What is better,Shimano derailleur external gears or Shimano Nexus hub gears.

[Mussels]

Thanks guys....it is obvious that both systems have their converts and both systems are needed,but the balance seems to be swinging towards hub gears. The very latest Nexus systems have all the internals of the Alfine but the Alfine has the ability to fit disc brakes,I did carefully confirm that with the Shimano rep at a trade show.
Thanks for all your comments

There was a Nexus hub that wasn't as good but I think they ditched that a few years ago.

 

[flecc]

For those who have only tried the newer Shimano hubs and believe all hub gears change easily, you need to try the SRAM P5 or S7 hub gears. They are so slow that stopping pedalling is essential, and on change down it's even best to slightly flick back on the pedals to ease through the change. On the plus side they are very tough and good for heavy duty applications like trikes and quad bikes. SRAM are currently designing a whole new hub gear range so this could change in the next year or two.

Shimano have always prided themselves on being the fastest changing gears, on derailleurs as well. They were the first company to build in ramp profile indents on the side of the derailleur cassette sprockets to help the chain rise up on changes. Their derailleur sprockets also have the shallowest teeth, the tops appearing to be cut off to assist the chain in leaving one sprocket for the next. In contrast, Campagnolo, SRAM and other make derailleur sprockets often have more tooth height, making for a little less wear.

 

[z0mb13e]

I've noticed that what appears to be a disc brake on some hub gears seem to have fins on the inside. As on this Kudos Cycles Nexus Tourer for example...

Am I right in thinking that this is actually a disc, a single sided one?

Having not seen one up close I wondered if maybe it was some sort of heat sink, but a disc seems more likely...

 

[flecc]

It is the optional heat sink and cooling disc for their roller brake, the latter working on a roller and ramp system.

 

[z0mb13e]

It is the optional heat sink and cooling disc for their roller brake, the latter working on a roller and ramp system.

Ah, that makes sense!

 

[bode]

Like several here, I was brought up in the 50s on Sturmey Archer 3-speed gears, and my first adult bike (which I owned for 20+ years) had the same. Later, derailleur gears came as a bit of a shock, especially the inability to change down when stationary. They have always seemed to me a rather crude (if effective) device. Plenty of opportunities for throwing the chain if they get out of adjustment or when changing up carelessly (or is that just me?) My next bike will certainly have hub gears.

If you do have to slightly pause pedalling when changing gear, isn't that just similar to changing gear in a car? I know that momentum is less of an issue in a car, but you know what I mean.

 

[rog_london]

What really puts me off even trying the Panasonic drive system is the feeling that it must be seriously hard on the chain and sprockets of a derailleur system. The latest Panasonic triples your power input as long as you're in the 'window' and that must have wear consequences. I have a roadie riding pal who goes through cassettes, chains and chainwheels at a high rate - and that's just *him* pedalling, mainly to and from work. Any comments from those who regularly ride fast with the Panasonic system? Obviously there will be those among us who don't push it that hard, but I'm sure many of us like riding as fast as circumstances and our legs permit.

Rog.

 

[NRG]

Well I backoff pedal pressure very slightly when changing up on my PCS with derailleur, if I don't the resultant crunch is not pleasant and cant do the chain or cassette much good. I also think weekly lubrication of the chain may be necessary with the high powered versions if the bike is used daily...

 

[flecc]

What really puts me off even trying the Panasonic drive system is the feeling that it must be seriously hard on the chain and sprockets of a derailleur system. The latest Panasonic triples your power input as long as you're in the 'window' and that must have wear consequences.

Not really as bad as it might appear at first sight though. There's two elements involved in looking at the effect on wear.

The first is sustained rider power. Nasa's widely accepted figures for healthy males cycling in the middle years are 200 watts for one hour and 100 watts for five hours. Then there's the cycle sport supermen like the legendary Miguel Indurain who was calculated to have exerted a continuous 450 watts on a one hour climb. Accepting that derailleur gears are primarily designed for sport use and that designers incorporate at least a 50% safety margin and often 100%, designs should be good for at least 650 watts of continuous power transmission.

The second element is the Panasonic system itself. Although there are nominal multiples of up to 2 times rider input, these are limited by the ceiling of the maximum power of the motor itself, typically peaks of 400 watts. To get that peak from the system on the 2 times power setting, the rider has to input 200 watts, which from above is the one hour input of the typical healthy rider. So the sum of the two is comfortable within the design limits.

Of course this doesn't cope with the likes of Indurain, but equally he would never have been likely to have ridden a Panasonic aided bicycle during his peak years, and nor would any any high performing club rider.

 

[bazwaldo]

Hi everyone,
I only have derailleur gear experience on my old Raleigh "Milk Race" tourer and my more recently purchase Bearprint E Bike.
Having nearly done 4000 miles commuting to work on the Bearprint since last October the gears have performed without any problems apart from freezing in 1st gear once during a very heavy frost. Despite his I got home on throttle only and only 5 minutes later than if I had been pedalling!
The Hub gears do sound very good and desirable with the OP advised benefits of low maintenance and with a full chain guard.
If I was looking for a new E Bike I would go for the Hub gear option.

Barry.

 

[Mussels]

Of course this doesn't cope with the likes of Indurain, but equally he would never have been likely to have ridden a Panasonic aided bicycle during his peak years, and nor would any any high performing club rider.

I had a club rider congratulate me on my stellar performance when I sailed past him up a hill on Tuesday, when I told him my secret he said he could do with that on his club runs. I think if the motors were descrete enough club riders would love them.

 

[HarryB]

What really puts me off even trying the Panasonic drive system is the feeling that it must be seriously hard on the chain and sprockets of a derailleur system. The latest Panasonic triples your power input as long as you're in the 'window' and that must have wear consequences. I have a roadie riding pal who goes through cassettes, chains and chainwheels at a high rate - and that's just *him* pedalling, mainly to and from work. Any comments from those who regularly ride fast with the Panasonic system? Obviously there will be those among us who don't push it that hard, but I'm sure many of us like riding as fast as circumstances and our legs permit.

Rog.

I do know that it wears the chain/sprockets quicker by comparing wear rates between the Cytronex and Emotion. The Emotion chain was replaced at about the same mileage but the rear sprockets had to be replaced only on the Emotion. In the end the chain kept falling off the chainwheel so was pretty worn. See my previous post about how much power is put through the gears. The times you notice this is when you find youself in to high a gear (seems a common enough occurance in London). You then are changing down at low cadences where the panasonic provides most of its power, so you really have to moderate it to avoid crunching. Not always easy when you are in a hurry.

 

[flecc]

I think if the motors were descrete enough club riders would love them.

The sport club riders who might exceed design limits wouldn't though. They are too proud of their timed ride results and hill climb performances. Having motors would make their type of riding pointless.

Those from the two London clubs who have their hill climb trials on White Lane in the North Downs brag about how high a gear they use on the climb, which includes a 1 in 3.3 portion. They certainly don't need motors! Once when I rode it that climb nearly killed me, despite using a high power motor and bottom gear.
.

 

[lemmy]

In modern times when so much engineering is so good, it seems almost impossible to have any hard and fast opinion on which is better.

Compare 50s Sturmey Archer 3 speed Hub with modern Shimano indexed derailleurs....no contest.
Compare 50s chain falling off free changing derailleurs with Nexus 8 speed....no contest.

Modern Shimano derailelur with modern Shimano hub gears....no answer to that one.

It seems these days either will do a sterling job, both are reliable and both need little adjustment, so it comes down to personal preference for one's own type of cycling..

Makes the choice harder but what a great positionus cyclists to be in.

 

[Teejay]

One advantage of hub gears is the ability to add a chaincase, with all the advantages that gives - at least on a bike used as day-to-day transport in the British climate. Kudos to their credit offer this as standard on their City and Tourer-Nexus models and I hope they continue to do so. All too few e-bike makers have done this so far.

...Or is it? Around 20 years ago I read in one of Rob Van der Plas' books about an experimental totally-enclosed chaincase for derailleurs being worked on by Shimano. "Great!" I thought, "best of both worlds", so I wrote to Shimano Europe asking when they were going to be available. They very graciously replied but said they weren't going to put it into production (I wonder why not?) but adding darkly that they still held the patents.

 

[flecc]

The mind boggles at the size in prospect for a chaincase enclosing a triple chainring, nine sprocket cassette derailleur and rear mechanism. The end result would make a bike look like a scooter/moped!

I agree with the sentiments though, and use the second-best of a chainguard on the derailleur of my folder: