Busch & Muller Toplight Line Plus Rear Light Owner Review

Busch & Muller Toplight Line Plus

Busch & Muller Toplight Line Plus

I have updated the lightening system on my Surly Long Haul Trucker to a dynamo powered system in part for winter commuting duties but also in preparation for my forthcoming Dreaming Tour where I require access to power on the road (Super-i-Cable charging system). This post is about the Busch & Muller Toplight Line Plus rear carrier light, model number 323ALT, its installation and my first impressions. 

The Light

Busch& Muller Toplight Line Plus

Mounted Busch& Muller Toplight Line Plus

First some details about the light itself. I purchased this light from at a cost of $AU23.50. Service from was very good, however the postage as is common with German retailers was slow. I would recommend if you are looking at purchasing these lights.

The model I have is the Toplight Line Plus. The Plus feature refers to the stand light function, that is the light will remain on for a certain period of time after the bike has stopped moving, e.g., at traffic lights. The light weighs approximately 53 grams and is designed to mount on a carrier with 50 mm mounting holes. It also has a built in reflector which is handy for meeting Audax lightening requirements. The Toplight is 94 mm wide, 17 mm in depth and 45 mm in height. One thing to keep in mind, this is NOT a flashing rear light.

The manufacturer’s claims for the light as given on the packaging are:

High quality. World novelty [translation issue I think :)] LineTec: Extremely good estimation of distance for other traffic participants. Patented lens system creates a wide light strip from two high output LEDs (lifespan of LEDs approx. 100,000 h). Fully automatic stand light. Maintenance free: no batteries required, dynamo power is stored in capacitor (charged after approx. 3 min ride). Parking function: stand light deactivation manually or automatically after 4 min.

LineTec is described by the manufacturer as their

patented lighting system with special effect lens. The single light of high power LEDs is fanned into a spatial dimension. The result is a uniformly glowing band of light. Why is this important? Yet at night they approached from behind a bicycle, could see only a single point of light and could not estimate the distance well. Because it takes the eye a spatial relation – particularly in the “spaceless” darkness. A rear light with LineTec lighting emits a “spatial” light. Therefore, other road users to assess the distance much better and faster.


My first impressions of the various features:

Plus: I like this feature. What happens is that a small amount of energy is stored in a condenser built into the light. So when you stop say at the traffic lights, the light draws on the energy stored in the condenser to keep the light glowing. I haven’t tested the time but have seen reports of around four minutes which should be sufficient for most traffic lights. I do however notice that going into stand light mode does drop the level of light output. Something to keep in mind. The light is also fitted with an on-off switch (red button) so one can the off light if desired. Just need to remember to turn it on the next time you go to use the bike.

Wiring: The light comes without any wiring or connectors. It really is designed to be wired to front light. In my case I have it wired to my Busch & Muller Lumotec IQ Cyo Senso Plus. The wiring for the rear taillight was provided as part of the Lumotec IQ Cyo kit. The wiring that came with the front light was more than sufficient to reach the tail light on the Surly. I have the tail light installed on the rear of my Tubus Cargo Expedition.

Operation: The cool thing with this light is that if you have it wired up to front light such as I have done, the front light becomes the controller or switch for the rear light. So turning on the front light on turns on the rear light. It makes it so much easier to use.


Mock-up of the wiring for the Busch and Muller Toplight Line Plus Rear Carrier Light

Mock-up of the wiring for the Busch and Muller Toplight Line Plus Rear Carrier Light

Mock-up of the wiring for the Busch and Muller Toplight Line Plus Rear Carrier Light

Installation was a pretty straight forward process. I first ran the wiring using electrical tape to mock up the wiring in place. In my case I have run the wiring under the top tube, down the rear brake cable and then along the centre of the rack out to the tail light at the rear. The wiring is pretty much out of sight and protected. The wiring can be connected to the light using two spade connectors or alternatively there are two holes in the light and a lever to lock the bare wire into place once it has been inserted into the light. This is the installation method I used. The terminals are also marked negative and positive, however as I understand it, the polarity is only important if there is a DC connection. As I am powering the light from the dynamo via the front light polarity is not a concern.

Busch & Muller Toplight Line Plus Mounted on a Tubus Cargo Expedition Rack

Busch & Muller Toplight Line Plus Mounted on a Tubus Cargo Expedition Rack

Busch & Muller Toplight Line Plus Mounted on a Tubus Cargo Expedition Rack

Busch & Muller Toplight Line Plus Mounted on a Tubus Cargo Expedition Rack

Busch & Muller Toplight Line Plus Mounted on a Tubus Cargo Expedition Rack and the Extrawheel Voyager attached

The light itself is bolted on to the rear rack via two studs at 50 mm apart. My Tubus Cargo Expedition has the mount holes pre-drilled at 50 mm spacing.


The light can be switched on or off at the light itself via the red push switch; alternatively it is operated via the front light. The latter approach is the method I use. So for me turning the front light on or off turns the rear light on or off at the same time. Nice and simple.

Preliminary night riding has been very positive with the light providing good visibility to the rear. It lacks a flashing mode but I do not see that as being an issue.

The Dynamo

SON 28 Dynamo Laced to a Mavic A719

SON 28 Dynamo

The light is powered by a SON 28 dynamo. This dynamo is a new SON model in 2011 and are specifically designed for LED lights.

The Good, the Bad and the Ugly

The Good

  • Stand light feature. This is really cool;
  • Continuous availability of light; no need to remember to charge the batteries. I just love being able to get on the bike and off I go with the lights going. No interference at all by me required;
  • Good brightness and light pattern suitable for an urban environment;
  • Easy to install;
  • Easy to operate on the go;
  • Turning on the front light turns on the rear light.

The Bad

  • Lack of flashing mode is a possible negative.

The Ugly

  • Nothing.

Related Resources

  • For photos of the light in use, see this review
  • dave mccraw reviews the light and includes an interesting seat post mount idea.

8 Responses to Busch & Muller Toplight Line Plus Rear Light Owner Review

  1. Ken Steinhoff 12 December 2011 at 12:51 AM #

    I use the Busch&Müller 4DToplight Senso Multi

    The standlight on it uses batteries. That’s one extra thing to think about, but they last a long time because they don’t come on often. I like the idea that I would have a working taillight if I had a wiring or other issue that would keep power from getting from the generator.

    I use a plastic spiral wrap held on by Velcro straps to hold my wire run.

    I saw a comment you made on that story in 2009 saying you were considering the jump to the SON. Glad you did it. You’ll find out how much nicer that is than hassling with a battery light. (You can simplify your life even more by never turning the light off.)

  2. Max 22 February 2012 at 3:43 AM #

    My mum’s new Vivente has this light on the back. In an attempt to turn off the standlight function, I pushed the red switch on the back. Now the light won’t come back on at all. Of course, it didn’t come with an instruction manual for the light, and I can’t find anything in English on the B&M website. Can you give any insights? Should it just be a matter of pushing the red button again? Or do I need to hold my mouth “just right” to make it work again?

    • Aushiker 22 February 2012 at 6:43 AM #

      It sounds like you have turned off the Busch & Muller Toplight Line Plus. The red switch is an on-off button. If you push the red switch it should go back to working okay. I doubt very much that you could turn off the stand-light function given the way it works. Hope it works again.

  3. JakB 24 May 2015 at 2:47 PM #

    Hello! My setup is SON 28 + B&M Luxos Lumotec IQ2 + B&M Toplight Line Brake Plus. My former taillight was the dynamo powered Brompton taillight. The former setup was working well until I’ve replaced it with the B&M Toplight Line Brake Plus. I didn’t change the wiring connections, I’ve just replaced the lights. Two wires connected the taillight to the front light.

    With the new setup, I can turn on the front light but my rear light won’t light up. What could I have done wrong? Help pls?

    • Aushiker 25 May 2015 at 4:24 PM #

      Sorry JakB I really don’t have a suggestion other than does the Brompton taillight need to be earthed?

      • JakB 25 May 2015 at 8:15 PM #

        I’m not sure, I just connected the two leads coming from the Luxos Lumotec IQ2 to the two connectors of the dynamo powered Brompton taillight.

  4. Massimo 28 October 2016 at 4:31 AM #

    In my toplight line plus, it broke a led, how do you replace it?

    • Aushiker 29 October 2016 at 11:12 AM #

      Buy a new one? Maybe someone else has a better idea but I suspect that is your only option.

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