nick_m

Hello everyone. I recently upgraded from old Tacx rollers to a Kickr Core, so smart trainers (and training with power) are new to me. I followed Wahoo's directions to do a 10 minute warm up and spin down using (only) their application. I then used my Garmin 520 to follow a route that I ride frequently, but I found that riding the route on the Kickr required much more effort than riding on the road. I can climb the 10-12% segments while seated, but on the trainer I had to use nearly my whole weight just to turn the pedals. Even some descents required a fair amount of power. As far as I could tell, I had the resistance settings minimized on the 520, and level, resistance, ERG and sim were all zero in the Wahoo app.

Are there settings or interactions that I'm overlooking? My first thought was a bad calibration/spin down, but I've run the process (followed by the ride) twice and the results were the same. Sorry if this has been asked and answered before; similar queries have been posted (by others) in various forums, but I couldn't find any responses.

Thanks in advance for your help!
Nick

zacster

A couple of things come to mind as a Kickr Core owner myself and new to smart trainers. First, which mode are you in? If you are following an existing ride, are you doing it in ERG mode or simulation? ERG mode would follow your power while simulation would follow the grade that you encountered on the ride. Second, I always find indoor riding to be more difficult than outdoor in any case. 200w indoors is hard, outdoors not so hard. Most people experience this. I have the advantage of having a power meter that will read the same either indoors or out, and it is always harder indoors. Riding my Kickr and using its power readouts in either ERG or Simulation mode correspond.

Add in to this equation Zwift and you can get totally confused by it all. I also have the advantage of having Central Park as one of my regular outdoor rides, and now Zwift includes it as a route except that the Zwift route doubles the grades of the hills as it displays, but then the default setting in Zwift is to halve the effort needed. When I hit Harlem Hill for real it is a small effort, in Zwift it feels the same even though it is saying it is a 10% grade at some points and that would be killer. 5% is probably the true max. Museum hill isn't nearly as steep, but still a 6% climb in Zwift.

Another thing to consider is that in ERG mode the power is constant so cadence x resistance is constant. If you your cadence goes down the resistance goes up and can overwhelm your ability to turn the pedals, which makes the resistance go up even further until you can't turn them anymore. The natural thing to do when fatigue sets in is to slow the cadence, and hence increase resistance, which goes against everything you thought you knew. When you start from a complete stop ERG mode shuts off briefly until you start spinning again but that may be a Zwift thing. Maybe that's your issue, the Garmin 520 doesn't account for the full stop and leaves you with infinite (or as much as it can muster) resistance.

nick_m

zacster - thanks for the reply. I uploaded the ride to the Garmin 520 as a course and then rode the course in Indoor Trainer mode. The Wahoo app was not running; the trainer was being controlled by the 520, which set resistance according to the course profile. On the 520, you can adjust resistance or set a target power (I did neither). I don't see a way to set either ERG or SIM mode on the 520, so I don't know which, if either, was in effect. Does the Kickr somehow "remember" the last mode you set in the Wahoo app?

Part of the problem is the noise in the 520 elevation data. I tried to get around that by re-creating the route from a map in Strava and then exporting it to Garmin Connect and then the 520. However, even taking that circuitous approach, I ended up with a half dozen 10% "bumps" on a gentle descent. I don't think the Garmin is presenting an accurate profile of the actual course.

Road Fan

I've been struggling with some of the same stuff with my Snap/Elemnt/Wahoo Apps/iPhone. I'm going from an older mechanical Kinetic Road Machine to this, and my first goal with it is to set up the Snap with Elemnt to default to the mode where it emulates wind resistance (thus in principle matching the Kurt). I have succeeded in setting it to a resistance curve, but not to make it default.

As far as local routes, some of them are on Map My Ride, thought Ride with GPS is the mapping tool that is compatible with the Wahoo apps. And if the route i have in mind is steepened a bit, that just adds to the fun. I need to build my climbing as well as my base endurance.

nick_m

I just had a quick look at Ride with GPS to see if they could export GPX files and I thought, perhaps mistakenly, that they didn't export elevation data. Can I go from a Ride with GPS map to a Garmin 520 course? I'm not aware of a way to use it in the Wahoo Fitness app to control the Core; is that possible?

Road Fan

I can't tell you what it does or doesn't do. I just know that RwGPS is listed on the Wahoo site as being compatible with Elemnt and associated components, and Map My Ride is not. I haven't tried RwGPS yet. But for what I want, I need good elevation data, too.

redlude97

I assume you don't have power on road outside to compare to?

nick_m

It's my first time with a smart trainer and power of any sort. There's definitely something in the GPX > 520 that's hosing things up. I exported from Garmin Connect what appeared to be a very clean version of the course, but when I tried to run it, the trainer essentially locked up. On the 520 screen, the profile looked like a porcupine - it was a series of infinitely steep spikes. Not sure where the elevation noise came from.

I re-ran the first version that I attempted, pushed through to the finish (21 miles, 1700 vertical) and found that my time was similar to my last outdoor ride. What really surprised me, though, was that my average heart rate and total calories were less than on the road. I'm not sure what to make of it; maybe it's all in my head and it's simply the perceived effort on the trainer that's harder.

zacster

I find estimated calories to be high, but HR is HR. You must have been working harder.

redlude97

Or its alot hotter/less ventilated, or they are more dehydrated indoors etc ...