bobframe

My fairly new Garmin Edge 605 works fine except for the "Grade" function.

This weekend as I was doing a long climb I looked down to see what the grade was and it read 8%. Within seconds it read 7%, then 6%, then 5%...all the way to zero (I'm still climbing BTW). Then it went to -1%, then -2%....all the way to -6% where it bounced between -5% and -7%.

It's been doing this since it was new. I had an Edge 305 and it worked perfectly so I know what it is supposed to do.

Garmin's tech support hold times are ridiculous so I thought I'd ask here.

Any suggestions?

Thanks.

foresthill

GPS vertical accuracy is not fantastic. This happens sometimes, especially if you've only got a few satellites (i.e. in a canyon, view otherwise blocked to the south.)

I'm surprised that it's different from your 305, tho.

bobframe

The 605 is not working correctly. Finally got through to Garmin tech support and they had me reset the unit. Will have to test it out.....

wrr1020

I have an edge 500 and while riding on the flats on one of my rides i looked down and my grade percentage said 320%. I pulled over laughing shut it off and turned it back on and was fine the rest of the ride.

ErichM

Edge 500 uses barometric pressure to measure elevation as opposed to GPS, which should be a good thing. The other day I started out my ride and looked down at the computer and it had similar readings to your 320%. Looked down a mile later and it was still foobar. Next time I looked at it it was fine. Not sure what happened!

When I transfered the data, the data was correct though. Elevation correction is turned off. So I'm not sure what was going on there.

bobframe

Does my Edge 605 use GPS for altitude calculations? Or does it use barometric pressure? If its barometric pressure, then how do I calibrate it?

Seattle Forrest

My Garmin's had me going faster than the speed of sound, and cycling across the Pacific Ocean, twice within an hour, thanks to my ultra-high PSI tires. Every now and then it has my heart-rate bouncing between 30 and 230. Sometimes asking it to save my data turns the thing off, without saving my data.

Yep ... I've seen that, too. Sometimes I'll ride 10,000 miles in a day ( and that's on a heavy cross bike! ), but when I upload the data, it seems I took a short-cut and might have only done 37. Which means that it's getting correct data from the GPS satellites, but the "computer" or "stats read-out" program is doing its math wrong from the GPS stream.

bobframe

Gawd....wish I'd know about all this before I dropped $400 on this thing. It's depressing.

ErichM

Take it back and get a 500... Or the new 800...

Seattle Forrest

Do you need the grade while you're climbing, or is it enough to be able to correlate it with the map, and maybe your other stats ( power, speed, HR ) later on? GPS is far less accurate when it comes to elevation than it is with lat/lon, so once you get the data in the computer, some programs will look up the altitude from better sources. That would let you get a better sense of the gradient when your unit goes wonky. But it's a lot of work-around...

thesmoothdome

I love being able to gauge my percieved exertion and heart rate against the grade, but I'm a tech weenie. I'd have a power meter too if I wasn't a cheap tech weenie.

RoboCheme

I'm pretty sure that grade and altitude are based on barometric pressure, not GPS on the 605. Every once in awhile, I lose the altitude on my 705 (and, of course, the grade), but I turn it off and on and it works fine.

Is your altitude reading changing as you ride? If not, you've got a bad unit.

thesmoothdome

Actually, the 605 is GPS altitude. The 500 and 705 are barometric pressure.

RoboCheme

Yep, you're right. Learn something everyday.

kwakster928

My garmin edge grade function is always playing catch up. It will show positive grade only after I have been climbing for 30 seconds. Not a big deal but oh well.

bobframe

My Edge 305 has a grade function and it works great...started showing grade almost immediately when climbing. I need grade so that I have some confirmation as to why I'm going so slow and why my legs hurt so much...

roadrider63

My 500 should be here within a week. I can't wait to try it out. Sad thing is around here I may only get 400 ft of elevation gain in a 25 mile ride....depending on which way I go..lol. Still looking forward to using it and all the data it provides.

Tulex

Check which version firmware it is running and check out the Garmin forum. There was an update for the 705, version 3.2, that broke it. People had to roll back to 3.1 or earlier to fix it. They even took the upgrade down so that 3.1 shows as the current version. It might be the case with the 605 and others.

ETA that it looks like the 705 and 605 share the same firmware? If so, most definitely check the version and downgrade to 3.1 or lower if you have 3.2.

bobframe

The unit is running the 3.10 software. Appreciate the tip on the Garmin forum...probably a better place to get the help I'm looking for.

Tulex

Bummer, I was hoping for you that it was a simple fix. It's a toss up as to what you will get from the forum. Not a lot of traffic there, but sometimes a mod or expert will reply. Hope you find the answer.

bobframe

Thanks Tulex. BTW, I grew up in Victor. Small world, eh?

nhluhr

My old Edge 205 (non-barometric) was also horribly inaccurate with grade. it gets better when you have a barometric altimeter but it's still not as perfect as you'd hope.