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> Rohloff internal gear hub, 14 speed alternative to derailleurs
MilitantGraham
post Sep 7 2008, 12:17 AM
Post #1


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Joined: 27-April 08
From: On the banks of the River Severn as it meanders it's way through the sun dappled leafy glades of the Wyre Forest.



For those who don't know, the Rohloff rear hub contains a 14 speed gearbox. Gear shifting is done with a single grip shift and takes place internally, there is only one sprocket.



Although there are only 14 gears, they are evenly spaced, so it ends up with about the same range of gears as a 24 or 27 speed derailleur system.
The Rohloff hub is noticably heavier than a normal 9 speed hub, but Rohloff argue that by leaving off two chainrings, front & rear derailleurs, one shifter and several links of chain, the total weight is about the same.
Rohloffs are ideal for hard tails with horizontal dropouts. Vertical dropouts or suspension will mean you need a tensioner, losing some of the weight and reliability advantage.

I've had mine for about 10 months, here's a list of all the pros and cons I can think of.

Good points;

On a hard tail with horizontal dropouts you can run it with no tensioner for that classic single speed look, making it virtually immune to rock strikes, stick entanglements and mud. No chain suck.

You can shift while stationary. Stopped unexpededly in a high gear ? No problem, shift to a low gear and get going again. this doesn't sound like much of an advantage until you get used to it then get back on to a derailleur bike and have to conciously think about what gear you are going to want to pull away in before stopping.

The gears are evenly spaced. No need to think "Shall I shift up three on the rear or up one on the front and down two on the rear". Just twist up or down as many gears as you want in one go.

If you somehow break part of the shifter or cables, you can change gear with an 8mm spanner at the hub.

It works every time. Click, up a gear. Click, click, down two gears. No whirr, whirr, clatter, which gear am I in ?

As there is only one sprocket, the spokes are wider spaced at the hub making a stronger wheel. No need for dishing the wheel and uneven spoke tensions.


Bad points;

They are unbelievably expensive. I think they are currently around 800 - 900 built up on to a rim. They seem to be going for around 500 second hand on ebay. I bought a pair of wheels recently for 550. Again, Rohloff argue that they will outlast the equivelent cost of broken and worn out derailleurs.

They use two full length cables. The shifting feels a bit heavier than a derailleur to start with. Once the cables get a bit stiff, it becomes a feat of strength to twist the grip. Regular lubrication is essential, ideally with mid-cable oilers. I've just fitted a pair of Flying Snakes to see if they are any better, although as there was not enough outer cable to do two full lengths, I had to buy two pairs.

If you don't like grip shift, hard luck. There is no trigger shift option.

The original cables are crap. The liner gets sucked up in to the shifter and jams it all up. I was warned about this before I fitted mine. If I had known it would happen so quickly I would have bought different cables straight away.

Some people say it makes the bike tail heavy. I don't notice it.

The rear disc fitting is unique. No floating rotor option as far as I know.

With only one gripshift, ideally you will want one short and one long grip. As they are only sold in pairs you will need to buy a pair of each.

There is no choice of gear ratios. You can alter sprocket sizes, but that shifts the whole range up or down. I would prefer to have slightly wider gaps between the gears with a lower 1st and a higher 14th.

You need to back off the power briefly while shifting. This becomes instinctive after a while and is only a problem when caught out by a sudden steep climb. Even then, I can probably stop pedalling, turn the shifter five clicks and start pedalling again quicker than I could flick a trigger shifter five times and wait for the chain to work its way across from one sprocket to another at slow speed.

Only available with 32 spokes. Not really a problem, but may limit your choice of rim.

It is slightly less mechanically efficient than a derailleur. I think it is something like 96% as aginst 98%. I take it this means riding 9.6km on a Rohloff uses the same energy as riding 9.8km on a derailleur.


The bottom line is;
I've got a do everything bike with a Rohloff hub. When I demoted that to a commuting bike and built up a race bike, I put a Rohloff on that as well.

People will naturally be suspicious of anything new and want to stick with what they know.
If hub gears were the norm and someone came up with this new idea of fitting lots of sprockets front and back and using some delicate and unreliable mechanism to bend the chain to line up with them, it might catch on with roadies desperate to save a few grams, but no one would seriously consider it for off road use where it's going to get clogged up with mud and tangle up with sticks.

That's my take on it anyway. If you've got any questions, just ask.


--------------------
I am a Mountain Biking God.
Unfortunately, my bike's an atheist.
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