So it turns out rim dynamos don’t suck anymore

A close look at Velogical's unique lightweight bottle dynamo

You had probably all but relegated rim dynamos — also known as bottle dynamos — to the history books, but this very neat dynamo from Velogical may make you think twice about their relevance today.

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(Editor’s note: before we get into the detail here, we’ve got a separate explainer to bike dynamos if you want to cover the basics of dynamo hubs and lights).

What makes the Velogical dynamo special?

Bottle dynamos are nothing new, with many bikes of yore having them (or those massive Eveready lights) as standard.

In fact, I expect a good number of you will vividly remember the low grumbling and slipping of a bottle dynamo when run ragged on a descent paired with the fear that it might actually blow up your pitifully underpowered incandescent bulb at any moment.

Times have moved on however and the €150 Velogical rim dynamo presents the pinnacle of modern bottle dynamo design (something I never expected to write).

This neat little alloy dynamo is incredibly well made and is built around super light and powerful neodymium magnets.

The mount looks a little bodged...
The mount looks a little bodged…
Jack Luke / Immediate Media
...but is actually really well made
…but is actually really well made
Jack Luke / Immediate Media

The dynamo is designed to mount on a ‘universal’ U-bolt based mount. This looks a bit inelegant at first glance, but in the hand, there’s no denying that it is a delightfully well engineered and well made little thing.

The Exposure Revo light is one of the nicest dynamo lights on the market
The Exposure Revo light is one of the nicest dynamo lights on the market
Jack Luke / Immediate Media

The dynamo weighed in bang on the claimed weight of 52g and I matched it with an 800 lumen Exposure Revo light (88g). This whole setup is competitively light compared to an equivalent powered battery-powered light, with the added benefit of infinite run time.

It’s worth noting that the Revo is a 3W lamp, meaning that the 1.5W output of the Velogical dynamo is only enough juice to light two of the light’s four LEDs — still more than enough to illuminate unlit back roads.

If you’re interested in the efficiency and drag of the dynamo, this excellent site (German language) has done a better job of testing it than I expect I would have ever been able to.

I chose the red 'Sport' version of the dynamo
I chose the red ‘Sport’ version of the dynamo
Jack Luke / Immediate Media

There are three versions of the Velogical dynamo available. As I intended to use the Velogical dynamo on my demi-go-fast Surly Steamroller test bike, I opted for the red ‘Sport’ model, which is designed to work from speeds of 10kph / 6.2mph and above.

You can learn more about the dynamo on the Velogical website. This long term review of the dynamo by Elessar Bicycle is also worth a read.

Fitting the Velogical Sport dynamo

The Velogical dynamo kit arrived neatly organised into unfussy freezer bags and foam packaging, clearly showing its ‘cottage industry’ provenance.

Fitting the dynamo is a relatively painless affair; the instructions are incredibly detailed and prescriptive, to the point of actually being a little confusing — the imperfect German to English translation definitely doesn’t help, but once you’ve wrapped your head around the basics, it’s pretty straightforward.

There are mounts for the dynamo available in a variety of sizes to fit seatstays and chunky carbon forks, and there’s even a prototype in the works to fit larger suspension forks.

A rather neat looking mount that allows you to fit the dynamo onto cantilever bosses is also available. If you want to totally commit to the system, there’s the option to have a small mount brazed onto a steel frame for the neatest possible solution .

The dynamo ships with little stick-on foam pads to protect frame tubes from marking.

No, the way I've routed the cable doesn't look great, but it works
No, the way I’ve routed the cable doesn’t look great, but it works
Jack Luke / Immediate Media

I will be the first to admit that the way I’ve wrapped the cable around the top tube of the Surly is pretty damned hideous. There are definitely much nicer ways to integrate dynamo wiring into a bike but as I’m planning on swapping this system between different bikes, I don’t want to commit to anything too permanent just yet.

Velogical Sport dynamo — early impressions

I’ve used the Velogical dynamo for many, many miles now and my early impressions are very positive.

My first ride featured the worst possible conditions for a rim dynamo
My first ride featured the worst possible conditions for a rim dynamo
Jack Luke / Immediate Media

My first ride with the dynamo was a very snowy loop around my native Perthshire — the most nightmarish scenario possible for a bottle style dynamo — and despite my hasty setup in a poorly lit laundry room, it performed absolutely flawlessly with no slipping, jamming or other problems.

A dynamo is a valuable addition to any bikepacking setup
A dynamo is a valuable addition to any bikepacking setup
Jack Luke / Immediate Media

Since then, I’ve been on a number of adventures with it, including a very muddy bikepacking jolly over to Wales. Again, the dynamo whirred away without complaint, lighting my way without fear of running out of battery life.

If you’re particularly sensitive to noise on a bike, you’ll probably find the low rumble of the dynamo running on the rim annoying, but I tend to stop noticing it after only a few minutes on the bike.

Disengaging the dynamo is very easy, but the drag and noise is so insignificant that I’ve taken to running it all of the time to improve daytime visibility.

The instructions stress that the wheel should be true to ensure the best performance from the dynamo. However, I have been shamelessly riding my Steamroller with a bit of a wobble in the rear wheel, and I’ve yet to have any problems, with the spring in the mount of the dynamo keeping it tracking fine.

When I first posted photos of the dynamo to the BikeRadar Facebook page, some were concerned that the dynamo constantly running on the rim could leave a mark. While I’m yet to test it on a carbon rim, the dynamo has left absolutely no mark on the Surly’s rims so far.

Who’s the Velogical dynamo for?

In a world where dynamo hubs have got increasingly light, more efficient and affordable, the Velogical dynamo exists as something of a niche product within an already niche market.

The dynamo can be disengaged by turning the small spring into the vertical slot
The dynamo can be disengaged by turning the small spring into the vertical slot
Jack Luke / Immediate Media

However, for those who don’t want to invest in a whole new front wheel or already have a nice set of wheels, the Velogical dynamo could be a compelling choice.

The ability to disengage the dynamo will also undoubtedly appeal to those who want to maximise performance during daylight hours.

Either way, I’m happy the Velogical exists as another option on the market and I’m looking forward to spending more time using it. Keep your eyes peeled for a full review (and a review of the Revo lamp!) in the near future.

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