shimano 11 speed efficiency

[SA_SA_SA]

In the cycle news section, the helical gears in the 11 speed shimano hub gear were described, as increasing efficiency, but the page is not marked, as being written by Chris Juden: so is claim this correct?

Also, I noticed the 10 speed STI drop lever review contained no lament about complexity and roadside fixabilty: even Dawes horizons seem to have STI rather than bar end shifters: (why not Kelly takeoff shifters, these would be better)?
On my drop bar's, I just use thumb shifters the 'conceptional equivalent' of a minoura lamp bracket bar.

Aren't 10 / 11++ speed derailleurs going to be so fragile / indexing sensitive to dirt, that in future an 11 speed hub will look better for touring? I still use 6 speeds!!

[TrevA]

My son uses Ultegra 10 speed on his cyclo-cross bikes (he has 2 matching ones). On muddy courses, these get covered in gloop/mud/dirt, but the indexing still works fine.

I personally think that roadside fixability is over emphasised (sp??). I've not had any trouble with my 9 speed STI's, nor my wife's 8 speed STI's. Aren't bar end levers just as liable to get bashed in transit?

[CJ]

In the cycle news section, the helical gears in the 11 speed shimano hub gear were described, as increasing efficiency, but the page is not marked, as being written by Chris Juden: so is claim this correct?

Dan Joyce doesn't actually say that. After the information that there is no direct-drive, that all the ratios involve spinning hub internals, he says:

Nevertheless, efficiency should be good. The 11-speed uses helical gears, whose teeth should engage more smoothly than the straight-cut profiles of standard gear teeth. And like Rohloff, the internal gears are lubricated in oil rather than grease.

As a matter of fact it's the oil that should make the Shimano 11-speed just as efficient as the similarly lubricated Rohloff, whilst the main effect of helical gears will be to make it less noisy.

Dan wrote that after we'd chatted about it on the phone, and whilst I'd have probably put it differently, I did not think when I saw the proofs that those two points were so conflated that they really needed to be teased further apart. I'm not even sure I could put it better without increasing the word-count beyond the allotted space.

[CJ]

My son uses Ultegra 10 speed on his cyclo-cross bikes (he has 2 matching ones). On muddy courses, these get covered in gloop/mud/dirt, but the indexing still works fine.

And I'm sure that he cleans the bike pretty thoroughly at some time during the six days that elapse between each weekend's cyclo-cross race.

An enjoyable cycle tour ideally involves a far different ratio between riding time and cleaning time - i.e. day after day of the former and none at all of the latter!

I personally think that roadside fixability is over emphasised (sp??). I've not had any trouble with my 9 speed STI's, nor my wife's 8 speed STI's. Aren't bar end levers just as liable to get bashed in transit?

An excellent point. Indeed they are just as vulnerable. The best shifters for drop-bar touring were SunTour Command shifters, that were not only more accessible from the tops but also protected from damage in transit. Bar-end are merely the least bad shifting option amongst the crumbs that presently fall in our direction from the racing man's table!

Ruggedness is only part of it. An ability to thrive on neglect is also important for practical everday use by normal people, who do not see why a bike should necessarily require more attention to its maintenance than a car.

[SA_SA_SA]

There are 'interrupter' brake levers for drops (the modern safe (non-terminal) extension levers):

if no command shifters/Kelly take off levers, and using combined drop brake/gear levers
why not have emergency 'interrupter' friction gear levers on the down tube: these would be disconnected until the fancy units broke/went out of adjustment, eg due to rear/front mech damage preventing indexing, when they could be switched in allowing
gear changing to continue. Someone would need to design and make them though.... so perhaps more chance of Shimano (or SRAM, who seem innovative) etc re-inventing command shifters.

Or you could fit minuoura lamp bar and thumb / twist shifters. Or twist shifters might go in bar end position with some sort of 22.2mm insert .

[Si]

There are 'interrupter' brake levers for drops (the modern safe (non-terminal) extension levers):

if no command shifters/Kelly take off levers, and using combined drop brake/gear levers
why not have emergency 'interrupter' friction gear levers on the down tube: these would be disconnected until the fancy units broke/went out of adjustment, eg due to rear/front mech damage preventing indexing, when they could be switched in allowing
gear changing to continue. Someone would need to design and make them though.... so perhaps more chance of Shimano (or SRAM, who seem innovative) etc re-inventing command shifters.

Or you could fit minuoura lamp bar and thumb / twist shifters. Or twist shifters might go in bar end position with some sort of 22.2mm insert .

Surely it'd be much less hassle and cost just to carry a spare band on DT shifter in your luggage?

[robinlh]

Because I spend most of my time when touring holding the bars on the straight bit or around the top bend,and very little on the brake levers unless I'm braking,I'm proposing to put some 8speed rapidfires next to the stem.
Go on,tell me why I should'nt,it'll save me ruining some perfectly good cork tape!
Robin

[robinlh]

One small point,are not helical gears less efficient than straight cut teeth?
R

[hubgearfreak]

One small point,are not helical gears less efficient than straight cut teeth?
R

i believe so, but they're quieter.

although having ridden the offerings from SA, sram rolhoff & shimano, i don't recall the meshing of teeth being particularly annoying.

it's a marketing thing. oooh, helical gears. who cares what it means if it sounds good?

[stoobs]

One small point,are not helical gears less efficient than straight cut teeth?
R

I thought that, too, although it could be only a marginal effect.

While I can understand helical gears being much quieter than spur gears in car gearboxes (witness old Land Rovers in first and second gear, and I think early Morris Minors IIRC, with their distinctive whine), does it make that much difference on a bike?

[Si]

Because I spend most of my time when touring holding the bars on the straight bit or around the top bend,and very little on the brake levers unless I'm braking,I'm proposing to put some 8speed rapidfires next to the stem.
Go on,tell me why I should'nt,it'll save me ruining some perfectly good cork tape!
Robin

will they fit the bar diameter?

[raymanh]

One small point,are not helical gears less efficient than straight cut teeth?
R

i believe so, but they're quieter.

although having ridden the offerings from SA, sram rolhoff & shimano, i don't recall the meshing of teeth being particularly annoying.

it's a marketing thing. oooh, helical gears. who cares what it means if it sounds good?

And helical gears are more durable/will last longer/wear less; bigger contact area

[rogerzilla]

The helical gears and oil won't add *that* much efficiency. In tests, grease-lubricated hubs don't significantly underperform oiled ones (all SRAM hubs are greased).

What matters is the number of epicyclic geartrains in series at any given time. The best epicyclic is about 97% efficient, and a stack of three is therefore only about 90% efficient. A design that avoids this by using compound planets and multiple suns that can be clutched or declutched to the axle, on a common gear ring, is better if it's done properly. Sadly the SRAM 7-speed in Berto and Kyle's tests was broken and couldn't be measured properly, because it actually uses triple compound planets.

[TwoWheelsGood]

And helical gears are more durable/will last longer/wear less; bigger contact area

They can supposedly handle more torque as well, although I've seen a 2:1 recommendation mentioned for the Alfine 11 in respect of the front chainring/rear sprocket combination.

More information relating to gears in general can be found on Wikipedia (usual accuracy disclaimer applies), and this mentions the advantages and disadvantages of helical gears. It's very likely that any oil supplied by Shimano for the Alfine 11 will contain additives designed to offset the effects of sliding friction, therefore if someone tries to use an Alfine 11 with cheaper/generic oil, the hub might suffer from a reduction in efficiency as a consequence.