Rear light suggestions for an aero seatpost - S3

Hello, I have a Cervelo S3 with an aero shaped seatpost. What are people using for rear lights in these situations?
Thanks for any suggestions.

Garmin Varia would work. It has mounts for aero seat posts.

You get that sweet sweet radar too.


The Lezyne rear strip drive models fit aero posts. I had one on my S-Series post too.

Can’t really tell from the photos but there a sharp cutout in the back of it that holds it in place on wedge post shapes, and a more rounded general outer zone that means it also fits round posts.


I dont have aero post but radar is pretty sweet. Was a skeptic until recenlty.

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This fitted to a Cervelo P3 aero seat post,plenty bright enough for tt’ing


I have one of these on my Propel, it might fit the S3 but the mounts are specific to the propel aero post

I know it doesn’t directly answer your question but I have been mounting a light on my saddle rails while i shop around. I just loop it through them and it is visible from behind.

Also: there are lights that mount on rear stays which also might be an option


Moon LX70 - one of the best rear lights I’ve ever owned and perfect for TT bikes with funny seat posts.


Bontrager makes the Blaze rear light and I love it. I got it to use it on my old BMC TMR01 which had an aero seatpost. I loved it enough to move it over to my Masi Evoluzione (regular seat post)… And then bought more to put on my my gravel and TT bikes (Trek Speed Concept, which also has an aero post and it just fits).

One more skeptical convert to the pricey (~$200) Garmin Varia. It transforms the experience on shoulder-less rural roads with light traffic – where I ride a lot. It reduces overall stress enough to be well worth extra cost – but I had to try it to believe it. If I were mostly in urban traffic, probably not. Or highways that have cars every few seconds but also an ample smooth shoulder I might also see it as just a cute gadget. But on narrow roads that we really do have to share every minute or two – worth every penny.

I love my See.Sense Ace, haven’t tried the aero mount but it looks like it would be effective.

Another vote up for the Varia Radar, its a great rear light, great battery life and I find it gives you a situational awareness without distracting from the most important view, your forward one! Another bonus is I find myself riding less in the gutter and tighter in when required. To me it’s got to reduce your overall chances of a rear end incident.

Also Posted this on another thread a while back, appears for a price you can get mounts for almost anything here, the link is for gopro mounts for aero tube seats but I’m sure you can do your own searches on the site. I’m sure the Varia mount supplied would suffice for your aero seatpost…

Moon nebula is great

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Ive been using Specialized Stix aero mount on my S3 seat post for a bit over 2 years now. Both the light and mount have held up VERY well, and affordable.

I use a Cycliq Fly6, which is a dual real light/camera. Comes with a mounting adapter for aero seat posts. Pricier than a regular light but after a couple of my friends had vehicular run-ins, it seemed like a worthwhile purchase.

I use the Varia radar too. The aero seat post mount that came with it is no good for D-shaped posts (like my Canyon Aeroad). A tiny bit of effort with some Sugru fixes pretty much any issue like this though - now I have it mounted upside down to the seat tube of the frame - looks almost integrated, and sits out of the way of my big fat seatpack aeropacking coolness!

+1 for the Garmin Varia. Knowing when a car is approaching really takes the stress level down.

I have an NK1K…which has a seatpost that doesn’t have a circular cross section.

I just put one of these lights on each seatstay instead of putting a light on the seatpost.

I was a varia skeptic…now convert. If this industry wants to talk about “game changing” items, this is one that actually could stand up to the commentary. Being able to ride along in a paceline, even mid-pack, and get the notification that a car is approaching from the back really does improve situational awareness. In the month that i have had it, its saved me a few close calls from drivers sneaking up and not giving enough space.

If you do go the route of a normal light, the only one i would recommend is the bontrager Flare R. That thing burns retinas and makes you visible on even the sunniest days from hundreds of yards away.


Not specific to aero seatposts but the Exposure Lights TraceR can be mounted to the rails of your saddle and is tucked away nicely.