Dynamo lights offer decent lighting that is always available so that longer rides can be undertaken in the confidence that your lights will not die when you are miles from home.

Dynamo lights are also permanently fixed to the bike and so are less easy to steal when the bike is parked.

There are two issues though:

  1. When you stop moving the power stops so your lights stop shining with potentially dangerous consequences.
  2. Unless the bike has a dynamo factory-fitted to the bike, retro-fitting a dynamo to your bike can be a complex task.

Let’s take a look at those issues.

One way to stay visible when you stop is to fit battery lights alongside the dynamo lights but that defeats the object of not having to worry about checking batteries on every trip. A better way is to invest in lamp units that include a standby or “standlight” facility. This uses a large capacitor to store enough power to keep your LED lights alight for several minutes which is plenty to cover any stops that you have to make in traffic.

There are two types of dynamo, a bottle type which clamps to the front or rear fork-leg and a hub dynamo which is built into (usually) the front wheel.

The Bottle Dynamo

The bottle dynamo is clamped in place onto either the front or rear fork leg so that the drive wheel at the top rests on the tyre as it turns providing your lighting power.

The clamp will damage the paintwork and it can be a challenge to get the drive wheel aligned correctly with the tyre but it is more staightforward to install than the hub dynamo and once set up, it should provide trouble-free service.

A hub dynamo has to be built into the wheel.

It is possible to buy a replacement wheel with the dynamo hub already installed or some bike shops will sell you the hub and rebuild the wheel using your existing rim but this is quite a lengthy task so it will cost.

If you are handy with the spoke key, you might want to do this yourself but you will need to work out which sized spokes you will need to lace in the new hub.

The bottle dynamo is easier to fit but it tends to cause an increase to the bike’s rolling resistance.

The hub dynamo is more difficult to fit but it offers very little resistance and is essentially free power for your lights (or for charging devices if you have an adaptor).