Hub gear range?

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Mick F
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Re: Hub gear range?

Post by Mick F »

Yes, even though expensive, it's still attractive.
My main gripe with them is that the gear ratios are too far apart and the total range is too wide.

I have no real need for less than (say) 25" bottom gear, but that would make my top gear 25 x 5.26 = 126" ie a bit useless.
Therefore, instead of paying a fortune for 14 gears, I only have 12 or 13 useable.

If Rohloff did a hub that I could get the bottom at 25" and the top at 110" I may be very interested.
I emailed them some time ago asking if they could produce a close ratio road-aplicable hub, and all I got was the curt reply, "No".
Mick F. Cornwall
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simonineaston
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Re: Hub gear range?

Post by simonineaston »

Brucey wrote:I've not had the SA 3xcassette hub apart but the SA hub is also based on the standard 3s, and unlike other current 3s hubs I think it does not have an actuator plate in it!
http://www.sturmey-archer.com/files/catalog/files/299/PART%20LIST%20-%20CS-RF3%20CS-RK3.pdf
This is good news and it may well mean that the CS-RK3 (disc) and CS-RF3 (rim brake) are actually a bit more reliable than the standard version of the 3s hub, in which actuator plate failure is depressingly common. If you have an actuator plate hub, best not backpedal when changing gear, and best to change the actuator plate ( a £1.50 part) every year or two.

As Bob indicates, the basic SA 3s hub is basically a strong unit in terms of its torque-bearing capacity; (for many years they have been used on tandems without much trouble). I think that in terms of load-bearing capacity, they are the strongest design if you have to choose between SRAM, SA and Shimano. Unless there is a flaw in the cassette-bearing parts of it, I'd expect the 3x9 hubs to be equally strong.

I'm planning this set-up on my next touring build, so this sounds Good. :-)
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Brucey
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Re: Hub gear range?

Post by Brucey »

Mick F wrote:Yes, even though expensive, it's still attractive.
My main gripe with them is that the gear ratios are too far apart and the total range is too wide.

I have no real need for less than (say) 25" bottom gear, but that would make my top gear 25 x 5.26 = 126" ie a bit useless.
Therefore, instead of paying a fortune for 14 gears, I only have 12 or 13 useable.

If Rohloff did a hub that I could get the bottom at 25" and the top at 110" I may be very interested.
I emailed them some time ago asking if they could produce a close ratio road-aplicable hub, and all I got was the curt reply, "No".


I think that they would get many more requests for a hub with a wider range, even if the gears were further apart, than they do of the sort you propose.

If you set the Rohloff up with the right ratio you can have a range from 21.5" to 113", which means (more or less) you have 13 gears that you want, plus another one for emergencies.

I personally think the gear intervals are just fine for touring purposes. If you had your (25" to 110", 14s) 'dream hub' then the gears would be at 12% intervals (instead of 13.6%). I would suggest that one way of accommodating this terrible 'gap' in acceptable cadence might be to adjust your speed by +/- 0.8% when this arises.... :wink:

cheers
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syklist
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Re: Hub gear range?

Post by syklist »

Brucey wrote:I personally think the gear intervals are just fine for touring purposes. If you had your (25" to 110", 14s) 'dream hub' then the gears would be at 12% intervals (instead of 13.6%). I would suggest that one way of accommodating this terrible 'gap' in acceptable cadence might be to adjust your speed by +/- 0.8% when this arises.... :wink:

From personal experience I would agree that the gear intervals are fine for touring. The equal intervals between all the gears is actually a very nice feature. To get fit this year I started fetching Syklist Junior from the kindergarten in the spring using my Dahon with a 24 speed DualDrive. I'd forgotten how annoying the uneven jumps between gears with a derailleur based system are and how much they disrupt your cadence when a relatively large interval appears. The Nexus 8 hubs are better than a derailleur in this respect as there is only one bigger interval (between 5th and 6th IIRC) the rest being pretty much the same.
So long and thanks for all the fish...
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Re: Hub gear range?

Post by Brucey »

I think that you do get used to different things; if I use an IGH with a wide interval for a few weeks anything else seems to have the gears too close together until I get used to that, and then it is all change again when I go back the other way.

I ride often on a bike with an unevenly spaced set of IGH gears and there are not many gears so I know which gear I'm in at any given time, so I know which interval to expect next.

However when I've had many more gears with evenly spaced ratios, I've often lost track of which gear I'm in, and have similarly been surprised when there is an unevenly spaced ratio.

As per the above post there is no way of avoiding unevenly spaced ratios with a derailleur based system. However there are ways of mitigating it;

- the half-step system. Works OK with a 5s or 6s block but the geometric series required for 7s or higher becomes impossible IMHO, and a third (granny) ring will usually have widely spaced climbing ratios (a one-and a half step if you like). Not my favourite system because the double-shifts required to use it properly are a PITA.

- the duplication system. Here you have a freewheel with (say) 2T intervals in the mid-range and enough overlap between the chainrings that you have intentional duplication of gears. This way you can have three chainrings, one for climbing, one for the flat and one for downhill/tailwind, and with each you can ride mostly in the 2T interval part of the freewheel. This doesn't give exactly uniform intervals but they are pretty close to that over much of the range. To get a wide enough range for loaded touring then 3T and 4T intervals are required at the bottom end of the freewheel and these are unevenly spaced. I have a touring bike set up like this; 28,44,50T chainrings means that I have many of the same ratios on a 2T interval freewheel by using either the 50T or 44T chainring, and a choice of chainline. With this system shifting between the two larger chainrings has an almost identical effect as one shift at the back, which eliminates most double-shifts. Not as easy to use as a rohloff, but for many years 'good enough' for me. :wink:

cheers
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syklist
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Re: Hub gear range?

Post by syklist »

But the point is, with all attempts to even out gear intervals on derailleurs you end up having to think even more about which combination of the two gear changers you have to use for the next change.

With a Rohloff you get the even spacing and you never have to think about gear changing, apart from twist one way to get a higher gear, twist the other way for a lower gear. No contest. :)
So long and thanks for all the fish...
Brucey
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Re: Hub gear range?

Post by Brucey »

syklist wrote:But the point is, with all attempts to even out gear intervals on derailleurs you end up having to think even more about which combination of the two gear changers you have to use for the next change.

With a Rohloff you get the even spacing and you never have to think about gear changing, apart from twist one way to get a higher gear, twist the other way for a lower gear. No contest. :)


sure, but keeping track of which of three chainrings I am/should be in isn't such hard work, and with the duplication system there is only one lever to move/think about after that. I agree it is not perfect but have yet to become mentally exhausted by this... :lol:

BTW not that I wish to drag anyone else into my own personal vortex, but I do adjust my derailleur gears (if I have a choice) to favour a better chainline . I similarly begrudge riding for extended periods of time in IGH gears that I know/can feel to be inefficient. This effect is quite noticeable to me on non-red band Nexus 8 hubs, for example, in which gear 4 is noticeably draggy, even in well-lubricated hubs.

I don't own a Rohloff, and I've not ridden one for long enough to know if I would ever feel the same way about it; reports of the measured variations in gear efficiency are not consistent, any more than different people's ability to perceive it might be. But I have heard some owners at least complain about the noise in 1-7, so I suppose it is possible that I'd end up knowing which gear I'm in just from the noise etc.

cheers
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pwa
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Re: Hub gear range?

Post by pwa »

It may vary, but with my Rohloffs the drive train makes a buttery whirring that is quieter than my derailleur systems sometimes are. It may sound a bit different for a minute or two, but it is not noisy. Gear 7 is subtly noisier, but still not noisy. Efficiency is sufficiently reduced to cause concern for Chris Froome on Mont Ventoux, but I can't detect much difference.
geocycle
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Re: Hub gear range?

Post by geocycle »

I never give the noise a second thought but even after 25,000 miles it is still there in gears 6 and 7. Most of the time road noise is far greater but on smooth Tarmac and amplification through a steel frame it can be heard. Here is a video of what I guess is a newish hub. You get an idea for the sorts of noises and how it functions http://youtu.be/yx-7_pfMGJc
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Mick F
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Re: Hub gear range?

Post by Mick F »

I think about stuff when I ride, and I think about stuff regarding the conversations on here. :D

Today, I was climbing a long hill. Most of the early part, I was in second gear.
28 front and 27 rear = 27.1"

Further up, I clicked to second gear ......... and was happy there for the most of the hill.
28 front and 30" = 30.5"

It made all the difference, and later, switched to 28f/21r = 34.9" for the rest up to the top.

How would I have got on with a Rohloff?
Just lived with it and got used to it?
Mick F. Cornwall
Brucey
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Re: Hub gear range?

Post by Brucey »

well

27.1" to 30.5" is a +12.5% increase and
30.5" to 34.9" is a +14.4% increase

vs the even 13.6% increase in gears that you would have with a Rohloff.

I'm not sure I would have noticed the difference tbh.

cheers
Last edited by Brucey on 25 Sep 2015, 9:23pm, edited 1 time in total.
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pwa
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Re: Hub gear range?

Post by pwa »

Mick F wrote:I think about stuff when I ride, and I think about stuff regarding the conversations on here. :D

Today, I was climbing a long hill. Most of the early part, I was in second gear.
28 front and 27 rear = 27.1"

Further up, I clicked to second gear ......... and was happy there for the most of the hill.
28 front and 30" = 30.5"

It made all the difference, and later, switched to 28f/21r = 34.9" for the rest up to the top.

How would I have got on with a Rohloff?
Just lived with it and got used to it?


I expect that's correct. There are some folk out there who go everywhere on one gear! Compared to that, trying to find the right gear out of the 14 you have at your disposal seems okay. Personally, I don't mind adjusting my cadence a little to make a gear work, but maybe you are different in that particular way. Each to his own.
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Mick F
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Re: Hub gear range?

Post by Mick F »

Thanks guys! :D
I did wonder what the difference was.
Mick F. Cornwall
Brucey
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Re: Hub gear range?

Post by Brucey »

FWIW if you use (say) 45/16 input on a Rohloff you get gears of

21.2
24.0
27.3
31.1
35.2
40.1
45.6
51.8
58.8
66.9
75.9
86.2
98.1
111.4

I think the bottom end gears are very similarly spaced to what you have now.

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Mick F
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Re: Hub gear range?

Post by Mick F »

Yes, you a correct.
(26.5mm diameter)

1st 24.7"
2nd 27.5"
3rd 30.9"

At the top end, the Rholoff is too wide I reckon.
These are mine.
28th 100.3"
29th 108"
30th 117"
Mick F. Cornwall
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