Motion Based Question

[SadieKate]

And from what I've seen and ridden of the Alps/Pyrenees, they're more like our Sierra roads with reasonable to high gradients; however, they pitch you up between the switchback instead of in the switchback like we do here, so you can often get more climbing overall. It was weird to have the actual switchback be the flat part where you can recover because it's so often not the case here.

Next time you're here and the trail is cleared, we'll ride the Flagline Tie singletrack. At the very end when your heart rate is highest the trail suddenly goes up the fall line and then the switchbacks and the trail between keep going up and up . . . and over roots and rocks. But then you get another 1000 ft above the South Fork drop. Yum.

Back to the original issue - and I'm not sure if anyone noted this yet, but weather can affect the barometric corrections. I spent a morning climbing the geysers and I and the other 5 people with Garmins all showed we were steadily descending. It was VERY odd, but the weather was changing dramatically from rainy/cold to warm.

Yup. But you've reported the weirdest case I've ever heard. Usually, it is just greater discrepancy between the climb/descent totals.

Just remember that weather patterns can cause some inconsistency, but generally not as much as GPS-only data.

[maillotpois]

Next time you're here and the trail is cleared, we'll ride the Flagline Tie singletrack. At the very end when your heart rate is highest the trail suddenly goes up the fall line and then the switchbacks and the trail between keep going up and up . . . and over roots and rocks. But then you get another 1000 ft above the South Fork drop. Yum.

Is it worse than Green Gulch? No thank you...

[SadieKate]

Much better traction and smoother over all. Of course, you top out at 7,000 ft but the grade has shallowed out by then. It is so worth it.

[SouthernBelle]

I couldn't figure out for the longest time why there would be a 2-3 feet difference in ascent and descent on some of my rides. I finally realized it was a matter of where in my driveway I hit the start and stop button. Slight climb out of my drive.

[OakLeaf]

Oh, none of them are THAT accurate. If you're within 2-3 METERS you're doing good. Usually I'm within a 10' range when I ride from the local Y and start my computer in their parking lot (pancake flat).

[jobob]

Agreed!

[kfergos]

Geologically a hill is (usually) anything less than 1,000 from base to and a mountain is anything more than 1,000 feet from base to top. The problem is perception -- short, steep, climbs can be killer compared to those long, long inclines.

I like my Garmin Edge 605 -- it says I can ride up a 45% grade! For those of us sans barometric measurement devices, what is the most reliable way to find the elevation profile of a route? Is mapmyride pretty accurate?

[SadieKate]

Oh, your elevation profile should be fine without a barometic altimeter. What goes astray is the cumulative climb totals as in "I climbed 3,212 ft in 100 miles." A GPS should give you a decent recording that the base of the hill was at X feet and the top was at x feet of elevation. But if the road has any undulations on the way up (which just about all do), the total climbing will be off.

Make sense?

[OakLeaf]

And another Doh! from my commute on Thursday.

I didn't reset the computer between legs. In the hour and a half I was at the gym, apparently the barometric pressure must've dropped a bit. So my whole return trip was 200 feet "higher" than the outbound leg.

Because it was all one trip, none of the correction algorithms (TC, ST or MB autocorrect) was "smart" enough to correct the elevation data throughout the trip. When I apply MB Gravity, that one is that smart - so my elevation profile is a nice mirror image as it should be for an out-and-back - but it gives me a total elevation gain that's like 40% greater than the autocorrect alone. Hmph.