FBinNY 

Someone's trying to put me out of business with a sealed chain system and in the BB gearbox.

I post it here without comment, except that it's an interesting idea with real benefits if it works, and figured folks here would be interested.

Read here

Lazyass

Looks interesting but having a mechanical like a broken chain while on a ride could be not cool, doesn't look easy to work on.

mconlonx

I like seeing BB gearboxes cropping up here and there.

Fully enclosed chain is also good. Looks like the back of the frame may include eccentrics to tension the chain?

FBinNY 

Direct drive combined with an enclosed oil bath system eliminates the common causes of chain failure. SS and IGH chains rarely break in use, so odds favor trouble free service in that regard. Threading a chain shouldn't be hard, using gravity to guide it down the tube until it picks up the sprocket.

Given the non-compatibility of the system, I'd be more concerned with the gearbox itself. Also, this is a non modular unit system, so a frame or gearbox failure is a total loss of both. While I think there's lots of merit to the concept, I'd rather let those with $6k in the small change jar do the beta testing.

I actually hope for the best for the maker, since the initial success might lead to more offerings, possibly a well designed touring or commuting bicycle.

AnkleWork

The sealed chain makes a lot of sense, but there is an overriding reason all successful geared bike transmissions are in the hub, not at the crank.

FBinNY 

Now that you've teased us, what is that reason?

cicli_masi

That's an awful lot of extra frame material...

AnkleWork

The weight can be lower by the same factor as the primary drive ratio, ceteris paribus.

JTGraphics

You have nothing to worry about chains will be around long after your gone

FBinNY 

That may be true, but he's coming in at a decent weight regardless. He also offers a decently wide range with decent torque capabilities (if it works), without the restrictions common in IGH hubs. That overcomes a major IGH limiter for off road use where offsetting the range toward lower gears is desirable but not allowed.

There's the added benefit for those who might want to use a similar bike for two purposes. The cost is removed from the wheels, so one can have 2 sets of wheels, each with appropriate tires and final drive sprockets, one for road/trail, and one for serious off road. (if the sproickets are different, it will probably mean swapping chains).

IMO- it's too early to tear this apart, since it offers the potential for real benefits to a class of user. OTOH we haven't seen if it can deliver what's promised, and/or how it will hold up in the real world.

Booger1

Pre-WWI Sunbeam (English) bicycles for the military had oil bath chains.....That part of it is not new.Didn't run through the chain stays,but you didn't wear a hole through the frame when the chain stretched either....

If I read this right,it has 16 speeds, I think you get 3 speeds per set of normal planetary sets?.......Where does the extra gear come from? 4 speed sets?

Nice to see people thinking out of the box.Could be real nice if it works as planned.

FBinNY 

Yes, but I needed a nice teaser to open then post.

SquidPuppet

I think the gearbox is fantastic. Located right where it should be for mass centralization optimized handling. I'd much prefer a traditional external chain for many reasons though.

FBinNY. He can get past the frame and gearbox being one unit too. Racing motorcycles have used "Cassette" transmissions for ages, with track specific ratios. It works just as it sounds, the entire sealed unit slips into a shell in the block. No reason he can't adapt the same technology.

Lots of exciting potential.

Thanks for sharing.

davidad

Tradition.

AnkleWork

Rather, he claims . . .
And, in fact, many medium weight riders can exceed his stated maximum torque input.

FBinNY 

I agree, and assumed there was some replaceability. That wasn't what I meant. My concern is that this is a single source item with no compatibility with anything else. So if he gets either the frame or gearbox wrong, the whole deal is shot.

It's easy to pan the concept and the product, and for all I know the product may have problems, but it opens interesting new doors which is why I posted in the first place.

Since I'm not a serious mtn biker, and always let others beta test products (unless I'm paid to do so), I'm not in the market. But I would like to see this happen because the concepts are interesting and can lead to some well conceived niche products.

SquidPuppet

Oh, gotcha.

I have always been fascinated with the potential of gearboxes for bikes.

A 250cc Two-Stroke motocross bike makes around 40 horsepower and had(s) a six speed gearbox the size of a cantelope. TINY. It's entire life is spent in a constant state of tremendously violent abuse. Red lined clutchless downshifts etc. Yet they perform trouble free for ages. With all the significant advancements in metalurgy and coatings, and the fact that humans can't generate much power, I've always wondered why there were not already compact light weight geaboxs developed for bikes.

FBinNY 

I suspect you don't see gearboxes so much on bikes because bicycles occupy a very unique niche in the engineering world. Almost all transmission applications involve speed reduction, working with high speed/low torque inputs to produce higher torque/lower speed outputs. Bicycles are the opposite, involving high torque input to produce higher speed output.

Add the weight constraints, and the need for high efficient at high torque, and life gets complicated. Also while our human engine isn't high power, consider the effects of the sizes of final drive sprockets. A typical MS will have a final drive sprocket about 1/3 the diameter of the rear wheel, so the chain is running at relatively low tension compared to driving torque. On a bicycle the final drive sprocket is much smaller so the chain and drivetrain are running at comparatively higher torques.

We pay for the high loads and lighter parts is short chain and sprocket life that would be totally unacceptable in any other application.

HillRider

Didn't Honda experiment with a Down Hill specific bicycle (yes bicycle, not motorcycle) that had an enclosed gearbox at the bottom bracket location? It turned out to be a pair of opposing cassettes and shifted like a regular bicycle except it was totally enclosed. Nothing ever came of it commercially.

SquidPuppet

Chain torque consequences aside, this made me think of something else. Because a bicycle's primary gear and driven sproket are opposite in size relationship (high final gearing vs low final gearing) from a motorcycle's, wouldn't that allow a bicycle gear box to be even more compact by a factor of "?"? Or do I have the math backwards. I aint an engineer. Obviously.

bradtx

FB, That looks interesting and I'm sure a segment of cyclists are interested in the concept, best of luck to all concerned.

I have hot rod cars, I still have one motorcycle and one of the most appealing aspects of a bicycle is the mechanical simplicity.

Brad

melloveloyellow

Looks a bit complicated if you get a rear flat or damaged rim.

Rowan

Cost is prohibitive and frame designers will be locked into what is quite a complicated BB casting. I suggest also that ride quality will be poor because of the dual chainstays and in all likelihood, the design of the BB assembly itself.

Chains and cassettes and chainrings for general cycling are very cheap by comparison, and anyone with a basic mechanical bent can work on them. Current manufacturers -- ie, those that dominate the marketplace -- are already well tooled and skilled at producing these items.

If you want a gauge as to the likelihood of success, look at the acceptance rate of internally geared hubs, and more importantly, their cost. If they were that good at the same price point, we wouldn't be buying bikes now with derailleurs.

Cute Boy Horse

You could also say that if we weren't buying bikes with dérailleurs, hub gears would be better.

Andrew R Stewart 

First thing I wonder about is efficiency. Second is service, flat tires and such. Third is industry politics. Andy.