Shimano Nexus DH-UR700-3D Dynamo Hub
32hole 544g inc skewer 6-month test £144.99

The Shimano Nexus DH-UR700-3D Dynamo Hub offers a high specification and relative simplicity compared with other contemporary dynamo hubs. This means some servicing e.g. bearing overhaul is within the scope of many enthusiast home mechanics. Drag is reassuringly low and overall performance is impressive. Then there’s weather sealing. A combination of contact AND labyrinth seals gives superior protection from the elements. The only minor consideration is that it's best suited to larger wheels (i.e., 26, 700c, 650b) and 32 or 36 hole drillings may limit the appeal for some riders.

Pros: Solid build quality, labyrinth & contact weather seals, reliable output and modest resistance.

Cons: Only 32 or 36 hole drillings, not suitable for smaller wheels.

Specification

Hub dynamos have come along leaps and bounds since the early Nexus units (I still have one 25 years down the line). Sure, there’s still some resistance but the drag is negligible in comparison. This Nexus is a 6v3w model, promising great output, especially with the latest generation of high-power dynamo lights, such as the K-Lite Bikepacker Ultra .

The latest internal construction is designed to further reduce drag. This extends to the hub’s bearing races, which are treated with Borozon and mirror polished for smooth, precise bearing rotation. Cup and cone bearings might not set the pulses racing but are easily found and don’t automatically mean tearing down the hub and sending away when they finally get the grumbles. In this instance, Shimano employs a grease seal along with the belt ’n’ braces contact and labyrinth seals to lock the grease in and elements out.

That’s not the green light to go river riding, bog snorkelling or blasting with pressure washers but should resist the worst winter can chuck at them. The barrel shaped shell is made from forged aluminium alloy, treated to a double anodised finish. Ours was black, but there’s silver should you prefer. Centre lock disc mounts make a lot of sense and are my preferred choice over the 6 bolt designs, which can succumb to corrosion related issues more readily, if you’ve not been liberal with the thread lock and careful with the torque wrench. The T25 Torx heads are also more prone to rounding off. Conversely, they’re easier to tame mid tour, since the T25 Torx bit is pretty universal on today’s multi-tools.

Test Bikes & Contexts

Ours arrived at the close of summer and I’ve been doing a fair mix of pre-dawn and late-night outings during this phase before racking up six months of steady miles. Denise, my gravel build runs an 800 lumen Exposure Revo Dynamo headlamp and I’ve done plenty of miles along gravel roads, singletrack and rural lanes resembling Paris Roubaix, thanks to a combination of torrential rains and crop harvests.

Contexts such as these should test seals and resistance. It’s also been switched to my fixed gear winter/trainer (running the K-Lite Ultra Low Drag Dynamo Light, disc brake and 700x30c road rubber. I should also point out I’ve only run front lights from the hub.

Resistance 3.75/5

Coming from the Shutter Precision SL9 resistance was palpable during acceleration, but, while the SL9 requires a consistent tempo to sustain the full lumens offered by higher power dynamo lamps, up to speed, the Nexus requires less input to achieve full power. For the most part, this wasn’t obvious on flatter sections, but clear on sustained climbs, especially when I was grinding along at 9mph or so, weary at the close of a long ride. On par with the Shutter Precision SP8, like for like.

Direct comparison with the Alfine is trickier to quantify, since the Alfine is built into a 26-inch mtb hoop. However, the Nexus has a slight edge on paper and, in my experience, when traversing similar terrains-on and off road. This may also be attributable to its 80g weight advantage.

Output 3.75/5

Much as I've come to expect from 6V3w models, including its Alfine Counterpart and of course, the Shutter Precision PD8 . Obviously, choice of lamp and capacitor plays its part, but I've found ours delivered the full 1300lumens from the K-lite family of dynamo lights at 13mph, and from 6mph, 250 lumens from the Exposure Revo from 6. This has been very practical for nocturnal trail adventures, provided a consistent and reliable beam pattern, meaning average speeds of 15-17mph.

Not on par with a battery powered trail lamp but plenty of navigational clout and, again, I've not been battling drag - I've regularly switched the lamp off and on and have been pleasantly surprised by how efficient the hub feels. So much so, and in keeping with the PD8 and Alfine units discussed earlier, I've been happy to leave the lights on, as a daylight running mode.

With high end lamps, such as the K-Lite and Exposure Revo, a sudden loss in tempo, say tackling a climb, or technical terrain has negligible effect upon the output, whereas models such as the SL9 favour a consistent tempo - consequently, I tend to climb out of the saddle and charge inclines, especially on the fixed, given there's little choice with ratios in the high 70s. The socket plays very reliably both with the standard plug type and those of the K-lite, continuing the reliability of connection, although, I always put a precautionary lick of Vaseline on the contacts to rule out midwinter's wet and sometimes salty stuff causing mischief.

Not streets ahead of the Alfine, PD8, or SP8 units in terms of resistance and output but where it really scores are in terms of weather sealing and serviceability. OK, so unlike some models, there is scope for bearing replenishment and re-greasing from the workshop - 17 and 16mmmm cone spanners, 13mm open ended for locknut, rather than do not pass go, return to the factory.

Durability/Care 4/5

As I said in my opening paragraph, while I've naturally deep cleaned the bike weekly, I've also been hossing along some very slimy, waterlogged backwaters, unmade roads and similar. It's worth noting that while labyrinth and contact seals are very belt ’n' braces they are only designed to protect against ingress from a deep puddle, not jet washing, or similar abuse.

That out of the way, the hub's finish, seals and other components look packet fresh This doesn't surprise me, given my long term, hell and sometimes high-water experience with Shimano hub dynamos. The Alfine has served through at least two hellishly wet, salty and generally grotty winters without so much as a blemish. I've also waxed components periodically, which obviously helps but does illustrate their finish quality.

Value 3.75/5

£150 is arguably midpoint. Shutter Precision PD8 is £30 cheaper at £119.99 and available in 32-, 36- and 24-hole drillings. Efficiency is reckoned to be 72% and I’ve been impressed with their performance long term. However, they “only” feature contact seals and once the bearings are cooked (20-25,000 miles, in my experience) the hub will need to be returned to the factory for stripping.

The Kasai Dynacoil 6 Volt Disc FS comes in at $169.99 (£129.53) Available in a choice of black, or silver and 32, or 36 holes, it is designed to be “field” serviceable i.e. repairable with common workshop tooling, which theoretically overcomes the need to tear the wheel apart and returning the hub to the supplier/factory.

However, the quick release (rather than thru axle) version only comes in a 6 bolt, not centre lock pattern, which makes sense, given the field serviceable tag but may alienate some. The SON 28 is something of an institution with a 5-year warranty and compatible with wheels between 16 and 29 inches. It’s also available in 5 colours, should this be important. However, it is not intended to be user serviceable and is £80 odd dearer at £232.

Summary

There are some minor compromises - 32, or 36 drillings will cater for most tastes, but not some specialist builds. There are also better choices for smaller wheels. Otherwise, the Nexus might not be exotic, but an extremely well-conceived, smooth running and well-sealed choice for general riding, one that has proved to be a superb companion for high power dynamo lamps.

Verdict: 4/5 Minor compromises aside, a solidly made and dependable hub dynamo that copes handsomely with high-power lamps.

Michael Stenning

Madison.co.uk – The UK’s largest cycle parts & accessories distributor

PUBLISHED MARCH 2025

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Shimano Nexus DH-UR700-3D Dynamo Hub 32hole 544g inc skewer 6-month test £144.99