Internal Geared Hubs?

[Alpe d'Huez]

Has anyone here used internal geared hubs? Like the Shimano Alfina 11 and Nexus 8? As I'm getting older, slower, heavier (ahem) and commutes and rides to the park are often "training", I'm looking at a newer more casual bike that I can still get out on, and these seem appealing in some of the hybrids like the Raleigh Cadent or Misceo, or the Diamondback Insight. But I have some questions.

First, I can't seem to interpret the gearing. For example, Shimano's page lists gear ratios for the Nexus as:

Gear Ratio 1: 0.527 - Gear Ratio 8: 1.615

I look at that and think, wait a minute. That's like having a crazy bailout 24x40 as 1st gear, and a 34x22 for 8th gear. That can't be right, often 1st gear (you know, the one for going up hills) on a road bike is in the 39x23 range. With these gear ratios your top speed on the flats would be maybe 12mph at 120rpm! I must be calculating the math wrong, even though I used this site. Especially when you look at this chart from Raleigh, which shows something different when looking at the gear inches:

Anyone have any better knowledge, or links?

Also, Shimano likes to say the gearing on these hubs can be custom changed to your needs. But I can't seem to find out how, outside of putting a larger/smaller chain ring on the front.

In case anyone wondered, I'm weeks, maybe months from buying. And before I do I'll get out to the LBS and ride some of these. But I thought I would ask around.

 

[Aapjes]

Use this calculator instead:

http://sheldonbrown.com/gears/internal.html

You change the gearing by choosing a different rear sprocket. The possible sprockets are listed on the shimano site (Sprocket Options). Alfine also allows you to choose between a 39 or 45 tooth chainring. For instance, a 45/18 Alfine-11 combo gives you 90 rpm speeds between 9.3 mph and 38 mph.

Keep in mind that these hubs are intended for tourers & commuters, so the gaps are big. Way bigger than a road derailleur setup.

Some gears are more efficient than others, depending on the number of planetary gears involved to create the proper gear ratio. This is not linear, so a gear can be much more efficient than the one next to it. If you are smart, you choose the gearing so you will use an efficient gear most of the time. A new hub is less efficient, due to excess metal on the gears, which will grind off over time (a few hundred miles max). For optimal longevity, you should ride in different gears a while and then replace the lube (with the metal shavings). The general rule is that a hub is less efficient than a derailleur setup, but over time they grow closer (the hub becomes more efficient over time and the derailleur system becomes less efficient as it wears). The hub will always have a penalty though. Alfine is more efficient than Nexus.

Some good reading:
http://hubstripping.wordpress.com/geared-hubs-vs-derailleur/
http://www.bikeforums.net/commuting...-hub-comparison-sram-s7-vs-shimano-nexus.html
https://thelazyrando.wordpress.com/tag/alfine/

 

[King Boonen]

My brother has an alfine 8, he likes it but lives in Cambridgeshire...

He's had it for a good few years now and has never had any problems with it, gets used in all weather and runs like new still. First to second is a big jump, the rest are pretty smooth in the 11 I think. Only problem is if you are used to shifting under load you'll have to change your habits.

If you want a go anywhere bike the real option is the Rohloff, but it's very expensive.

 

[Bustedknuckle]

Has anyone here used internal geared hubs? Like the Shimano Alfina 11 and Nexus 8? As I'm getting older, slower, heavier (ahem) and commutes and rides to the park are often "training", I'm looking at a newer more casual bike that I can still get out on, and these seem appealing in some of the hybrids like the Raleigh Cadent or Misceo, or the Diamondback Insight. But I have some questions.

First, I can't seem to interpret the gearing. For example, Shimano's page lists gear ratios for the Nexus as:

Gear Ratio 1: 0.527 - Gear Ratio 8: 1.615

I look at that and think, wait a minute. That's like having a crazy bailout 24x40 as 1st gear, and a 34x22 for 8th gear. That can't be right, often 1st gear (you know, the one for going up hills) on a road bike is in the 39x23 range. With these gear ratios your top speed on the flats would be maybe 12mph at 120rpm! I must be calculating the math wrong, even though I used this site. Especially when you look at this chart from Raleigh, which shows something different when looking at the gear inches:

Anyone have any better knowledge, or links?

Also, Shimano likes to say the gearing on these hubs can be custom changed to your needs. But I can't seem to find out how, outside of putting a larger/smaller chain ring on the front.

In case anyone wondered, I'm weeks, maybe months from buying. And before I do I'll get out to the LBS and ride some of these. But I thought I would ask around.

The hubs are foolproof, work well. As for gearing, ride one to see if the gearing suits you...the chart means not much...bunch of numbers.

 

[Alpe d'Huez]

I think you're right in that I'll just have to ride a couple to check them out. I do like the idea of it though, especially as I get older and don't ride as much, or as fast, as I used to. Though I will ride in wet or nasty weather. The Rohloff is too rich for my blood.

Thanks Aapjes for the links and explanation about the rear sprocket and combinations. Just looking at some more math, the Shimano hub ratio numbers mean essentially nothing because they are not connected to any sort of length (ie, no sprocket or chain ring factored in).

Using various sites I've concluded that the stock on the bikes I listed, just sticking with the Nexus 8 for example, are more akin to having a 44 chain ring on the front, and an 8-speed cogset ranging from 13-39 on the back. The big jump indeed seems to be from 1st to second, which would be about a 32-33 cog. The 11 speed is similar, just more. But I think you're correct in that the real key is to find the gearing so you will use an efficient gear most of the time and go from there.

 

[Aapjes]

Rohloff is what happens when Germans say: "Ok, now we stop kidding around." Very consistent gaps, top notch reliability and very good efficiency for a IGH (90-93%). It would be my choice if I would do a non-stop around the world cycling trip. But it is too expensive for more casual applications. Another fun thing to look at is the NuVinci N360, which is a CVT for bikes. So it gives continuous shifting and you don't actually have individual gears. Wouldn't recommend it for most people though due to very poor efficiency (~80%). But a very intriguing concept.

Anyway, a lot of people like geared hubs in theory, but it's a choice with pros and cons. In many ways it is like a single speed setup, which give a lot of advantages. They really shine for bikes ridden in bad weather a lot with good mudguards, tough tires, chain guards, etc. My experience though is that maintenance on these build up bikes is a real pain. Just getting the rear wheel out can be a job unto itself on a build up Dutch city bike. The big upside of an IGH is that you don't have to do a lot of maintenance, though.

Anyway, when looking at the bikes you linked I noticed that 2 have rim brakes. Nexus doesn't allow for disc brakes, so rim brakes are the only option for steep, longer climbs (rollerbrakes are an option on a Nexus and are common in Holland). These are not great for bad weather of course. Alfine allows for disc brakes. The Misceo has disc brakes, but also has a Gates belt drive instead of a chain, which is another big topic unto itself. You can read more here:
http://cyclingabout.com/index.php/2012/05/carbon-belt-drive-everything-you-ever-need-to-know/

PS. This seems nice too: http://cremecycles.com/shop/ristretto/ristretto-silver-solo-detail.html
PS2. In the category wowzers, you have this Alfine Di2 bike: http://www.norco.com/bikes/city/urban/indie-drop/indie-drop-alfine-11-di2/

 

[avanti]

A guy in my bike club rides a multi gear hub (quite a few gears to selext from). It takes longer to fix a flat tire because he has to remove a bracket/chain stay screw and undo two shift cables.
He uses a belt drive with his multi speed hub and rides around 10,000 miles a year.

Incidentally back in the late 50s & early 60s UK time trial riders used a Sturmy Archer 3-speed fixed gear hub (type SFW as I recall)

 

[YollyTran]

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[Almeisan]

Somewhat oldish thread but I just wanted to get some info on hubs from a road cycling crowd.

I have been using bikes with hubs since childhood. They always break. Bike mechanic always says 'don't shift when peddling' but of course when you spin with 70-80 rpm and you shift, you can't even do that if you try or else you stop spinning for 1 second. And you shift gears when accelerating, of course.

So are these things complete waste of money for people who put 400-600 watts or more on their gears every time they take off from a traffic light and who like to spin around doing 25km/h or faster?
I like the idea of low maintenance and 30 gears is way too much for a normal bike on the flats.