What I learned doing the Dunwich Dynamo on my fixed gear bike

The Dunwich dynamo is one of those ‘organised coincidence’ rides where there’s no official organising body, just an understanding that it’s on the Saturday closest to the July full moon and that it starts at London Fields, in Hackney, and ends up at Dunwich beach in Suffolk. People do tweak the route a bit but there’s definitely a standard by this point, which passes by catered pit stops that volunteers operate for for the hundreds and hundreds of people who’ll pass them by. There’s no one doing proper estimates but I think at least 2,000 people did the 2024 ride.

Despite me having been a cyclist in and around London for about 6-7 years, I’d never done the ‘Dun Run’ before. It had coincided with the now sadly discontinued London Orbital Audax (the night of a full moon being particularly good for long rides to spare you cycle lights battery life). But in 2024 the calendar worked out that I could give it a go.

I don’t really have a proper road bike anymore, so the best I had on offer was my green steel fixed gear bike. The frame and fork was sold to me second hand by someone who said he’d had it custom painted but didn’t like the colour, saying it looked too much like a lawnmower. Fortunately, lawnmower green is my favourite colour for a bike, so it was a great match. I popped all the bits I had on my old Specialized Langster (which I’d had languishing around since a weld failed on it) and put a set of old-timey swept back flat bars on it.

I’d done some longer fixed gear rides before, such as the Audax I did a few years ago before the pandemic, but it had been a bit of a break so the nerves were getting to me a little in the run-up. Luckily, it ended up being a marvellous ride. Hopefully you can learn a bit from this blog post and feel like a fixed gear Dun Run might be the thing for you in 2025.

I started at 6pm and think you should consider doing so, too

Everyone has different takes on when a good time to start the ride will be. Some clubs favour an 8pm start which does mean you probably have less traffic to contend with on the way out from London Fields through Epping Forest. But I wanted to ride in as much daylight as I could, firstly so I could better spot potholes and other road hazards, but also because in my experience with fixed gear riding, being able to see further away makes it safer and easier to keep momentum on downhills to get you up and over dips, because you don’t have the option of just shifting down and spinning your way up inclines.

Because of my earlier start I also had plenty of battery for my lights. I rode with three on the front and two on the back so that I could just switch lights when they began running out of charge.

The earlier start did mean I started my ride in quite a quiet way, as most people seem to stick around in London Fields until about 7 or so. So it felt a little quiet on the roads to start with, but I was soon caught up-with by speedy riders in the hours following.

Because of how early I made it to the final catered rest stop, about 40 km from Dunwich, I enjoyed a nice long break at the Gosbeck Village Community Hall where I could get a good look at the kinds of bikes people were bringing along and say hi to familiar faces.

The actual riding itself

On the whole I’d say the Dynamo is probably one of the best rides to do as a first long-distance fixed gear route. At c. 180 km long and about 1200 metres of ascent, I found my 44/16 ratio very good for muscling up the climbs without my legs getting too spinny on the descents. You should bring enough lights so that you can use them on full beam during the dark hours, because there is no street lighting on the country lanes that make up the bulk of the route and you want to be able to see the road surface ahead for potholes, gravel, broken glass etc.

Eating and drinking

I was very pleasantly surprised with the amount of catering on the ride. It was very much like a five-star Audax in the quality and frequency of tea, coffee and snacks.

I’d prepared by buying a bag of brioches and some sausage rolls, and had 2.25 litres of water to drink with me. This seemed like the right balance to me, coupled with a few extra bits to eat at the catered stops. It was great to see that oat milk was supplied with tea and coffee at all the ones I stopped in at. So I didn’t have to leave my bike unattended outside a shop at any point.

At Dunwich beach itself there are two queues for the cafe. One queue – the long one – is for hot food. But if you just want something to drink or some snacks, there’s a separate shorter one which is a blessing if you just want a can of IPA and a bag of crisps.

The coaches back, organised by Southwark Cyclists

I bought a £60 ticket for the bike return and coach service, organised by London Cycling Campaign local group Southwark Cyclists. I bought it a few weeks ahead of the ride, but they did sell ‘early bird’ tickets for a few quid less. How the coaches work may be different when you use them, but essentially, you queue up at the beach to be assigned a coach (and a lorry to put your bike on). Then you get on the coach when your time is called and you drive back to the drop-off point in Lewisham, where your bike will hopefully turn up at around the same time. Don’t bother trying to ask if they can drop you off somewhere else, this is a massive undertaking with hundreds and hundreds of people and no one is going to tolerate a detour and stop in at your house.

I was very impressed with how it went down. I ended up on a coach which departed from Dunwich at 11am and we made it back to Lewisham, near the Millwall ground, around 2:30 pm. The bikes turned up not long after and the drop-off point was directly on Cycleway 10 so getting back in to London was easy.

A special thank you to the volunteers who made it happen. Your other options are riding back (yikes!), or riding to Ipswich and getting a train, hoping that you manage to squeeze on without being thrown off by a conductor. Lots of people do the ride on folding bikes in great part to make the return trip easier, which is not a bad idea at all.

Find out more

There’s no event website, being as it is, an organised coincidence, but a good resource for info is the unofficial Facebook group https://www.facebook.com/groups/47776534011

It contains a tab with .gpx files and other info you may like ahead of the ride.

The Southwark Cyclists website is where you’d want to visit to get your coach return tickets. Don’t ask me when the 2025 ones will go on sale, I don’t know. The website’s here https://southwarkcyclists.org.uk/

I warmly recommend the Dun Run, just be sure to do plenty of preparation of yourself, your bike, and your return trip, and you’ll be rewarded with a great night’s riding and the best-earned swim in the sea of your life.