I love the form factor, features and user interface of my BOLT. However, I am disappointed by two issues and I’m hoping they are the result of a problem with my unit, not the product as a whole.

First, the displayed (current) GPS speed readings are all over the place. The displayed speed routinely bounces +/- 2 mph during steady efforts. I can sort of guess my speed by averaging the numbers I get, but this is really frustrating. The problem is even worse when riding with even minimal tree cover. It is common in such conditions to get readings that vary between, for example, 16mph and 25mph from second to second. I have used Suunto watches and Garmin Edge units cycling in the past and have never experienced anything like this level of inaccuracy before. (Perhaps there is a smoothing function that I need to enable?)

Second, the BOLT routinely provides elevation (total gain) data that is 15 - 20% higher than what is either suggested by route planning services like Ride With GPS or that my friends record, even on on other Wahoo devices. Recently, I did a ride that RWGPS suggested would have 5,000ft gain. My friend’s Garmin Fenix report 5,600. Another friend’s ELEMNT, 5,700. My BOLT? Almost 6,800. That is way outside acceptable deviation.

Has anyone else had similar issues? I contacted Wahoo and was told to get a speed sensor and that elevation data can be affected by climatic conditions. Not helpful.

I don't pay attention to elevation, living in a mostly flat and Long Island.

I have noticed the speed jumping you describe, and I use a Garmin speed sensor. It's made me go look to see if the speed sensor is connected. But in truth it doesn't seem any worse then the Garmin 810 I was using last year and I really don't find it bothering me.

I'll pay attention in the future and not that there's a Google group for Wahoo. https://groups.google.com/forum/m/#!...o-elemnt-users

For speed, this is why people commonly get a speed sensor of some sort. It isn't subject to the GPS signal quality problems.

As for altitude, yes, most units (Bolt, Garmin, etc) these days have a barometric pressure sensor to measure subtle changes in air pressure, and it uses that to work out the current altitude. Generally this is more accurate than relying upon GPS, but if a weather front is moving through and the background air pressure is changing during the period that you are riding, then the altitude is going to show a drift of some sort. Some units re-calibrate from time to time (and I guess interpolate any data taken since the last re-calibration) - my sense is that Wahoo doesn't. It just does one calibration (setting the altitude from GPS) when it first starts up, and that's it.

GPS accuracy can be all over the map and not the fault of the computer. If you're bike computer doesn't have a good view of the constellation of GPS satellites, the accuracy will be bad pretty fast. If the positional accuracy is bad, you're speed is going to be bad. You can add a field to your display that is GPS accuracy (measured in feet) to see if that's the problem. Best accuracy is going to be 4 meters or 13.1 feet.

Vertical gain can be kind of wonky no matter what. Every computer out there is trying to get it from some measurement and filtering of barometric change. Some, I'm sure, try and use GPS to help add to the accuracy and avoid some of the pressure change issues although that is dubious since GPS is not very good at vertical measurements either.

I agree that the 6800' vs 5000' is probably out of bounds. But I'd try it with a speed sensor on first just for grins (you're going to have to do that anyhow - and should). I'd also note that 5800' or 5600' vs 5000' as the standard are also not accurate measurements either (off by 12-18% = pretty crappy accuracy). Altitude is an issue on any bike computer I've ever had. And therefore, grade measurement is also usually problematic. If it's always out of bounds by nutty amounts, I'd ask for a warranty replacement. But do recognize that most of the data displays related to altitude are going to hurt for accuracy.

J.

I received my Wahoo Elemnt yesterday so looking forward to seeing how it goes. It will be interesting to see if I am getting any noticeable accuracy issues.

If I could find a GPS that over-reported elevation gain, I think I would dance a joyful jig. Instead, I have a Garmin 520 that regularly reports 10-25% less climbing than everyone else I ride with, all the time. Why do I have to be the guy with an accurate unit? Where's my free elevation?