SoCal ZX-14 Rider
Expert Class
Posts: 351
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posted September 07, 2006 11:23 AM
GPS vs speedo readings
Iv'e read about some of you guys using a gps to see how fast you are really going.
I just purchased a Garmin GPSMAP 60CSx with a max speed readout (awsome unit) and in It's specs it states it updates every second.
My question is how long do you have to maintain speed to get a correct reading from this thing.
I have a secure 1/8 mile area going to work where I roll it up and bump 150mph on my speedo but it only read 133 this morning. I do it most mornings and the reading are between 131 - 133mph. I dont' know if I have to mantain the speed longer or if the speedo is just way off.
Maybe it won't read 150 because im not up there for more than a sec but im going 145,146,147 ect... for more than a second why is the reading so low?
Any of you guy have any experience with gps?
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fish_antlers
Administrator
The Truth is Out There
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posted September 07, 2006 11:30 AM
145mph indicated was 123mph.... garmin 2820
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fastestbusaaround
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Posts: 7889
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posted September 07, 2006 11:32 AM
No...it's bang on...if it says 133, it's 133 (in a straight line only) not on a curve. Too long to explain why it won't be bang-on on a curve. Your bike with the stock gears and tire size, should read about 138 on the GPS. The bike is off by 7.5-8% on the stock setup. The 1-second updates are quite sufficient to accurately post your speeds. We are a Garmin distributor and I've used them all at one time or another. The indicted speed on your Garmin is right on, you can take that to the bank.
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fastestbusaaround
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posted September 07, 2006 11:35 AM
quote:
145mph indicated was 123mph.... garmin 2820
According to that, the speedo is over by 12%...that's quite high IMO. We usually don't see anything over 8% max. Your ZX14 must have been built on planet Bizzaro, you know the one that Bizzaro Superman was from? 
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TeamSpeed
Expert Class
Posts: 449
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posted September 07, 2006 11:47 AM
 Edited By: TeamSpeed on 7 Sep 2006 12:48
My bike was off 9.25% at 60mph. Your error is also not linear, you have to pick one speed you want to make accurate, with the understanding that you will be reading slow under that speed, and reading faster over that speed (or vice versa, cannot remember which).
Just need to wait for the new Garmin coming out just for motorcycles! It looks way cool.
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SoCal ZX-14 Rider
Expert Class
Posts: 351
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posted September 07, 2006 11:49 AM
So if im understanding right the speed does not have to be maintained for more than a second to get the accurate reading?
I just bumped 150 mph on the speedo, less than a second. Longer probably would have put me into the wall on the next turn.
This little place is a transition road between freeways, one lane, walls on both sides and an 1/8 mile straight between the 2 middle turns. Hold it on for too long and powwy ooops could happen, funner than shit though.
Maybe I'll go find a longer road. lol
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fastestbusaaround
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posted September 07, 2006 12:56 PM
Correct SoCal...and TS, my bike at 200KMH or 100KM or any speed, shows the same variance in % as does my 10R.
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kspz3
Expert Class
Posts: 334
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posted September 07, 2006 02:17 PM
If your speedo at peak speed says 150 and you have an 8% error then at peak speed you are going about 138MPH. If you are accelerating at full tilt, one second before that the speed would have been about 130MPH (by my calculations at least - actually modeled) with an average speed around 134MPH since it is calculating your average speed between the one second interval. This of course assumes it catches you exactly at peak....... and not a half second prior to peak - this calcualates very close to your reading...... If you cruised over distance at peak speed then it should capture 138MPH.
KSP
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SoCal ZX-14 Rider
Expert Class
Posts: 351
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posted September 07, 2006 02:18 PM
Cool thanks
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fastestbusaaround
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posted September 07, 2006 02:25 PM
quote:
So if im understanding right the speed does not have to be maintained for more than a second to get the accurate reading?
I just bumped 150 mph on the speedo, less than a second. Longer probably would have put me into the wall on the next turn.
This little place is a transition road between freeways, one lane, walls on both sides and an 1/8 mile straight between the 2 middle turns. Hold it on for too long and powwy ooops could happen, funner than shit though.
Maybe I'll go find a longer road. lol
Don't remember if the 60CX has this, but you might check to see the top speed the device recorded...that feature exists on all of the Garmin automotive units...
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SoCal ZX-14 Rider
Expert Class
Posts: 351
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posted September 07, 2006 02:46 PM
The gpsmap 60 CSx has max speed on the trip computer page. You have to remember to reset it each time you turn the unit on.
It will not add more speed to an existing trip, a trip being the time between turning it on then off.
This is a sweet unit and first I have ever owned. It has more bells and whistles than any unit I could have wished for.
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hawkman
Zone Head
Posts: 747
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posted September 07, 2006 03:11 PM
My garmin on my ZX-12R showed my speedo to be off up to 10% at 200mph indicated. Ran out of room the two times I had it up to 200mph, but was there long enough for the GPS to read 180mph.
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stevewfl
Moderator
Posts: 27920
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posted September 07, 2006 03:22 PM
quote:
Just need to wait for the new Garmin coming out just for motorcycles! It looks way cool.
I'm waiting patiently on a new latest and greatest to come out, and I'm pulling the trigger
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2010 Concours14
'08 R1 YAMAHA
ZX14 gone!
CBR600RR track bike
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fastestbusaaround
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I eat Fish...
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posted September 07, 2006 03:42 PM
quote:
The gpsmap 60 CSx has max speed on the trip computer page. You have to remember to reset it each time you turn the unit on.
It will not add more speed to an existing trip, a trip being the time between turning it on then off.
This is a sweet unit and first I have ever owned. It has more bells and whistles than any unit I could have wished for.
It should always have the fastest speed you hit, until you reset it...I would think, at least that's the way all the other Garmin units work..
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fastestbusaaround
Needs a life
I eat Fish...
Posts: 7889
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posted September 07, 2006 03:42 PM
quote:
quote:
Just need to wait for the new Garmin coming out just for motorcycles! It looks way cool.
I'm waiting patiently on a new latest and greatest to come out, and I'm pulling the trigger
It's the ZUMO 550 from Garmin...see it on their site!
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SoCal ZX-14 Rider
Expert Class
Posts: 351
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posted September 08, 2006 07:37 AM
I didn't want a big gps. This one fits nicely in your pocket. Where I park my bike I would have to take the bigger model off the bike, find a place to store it.
You can velcro this to the tank or keep it in the pocket. It is Garmins latest and greatest pocket size.
Garmin GPSMAP 60CSx with 1 gig memory card, color screen. I can fit almost the entire US on it with its memory.
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dbeadling
Zone Head
Posts: 699
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posted September 08, 2006 08:17 AM
got a garmin c340 with ram mount bolted to tech mount with bel rx 65 . works great but not water proof.....I am waiting for the zumo to be released. I cant live with out one.its fun knowing where the gas... food and what ever is over the next hill
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ninja14
Pro
Posts: 1136
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posted September 08, 2006 08:54 AM
I've had my handheld unit display over 500MHP while on a plane.............don't think my bike will get there :-)
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2006 Turbo ZX-14.
2005 V-max 20th Anniv.
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