I'm almost certain I want to get a Lezyne Super GPS but I'm not sure what speed, cadence and heart rate sensors to pair with it. Does anyone have experience with the Lezyne and can suggest best sensors for it?

I've had my Lezyne Super GPS for about 3 weeks now, I'm pretty happy with it. Battery life was the deciding factor for me.

I use a Wahoo Tickr HR monitor and the Wahoo Blue SC speed/cadence sensor. I'm finding I have to tell the Lezyne that my wheel is a smaller size than it actually is -- it doesn't seem to matter when I upload the ride; but when I'm actually on the bike it's telling me I'm faster than I really am. Other than that no issues.

Presumably the reason it doesn't matter is that whoever you are uploading it to (Strava?) ignores the speed data and recalculates speed from GPS points.

I've used the Garmin "magnet-less" speed and cadence sensors with my Lezyne Super GPS and the sensors paired and operated as expected. I recently added a PowerTap hub so I've ditched the speed sensor (since wheel revolution data from the PT makes it redundant). I also use an old Garmin HR strap that came with a Forerunner GPS watch.

One note for anyone considering the Garmin "magnet-less" speed sensor ... I have observed strange low/unstable speed readings when crossing some bridges. The problem is not related to the computer (same results on a Garmin, ANT+ enabled phone, and Lezyne) and I suspect has something to do with metal embedded in the roadway. Probably not a big deal for most people, but in Florida riding bridges is the closest some of us get to training hills so this problem was more than just a minor annoyance for me.

Just as a piece of information as it is probably too late for the original poster, I paired my Super GPS with Cateye speed/cadence and heart rate sensors. Worked fine, but seemed very slow to pair; slow enough that I was worried at first. Initially I agonized over buying the Lezyne unit because they don't have their own sensors (at least so far). However, what eventually sold me was the reported difficulties and/or expense of other brands: Cateye, Sigma, Wahoo, Garmin, etc.

I have a Lezyne Super GPS with a Powertap G3 and Polar H7 HRM. They both work perfectly. I tried to use it with a lesser known HRM called Zephyr HxM and it seemed to pair and would give an accurate heart rate but the number on the screen would disappear for long segments of time. I called tech support and they told me that model is not supported. So, you can't assume all Bluetooth LE devices will work. He told me most ANT+ devices will pair and work since there are tighter standardization rules on ANT+ than BTLE among the sensor manufacturers. For a list of devices that will definitely work, Lezyne has posted them on their website.
It is on the Lezyne homepage; just hover on the "GPS" dropdown and then click on "connecting to devices". Includes year 10 and 9.

???

How much smaller? That is, what is your wheel size and what number are you using?

Keep in mind that the speed is determined by multiplying wheel rotations counts per second (from the sensor) and the horizontal distance the bike moves in one complete wheel rotation (the effective circumference). The effective circumference isn't the wheel size.

Note that the effective wheel diameter (and circumference) is slightly smaller with you on the bike than off it.

That is, you'll need to use a smaller circumference number for heavier loads and lower tire pressure. Different tires of the same width might cause the number to be different too). There are too many variables to allow a single table of numbers work for everybody.

Ideally, you'd measure the actual circumference by doing a "rollout" (see how far a wheel rotation travels with you on the bike.

Seeing that my original post was more than a year ago I've long since forgotten the specifics but I eventually got the numbers dialed in by biking a known distance and adjusting the wheel size until the numbers matched. On this particular bike I normally run a 700x38 Specialized Trigger Pro at anywhere from 35-45 psi, I forget exactly how wide they measure with calipers on a TB14 rim but it wasn't exactly 38mm. The wheel circumference I came up with that gave me accurate distance figures was 2120 mm. I think the "official" circumference in the Lezyne manual was something like 2192mm.

You would think, since it's a GPS unit, they would have programmed in the capability for the computer to automatically figure out the wheel circumference and adjust it, but I guess for >$200 that's what you get. Maybe the new generation of the device does that, I don't know.

This is a good description of what you did.

The "official" number on the table is a guess.

The difference would produce a 3.3% error in the speed (0.5 miles at 15 mph; 1.65 miles at 50 mph).

The 72 mm difference in effective circumference is about 1/2 inch (11 mm) difference in the height of the axle from the road. (Keep in mind that the height we want is with a load on the bike.)

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Different tires, different rim widths, different pressure, different rider weights all mean that a table can't be expected to be very useful (unless you are lucky). The real width of tires is often different than the indicated width (38 mm, in your case).

You don't care about the width of the tire anyway (you care about the height of the tire under load).

The issue isn't the unit. The number (the distanced travelled) really has to be measured.

No. The number you used from the table isn't what your wheel size actually is (it's just a guess).

You had to tell the unit the actual real size of your wheel to get the right speed/distance.

There might be inaccuracies and variation with that method too.

You seem fun.

Says the person who used calipers to get a mostly-irrelevant number.