Indoor profile - speed and distance calculation when on a turbo trainer

Thanks brad

Sadly I’ve concluded the same. 

However it would actually be very simple for Garmin to add this feature as all they need is to plug the power data they already get into a simple algorithm to convert it to speed. This is all the training apps are doing and Garmin do much more complex calculations for other data. 

The Garmin indoor mode seems underdeveloped really as all it seems to do is turn off GPS. 

I will probably just give up as covered above as it’s not that important and the whole ecosystem is all a little too proprietary and is not really designed to work that well together necessitating various hacks to get various bits of data to where you want them to overcome the various shortcomings of various different bits of software!

I thought the collective conclusion was Garmin did not, and some, including you thought could not, do it?

if you can tell me how to get accurate speed data on my Garmin head unit with any trainer/app combination that would be very helpful. 

I think you might still be misunderstanding my question though. I want accurate speed data on my Garmin head unit whilst using erg mode on my trainer. To my mind it shouldn’t matter what that trainer is and I can’t see that it has anything to do with what app I’m using to control the trainer. 

I believe the solution Garmin ought to implement is a simple calculation based on the power output coming from the trainer (which it gets by connecting the trainer as a power sensor). 

I want the Garmin head unit to do it so i get the speed data with all the other rich Garmin health data when i upload it to Garmin connect. 

I can upload the file from the training app and this does have accurate speed data (as they do do the calculation) but not all the other Garmin health data so I would prefer to dual record on the Garmin head unit. 

I think I get what you are saying now. Basically, that your Garmin is not recording the FE-C speed data being broadcast by the trainer. I wonder why Garmin don't just record what is being broadcast. Have you tried using ANT+ rather than Bluetooth?

Directory - THIS IS ANT I wonder if this might help you?

i think You dont understand the OP's wish: he wants a special(aka virtual) speed value (and distance ) from power , and not from the real physical speed of the rear disc. so he wants a similar formula implemented into the Edge (as natively or by CIQ app), where he can fill all the datas (bodyweight, bike weight, rolling resistance, CdA ) as here : https://www.gribble.org/cycling/power_v_speed.html    the head unit will compute the virtual speed on-the-fly (and ofc the virtual distance too) from the (different) power values (lets say if he is pedaling with 150W then the virtual speed will be 30km/h, but if he is pedaling with 400w then the virtual speed will be 45km/h and doesnt matter which rear cogs are used or on small or on big ring on the front and doesnt matter the cadence change ofc) and writing this data into the FIT file instead of the actual, rpm and gearing-based speed which is coming from the speed of the physical rear disc in the indoor trainer .  (because that is a constant value if you pedaling 90rpm for 2 hours but different power levels in ERG mode)

so this is what Garmin never will do, for sure, a time-millioner programmer may do in a CIQ app

Thank you Luko. This is 100% it - you’ve got it completely!

I also agree that Garmin, despite having an explicit indoor mode, are very unlikely to bother implementing this so I gave up on it a few weeks ago as it’s not really important as discussed above. 

I’d rather Garmin focus on fixing their long list of small bugs and general usability and UI issues on the Edge units (I have an 840). My forerunner 265 by contrast seems very stable, solid and well designed!

Hi,

it annoyed me too for a long time;) I had a similar problem with Garmin until I replaced the trainer with Wahoo KICKR CORE, which simulates speed quite well for Garmin devices (I have Egde 840, Fenix 6 Pro). This morning I rode 40km on Zwift in relatively low power zones on the "Triple Flat Loops in Watopia" route.

ZWIFT: 40.25 Km, speed 26.5 km/h, time 1:31:12
EDGE 840: 38.55 Km, speed 25.4 km/h, time 1:30:57

It is similar in the case of ZWIFT training with ERG MODE enabled. You can enable speed simulation in the KICKR CORE options, it will definitely not be 100% consistent with Zwift speed data, but it's better than nothing ;)

I use Zwift, I don't do climbs and it works for me - the question is whether it will work at an altitude of 1000m or more...

Regards,
Darek

In my opinion, Garmin devices should have a dedicated ZWIFT profile - that would be the easiest ;P

what you experienced is just accidentally, it is depending on the Zwift's course (flat, mid-flat, hilly, or superhilly), solo or bunch ride and on power level. the Zwift's virtual speed and any trainer's disc speed wont be similar, sometimes you get a close match (if the variables have special values) but as i wrote that is accidental. Doesnt matter the brand of the indoor trainer. (and it is in SIM mode. If You do a Zwift course in ERG mode, you will get completely different values, pointless to compare these.). And the OP has/had problem with ERG mode where you use only 1 gear combo during the entire ride. so it can be small ring front-biggest cog rear and big ring front-smallest cog rear. with the 1st setup, at 90rpm You will have apprx 8km/h disc speed for the entire ride, but you can ride in Zwift even with 50km/h on Tempus if your power is 300-350w range and riding in a bunch (with A pace partner or similar), or with the 2nd setup , your rear disc speed will be 60-70km/h with 90rpm, but you climb on the Alpe with 6km/h (with 150-200w, depending on bodyweight, ofc). Ok , some trainer has limitation (cant brake enough big power with 1st setup and cant brake so low power with 2nd setup), the ideal for ERG mode is small ring front and 5th,6th sprocket rear (so somewherer 34T-19, 36T-19 or 39T-19 or -17, depending the type of the rear casette), it gives you with 90rpm 20km/h for the entire ride with 100w and with 400w also.