PRODUCT REVIEW: Blackburn’s Atom SL cyclometer an affordable electronic marvel

Cyclometers I've owned over the years compared to the Blackburn Atom SL.

Cyclometers I’ve owned over the years compared to the Blackburn Atom SL.

As I begin this review of the Blackburn Atom SL 5.0 cyclometer, let me take you for a quick trip down Memory Lane.

I worked for Palo Alto Bicycles mail order in 1984 and we were the first to ship the groundbreaking Avocet cyclometer. After clearing up some early problems with the gate array chip, it went on to be a huge success and was the cyclometer of choice in the Tour de France peloton in the late 1980s.

Since then, cyclometers have matured and we have at least a dozen models and brands. Still, I’m seeing innovation in the Blackburn Atom SL cyclometer.

I bought my first full-featured wireless cyclometer similar to the Atom in 2003 — the Specialized Speedzone Pro. The Atom SL 5.0 (6.0 has cadence) follows that kind of cyclometer, where altitude is measured.

One selling point stands out about the Atom SL 5.0 — price. It’s about $60, 70 percent less than what I paid for the Specialized cyclometer and the VDO. A great value!

Atom SL 5.0 features: Speed – current, average (up/down arrows), maximum; Odometer; Trip distance; Ride time; Time of day; Wheel size; Estimated Time of Arrival (ETA); Temperature; Altimeter; Slope; Total Altitude gain; Maximum altitude gain; 2nd bike setting.

Materials that come with the Atom SL cyclometer.

Materials that come with the Atom SL cyclometer.


Distance: We expect an accurate cyclometer and Atom SL 5.0 does not disappoint. It recorded exactly the same distance — 62.5 miles — as my Garmin 500 on a ride. The altimeter is also precise, within 10 feet of a climb to 2,625 feet on Hwy 9.

Slope is accurate as well, but as with all cyclometers measuring gradient on a steady climb, your numbers will shift as you climb. It’s a quirk that I don’t fully understand, but after a while you’ll know which number is accurate: usually the first one or two results.

Accuracy greatly depends on wheel/tire measurement. This measurement varies with body weight, tire pressure and tire wear.

The manual describes how to get the best measurement by rolling out the wheel for one circumference, but you can do more. Sit on the bike while doing the roll-out. Body weight reduces the rolling distance by 0.5 to 1 inch. Measure several times for the best accuracy.

Entering the measurement in millimeters calls for closely following manual instructions. Note that if you reset the cyclometer, you reset the wheel size to its default of 2150. (My tire setting came in at 2115 mm for a 700×28 tire while seated.)

Altitude: Don’t expect accurate readings at high altitudes. I’ve seen variances of 1,000 feet and more in cyclometers, which I call a “feature.” However, the Atom SL altimeter is 99 percent accurate at lower altitudes (up to 5,000 feet or so), remarkable considering it’s an affordable consumer device.

Bike cyclometers use a tiny built-in barometer where the analog reading is converted to a digital electronic signal. It’s incredibly complicated stuff.

Meanwhile, atmospheric pressure changes by the hour, even minute. Set your altitude before a ride to ensure the best accuracy. Even then, if there’s a change in the weather during your ride, the altitude will be off. However, the number we care about most — cumulative altitude — will be mostly accurate.

Temperature: All cyclometers heat up when exposed to direct sunlight and hot plastic invariably affects the reading by up to 10 degrees. In cool weather or shade, the Blackburn Atom SL temp gauge is as accurate as any cyclometer I’ve used. It displays temperature to tenths of a degree.

User interface
Font size is great for speed and satisfactory for other readings, even for my aging eyes. The displays are appropriately spaced. What stands out about this unit, over other cyclometers I’ve used, is Scan mode. In scan mode all of the cyclometer’s readings cycle through in about 25 seconds. You will still manually push the Set button for each reading to cycle through those readings listed in the manual under Bike mode and Altimeter mode.

Scan mode is an improvement in usability because there’s no constant button pressing to see a particular reading, or squinting to read tiny type. If you think the Atom SL’s text is small, some other brands have even smaller text.

The manual describes cyclometer settings, but as with any electronic device, it takes practice to master (remember) the functions. Some cyclometer owners express frustration over changing settings. That frustration is common to all electronic devices, not just cyclometers. Be patient and take time to understand how the settings work. Most importantly, remember that “Set” is the left button and “Mode” is the right button.

The manual’s type is small, typical for most bike cyclometer manuals, but at least there’s a printed manual! When was the last time you saw a smartphone come with a printed manual? If you’re having difficulty reading the manual, go online to see it in a large-font PDF.

The batteries last about a year, typical for CR2016 (wireless transmitter)/2032 (wireless receiver) 3-volt lithium. Four Phillips-head screws must be removed to access the receiver’s battery compartment.

Mounting is a breeze and you have options. It can be mounted on the stem or the handlebar. I like the mount because it uses a convenient Velcro strap that holds securely. While not explained, the strap goes on a certain way. My photo shows how it mounts.

A close-up showing how the strap mounts to the handlebar.

A close-up showing how the strap mounts to the handlebar.

The transmitter takes two pull ties that wrap around the fork, while the magnet screws onto a spoke. Be sure the transmitter is no more than 22 inches from the cyclometer (receiver) for the best accuracy.

If you’re someone who will be riding in hills and don’t want the hassle of constantly charging batteries, the Blackburn Atom SL 5.0 is an outstanding value.

PROS: Best value for the price, every function you could ever want, excellent mount, accurate, scrolls through features, small.

CONS: Lacks explanation for mounting the Velcro strap, small type in instruction manual, prefer showing trip mileage instead of altitude on the main screen.

Check the Blackburn website for shops selling the Atom SL:

Addendum: (7/21/2015) The speedometer function stopped working, probably from a bad transmitter. Disappointed. If it happens to you, be sure to return under the lifetime warranty.

2 Responses to “PRODUCT REVIEW: Blackburn’s Atom SL cyclometer an affordable electronic marvel”

  1. jay Says:

    I’m current using a Garmin 200 (their entry level model) and do you know if it uses a barometer to track total climbing? I think it really overstates total climbing.

    In the early ’90s I have the Avocet Vertech and I had to call the PA airport before rides to get the current barometric pressure and enter that into the device. I think it measured climbing in increments of 10 feet so that very slight ups and downs wouldn’t be recorded. I liked that. I recall that the total climb it gave me doing a Mt. Hamilton loop from the country club (using Foothill Road) was about 7,800 feet.

    I had that original Avocet that I bought at PA bikes. I may check this one you’ve reviewed out sometime for my second bike.

  2. Ray Hosler Says:

    They have a barometer. It could be a digital aneroid barometer or a MEMS barometer, but more likely aneroid. Here’s some info on how it works: MEMS –

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