See Sense Ace (Rear)

Click here to buy for £44.99

Before I kick off with this review it’s really worth re-reading my review of the See Sense Icon rear light which you can find here but also my Q&A session about their future which you can find here.

It’s also worth remembering how we got here. Below is a pic of the original See Sense light. It was unique, it was brilliant but it was a little eccentric. No on or off buttons and relied on you to turn it upside down, rotate etc to turn it on and off and alter stuff. It’s brilliance however, is without doubt.


Skip forward to the Icon, launched a few years ago, and we get less eccentricity and more features, such as the mobile app and improved performance in relation to braking and auto detection. It also got quite a bit smaller. But, skip forward another few years and we’re really ramping up how small a light can be while still incorporating the features of its predecessor.


It’s super cute. Bear in mind too that the Icon, pictured left above, doesn’t have it’s mount in place and that the new Ace, even with mount, remains smaller than the Icon without mount. It’s considerably lighter and just, very sleek and modern. Some of the surface area is clearly lost by the smaller size but, in practice, that doesn’t amount to any change in visibility or brightness. It does lose some lumens to the lesser of the two original Icons (2 x 95 lumens plays 125) but that doesn’t really amount to very much. It really is an excellent evolution of what was actually a pretty amazing bit of kit. In a world of spin and review I can honestly say that the Icon has always stood out. It’s ever present on the darker days and just keeps on going.



Let’s start with what’s in the box. Even the box itself is way smaller than the one that the Icon shipped in. It’s hard to believe there’s a light in there. Another bonus is that it should, even with packaging, slip through the letterbox if you’re not at home.


It’s pretty much as before, so you get mounts, rubber bands, instructions and a charging cable. The eagle eyed amongst you will note that before, the Icon had arms either side to take the rubber band and that, in essence, it’s mount was built into the charging cover. That meant should you want to go aero or mount in some other way, you had to bodge or buy additional mounts. Now, the light is just the light and the mounts are elsewhere. Given the astonishingly small RRP (£44.99) for a 125 lumen light the amount of stuff you get is truly impressive.


Taking a look at those mounts, you get the main mount (centre), an aero mount (left) and a clip mount. The latter is a great idea for sticking it to rucksacks but also, if you’re a winter runner, this could be a great addition. Now you stick the main mount on, say, your seatpost, attach with the right size rubber ring and then clip your Ace into the bracket. More on that in a moment.


You get a comprehensive set of mini instructions which you should keep safe. It’s good to say actual instructions included rather than sending you to the internet or the App. On that, the iOs version is live (and I’ve therefore screenshotted that later) but the Android version is a week or so away at the time of writing. Everything works WITHOUT the app but you get more functionality and control with it. We’ll also come back to that.


It really is tiny. The power button is straightforward, long press for on and off and then presses to cycle through different types of flash. The rear has a small plastic cover to keep the rain out. It’s IP67 rated and, provided you don’t stick it absolutely in line with your tyres in the wet you shouldn’t see any problem. You shouldn’t get any issue with IP67 anyway, given that the test is to withstand 1m of water for up to 30 minutes, but it’s good to be sensible, particularly if you’ve not reinstalled the cover correctly. Around the right hand visible side on the photo you can see a series of notches (which are also present on the other non visible side). Those allow you to clip the light into place in 3 positions. Thee effect of that is to mount it neutrally or with an upwards or downwards angle depending on what your seatpost is like. Because the mount remains on the bike (you unclip with a small fixed lever) removal is much much easier than before. It’s probably worth investing in some spare mounts if you want to move even quicker between bikes.

I’ve not been able to test the ANT+ connectivity as my Fenix 5 doesn’t pick up the sensor but I understand that it does work with devices such as the Garmin 1000 in effect as if these were Garmin lights, i.e. turning them on and off etc.


In use it’s 125 lumens, will run for 10 hours and is really really bright. You get a series of flash types ranging from solid to psychedelic. If defaults to 100% brightness, which is easily good enough for the day as well, but, using the app, you can turn this down. So, let’s take a look at the app.


Connection is ridiculously easy and it paired first time with no issues. You can turn it off and on, engage brake mode, change the flash cycle etc, just like you could do before. It’s a way better looking app, clean and efficient.


Once again the auto crash alert and auto theft alert are present. I’ve set mine up, tested it and it’s pretty seamless. As with my previous icon review I can’t test falling off so we’ll take it as read. The theft alert can be set to particular zones. You can see how effective the old one was here.


All those reactive technologies are still there. So, as stated on their website, “When you face moments of increased risk on your commute (e.g. at junctions, filtering traffic or high-stress intersections), ACE reacts by automatically flashing brighter and faster to make you more visible to other road users. It also shines powerfully both in daylight and at night-time, helps you be seen from over a mile away, and gives you 200° of side visibility.” There is always criticism of gimmickry from some quarters in relation to bike safety but, for me, the Ace (and its predecessors) are just better lights than the competition in what they offer as extra protection.

And then, then the really clever stuff. It’s hard to evaluate, yet, how successful this is but it has to be a really good thing. Have a look at how See Sense are helping with connected cities and cycling safety here. There will, inevitably, be comments about data collection but the whole thing is compliant, anonymised and really really helpful. If it even achieves half of its aims then we really are looking at a truly useful societal product. A game changer. Which is probably why British Cycling have made See Sense their official light supplier and crowdsourced data and insight supplier. A partnership that will only help to develop See Sense’s exposure and lead to further future innovation.

Much of what we have in the Ace is as before. It’s that bit better, that bit smaller, that bit more useful, and then we come to the price. It’s £20 cheaper than the Icon and 2 years on. Ok, it’s technically a little less lumens but it’s practically as bright, it’s lighter, it has more useful mounts and it’s just a brilliant little thing. Get one, get the front as well, in fact get them as a bundle and that’s a mere £79.99.  They’re essential lights, as cheap as the non smart competition. Ace? Excellent product name, bang on.

10 thoughts on “See Sense Ace (Rear)

  1. I have the Ace connecting with Ant+ to my Garmin 520. the firmware needed to update first though as out of the box ANT+ wasn’t working – but the IOS app alerts when new firmware is available and allows you to upgrade.

    Ant+ connectivity doesn’t seem to be polished yet though – I think there is some way to go. On powering up the Garmin it detects my Ace Rear, creates a light network, and switches it on. You get low batter alerts on the Garmin too. – This is solid and works well. There are numerous options in the 520 Lights menu which don’t correspond with the flash/solid modes in the IoS app – so you cant select “Constant”, “Flash” “Twin” etc on the Garmin interface – I leave it on the AUTO setting and it seems to be fine. Garmin interface also offers to switch on lights when you first power up the Garmin or when you hit “start ride button” this is “Timer” in Garmin speak. This Timer option doesnt seem to work yet with ACE – selecting it still seems to make light just switch on when Garmin first powers up. Switching off across ANT+ doesnt seem to work at all yet – I would expect Ace to power off when Garmin is powered off – but it doesn’t – it just keeps going. Similarly on the Garmins “Timer” setting I would expect the light to switch on & off again in sync with the “Timer” but it doesn’t. There also seems to be some glitchiness when you select a certain Light Pattern from the IOS app – this selection doesnt always correspond to what the light does when you switch it on by powering up the Garmin.

    I’m not sure how useful crash detection is for me when 520 offers it anyway (maybe I will try a comparison to see which is most sensitive/best)

    I am a bit concerned about the mount though – it looks as if the light might pop out of it when I am shredding the gnarl to the max through Hailey Park – so far though its been robust and not budged a mm though – but for peach of mind I’d like a small hole/tab for a string loop to catch it if it fell.

    All in all though a very bright/powerful light in a small and easily mounted package – obviously some ANT+ niggles to be worked through – but the firmware upgrade process seems to work well so fingers crossed any niggles will be resolved in due course.


  2. Great write-up, and thanks! I am very happy with my Garmin Varia 510. I will never give it up, but this is a nice alternative IF you’re a commuter or city riding. Less so if you are a road rider, where the Varia technology shines. If you haven’t tried one, you owe it to yourself to give it a go.

    Liked by 1 person

      1. It is rather a lot. I have to say, I don’t think the ace is just for commuting, I’ve used the icon as pure road cycling for years. Also my commute is 17 miles each way in the pitch black at this time of year.


      2. The actual light output is not as bright, however it has variable flash frequency as a vehicle approaches which actually is more attention getting than just a constant flash frequency. Plus the added benefit that you see on your head unit whats behind you without turning around or looking in a mirror. It’s especially valuable in noisy traffic where your audible clues are diminished. YMMV!


  3. ANT+ integration – I have updated the firmware using IOS app (was very straightforward) so my rear now talks to my Edge 520 via ANT+. Communication between the Garmin and Ace is now robust but I don’t think the firmware is the finished/polished object yet. When you I power up the Garmin then the Garmin creates a Light Network and the ACE will switch on, but some of the options in the Garmins LIGHT menu don’t correspond to the ACE Light options that are in the IOS app. I just left the Garmin light menu selection at Auto. The Garmin options (presumably for Garmin lights) allow you to select for the Lights to come on either when you power up the 520 or when you hit Timer – (thats when you hit the button to start recording a route to you and me). The Ace switches on for the power up option fine, but if you select the Timer option – it still seems to come on when you power up the Garmin…rather than waiting until you hit the start/timer button. Whether you are in Timer or Power mode the ACE doesnt seem to switch off when you power off the 520. As I don’t have any Garmin lights I’m not sure what the expected behaviour should be…but just remaining switched on when the computer you’ve synced to has been switched off seems wrong.

    ACE will tell you via the 520 when its running out of power – I found this quite handy the other day when it piped up to let me know it was flagging, having said that it must have lasted another 30mins or so easily so a reasonable margin.

    On occasion the mode you select via the IOS app doesn’t seem to be preserved on the unit if you subsequently switch it on and off via ANT+/Garmin. So there’s definitely some scope for refining the firmware a bit.

    Physically the unit is excellent – small and very bright . I am a little wary of the clip – it looks as if the light will just pop out of the clip whilst I am shredding the gnarr to the max on the Taff Trail but so far its been rock solid – including when I’ve bumped up and down some steps that were enough to set the EDGE 520 crash alarm off (oh yes crash alarms – I now have 2 – one on the Garmin and one on the ACE – which one is best/most sensitive/oversensitive – I don’t know yet – I haven’t deemed it necessary to set it up on the ACE…the Garmin one seems to work). For piece of mid for those of us who fear the unit popping off it would have been nice to have included a small hole/tab through which you could loop a bit of string to catch the unit if it did decide to pop off though


  4. At the moment (October 28, 2018), the ANT+ performance with my Edge 1000 is disappointing. Front light connectivity has been disabled, because of issues with connecting multiple lights to the Edge. Rear light connectivity is unreliable – the connection drops out repeatedy. Both issues are supposed to be fixed with future firmware updates.

    The quality of the rubber connection bands/o-rings is iffy too. I snapped two of them when installing my lights.

    My personal experience, YMMV.


  5. I can’t get pairing with an Android phone, so I’m not able to benefit from all that cool stuff. Nor am I able to update the firmware. I see from one of the other comments above, that a Garmin 520 will connect once there’s a firmware upgrade, but that doesn’t help me. I’m waiting to hear from see.sense for any recommendations.


      1. They provided access for me to the Android Beta of their software app. Android easily connected to the device, and it was able to update the firmware for the device. Once the firmware updated, the Light quickly connected to my Garmin.

        The beta is not fully functional, but at least the basic connectivity is now working.


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