Why is there no 6 speed IGH

[Brucey]

Wouldn't a step-up 2x stage be more efficient?

do you think there is very much difference between a gear-down and a gear-up?

cheers

[Brucey]

re SA five speed hubs; these have selectable sun pinions but are otherwise like a 3s hub. This means that there is only one ring gear and the gear trains cannot be put into series, so only five gears.

A potted history of the SA 5s gear is as follows (from memory);

- SA patented a 5s gear in about 1930
- SA produced prototype 4s gears before WWII
- SA mass-produced FG and FW 4s gears starting around 1947 , also FM and FC gears some with wrought aluminium shells.
- SA 4s gears had been converted (by amateurs) to 5s gears by around 1950
- SA produced 'SA5' gear around 1966 with LH pushrod/bellcrank
- SA produced SA5-I gear around 1978 with LH pull chain
- SA produced SA5-II gear around 1980 with LH pull chain and revised springing
- SA produced cast Alloy shelled hubs in the 1980s
- SA produced the ill-fated 5-star hub in the late 1980s/early 1990s (final -and arguably worst- twin toggle 5s hub)
- SA produced the 'sprinter' 5s hub with dog locking suns, and single toggle operation mid 1990s
- SA produced ball-locking 'sprinter' hub late 1990s
- SA produced revised versions of ball-locking sprinter hub in Taiwan ~2002-2010
- SA produced X-RD5 (W) hubs with dog locking suns ~2010 onwards.
- 2014 SA announce new C50 5s hub for electrically-assisted bicycles. Nearly all other 5s hubs are not listed in the 2015 catalogue but (for now) some seem still to be available.

All the 5s hubs that made it to production (apart from the (W) hubs, and converted FM,FC hubs) have the same ratios.

cheers

[SA_SA_SA]

...do you think there is very much difference between a gear-down and a gear-up?...

I think I remember reading somewhere that in bicycle wheel epicyclic gears stepping up was more efficient than stepping down: I think either/or both in blurb/reviews about the SA 8 speed ot Tony hadland's book.

[[XAP]Bob]

it's an SA 5 speed - with a standard 3 speed, but two selectable sets of planets -

can you remember the model/type?
tks

[Brucey]

...do you think there is very much difference between a gear-down and a gear-up?...

I think I remember reading somewhere that in bicycle wheel epicyclic gears stepping up was more efficient than stepping down: I think either/or both in blurb/reviews about the SA 8 speed ot Tony hadland's book.

that may be the case, but if so I've failed to notice that when looking at the available test data. Maybe I should have another look. If anyone knows of any test data that shows this clearly, do say.

On the face of it the hypothesis seems unlikely in that the same gears might be used with the drive simply reversed, the only difference (for the same net gear/wheel speed) is that with a reduction gear train, the average speed in the gear train is higher, and the loads are lower. Possibly (esp with thick grease and poorly shaped gear teeth) this might appear to be less efficient. Or perhaps it is that (in the real world) something else affects the efficiency, eg, for the same net gear, (esp for small wheelers) a gear-up hub will usually employ a more efficient chain and sprocket?

I have always taken the view that because (outside of alpine touring) most riders do most cycling on the flat, it is most likely best for overall efficiency if the most used gears are also the most efficient ones. That is also pretty much how Rohloff have set their hub up, too. I note with interest that the Rohloff is one of only a few gears on the market where a traditional (i.e. up or down gearing planetary geartrain) is used in series with a reduction gear to achieve a wide gear range with good overall efficiency. My proposed 2x3 gear does the same kind of thing, but in a much simpler way, obviously.

BTW Bob's 5s gear is one from the 1980s, essentially S5-II mechanicals in a different looking shell, I think. 90% of the internals would be hard to tell apart from a 1947 FW hub.

cheers

[[XAP]Bob]

BTW Bob's 5s gear is one from the 1980s, essentially S5-II mechanicals in a different looking shell, I think. 90% of the internals would be hard to tell apart from a 1947 FW hub.

In which case it is slightly later than the advertised age of the bike (1975 IIRC) - but no less lovely for it. And to be fair the bike now has an ahead adaptor and specialised drop bars (i.e. bars that I had in the garage)

As a gearing system goes I really like it - wide enough range for reasonable speed, and the ability to get up most hills around here - simple simple mechanicals, with a neutral gear to leave the bike parked in (just a further deterrent to theft)

The hub now gets regular injections of Brucey's Magic Grease (as does the 3 speed in my trike).

[Brucey]

I'm thinking it is this one;



but I've not checked 100%.

This parts breakdown
http://www.sturmey-archerheritage.com/images/photos/pic-131.1.jpg
indicates that they used S5-2 mechanicals in an aluminium shell and renamed the hub simply 'five speed'.

cheers

[[XAP]Bob]

Looks right, different shift levers also suggest that one or the other are a later addition.

[Brucey]

there is a suggestion that the alloy shell appeared first in 1983. Most hubs had a date mark on them, but on some it was only ever printed on the hubshell, so can easily get rubbed off.

cheers

[[XAP]Bob]

I can't see a date mark on mine, and the oil port is central (rather than over to one side as indicated in the internals diagram) but I expect mid eighties isn't an unreasonable guess.

I ought to look for a frame number and see if that can date the frame itself - I know the brakes are new, the stem/bars etc. The aero levers aren't new by a long stretch, but they are aero, they're probably of similar age to the bike and hub (but unrelated until recently)

This seems as good a place as any for me to record the following:
the 531 label on the bike is referenced second from bottom on page 6 of http://www.hlloydcycles.com/531%20history.pdf:
"Plain gauge main triangle. Medium spec cycles. Used 1977 to 1982
531W77-82 42 x 32 mm approx"

[jimlews]

And which is or was the best Sturmey Archer Five speed?

My vote would go with the FW though it isn't a five; or is it?

I never found much use for the + 50% top gear of the S5 however many levers were needed.

[SA_SA_SA]

Would the 'Brucey Special' 2x3 6speed hub have one or two control cables?

[[XAP]Bob]

Would the 'Brucey Special' 2x3 6speed hub have one or two control cables?

Three obviously

[Brucey]

And which is or was the best Sturmey Archer Five speed?

My vote would go with the FW though it isn't a five; or is it?

I never found much use for the + 50% top gear of the S5 however many levers were needed.

You can set the hub up with 3rd or 4th as 'normal'; the former makes 5th less useful but lowers the average losses in the hub in all but rather hilly terrain.

I think that the S5 was a good hub and so are converted FWs/FGs, provided the LH pushrod is done in the right way.

The S5-II/III hubs are OK but are more likely to slip than the above hubs.

The ball-locking sprinter is a good hub up to a point; I don't think it is any stronger than the above hubs but it is slightly easier to use.

All the single-toggle 5s hubs are to some extent let down by internal build quality, lubrication, shifter, and instruction manual issues. Basically how they tell you to shift will definitely break the hub. If you follow the instructions for a 1947 FW or FG hub, you won't be so likely to break it....

cheers

[Brucey]

Would the 'Brucey Special' 2x3 6speed hub have one or two control cables?

two, I reckon.

cheers