# Why use internal gear hub



## novetan (27 Jun 2020)

I see most foldable bikes with 3 sp and abv are mostly installed with internal gear hub . While I understd hub has longevity and easier to maintain than std derailleur, it is so much heavier and costlier. And esp 3 sp, why Brompton not using the std cog with derailleur? Is it because of folding issuing? I owned a road bike, it is not difficult to maintain. And for those weight weenies that try to pinch a few grams here and there, the hub is the part that save you a ton. And for that matter, why 6 sp isn't using cog as alternative or an option?


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## raleighnut (27 Jun 2020)

novetan said:


> I see most foldable bikes with 3 sp and abv are mostly installed with internal gear hub . While I understd hub has longevity and easier to maintain than std derailleur, it is so much heavier and costlier. And esp 3 sp, why Brompton not using the std cog with derailleur? Is it because of folding issuing? I owned a road bike, it is not difficult to maintain. And for those weight weenies that try to pinch a few grams here and there, the hub is the part that save you a ton. And for that matter, why 6 sp isn't using cog as alternative or an option?


It'd be the folding issue with a derailleur.


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## Cycleops (27 Jun 2020)

You have to think who Brompton's main customers are. They are commuters who require their mount to be clean and easy to fold, they can't be doing with an oily protrusion which may get in the way of a fold.
Other makers do use a derailleur on their folders but might not be aiming them at this sort of user, they have hub gears or SS for them. Plus with 16" wheels the mech is too close to the road picking up dirt and damage.


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## Fab Foodie (27 Jun 2020)

....also, folders are primarily designed for short distance/commuting for which speed and weight are not the issue, however, simplicity, low maintenance, easy cleaning are important issues. The hub is a winner, PLUS, you can change gears without peddling which in urban commuting is pretty useful.
Some Bromptonistas fit 14 spd Rohloff hubs tho....


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## Rocky (27 Jun 2020)

I love the hub on my Brompton. It’s low maintenance, goes on for ever and easy to clean. The ratios are fine for everything I’ve ever done on it, including all but the steepest hills.


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## HMS_Dave (27 Jun 2020)

I think you skimmed off the positives too easily there. It is as you say, low maintenance and have a long life which are excellent reasons given the target customer. At the end of the day it is made of steel it was never going to be as light as it could be but with that it has very long life and strength. They're folded and picked up with little complaint. With the amount of years they've been going like that and the amount of people who buy them if say not a lot what much changed about them.


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## Tenkaykev (27 Jun 2020)

Mrs Tenkay has a 14 speed rohloff hub on her Roberts tourer.
It is a wonder of engineering excellence but it's quite a lump. 
I'd wondered about whether a six speed version would be practical so they could drop the derailleur, but I suppose it's a matter of cost, complexity and demand.


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## bikegang (27 Jun 2020)

Standard snap ring hub can only take up to 3 external cogs. Which can be easily modded with Unibody cog set and compatible to most stock parts.






X3 Unibody cog set

Anything over 3 will require some extensive modifications, such as longer tensioner arms, clamp or filing the frame end, longer custom free hub body (wheelset) or evern a dedicated chain puser, DR spring set.





Custom longer free hub body for 4 cogs

This modification that uses 7 speed sprocket cassette (11-28t) is probably pushing the limit. You can tell the chain pusher and jocky wheels are all new design to allow longer and smooth travel between sprockets.


Linear chain push 7 speed 28T external cogs system


I will think Duo chainring (33/54T) with 4 speed external cogs (11-14-17-23T) might be a best combination to replace BWR 6 speed (302%). It will save quite a few gram and a wider gear range of 345%.





33/54T Duo-chainring


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## Schwinnsta (28 Jun 2020)

I think its partly historical, when it was invented. For a 16 inch wheel, a standard derailleur would have been very low and not as robust.


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## berlinonaut (28 Jun 2020)

novetan said:


> And esp 3 sp, why Brompton not using the std cog with derailleur?


The do - they are offering the 2speed. Knowing both, personally I prefer the 2 speed Brompton over the 3-speed-hub one and can not really see a disadvantage but many advantages. Still many buyers prefer the 3-speed hub over the 2-speed, so why should Brompton not be offering it?


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## mitchibob (28 Jun 2020)

Tenkaykev said:


> Mrs Tenkay has a 14 speed rohloff hub on her Roberts tourer.
> It is a wonder of engineering excellence but it's quite a lump.
> I'd wondered about whether a six speed version would be practical so they could drop the derailleur, but I suppose it's a matter of cost, complexity and demand.



Isn't that what Mark Beaumont used during this solo around the world record?


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## MichaelW2 (28 Jun 2020)

A hub gear runs cleaner than a derailleu system. Cleanest is hub gear + belt drive but you can't do a Brompton fold with a belt.
I use 8 speed hub gear and find it clean, simple and low maintenance. Mine has about 30k miles


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## Once a Wheeler (28 Jun 2020)

I am a great fan of derailleurs but from an engineering point of view they have their shortcomings. No engineer likes a traction system where the elements run out of alignment and , obviously, the derailleur depends on misalignment in order to function. Similarly, a system running in a closed compartment, such as a hub, is protected from the elements and easy to keep lubricated. I have often wondered why no-one has commercialized a gearbox set in the bottom bracket. It must have been tried out at some point. Perhaps it is the moment for an innovator to take a new look at the concept with modern materials and techniques. Such a gearbox would mean the cranks no longer drive the chainwheel directly: instead, the cranks would drive into the gearbox and the gearbox would drive the chainwheel. So, over to the innovators. Meanwhile, I will keep my gears where I can see them (and maintain them).


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## MichaelW2 (28 Jun 2020)

Once a Wheeler said:


> I am a great fan of derailleurs but from an engineering point of view they have their shortcomings. No engineer likes a traction system where the elements run out of alignment and , obviously, the derailleur depends on misalignment in order to function. Similarly, a system running in a closed compartment, such as a hub, is protected from the elements and easy to keep lubricated. I have often wondered why no-one has commercialized a gearbox set in the bottom bracket. It must have been tried out at some point. Perhaps it is the moment for an innovator to take a new look at the concept with modern materials and techniques. Such a gearbox would mean the cranks no longer drive the chainwheel directly: instead, the cranks would drive into the gearbox and the gearbox would drive the chainwheel. So, over to the innovators. Meanwhile, I will keep my gears where I can see them (and maintain them).


Schlumf drive
Pinion
Truvativ Hammerschmidt

The are expensive and not widely used.


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## raleighnut (28 Jun 2020)

Once a Wheeler said:


> I am a great fan of derailleurs but from an engineering point of view they have their shortcomings. No engineer likes a traction system where the elements run out of alignment and , obviously, the derailleur depends on misalignment in order to function. Similarly, a system running in a closed compartment, such as a hub, is protected from the elements and easy to keep lubricated. I have often wondered why no-one has commercialized a gearbox set in the bottom bracket. It must have been tried out at some point. Perhaps it is the moment for an innovator to take a new look at the concept with modern materials and techniques. Such a gearbox would mean the cranks no longer drive the chainwheel directly: instead, the cranks would drive into the gearbox and the gearbox would drive the chainwheel. So, over to the innovators. Meanwhile, I will keep my gears where I can see them (and maintain them).


Pinion make a front 'gearbox' drive.


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## rogerzilla (28 Jun 2020)

Gears in the BB have to cope with full pedalling torque, which is similar to that from a large petrol engine. They need to be bigger and heavier than they do at the rear hub.


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## Tigerbiten (28 Jun 2020)

Small wheel folders tend to have short chainstays.
This makes the angle of the chain in first and top gear a lot more extreme once you go to a multi sprocket cassette.
Therefore a bigger risk of it jumping of the chainring.


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## Fab Foodie (28 Jun 2020)

bikegang said:


> Standard snap ring hub can only take up to 3 external cogs. Which can be easily modded with Unibody cog set and compatible to most stock parts.
> 
> View attachment 532766
> 
> ...



I added a Stronglight 50:36 standard square-taper cheapo chain set to my S6L and it works a treat :-)


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## FrankCrank (29 Jun 2020)

Bromptons have been around for 40 years now, and Sturmey Archer 3-speed hubs for over 100 years. Guess they're both doing something right.


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## rogerzilla (1 Jul 2020)

Also, for folding reasons, Bromptons want a narrow rear spacing (I think it's about 112mm). Modern derailleur hubs are at least 130mm.


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## welsh dragon (1 Jul 2020)

I have a nexus 6 speed hub gears on my bike . It's brilliant. No mess no fuss and literally no maintenance in the 4 years I have had it. What's not to like.


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## Littgull (1 Jul 2020)

I am a huge fan of hub geared bikes. I have 2 x Rohloff geared Thorn bikes, a Brompton and a Nexus hub geared belt drive bike. The latter being almost exclusively used for commuting 20 miles per day to work in all weathers for over 10 years prior to my retirement in 2017. I've never had a single problem with any of my hub gears.

I think the negative often expressed about hub gears being heavier in weight is more often a spurious argument, as with most hub gear set ups there is only one chain ring, no front or rear derailleur and no cassette. Also, the simplicity of hub gears makes it a joy to not have the regular hassle of having to re-index derailleur gears as well as having the advantage of longer chain life.


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## roley poley (1 Jul 2020)

no dishing = stronger wheel ..one size spoke fits both sides of the hub if broken on tour


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## raleighnut (1 Jul 2020)

Littgull said:


> I am a huge fan of hub geared bikes. I have 2 x Rohloff geared Thorn bikes, a Brompton and a Nexus hub geared belt drive bike. The latter being almost exclusively used for commuting 20 miles per day to work in all weathers for over 10 years prior to my retirement in 2017. I've never had a single problem with any of my hub gears.
> 
> I think the negative often expressed about hub gears being heavier in weight is more often a spurious argument, as with most hub gear set ups there is only one chain ring, no front or rear derailleur and no cassette. Also, the simplicity of hub gears makes it a joy to not have the regular hassle of having to re-index derailleur gears as well as having the advantage of longer chain life.


They are slightly less efficient than a clean well lubed and maintained derailleur system but better than the gunked up rusty set up often found on commuter bikes.


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## Drzdave58 (2 Jul 2020)

All I ride is IGH bikes...I can’t see ever going back to derailleurs.


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## raleighnut (2 Jul 2020)

Drzdave58 said:


> All I ride is IGH bikes...I can’t see ever going back to derailleurs.


Not even ones this sexy,


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## MichaelW2 (2 Jul 2020)

raleighnut said:


> Not even ones this sexy,
> 
> View attachment 533672


It has horizontal dropouts so a Nexus hub should fit nicely.


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## rogerzilla (2 Jul 2020)

A 3-speed Sturmey-Archer (oiled as opposed to greased) is just about identical to a derailleur system for efficiency, taking into account the loss from the jockey wheels and sprung chain tensioner of a derailleur. It's probably MORE efficient in the middle gear (direct drive). When you go to more than 3 speeds, hub gears start to become less efficient, especially when the drive goes through more than one epicyclic (each of which adds a minimum 3% loss). 

SRAM used to make a 7-speed with no cascading of the drive but it had many other problems instead.


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## berlinonaut (2 Jul 2020)

As this thread is about folders and the Brompton in particular: Hub width has been mentioned already, the weight has not. Te 2-speed saves massively weight over a 3-speed on a Brompton - anyone who carries his bike regularly will be thankful for that. In general I do prefer hub gears and within them the Rohloff is clearly my favorite (whereas with many others I dislike the losses in the hub, the spacing of the gears, the limited range, the weight-power-ratio or something else). Which led to me having a bunch of bikes with the Rohloff and some with other hub gears but barely bikes with dreailleurs apart from the 2-speed Brommi. I recently akquired a deralleur bike and must say I am impressed - as it is basically new there are no issues and it clearly feels more efficient than the Rohloff, let alone any other geared hub.


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## 12boy (2 Jul 2020)

I use 5-20 synthetic oil in my two 3 speed SA hubs and the only downside is seeping oil. I've ridden my surly steamroller with one in -18 C temps and there were no problems. One of the drawbacks to small wheels is the difficulty of getting higher gear ratios and the SA hubs with high 33% higher than the direct drive gear is a good way to do that. I also have a 3 sprocket rear wheel with 11-14-17 sprockets, courtesy of Bike Gang which also works very well although it doesn't have the high gear the SA hub has. It is lighter, though and does not seep oil. Like Fab Foodie I have 2 chainrings, 58 and 38 tooth, so I have a granny gear option for 12% grades although I could use a sub 30 gear inch setup at times. One of the things I enjoy about my Brompton is tinkering with and trying out various options. It really is a fun machine.


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## SkipdiverJohn (2 Jul 2020)

Once a Wheeler said:


> I am a great fan of derailleurs but from an engineering point of view they have their shortcomings. No engineer likes a traction system where the elements run out of alignment and , obviously, the derailleur depends on misalignment in order to function.



From an engineering perspective, derailleurs are absolute shite! And the more cogs you try to cram on the back wheel, and the shorter the chainstays you run for quicker handling, the more shite they get. That's before you start to consider unwelcome knock-on effects like weakening the rear wheel due to all the dishing and running with huge variations in spoke tensions. Their only saving grace is they are the cheapest way of getting the widest possible spread of gears. A reliable functional hub gear, by it's very nature, has to be a fairly decent bit of engineering, which imposes a price floor on what you can build them for. On the other hand, low end derailleurs are essentially just stamped out of pieces of sheet steel., which means at a mass production level the individual bits cost pennies to make.


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