26.17 Grade, still, but I have come up with a solution for me

You might try some IQ grade apps.  I tried a few and they work better than the native Garmin grade field.  One "Sensible Grade."  There are others that I don't remember ATM.

Thanks.  The fact that IQ apps can do grade with native Garmin apps/programmers cannot is very telling and sad.

I'll give that one a try. 

Thanks again

Considering the fact that we have barometric pressure derived altitude and grade calculations on simple bicycle computers (Cateye, VDO,...) for, say 25 years, the fact that pretty good algorithms to calculate grade based on elevation and travelled distance have been in place just as long, a.o. made and optimized by the appraised Jobst Brandt, and that air pressure sensors have become much more accurate, having a higher resolution and a very fast response time and temperature compensation, having this all done well should be a walk in the park for Garmin. I really do not understand why this takes so long.

As bad as this has been, I don't think they care.  Sad.

Tried Sensible Grade yesterday and WOW! 

Outstanding IQ app.  Much more responsive, even on short MTB trail climbs.  Sure, it might not report the grade instantly, but if you look at it just past the steepest part, it will catch up and show you what you just climbed.  To be honest, that works out, because I didn't really have time to look while climbing or descending.

The fact that it also reads the grade in tenths really helps you see it changing and gives confidence that it is working.

Wish I could give you ten upvotes!

UPDATE:  See looigi's suggestion and my review of Sensible Grade IQ app.  This is the answer for me.  Can't believe Garmin doesn't buy one of these apps and integrate it.  Oh, on second thought, I hope they don't as I'm sure they'll screw it up.

Anyway, give it a try!

It seems that 26.17 made things worse. I don't know if my 540 reported gradient correctly before that, as I don't have an authoritative official alternative source to check the values against, but at least it was 0% on flat, positive when climbing, and negative when descending. And it was consistent for the same segments. But I can tell 26.17 has bugs because it shows me negative numbers on flat, 0% when on slight climbs and like -6% on just slight descents.

How laggy is it? I don't look at gradient all the time, but when I'm interested in checking it out, I would like to know the current gradient, or at least the gradient for the past, say, 5 seconds.

I'll assume you are asking about Sensible Grade.  The delay is roughly on the order of two to three seconds.  I'm the same as you, particularly on the MTB, don't really have the time to look at the toughest part of the climb.  I did see it jump up to a bit over 20% on one short, steep section, which I believe to be correct.  With the tenths of a percent displayed, it seems to at least show pretty quickly that the grade is increasing.  About the quickest response I've ever seen, even when Garmin was working at it's best.

I agree, before 26.17 it might not have been great but it was at least reasonable.  Then with 26.17 I started getting grade readings that were obviously wrong and with 26.18 the stupidity has continued.  It’s really disappointing and making me wonder if I shouldn’t begin researching other companies.  This is really though to understand, how they could make this worse.  My old 500 series worked better than this latest crap,