One obvious method would be two folks measuring simultaneously. Each rider calibrate and figure out what your Jones counter(s)should read at one mile. Each rider stop at one mile. If your bikes are at the same spot at one mile, then you are doing fine. If one rider is thirty feet ahead/behind then something is wrong. Yes, Pete taught me this. Also, a hard tire is best.
Close only countsin horseshoes wrote:
One obvious method would be two folks measuring simultaneously. Each rider calibrate and figure out what your Jones counter(s)should read at one mile. Each rider stop at one mile. If your bikes are at the same spot at one mile, then you are doing fine. If one rider is thirty feet ahead/behind then something is wrong. Yes, Pete taught me this. Also, a hard tire is best.
Friend, we've established that 2 rides must be w/in .0008, about 4', for an acceptable measurement so your example above is superfluous. Pete R didn't have to teach you that -it's in the measurement manual. I'll give you Pete would make a good measuring mentor.
Mr. Ridiculous Pants wrote:
I can't believe that one anal retentive moron, who can't comprehend that his car odometer is not as accurate as course certification methods, could generate such a long discussion on such a completely ridiculous topic. As malmo first stated - just run!
On a similar note I find it absurd that some people with Garmins will measure their runs to the 1/100th of a mile so that they can round up to get ONE extra total mile per week...
AAAGGGHHH! Just run.
On a similar note, I find it absurd that some people get so upset about how other runners measure their runs.
AAAAGGGHHH! Just run.
Lighen up. You got something against Pete?
I wish I had the link, but I saw a guy's blog where he ran a couple miles around his local track. He then showed the GPS coordinates on a map. A couple of time, the GPS had him running about 20 meters off the track and then back on the track. Over a half marathon, such errors would easily contribute to a .1 or .2 discrepancy.
The problem may also lie with lazy race directors and race day production crews who do not go out and make sure all the mile markers are correct according to the course certification. Many of my local races are run on the same city streets. As a result, there are multiple different mile markings. At a number of races, the mile markers have been jacked because they just assumed that the mark on the street was correct.
scotth wrote:
Friend, we've established that 2 rides must be w/in .0008, about 4', for an acceptable measurement so your example above is superfluous.
4 meters, coach.
http://www.runnersworld.com/community/forums/shoes-stuff/gear-electronics/garmin-305-inaccurate-400m-trackPrecious Roy wrote:
I wish I had the link, but I saw a guy's blog where he ran a couple miles around his local track. He then showed the GPS coordinates on a map. A couple of time, the GPS had him running about 20 meters off the track and then back on the track. Over a half marathon, such errors would easily contribute to a .1 or .2 discrepancy.
1.05 miles is 80 meters off.
garmin 305 inaccurate on the 400m track
posted at 2/27/2010 4:28 PM CST
jprady
Posts: 1
First: 2/27/2010
Last: 2/27/2010
I run in lane 1 on the 400M Duke track in Durham. The garmin pace/distance is off on my 305. It is about 10 seconds off each mile.
It consistantly measures every 4 laps at 1.05 or 1.06 miles which makes it useless on the track. Is there any way I can fix this problem? Is this because of the turns on the track? It says I am running a lot faster than I really am.
It is not just mine either. Others have the same issue.
Thanks,
Jarett
Reply Reply With Quote
stuck with match.com wrote:
I believe in order to certify a course you have to add a distance, of .1 miles or something like that.
Are You Qualified? wrote:
How about you don't say things if you aren't qualified. Any statement that ends with "or something like that" should probably just be kept to yourself in the first place.
USATF course certification process:
http://www.usatf.org/events/courses/certification/manual/calibrating.aspThey use a working constant of 1.001. That would change a 13.100 mi course to 13.113.
It's likely that your extra distance is due to not running tangents.
+1
Useless toy wrote:
I run in lane 1 on the 400M Duke track in Durham. The garmin pace/distance is off on my 305. It is about 10 seconds off each mile.
It consistantly measures every 4 laps at 1.05 or 1.06 miles which makes it useless on the track. Is there any way I can fix this problem?
Easy to fix. For less than 10 bucks you can buy a digital watch that starts/stops/pauses/resets just by pushing a little button.
You already know how far one lap on the track is. Why do you need something as inaccurate as a GPS device to tell you what you already know is wrong?
malmo wrote:
4 meters, coach.
For a 5K it would be 4 meters, actually closer to 17 meters for a half marathon. Still precise riding over that distance.
I have no idea how I calculated 4 meters. Must have done it on a Garmin calculator!
This thread is a classic. Keith has actually posted multiple times without raving insults to republicans. I bet the OP is republican.
10/10
Based upon the reaction you got...YOU WIN! One question tho....Were you wearing your fanny pack when measuring, and/or an iPod.
The fanny pack could have unbalanced the drivers side of the car enough to pull the car to the left, making you over correct, therefore, making you not drive a straight enough line.
If you were not wearing a fanny pack, then it most def could have been you iPod emitting enough electrical interference to upset the rotational coefficient of the speedometer, causing it to over-spin, therefore adding extra unwanted distance to the calculation.
If you would like, I could put together a Power Point Presentation to outline all the physics and detailed math calculations involved.
malmo wrote:
I have no idea how I calculated 4 meters. Must have done it on a Garmin calculator!
My brain was on 1/2 power when I said 4'. What I meant is: the .0008 represents about 4' per mile. Two rides must agree to w/in about 4+' per mile or about 40+' in a 10 mile.
I've tracked odometer accuracy on my last 3 cars. They were roughly off by 1, 3, and 4%. If you measured 13.24 with yours, then you've got a great odometer, relatively speaking.
Actually I am the op and I'm not a republican. I am very liberal
I just want to say as the OP thanks for this discussion. I ran my half marathon yesterday and I gotta say I was nervous because It was my first time moving up to the half but I ran a breakthrough race. I was just anal about the mile distances but I think it was all just tangents and such because portions of the roads were "S-shaped" for a bit so cutting tangents was pretty important to optimize performance in running as close as possible to the true distance (and not more than)
Thanks. Good discussion on a topic a lot of people know very little about
Close only countsin horseshoes wrote:
Lighen up. You got something against Pete?
Friend, what makes you think that? I'd say what I said if you were measuring w/any experienced measurer. And, I believe I said Pete R would make a good mentor. Perhaps you missed that.
"It's a, such a sadness, that you think you've measured a course..... on your f***ing Garmin. Get real!"
You obviously missed the fact that two rider's measuring at the same time was something those posing questions here did not think about. Not everyone has read the "manual" as you stated. You need to work on your communication skills. Give yourself bonus points for using "superfluous" as your word for the day.
scotth wrote:
Close only countsin horseshoes wrote:Lighen up. You got something against Pete?
Friend, what makes you think that? I'd say what I said if you were measuring w/any experienced measurer. And, I believe I said Pete R would make a good mentor. Perhaps you missed that.