[Closed] Shimano Gearbox

Will have a little bit more friction than a well sorted derailleur but that can be offset by it being kept clean inside a box. Def think that a mech in a box solution ios the way forward but how on earth are Shimano able to patent this with the Honda gearbox (and all the others) in existence? (though this seems to be more about the lube than anything).

Mine would look a lot like this but would have a freewheel to limit rolling drag and electronic shifting to do away with cables and allow shifting while coasting. I'd not be bothered about actual actuation while coasting if the change is slick and fast and the friction caused by having the gearbox and rest of the transmission turning all the time would be a huge drag. Literally.

If the suspension and shape of the bike can be sorted to be a pleasing thing I reckon lightfighter is right, these really could be the future, especially if we can go to single sided narrow back ends and enclosed drivechains like the Millyard.

points of interest in the techno blurb........

uses same casing / fitment as shimanos step ebike motors

designed to be removable for service / repair

2 inverted cassettes providing 13 gear ratios , shifting by electronic actuator

will be developed for both road & mtbs

drag reduced by low friction coatings on cogs

a variable transmission version with stepless gears" feasible" for the fututre

it looks immense , makes pinions offerings / design on a gearbox look "basic"

. The chain guiding mechanism 48 can have a
similar structure to a structure of a bicycle rear derailleur .

Other embodiments involve cogs. I am not sure any of the internal mechanical arrangements are new until combined with the amazing lubrication system.

The claims do not bother to go into any detail about the mechanical arrangements. Whether this is because Shimano haven't come up with any mechanical arrangement they regard as patentable or because the mechanical arrangements will be/ are being applied for separately, I don't know.

It does appear to be all about the lube though.

This comes days before Bosch are to announce details of there own gearbox

They’re only pursuing the patent application in the US and possibly Germany, and the focus is currently effectively entirely on the lubricant. Reading between the lines, it doesn’t look like the gearbox a major focus for them in this patent or they’d be pursuing protection in more countries, and they would actually have claims to the gearbox per se. If the gearbox itself is a focus for them I suspect there must be another patent directed to it, but I can’t be arsed searching for it.

Ps, it was filed in 2017 and automatically publishes after 18 months, so the timing with that Bosch thing is only a coincidence

a variable transmission version with stepless gears” feasible” for the fututre

You can't have stepless gears with cogs and a chain drive, so that would have to be a fundamentally different design, rather than being a variant.

I do not understand this type of system. surely the parts will wear more with a derailleur in a box set up compared to a layshaft gearbox ( pinion) or an epicyclic ( alfine / rohloff) thus negating one of the main advantages of a gearbox. what am I missing?

To go back to the point about drag. I strongly believe the drag is not as bad as folk make out especially once the gearbox is run in. My rohloff is still getting smoother and quieter after many years and many thousand miles of useage.

However to me it irrelevant. I am riding for fun not racing. I do not care if a 10 min climb takes 30 seconds longer or that It takes me 5 mins longer to do a 40 mile ride. It just makes no odds. I have still had the same downhills to enjoy, seen the same scenery, got to the same pub

I kind of agree TJ, however my old Shimano Nexus remained 'gloopy' feeling even after 3 years of daily 12 mile commuting.

The derailer in a box removes all the muck that both wears gears out and reduces efficiency. Combine that with modern electronic shifting and this here patented slick coating and Shimano could be onto a winner.

It will wear out, but over a much, much longer time. It will meet and exceed the derailer efficiency. It won't weigh much more, if anything.

I doubt it will exceed derailleur efficiency - 3 chains instead of one?

There's a lot of comments from people saying how pointless it all is because derailleurs work fine and they've never so much as bent a mech hanger in 30 years etc...

What kind of riding are these people doing? I could make a derailleur last forever but not if I was 'mountain biking'. I've bent dozens of mech hangers, ripped a few off and even put the rear mech straight through the spokes.

So yes, my current set up works fine but I'm also excited about anything that completely changes the shape of MTB drivetrains in general. I'll take an electronic shifting gearbox on a 29er DH bike please.

surely the parts will wear more with a derailleur in a box set up compared to a layshaft gearbox

They will be able to use steel cogs instead of aluminium, plus wider chains and thicker sprockets, and it will be protected from dirt and mud so they can put an oil bath in the bottom of the casing to keep everything lubricated. Given that chain driven camshafts in car engines run for five to ten years and millions of revolutions, a properly done chain gearbox in a case should be fairly durable.

I doubt it will exceed derailleur efficiency – 3 chains instead of one?

Yes, but a lot of the friction in a standard derailleur setup will be from the chain having to wind through the jockey wheels in the tensioner, which is where rubbish tends to collect. Also from the chain having to run at an angle as you shift to the extremes of the cassette. The chains running inside the gearbox should be fairly low drag because they won't have to run at an angle and should be properly lubricated. A chain tensioner will still be needed for suspension bikes, but it will only require a single jockey wheel and the chain won't have to wrap right around it like with a traditional derailleur. I doubt that pro road racers will be interested, but it should pretty be pretty close to a normal derailleur for an MTB that's coated in dirt and mud, with leaves and sticks getting ground through the cassette and derailleur.

Friction in a standard derailleur setup comes from the angle of chain line. A clean chain in a straight line is something like 99% efficient even with normal lube and metal, only decreasing with angle.

So this could still end up more efficient than a gearbox. Clearly they think so, otherwise they'd not be putting the effort in to develop it (if they actually are).

One reason for the patent could be to stop someone else patenting something similar. Once in the public domain it's much harder to patent.

It is a very narrow thing. It is limited to systems having that particular lubrication AND some types of bicycle transmission. They haven't invented the lubrication system itself, otherwise they would have tried to patent it on its own, and similarly for any type of transmission. To get a patent they would have to demonstrate that it was not obvious to combine an apparently known lubrication system (though I cannot say how well-known) with known bicycle gear designs. This is likely to be difficult and even if a patent is granted, it will be highly liable to be overturned by anyone interested enough. The argument they would have to run is that the selection of that type of lubrication for a bicycle gearbox* had particular and not obvious benefits.

Anyone know anything about lubricants - is the system they mention particularly unusual/obscure?

* where this means any enclosed drive ratio changing system, not just one involving meshing tooth type gears.

However to me it irrelevant. I am riding for fun not racing. I do not care if a 10 min climb takes 30 seconds longer or that It takes me 5 mins longer to do a 40 mile ride. It just makes no odds. I have still had the same downhills to enjoy, seen the same scenery, got to the same pub

I'm the same but for me that just means nowt wrong with my current 10/11sp rear mechs and cassettes