SON Rear Light - Seatpost Mount - Black / Red

Customer Reviews (2)
4 / 5| Write your review
£69.99 Please note this product has selling restrictions to your country. was
Manufacturer : 
SJS Cycles part number : 
Manufacturer part number : 
The SON rear light is of minimalistic and robust design as well as noble looks. Many customers have been looking for a rear light like this for a long time. Now also sportive bicycles that don‘t come with rear racks can be equipped with dynamo-powered rear lights thanks to versions for seatpost mount and mudguard mount. They fit technically ideally and are of good looks just as well.

The rear light has an anodized aluminium housing, electronics and optic parts are potted watertight. The coaxial cable for connection to the headlight is firmly fitted. With standlight.

- Fully watertight
- Milled aluminium housing
- Impact resistant
- Coaxial cable for headlight connection
- Integrated standlight capacitor
- Compatible with all common dynamo-powered headlights
- 190cm cable

Available in Rack Mount (50mm spacing) or Seatpost Mount (26 to 31.8mm)
Product Reviews (2)
Questions & Answers (5) Q & A
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Product Reviews (2)
Overall Product Rating 4 / 5
Works well, wish it was on par with the front light
By Bruce Edwards
05 Jan 2021
3 / 5
I recommend this product
ConsExpensive and only 1 light mode
ProsWorks well with SON ecosystem.
Does the job and pretty bright. Wish there was a flashing version (non German regulation compliant).
Crimping and heat shrinking the connectors to hook up to edelux II front light was straight forward and managed to internally route the cable. Also added some solder to the crimped connectors for a better contact and to add durability.
Wish that the cable could be disconnected at the rear to make internal routing a more practical and flexible option allowing the light to be more easily disconnected an demounted.
Got the larger wire so I could mount it on the seat tube instead of the seat post which works well and gives a lower position so it's still visible with a bikepacking seatpack mounted.
If doing lots of night riding I would add a battery powered rear light with a flash mode for UK riding for a bit better visibility and peace of mind.
Brilliant light, great customer service, I'd highly recommend
By Anonymous
10 Jun 2020
5 / 5
I recommend this product
ConsShrink wrapping is a pain to fit
ProsSecure, discreet fit, bright light
Moderately straightforward to fit after watching a video and reading the instructions, but applying the shrink wrapping to to protect the cable connections is a pain to get right. not sure there is anything which could be done to make that easier though. The fit is very secure on my bike and the finish is brilliant. The light is impressively bright and has a capacitor fitted to give a stand light after a few rotations of the dynamo.

I chose this rear light on recommendation after sending a message to customer services. I got back a very helpful reply sent with little delay.

Thanks for your help!
Questions & Answers (5)
Cable length
21 Mar 2021
What is the length of the cable supplied with this light? Thanks.
Thank you for your enquiry, it is 190cm

Wd 22/03/21
25,4mm seatpost and product photo
26 Jan 2020
1. According to the instructions there is a rubber shim to attach the light to a 26mm seatpost. I assume it's possible to attach it to a 25,4mm seatpost using a thicker rubber piece, right?

2. Is the second photo correct? It looks like it belongs to the rack mount version.
Hi, yes rubber shims are included for different diameter posts. You are correct the second photo is wrong, we will update it. Thanks 27/01/2020
A couple of questions...
11 Aug 2019
I have a SON28 which powers an Edelux I front light.

1) Can I power this rear light by connecting to the spare socket on my Edelux light ?

2) The SON28 develop 3 watts of power. The Edelux I front lamp that I have consumes 2.4 watts. What does this rear lamp consume and would the total load stay within the 3 watt rating for the dynamo ?

3) HOW does this rear light get secured to the seat post e.g. how does it tighten securely (this doesn't seem obvious from the photo or any descriptions)?

thanks in advance....

Yes the SON28 can happily power both of these SON lights you mention, you simply plug the wire into the bottom of the Edelux, and run the extra onto the spade, connecting to the side of the bracket so it grounds there.
The rear light using a rotating wheel to tighten the bracket.

Thanks - 12/08/19
Do You Think This Lights Bracket Could Fit A 32.4 Mm Dia. Seat Tube?
14 Apr 2017
Or can you envisage any work arounds to make it possible?

Unfortunately this light would not be able to fit to a seatpost with a diameter of 32.4mm as the band the hold it in place is not long enough to cope with a post of that size. There is no work around that we know of that would allow this light to fit to a larger diameter post I'm afraid.

Will This Connect To My Existing Son Dynohub/Edelux Setup?
08 Sep 2015
Do I need to do anything special?

All of the cables and fittings are supplied with this rear light so you should not need anything else to fit it and to wire it up to your front light.