mstateglfr 

Do you often find yourself in a situation where you really need to shift when stopped? If so, then shift in the 15 feet before stopping. We are talking about igh here, so it's paths/roads where you see what's coming up.
Or if you do forget to shift in the 15' before stopping, then shift while stopped, lift the saddle with one hand, and spin the pedals half a turn.


What has never popped into my head when stopped is 'this pesky RD doesn't allow me to shift while standing here! I had to shift 10' behind me!'.

cudak888 

That's the difference between the voice of rural riding vs. riding in ridiculously congested cities that have limited bicycle infrastructure. All of what you've described is fine when you either have the road to yourself or are in a protected bike lane with limited congestion and driveways, where everything is orderly and there's no real question about what's happening next.

I don't see how the choice of IGH equals riding on "roads where you can see what's coming up." If anything, I see IGH being used as the ideal tool for reacting where one cannot necessarily anticipate what's going to happen and visibility may be limited: Driveways, drivers making their precious little right turn on reds (or unprotected lefts on green), pedestrians, other riders meandering about - these situations are where an IGH shines. One has the opportunity to feather the brake and downshift a few gears while freewheeling, anticipating the need to slow or stop, and if not, throw it right back into whatever gear was being used for cruising and power on.

Besides having to anticipate shifts, one has to wait for the chain to swap cogs on an RD as well, something that has arguably become slower with Shimano's ramped systems. On an IGH? Nearly instantaneous. Some combinations from the era of friction shifting and no ramping also allowed for much quicker slam-bang trips across the cogs than Shimano allows now.

-Kurt

bargainguy

Was that the CrissCross? I remember working on a few of those, with the stay-mounted RD, butterfly bars & twist shifters.

It was a decent enough bike (for a hi-ten 90's hybrid), but the stay mount RD didn't function any better than a hanger mount RD.

mstateglfr 

No, that isn't the difference between riding in a city and riding on rural roads. My comments were specific to riding in a city/suburbs in roads and not on protected paths. Sitting at stoplight, I have never wished for igh. This applies to all my riding in my mid-sized city and metro as well as all my riding in the city of Chicago and suburbs(clearly congested). It applies to riding roads where you are part of traffic and following traffic laws.

As for having to wait for the chain to move from cog to cog, good lord. Shifts are perceivingly immediate on my bikes- you click the shifter while pedaling and the shift happens right then. It's funny- igh is not thought of as a performance bit of bike tech, yet you are saying shifting that is faster than what pros use is needed to even to ride around a city.

With a derailleur, I can do exactly what you describe- shift to an easier gear while coasting and anticipating having to slow, and then shift back if I don't need to slow. That is easily done with a derailleur.

Your claim that shifting may be slower with ramped components, yes I understand why- the chain 'waits' for the ramp. In practice though, there is just no difference. And shifting is significantly easier with ramps, especially under load. It reduces wear too.
Since we don't ride in a vacuum, let's not claim ramped shifting is actually slower or somehow less ideal.



I will try to be on the lookout for the next time I am riding in traffic within a metro and think to myself how the experience would be better if I could just shift while stopped. It'll be awhile, I'm guessing.
When riding thru a downtown area wherr lots of stopping is possible, I do keep the bike in an easier gear so starting is faster. It works since I'm also not usually going fast. I don't think I would be riding faster if I had an igh drivetrain as I ride at a speed that matches the conditions around me.



This has been enlightening. I have found out you know more about where and how I ride than I know. And I learned a properly tuned derailleur doesn't shift fast enough for riding in a densely populated area.
I'll have to remember to tell my friends that live in downtown Chicago and commute all over in bike that they are doing it wrong, or that they ride in an area that isn't actually congested.

cudak888 

I never took issue with your personal preference for derailers, but it seems as if this discussion has turned in this direction.

That's unfortunate, because you've brought up some excellent counterpoints about the speed of high-end Shimano equipment which I do agree with and wouldn't mind discussing further - but not if it's going to involve unnecessary passive-aggressive remarks over how either of us chooses to ride.

-Kurt

sincos

IGBBs are quite a bit heavier, more expensive and rather less efficient than IGHs, which are rather heavier, more expensive, and a little less efficient than derailleurs. So there's that.

RiddleOfSteel

Yeah don't expect me to develop one or adapt to one unless it's practical in weigh, price, and performance [so says the man with enough Dura-Ace on his bikes....."But I got it for a good deal!" Sure, whatever makes you and your logic sleep at night...].

Road Fan

AW? Just starting with the big parts we can see, a common first step with an AW is to go with the 1950s alloy hub shell, maybe with the flanges thickened to match modern spokes well. What suggests itself to me next is drillium the rear sprocket. If it is spoked the optimum strength to weight to diameter (roller chain friction) should be found, stuying the trade-offs. You could even make a steel gear ring and swage it onto an optimally lightened Al center for the sprocket, again optimized.

Inside the AW IGH, over the years S-A has done work to max out the capability of the "spawn" of the AW, with some units up to 8 speeds.

Is there not already enough to work with?

Now, minimum mass? That's real engineering, and not the kind I'm practiced in!

Regardless of what I can design versus what I can't, I really like the idea of using internal lightweight aluminum inserts to reinforce an aluminum shell. But milling such contours into a shell might be better. Hydro-milling? Electro-milling?

Time for this one to go home!

tcs

Not seeing how this 'swinging twin idler pulleys' design copies the XC Sport.

tcs

"Light, strong, cheap: pick two."

How much is the market willing to pay for three speeds?

tcs

Lots of experimenting/patents on IGBB in the 1890s and 1900s. If it's not too much Vintage for this thread, here's a 1937 Adler: https://onlinebicyclemuseum.co.uk/19...gang-type-157/

The cats that designed the Pinion were quoted as asking, "Motorcycles have centered-mounted gearing. Why don't bicycles?" IMO the question they should have asked was, "Clever folks have tried center-mounted gearing for bicycles off and on for 120 years. Why has it never worked out before?"

cudak888 

Well, preferably something more refined than the Nuvincis. I've tried them and though they work, there's something really cheap and plasticky about how the resistance selector feels.

The other issue with it is standardization. Despite all the new bottom bracket designs out there, nothing has really caught on to replace the universality of the English-threaded BB. The only thing that's giving it competition are mid-drive e-bikes, but even those are coming with square taper bottom brackets.

Old standards die hard when they work.

I should have clarified with the SRF-3 over the AW. That's the current aluminum-shell variant of the 1980's N.I.G. AW and really the starting point for any current attempt at AW modifications.

Either way, I'm sure someone can engineer a lighter 3-speed hub. Heck, Shimano arguably has with the Nexus 3. Even at that, gear spacing really doesn't become ideal, even for flat terrain, until you're at the Nexus 8.

All the Sturmey designs after the S5 series diverge quite hard from the AW internally (some may argue the current 5-speeds are inspired by them; there's truth to that), but their 8-speeds have very little in common. They use control pawls to engage each gear ring, similar to the 8-speed Nexus.

I wonder how they've managed to reduce drag in that system.

Also, does the world really need a 10 tooth cog that will wear excessively quickly and not be available as a service part without replacing the entire cassette?

Do you mean "how much is the market willing to pay for IGH hubs?"

Admittedly, it's a hard sell, but it's not as if any current manufacturer short of Rohloff has tried to manufacture an IGH aimed at performance, and we're in a world dominated by derailers in general, excluding some countries that are heavily invested in city bicycles (hello JaccoW!). Shimano's Alfine 11 is marketed as high-end, but it's closer to a fancy Nexus 8 all-around hub than anything else.

-Kurt

base2 

With the advent of 3d printing in modern manufacturing it's hard to believe Sturmey Archer isn't already on this, somehow.

I'm imagining honey-combed aluminum inserts in the planets & "spoked" ring gear with material removed forming a hollow under every gear tooth & pressed into a windowed shell, hollow pins & axles & tolerances so tight an oil bath would be used.

Basically all the extraneous material left due to excessive conventional manufacturing cost could be removed with the click of a mouse. Even a 20% reduction in weight would be compelling.

I have IGH's & even though they are fine, I still wince at the sight of the weight listed on the spec sheet. Ouch!

georges1

I wonder what is the usefulness in a such design kinda like in the shadow derailleurs. Non shadow derailleurs with on pulley worked before that.

base2 

Shadow derailleurs place the entire derailleur under the shadow of the bike when viewed from above. There's nothing to stick out to get hit by a rock or trail side debris. Tucking the derailleur closer to the centerline of the bike means less rides cut short due to busted hangers.

The advantage to the new design this thread is about is even more chain take up. This could be used to support even larger cassettes than now, or the same cassettes with a smaller derailleur. A smaller derailleur wouldn't hang down so far & would be a boon to small wheeled folder bikes or be that much further from injury by trail side debris in normal sized wheels.

Darth Lefty 

This is probably a response to the LAL Supre derailleur, which is now being sold on a Nicolai MTB. It has a single idler gear by the cassette and it offloads tension and clutch duties to a separate sprung and damped arm on the frame. It confers some advantages over a conventional derailleur for a long travel MTB. It's fully protected inside the swingarm triangle, and nearly eliminates chain growth by putting the lower run higher up in line with the pivots. But it absolutely does not mount on the old Campagnolo style hanger.

https://lalbikes.com/
https://en.nicolai-bicycles.com/nucleon-16/

georges1

Interesting and thanks for the explanation. But there were already rear derailleurs with big cages and small cages which were doing the job well back then and even now . The older deore xt and even non modern shadow xt trekking derailleurs can take abuse quite well. The latest road shimano groups have taken the shadow design which aesthetically I am a not fan of anything made after the dura ace 7900 and ultegra 6700 but that is my personal point of view of course.

tcs

Kindernay.

tcs

Clever folks are trying. Not to be too judgemental, but clever folks are trying and so far failing:

cudak888 

Fascinating! Thank you for pointing those out. I have a new rabbit hole to go down.

-Kurt

tcs

There's also the new 3x3 Nine hub:

https://www.3x3.bike/en/nine-gear-hub/