress'."
 
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