Internal hub or derailleur - newbie question

[jonnyro]

I currently have an old 21 speed Ridgeback. It was never right - frame too big - and I struggled for years. The time has come to get a new bike.

I don't know anything about gears so sorry if my approach seems a bit non-technical. My cycling is urban, mainly London outskirts and includes some reasonably gentle hills for which I shift down to pretty much the lowest or second or third lowest gear on the Ridgeback. (OK, I'm not fit and approaching 60). Not sure about technicals such as ratios, but just sat the bike upside down on a table and on the lowest gear one pedal turn equates pretty closely to one wheel turn. I neeed that kind of ratio at the bottom end I think. In the Ridgeback's top gear one pedal gives me around four turns of the wheel. I might not use that gear much but on the flat can coast along quite nicely in the higher gears.

I really like the idea of an internal hub gear. But I can't/don't understand how the ratio things work. If I got a bike with a seven speed IHG (Shimano Nexus 7) would my lowest and higest gears be similar to the 21 speed derailleur on the Ridgeback.I do want the same ease of pedalling on the hilly bits with a bit of speed on the flat.

Many thanks

[PH]

If I got a bike with a seven speed IHG (Shimano Nexus 7) would my lowest and higest gears be similar to the 21 speed derailleur on the Ridgeback.I do want the same ease of pedalling on the hilly bits with a bit of speed on the flat.

Many thanks

The simple answer is no.
The range is the difference between you lowest and highest gear. On your current bike that is likely to be somewhere around 450%, your top gear will get you 4.5 times further per pedal revolution than your lowest.
For comparison a Shimano 7 speed nexus is round 250% and an 8 speed 300%. You can have the same bottom gear, or the same top gear, but you can't have both.

[Brucey]

you seem to have a gear range that goes from 1:1 to 4:1, which some folk would express as 400%. The other (traditional) way of looking at it is in 'gear inches' i.e. the equivalent wheel diameter (in inches) for a bike where the pedals are attached directly to the wheel (like a pennyfarthing). In which case your gear range might be from ~27" (low gear) to ~108" (high gear).

In the most simple and general terms it will be cheaper and easier to get that gear range in (say) a 3x7 derailleur system, and when you do, the system will (when it is new) usually be more efficient than a hub gear, the same weight or lighter, and the gears may (or can be made) closer to one another. Any bike shop ought to be able to repair the gears when they wear out or get damaged.

Typically when you choose an IGH then you are choosing to prioritise longevity, lower amounts of maintenance, and running costs over the absolute range or spacing of gears. It is also easier to build a bike with an IGH and a chaincase whereby you get to keep your trousers clean.

So if you compare a mid-price hybrid specification you might end up with (say) a Nexus 8 or Alfine 8 hub as an alternative to a derailleur system.

This chart compares derailleur gears (of the sort you describe) with an 8s hub gear. You can see that you have fewer gears, a narrower range and bigger gaps with the 8s hub. But you might find that compromise preferable to the derailleur setup for the reasons above.

http://ritzelrechner.de/?GR=DERS&KB=28,38,48&RZ=12,14,16,18,21,24,28&UF=2185&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=SNI8&KB2=42&RZ2=21&UF2=2185

you can play around with the settings in the gear calculator; if you get stuck just reload the link above.

cheers

[RickH]

One in between option to get a bigger gear range is a hub gear with a double chainset. That does, of course, also require a chain tensioner.

I have a Circe Helios tandem, that is approaching 10 years old now, which came like that from new using an Alfine 8 speed which effectively makes it a 10 speed - shifting chainrings is around the same as going up or down 2 gears. This setup has worked pretty much faultlessly in that time.

[jonnyro]

Thank you everyone for your replies. They were very helpful and I have decided that as I want the full range, however much I would have liked an internal hub, I shall go for a derailleur.

[Brucey]

I was going to mention that a top gear of 'only' 90" or so is good for about 30mph. When you are riding any faster than that you are basically pedalling downhill for fun. Thus in terms of gear range, the range of an 8s hub is arguably 'enough'; higher gears than this are basically a luxury rather than a necessity.

cheers

[mikeymo]

I've had both. I would take a little longer before you reject IGH bikes.

Here's my experience. I've gone from hub to derailleur. I have a variety of hub geared bikes. All Shimano Nexus/Alfine (8 speed).

The last one I bought was one of these:

https://www.thebikelist.co.uk/2012/ridgeback/journey

Then I made a 27 speed derailleur bike:



The gear range of the IGH (Alfine Eight) is 308%.

The gear range of the derailleur is 530%.


My derailleur bike has a "triple" chainset (3 cogs at the front). Which is what you need to get a gear range as wide as I have. Warning - "triples" are going out of favour with the manufacturers. Which according to Road CC is what the actual manufacturers say:

https://road.cc/content/feature/221157-death-triple-chainset

You can still buy triple 9 speed (3 cogs at the front, 9 at the back), but choices are becoming limited. That is another discussion (and has probably been had), but is worth bearing in mind for longevity/spares. If you are a bit like me (and it sounds like you may be, certainly age wise!), then triples are really nice. 90% of my cycling is on the middle ring, the small one for steep hills, the big one if I'm on a downhill with a following wind.

So if it's "range" you are really interested in, just tread with caution if a cycle shop tries to sell you a "double". You'll probably get more range than an IGH, but almost certainly not as much range as a triple.

Anyways, what matters perhaps as much as the width of the range, is where certain gears are. I don't want to go fast, so having a really high top gear isn't that important to me. I could live without the high gear (fast downhill? I'll just coast). I couldn't live without the low gear (get off and push? I'd rather not)

"Gear inches" is one of the ways of comparing gearing. Here is a calculator:

https://www.sheldonbrown.com/gear-calc.html

Plugging the details in for my two (main) bikes:

My IGH - 27" to 85". The low gear is the one to go up hills.
My derailleur - 22"-117". Easier to get up hills.

HOWEVER, those could be changed. On the derailleur I could change some or all of the front chain rings (and might). Or I could change the cassette. On the IGH I could change either the (single) chainring or the (single) hub sprocket.

How do they compare? I found the IGH a LITTLE (but not much) lacking in range. Or perhaps better put, sometimes I'd like a bit more range. The derailleur has easily enough range.

I'm going to guess that if you're at all like me, you aren't interested in hurtling down hills hunched over the handlebars, grimacing at the wind in your eyes. But you'd quite like to be able to get up hills, so it's the "low" gear that is of interest.

In which case, comparing my two bikes, I've got up every hill on my derailleur with a 22" bottom gear. Including some fairly steep ones up here in Yorkshire. If I was going on tour, with more weight on the bike, I would probably change things a bit to get that even lower. I've never NOT got up a hill on the IGH, but then I haven't cycled on it much since building the derailleur - that's not because I don't like it, it's just that I nicked some parts from it to put on the other.

With the Alfine Eight (or Nexus, the same for the purposes of our discussion) if you changed the front to a 37 tooth chainring, you would get a bottom gear of 26" gear inches. That stays within Shimano's torque limits for that hub. I think they are safe to exceed, Brucey will know. If you put an even smaller chainring on (or larger sprocket) bottom gear will be even lower.

The Alfine 8 (or Nexus) is well regarded for longevity/reliability. There is also an Alfine 11, with a range of about 400%, IIRC. It costs a bit more probably. There is also a Rohloff 14 speed IGH, which has about a 500% range. It is VERY expensive, but also very highly regarded. I don't know your financial means. You may well be a fabulously wealthy eccentric millionaire, like me. In which case get the Rohloff.

I personally hated the look of derailleur gears, and still think they don't have the elegance of IGHs. And there's oil and muck involved. And a derailleur to break. Yes, I had to drive out to rescue my extremely experienced road cycling buddy when his broke. IGHs are simple and reliable, until they're not. Also mending a puncture with an IGH is more of a faff, I would use puncture proof tyres with one. But I use puncture proof tyres on everything.

[Sid Aluminium]

Various hub gears:

Kindernay 543% ££££££££££££££
Rohloff 526% ££££££££££££££
Shimano Alfine 11 409% £££££££
Enviolo 380 380% £££££
Enviolo 330 330% £££
Sturmey Archer 8 325% ££
Shimano 8 307% £££
Shimano 7 245% ££
Sturmey Archer 5 243% £

[Billy007]

I am a newby too! Hi.

I would like to add that I have a bike with an Alfine 8 speed hub a Cube Hybrid bicycle. If you look at just the range of gears from lowest to highest this does not give much indication of what the bicycle with this hub is like to ride. For the Alfine 8 most of the gears have increasing, or decreasing steps of around 14-16%. However the two gears I like to ride in most 4th, 5th and sometimes 6th are separated by jumps of 17.5% and 22% in difficulty or hardness to turn the pedals. Going from 5th to 6th is like going from the 19 cog to the smaller 15 cog on the back of my older derailleur bicycle missing out cogs 17 and 16 all together. When I am carrying full bags on my bike it makes me think twice about changing up, or even if I am not carrying bags. I find I have to pedal pretty hard and fast before I change from 5 to 6 otherwise it is just too hard to pedal and I have to quickly change back down before I lose too much speed. Gears 7 and 8 are a no go unless you are going down hill with the wind behind you. Maybe the hub is better for you if you are a stronger cyclist but unfortunately I am not.

I would like to try a Rohloff hub as I have heard their hubs have more gears which are better spaced and more suited to general riding and perhaps cycle touring. But they are expensive.

Hope this helps you.

[mjr]

Gears 7 and 8 are a no go unless you are going down hill with the wind behind you. Maybe the hub is better for you if you are a stronger cyclist but unfortunately I am not.

Sounds like a larger sprocket or smaller chainring might be good.

For what it's worth, I tour on a SA AW set to give 42, 54 + 72 inches, a range of only 171%, yet I've only walked a short bit of 14% in Luxembourg where I couldn't restart after stopping to let a tractor past. I kept riding up a few miles of 11% OK.

[Carlton green]

Gears 7 and 8 are a no go unless you are going down hill with the wind behind you. Maybe the hub is better for you if you are a stronger cyclist but unfortunately I am not.

Sounds like a larger sprocket or smaller chainring might be good.

For what it's worth, I tour on a SA AW set to give 42, 54 + 72 inches, a range of only 171%, yet I've only walked a short bit of 14% in Luxembourg where I couldn't restart after stopping to let a tractor past. I kept riding up a few miles of 11% OK.

H’mm, I’m not a weak cyclist but I wouldn’t regard myself as a strong cyclist either, today I’d say that I’m a just little below average - so basically nothing special but getting along nicely enough. Depending upon what direction I set out from home the countryside around me ranges from flat to 20% gradients ... might occasionally even find some even a bit steeper still. The AW hub that I’ve got has a top of 69” ( it’s a compromise of parts that’s maybe a small fraction too high for me for best utility) and I’m happily covering the miles on my Sturmey AW hub. Folk have literally cycled around the world on an AW so it wouldn’t be wise to write them off. They are cheap, they work well and when the hill is steep I have the perfect excuse to get off and walk (it’s ‘only’ a three speed) rather than flog up the hill. Yes, at one time I too was sceptical about using just a three speed hub. However, having overcome my prejudices, I’ve discovered much to like about a well set-up three speed hub.

The OP might find that this thread illustrates what (wide range of things) a three speed hub can be used for:
viewtopic.php?f=16&t=134797

[Tigerbiten]

You need to decide at what speed you want to start freewheeling.
If you're happy at around 25 mph then a top gear of around 90"-95" will probably be fine.
If you want to top 30 mph then you'll probably need a top gear of over 100".
It's fairly easy to setup a derailleur bike with the range you want.
But if you accept that you'll not bomb downhill, then you can shift the limited range of an IHG downwards to give you an acceptable low first gear.

I now run a Rohloff with multiple chainrings on my bent trike.
Because of my ultra silly low first gear I spin my first range out at only 14 mph.
But the other ranges are at 20 mph, 35 mph and 50 mph.
So not only can I crawl uphill but I can bomb down the other side .......

You normally setup an IHG for simplicity.
But combining one with multiple chainring/sprockets it fairly easy to open up the range.

Luck ...........

[Billy007]

Gears 7 and 8 are a no go unless you are going down hill with the wind behind you. Maybe the hub is better for you if you are a stronger cyclist but unfortunately I am not.

Sounds like a larger sprocket or smaller chainring might be good.

For what it's worth, I tour on a SA AW set to give 42, 54 + 72 inches, a range of only 171%, yet I've only walked a short bit of 14% in Luxembourg where I couldn't restart after stopping to let a tractor past. I kept riding up a few miles of 11% OK.

The current set up of external front and back cogs is what Cube supplied the bike with so I don't really want to start changing these. In any case even if I did, which I don't, then the big steps between individual gears within the Alfine 8 hub would still remain especially gear 5 to gear 6 which is a 22% increase in hardness to pedal from 56.6 gear inches to 69.5 gear inches. The problem seems to be with Shimano themselves making such a large step between these two gears with the Alfine 8spd hub. On the 11spd Alfine hub there seems to be a gear in between these like a gear 5.5 at 64.4 inches which is only a 13% increase, although on the Alfine 11spd this is gear 6 and gear 7 comes in at 73.9 gear inches.

I am looking for more gears to make pedalling easier, not less.

I hope this helps you better understand.

[Brucey]

you always have a choice between gear range and gear spacing. It is a very good idea to work out what you like before you buy a bike, as changing it afterwards can be complicated or expensive.

FWIW a 20% gear gap sounds large but really it isn't that big. To accommodate this interval all you have to be able to do is to be happy pedalling ~9% slower or ~9% faster than your optimum. Some folk really don't like this but most find a way to be happy with it.

NB simply dismissing the idea of changing the gearing by using a different sprocket size is not a very sensible choice. IME if you have widely spaced gears you will spend a lot of the time in just one or two gears; choosing what those gears are exactly is almost as important as choosing a singlespeed ratio, especially if you ride the same routes often, and often find yourself 'between gears'. Changing the sprocket is both cheap and easy to do, so you should try this first if you are not happy.

If you are not happy with the interval between 5 and 6 then adjusting the gearing might put that size gear ratio in the gear 6 to gear 7 range, which is only about a 16% interval.

cheers

[fausto99]

I really like the hybrid setup I have on my Moulton; a SA 3 speed AW combined with a 6 speed derailleur. Not for the technically challenged but a great combo and much more elegant than a triple chainset. What I don't like about it, and this is a real biggie, is the weight. According to the SJS site it weighs 1032gm! That's why I don't have a hyrbid setup on any of my other bikes.

I'd love to know if anyone has modified an AW successfully to reduce the weight, and by how much. I've wondered about drilling the shell and then making it oil tight with a wrap of woven carbon fibre. I suspect it would not make too much difference as there are lots of other bulky steel parts, planet cage, lock rings, etc. Any thoughts?