Shimano Nexus Hub Gears

...just posted an opinion on Shimano cycle gears a month or so and here I am again, posting another.

“What gives?” I hear those of you that actually give ‘a monkey’s’ asking.

Ah well, the first time it was because I am building myself a new bike.

Now, it’s because my two sheds don’t look anywhere near full yet, and because I can’t turn down a tasty bargain, courtesy of e-Bay.

Anyway, some ...
...what’s so special about these Shimano Nexus gears that would divert me from my aim to build a bike?

Well, chiefly, they are hub gears (he said, expecting you all to say “Oh well, that explains it all then!). Oh yes; AND they have a nice bike attached to them.

HUB GEARS IN GENERAL

I’ve always had a thing about the good old Sturmey-Archer 3-speed hub gear that many people cut their cycling teeth on. They ... more

I only just posted an opinion on Shimano cycle gears a month or so and here I am again, posting another.

“What gives?” I hear those of you that actually give ‘a monkey’s’ asking.

Ah well, the first time it was because I am building myself a new bike.

Now, it’s because my two sheds don’t look anywhere near full yet, and because I can’t turn down a tasty bargain, courtesy of e-Bay.

Anyway, some people are three-car families; I’m a three-biker, so what?

Now then, what’s so special about these Shimano Nexus gears that would divert me from my aim to build a bike?

Well, chiefly, they are hub gears (he said, expecting you all to say “Oh well, that explains it all then!). Oh yes; AND they have a nice bike attached to them.

HUB GEARS IN GENERAL

I’ve always had a thing about the good old Sturmey-Archer 3-speed hub gear that many people cut their cycling teeth on. They were reliable, and could be changed standing still OR pedalling OR freewheeling, and needed little adjustment. Such adjustment as was needed was simple in the extreme – disconnect the control cable, let the mechanism ‘relax’ into top gear, and then take up all the cable slack. Voilà, all three gears would snick neatly into place, or ‘indexed’ as they’d be called today.

Their limiting factor was the pitifully small amount of ratios available although later versions saw them creep into the four and even five speed formats but not with much success.

It was little wonder that the dérailleur system of exposed cogs and chains that jump from cog to cog became the de facto gear change mechanism for most cyclists. After all, 8 cogs at the back and 3 up the ‘pedals end’ would give you 24 combinations compared to three in a Sturmey-Archer hub, right?

Wrong. In many set-ups, you’d lose 2 of your 24 anyway as the chain baulks at stretching diagonally from the largest front gear to the largest back gear (and from smallest to smallest). The remaining 22 ratios aren’t all they’re cracked up to be either. In the 24-speed bike that I’m most of the way through building, some of the remaining ratios are so similar to each other as to be of little benefit. I worked it out one day that out of 24 so-called ratios, about a dozen of them were different gears of any significance. Not only that, but dérailleur gears can STILL only be changed whilst pedalling – not freewheeling OR standing still.

Getting caught out by traffic lights on an up-hill section is a real pain, leaving you to go red in the face as you strain to shift the bike into a lower gear when the lights go green. Also, accidentally twiddling with your gear controls as you kick back to get the pedals in a good push-off position is a highly effective a way of dumping the chain.

SHIMANO NEXUS

This is where Shimano Nexus hub-gears come into their own for commuting purposes. Not only do they possess all the good old Sturmey-Archer attributes of user-friendliness, but they also have ‘enough’ gear ratios, 7 or 8 to be precise, with more on the way, it’s reputed.

The bike I bought has a Nexus 7-speed gear mechanism, combined with a self-contained rear hub brake. The latter is still hand-controlled unlike the back-pedal brake so popular on many ‘sit-up-and-beg’ continental bikes. I hate the back-pedal versions with a vengeance, as so often, they can strand you with your pedals in a very poor position vis-à-vis pulling away again. This can leave you dangerously unprepared for moving out into traffic. My rear brake is a different kettle of fish. It is lever controlled in the usual way, with a smooth and progressive feel to it, although I can only imagine how hot it gets on the really steep downhill section in Richmond Park! No wonder it has a heat fin to dissipate excess warmth.

Coming back to the gears, they are a delight to use. As you’d expect, you can change them at will, whether standing at lights, pedalling or coasting, although you can’t pedal hard – this prevents them from changing until you relax pedal pressure. The gear selection comes from a right-hand twist grip with 7 click-stops. Unlike my previous experience with hub gears, the slackest cable position comes with bottom gear, not top, so I’ve spent a few days getting used to that, but otherwise, there’s nothing to learn, more like un-learn really.

The hub is available separately for you to have wheel built around it. In this state it costs around £90, which is about the price of Halford’s cheapest bike! The add-on brake costs a further £20, so getting the whole damned Trek bike for £200 seems like a good deal, especially as it had cost £500 a year before. A complete new rear wheel with rim, spokes, gears, tyre\tube and brakes would cost about £150 at these prices.

USING THEM

Pulling away from lights, you can click up through the gears like a racing driver would, although of course, your 0-60 time is hardly likely to impress Jeremy ‘Phwoar’ Clarkson. You do get the odd look of begrudging approval from motorists as they overtake you 50 yards further down the road than normally expected. More frequent is the querysome look from other cyclists, some of whom actually venture to ask where I got the gears from, and don’t I know it’s illegal not to have a back brake (well, it’s not obvious that I have one at first glance).

Maintenance is almost non-existent. The unit is sealed with long-life lubricant, and the gear change cable is only likely to need adjustment if you have a puncture involving rear wheel removal. Here again, it’s not difficult. You select fourth gear and line up two red marks on the cable linkage. (See picture below) Minor amounts can be achieved by turning the cable-adjuster at the twist-grip end.

There doesn’t seem to be any dead ‘neutral’ spot to take you by surprise as long as you keep the gears adjusted. These can leave you flailing wildly just when you expected to be meeting maximum resistance from pedalling, and do untold damage to your chances of having children.

The hub is a smart if slightly bulky drum, with a high gloss stainless finish. It doesn’t seem too difficult to keep clean. One thing that becomes apparent, especially if you own a bike with dérailleur gears too, is that this one’s chain is a more solid affair. This is because it doesn’t have to perform any contortions bending sideways with this kind of gear – it stays parallel and aligned with the two gears at either end of it, therefore a slim chain is not needed.

Freewheeling emits a slight clicking, and there is a faint ticking noise emitted whilst pedalling in top gear. Curiously, the old Sturmey-Archers did this too. I have now done many miles of road commuting with these gears, and I have to say that they’ll become my ‘gears of preference’ for general urban use. My 24-speed bike will be nice when it’s re-sprayed and it will stand me in better stead over longer distances, but the Trek with 7 speeds is my baby for now. Ironically, with more ratios, the Shimano Nexus would also be a good gear mechanism for off-road use as there are no external parts to get muddy (or banged on a rock) or brakes to get wet, unless you ride through least 15” of water. The only ‘off-roading’ I do is mounting a kerb to use an ATM.

All I need to do now, is get rid of those treadless slick tyres proclaiming ‘FAT BOY’ in large red and white letters, for something a little more staid, possibly with some TREAD, as befits my ‘advanced years’ and a less insulting motif, ‘Pleasantly Plump, But At Least I’m Exercising’ perhaps!
 

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