Hub Gears

[mike killay]

Simple question
Do the new 8 speed hub gears allow you to change down from top to bottom when stationary?
The old Sturmey Archer 3 speeds would do this without any problem.
I am attracted to a modern 8 speed hub gear, because on engineering terms alone, a derailleur is a horror. (Albeit a horror that defies all engineering practice and actually works). The reason is that a hub can have a stronger chain and cogs.

 

[peasjam]

Yes it does. I've had an Alfine 8 on my Cannondale for a few years now and for a hybrid bike I wouldn't consider anything else (other than the 11 speed version...)

Matt.

 

[eddieo]

I have 2 new bikes, one with shimano 8 gear nexus red line hub and the other with XT derailleur

although it is nice being able to change while stationary, on a hill at lights etc...The XT gears are MUCH more sporting and smoother adding to a different riding experience in my opinion

 

[Biged]

I have 1 new bike and a number of older ones the new one with nexus 8 sp red line, all the older ones have deraileur gears, shimano mostly.
The reason i chose the hub gears is because i think deraileur gears are rubbish, they clunk, they always need adjusting, they are messy and you cant change gear while stationary.
One man's meat is another man's poison

 

[indalo]

Simple question
Do the new 8 speed hub gears allow you to change down from top to bottom when stationary?

Simple answer; yes.

Having derailleurs on three bikes and an 8-speed Shimano unit on my ebike, I'm now a big fan of hub gears. I remember well the old 3-speed Sturmey-Archer system I had on a bike in my youth which seemed pretty indestructible but I have to say I did wonder when I was buying my electric bike with an 8-speed hub. Any doubts I had about fragility with the enhanced power from the motor soon disappeared. A little research reveals that one, Sheldon Brown, was also an aficionado of internal hub gears and I'm pretty sure our own Flecc is another although he can speak for himself.

Why do I like them? I think it's my engineering background and the fact that they are reliable, low-maintenance, work smoothly and don't wear out chains quickly.

Although they are not generally associated with racing or sports bikes, invariably the domain of derailleurs, they do seem perfectly matched to comfort or leisure bikes. There's probably an explanation as to why multi-geared derailleur systems are de rigueur for fast road bikes and it may be simply a gear-range issue but I'm sure others will know better than me.

In my experience, derailleur gears seem to need frequent adjustment whereas, once set up, I've never had to touch my Nexus adjustment since.

I love 'em!
Indalo

 

[flecc]

Derailleurs are much more efficient, hence their use on sport bikes, but on general use bikes the convenience of hub gears outweighs the efficiency issue. This is especially true on e-bikes where the added power easily hides any inefficiency.

 

[mike killay]

Derailleurs are much more efficient, hence their use on sport bikes, but on general use bikes the convenience of hub gears outweighs the efficiency issue. This is especially true on e-bikes where the added power easily hides any inefficiency.

Flecc,
Can you tell me if the 8 speed hub gears have the same range as an 8 speed derailleur? I realise that the size of the chain wheels comes into this but in general, does the epicyclic design mean that the range is much more restricted between high and low?

 

[peasjam]

I have 2 new bikes, one with shimano 8 gear nexus red line hub and the other with XT derailleur

although it is nice being able to change while stationary, on a hill at lights etc...The XT gears are MUCH more sporting and smoother adding to a different riding experience in my opinion

The Alfine 8 speed hub is noted for being much smoother and with a quicker shift than the Nexus, and Alfine 11 is supposedly better again. The 11 is silly money though...

 

[Mussels]

Flecc,
Can you tell me if the 8 speed hub gears have the same range as an 8 speed derailleur? I realise that the size of the chain wheels comes into this but in general, does the epicyclic design mean that the range is much more restricted between high and low?

The Alfine 8 hub has a much bigger range than a 7 speed derailer, this is good but has the downside of bigger steps between the gears. On an ebike this doesn't matter much and I greatly prefer the Alfine option.

 

[peasjam]

I've also found that it feels like it's grouped into four lower and four higher ranges rather than a smooth transition from 1 to 8. This means there is a noticeably larger step between 4 and 5 than any other gear.

 

[flecc]

Flecc,
Can you tell me if the 8 speed hub gears have the same range as an 8 speed derailleur? I realise that the size of the chain wheels comes into this but in general, does the epicyclic design mean that the range is much more restricted between high and low?

There's no restriction on hub gear range since many of the gears can be obtained by compounding, using the transmission through more than one of the epicyclics. This can hugely multiply a ratio. In practice though they go up to 500% range in the case of the Rohloff 14 speed hub gear. To exceed that a derailleur would need something like an 11 to 33 teeth rear cluster and a 24 to 48 teeth triple chainring giving 600%. Not many go that far.

The gear spacing that others mention is an issue which disturbs optimum pedalling rhythm, hubs varying widely in this respect. Once again the Rohloff is tops since all 14 gears are evenly spaced. It's not perfect though, since the lower seven gears are noisy enough to make some pedestrians look round and is notorious for an occasional glitch in changing from 7th to 8th, suddenly ending in 14th sometimes which is more than disconcerting. It also costs around £1000 now.

One can also get a 500% plus range from the NuVinci hub gear which is in fact a CVT, continuous transmission transferred though a ball and ramp system so that there are no gears, just a continuous range which one twistgrips through. Sounds perfect once again, but life not being like that, it does have a slight coarse patch around the centre of the range and is the least efficient of all, less so than epicyclic hubs. Not one for keen cyclists who want the best efficiency, but it works well and is very strong.

 

[indalo]

Flecc, you mention three distinctly different systems, all of which seem to have their place in cycling. Do you have a personal favourite or is it a case of "horses for courses" completely dependent on the activity you wish to pursue?

Regards,
Indalo

 

[flecc]

I'd say the Nexus/Alfine 8 speed hub Indalo, enough gear range for an e-bike anywhere in the UK, especially with a Pansonic system.

When a non e-bike or a very low powered one there are other aspects that I didn't cover above, these connected to where the direct drive gear is. With the exception of the Nexus 7 gear hub with has only indirect gears, hubs have one gear as a direct drive where the rear sprocket just drives the wheel so is at 100% efficiency. That's normally the middle or almost middle gear, on the Nexus/Alfine 8 it's 5th gear from the bottom. The further a gear is from that direct drive, the greater the inefficiency, so the majority who ride in top gear most of the time are suffering some poor efficiency.

It follows that riders in flattish territory who don't need very low gears could change their sprockets setup to leave the direct drive gear at the speed they mostly cycle at, getting derailleur-like overall 99% transmission efficiency. The top three gears would then be overdrives.

One hub gear is an exception to the above, the Sunrace-Sturmey 8 speed hub has the very unusual arrangement of direct drive being bottom gear, meaning it's top gear far removed from that is very inefficient. That might seem silly, but there are benefits. It means that when climbing the steepest hills in bottom gear one gets the best efficiency with no watts of exertion wasted when each one is precious. Conversely, the most inefficiency is when the going is easiest of all on the flat when one has some watts to spare.

The other bonus of this Sturmey system is that the chainwheel is very small due to all rear gearing being upwards. Therefore with front and rear sprockets being near to equal and of good size, the chain transmission enjoys high efficiency, there's less likelyhood of chainring damage and it's very easy to arrange small very compact chainguards. As ever though there's a catch, that's the fact that most time is usually spent in upper gears so the sum of the inefficiency experienced is high.
.

 

[eddieo]

And there was me thinking you liked the XT set up as fitted to our favourite bike the X series Flyer ?

Sorry, but have been riding the Bosch bike all week (nexus red line) and when I get on the specialised with XT gearing, it feels in a different league, a breath of fresh air and the hub simply a clunker in comparison. By all means hubs for regular commuting make sense but the XT are sheer joy.....

 

[Biged]

The Alfine 8 speed hub is noted for being much smoother and with a quicker shift than the Nexus, and Alfine 11 is supposedly better again. The 11 is silly money though...

The Alfine 8 speed hub and the nexus 8 red line have identical internal parts so they should be identical in operation.
The Alfine 11 speed is now the upgrade.

 

[CheKmx]

I thought the range on the NU Vinci was 360, do they have a new model out offer greater range?

 

[flecc]

I thought the range on the NU Vinci was 360, do they have a new model out offer greater range?

Thanks for the correction CheKmx, my mistake. The NuVinci was 350% but the new model recently announced is 360%, te other improvements being size and weight reduction. For range it's better than all but the Rohloff and Shimano 11 speed.

 

[flecc]

By all means hubs for regular commuting make sense but the XT are sheer joy.....

Of course Eddie, that's in part why I was stressing the efficiency aspects above. A good derailleur really takes some beating, but the maintenance issues can become tiresome, as can the costs over time. For general use the worry free aspects of hub gears win the day.