Elevation Correction: Enable or Disable

David Leventhal

Here in Dallas we don't have very many big hills.  We have some hills with decent grade, but they aren't very long.  I have to actively seek them out on my ride because they aren't just lying around waiting for me to build fitness.  As I am getting ready for CDA I'm trying to be mindful of hitting the hills I do have available many times while out on my rides.  I don't want to get caught on race day having not done some good hill work in the prep phase.

That begin said - I've noticed that the difference in elevation between the Garmin "enabled" & "disabled" is pretty big.  Frankly I don't care which one is right...I just would like to know which one is more right so I know if I'm getting the amount of hill work in that I want.  Here are two examples from my 4 1/2 hour ride yesterday and my 3 1/2 hour ride today...those are significant differences in elevation change.

Thoughts?

 

Coach Rich

David,

I can't answer your question re the Garmin elevation function but I think you're overthinking the issue of total gain on an IM course. Please read this. Notes specific to IMCDA:

• 4-5k of gain across a 112 miles isn't a big deal. You might think it's a big deal because you don't have many hills around you but it's not. That amount of gain across that many miles is truly "just a bike ride." 
• The IMCDA course, the current version of it, is VERY easy to figure out. There is no mistaking when you're on a hill, that hill isn't particularly steep (steepest grade on this course is 6%), and the hills are long enough that you'll "get it" -- just sit down, ride the bike sensibly, and watch everyone else destroy their races 

The EN Method:

• Get strong
• Get light
• Put the right gearing on your bike
• Know what effort works for you on climbs.
• Have the discipline on race day to do what you know you're supposed to do vs what everyone else is doing around you. 

David Leventhal

Thanks Rich! I hope I'm overthinking it!! All I know is that first hill in California was a shock to my flat Dallas world. That was the biggest hill I'd ever ridden. Having no real sense of how much gain 5700 feet is, my fear is that CDA is filled with those types of monsters.

Swanie

Elevation Correction should be enabled for the most accurate depiction of your ride. Here is the description of Elevation Correction per Garmin Connect:

• 
  
  What are Elevation Corrections?
  

  Elevation Corrections cross reference the horizontal position (latitude/longitude) provided by the GPS with elevation data that has been acquired by professional surveys. When corrections to elevation data are made, each trackpoint of your activity now contains the elevation from the web service, not the elevation provided by your GPS device.

  
  

  Garmin Connect selectively applies corrections to depict a more realistic representation of your elevation experience. Activities recorded from devices without a barometric altimeter are enabled with Elevation Corrections by default. Alternatively, activities recorded by devices with a barometric altimeter generally contain accurate elevation data and therefore Elevation Corrections are disabled by default. For those users who are familiar with the MotionBased Gravity service, this is the same service.

  
  
  
  

If I take a ride that is flat as a pancake for 10 miles then climbs to my house at 500' elevation. the Elevation Correction enabled states my gain is 520'. With the Elevation Correction disabled it shows a gain of 1094'. 

Coach Rich

Posted By David Leventhal on 11 May 2014 06:29 PM


Thanks Rich! I hope I'm overthinking it!! All I know is that first hill in California was a shock to my flat Dallas world. That was the biggest hill I'd ever ridden. Having no real sense of how much gain 5700 feet is, my fear is that CDA is filled with those types of monsters.

If you're talking about that first big hill that's inside the base, on the backside of the course (about mile 28 or so) that's about .7mi @ 8%. There is nothing on the CDA course that's greater than 6%.