Silva Spectra A bike light review – brilliant light, dreadful bike fit

Originally published on 9th January 2023 and given a two-star rating. We have subsequently downgraded the rating after additional testing. 

Silva’s new Spectra A bike light is by far the most powerful I’ve ever tested with a crazy 10,000 lumen headline output. With such a powerful output it easily competes with the best mountain bike lights, however, the head unit is let down by almost every other part of the design when it comes to bike use though so it’s not going to feature on our best mountain bike lights list without a big rethink though.

Design and build

The huge power of the Spectra comes from a three, two, three pattern of eight Cree XLamp XHP50.2 LEDs behind individual LEDil TINA2-RS lenses. These sit in a flat face with deep wavy fins across the back of the head for maximum cooling. The head hinges onto the bar mount block with a thumbscrew on one side to set the angle and plus and minus power switches on the front. This then slides into either an equally bulky offset bar mount or a glue/strap-on helmet mount.

You’ve then got a laptop-style battery (as in its shape and not far off the size of a laptop) with a massive 96Wh capacity and a five-step LED charge indicator along the side. This connects to the lamp with a thick cable with a very well-sealed connector and the whole system is IPX5 water-resistant rated. 

The A kit comes with a bar mount for the Bluetooth remote, a neoprene wrist strap, and an extender cable to work with the helmet mount. GoPro-style mounts, a 'battery harness’ backpack, a carry bag, and a splitter cable to use two batteries (£170.99 / €200 each) are available as extras. 

Performance

Turning ‘night into day’ has been a light marketers cliche since the early days when it meant a feeble pool of yellow light that reached barely beyond your front wheel for a few minutes. It’s fair to say that the Spectra A has more light than you’re ever likely to need at bike speeds though and I’m not surprised that the helmet mount images are on Motocross/Snowmobile helmets. The eight LEDs give a decent breadth of spread with soft edges too. So while most of the power goes straight down the center there’s enough peripheral to run the bar light on reasonably twisty, technical trails without wishing you had a helmet light as well (apart from on tight switchbacks, etc. obviously). 

While thermal throttling (reducing power if the light overheats) means we couldn’t get an accurate run time at consistent max power the three-hour warm conditions burn seems possible. That drops to an hour in sub-zero conditions but I still never worried about getting home even on epic winter night rides. Not least because I was generally fine running the Spectra in the level two (800 lumens) or level three settings (2500 lumens) occasionally using level four (5,000 lumens) for the fastest, sketchiest descents with level one (80 lumens) for admin like van loading, lighting up trailside repairs etc. The five levels are controlled from the base of the mount or a Bluetooth remote that sits on a rubber bar mount or neoprene wrist strap with a tiny LED traffic light on the side to show the current mode.

There’s also an automatic dim to 250 lumens ‘limp mode’ as soon as you hit the last 10 percent of battery life. We’ve had no issues with leaking or misting on very wet/cold rides either and the flat face makes the light easy to wipe clean if it gets covered with spray. Do that quickly though as it’ll bake on with the heat otherwise. 

The charger is a specific plug-in block rather than a more convenient USB but it’ll fill the pack from empty in four hours and you get all the interchangeable heads needed to take your Silva globetrotting. I’ve had a Silva running headlamp for years which has never faltered so hopefully, the Spectra will be similarly reliable too.

Problems

This all makes the Spectra sound very impressive so far, and it’s certainly got real uber-light potential. Unfortunately from here, it’s a list of issues so long and basic that I wonder if they’ve actually used it for real mountain biking on a modern bike.

Unless you crank the tiny T15 Torx bolt up as well as the thumbwheel, the head mount will flop forwards or fall backwards as soon as things get rough. The bar mount isn’t slotted either so fitting and removing means completely unthreading and rethreading the very long bolt. There’s no upper lip/visor on the lamp head either so if you get over the front out of the saddle on a climb etc you get blinded. The mode buttons on the front are really hard to reach and the mount is unnecessarily bulky.

The remote switch helps but the LEDs on the side are hard to read, it’s really easy to knock out of its bayonet mount without noticing and it loses charge very quickly so it’s been a non-starter on several rides. Unlike a lot of far cheaper lights that have an app for changing modes and run times, the Silva is stuck with its presets.

The indicator on the battery is useless too as you have to slide a neoprene sleeve over it to attach it to the frame using very thin, over-stretchy straps. The flat, broad shape means you have to let it dangle vertically under the top tube although I rarely had space for this, except on hardtails/gravel bikes, if I was running a bottle. With the battery in this position, the battery swung and slid about as soon as the bike moved. That meant I generally had to balance it on top of the top tube where it constantly knocked my knees out of the saddle or fell off sideways as the straps were too stretchy.

Any hope of helmet use salvation was short-lived too. The long strap slots make it hard to get a secure mount from either of the sets of straps provided. As a result I tried five different helmets before I found a vent/flat section arrangement that worked without obvious wobble. The weight and super tall format of the head unit was bearable for gentle trail use – if carefully mounted dead center. A second ride with a few jumps and drops was such a neck straining nightmare I had to remove the light completely before it ended up giving me whiplash.

Verdict

Silva’s Spectra has more light power than anyone is likely to need with the run time to back it up so there’s the potential for it to be the ultimate off-road light for the most demanding, extreme, and epic riders. There are multiple practical issues with almost every aspect of actually using it on a bike or on your helmet though.

Finally, considering the massive price, the control and customization options are disappointingly primitive, which completes an initially promising but ultimately very frustrating offering from the Swedes at Silva.

Tech specs: Silva Spectra A

• Price: £669.99 / $799.99
• Weight: Head and mount 258g, battery and sleeve 585g