fsusux
Banned
Are you running GPS on your HiPo bike?
Speedo Error Myth
- Thread starter Tufbusa
- Start date
Well Great! But your Wrong... And a Poor Judge of your own "Good Judgment" a measure that should never be left to oneself.
8 years and countless reviews and observations tell me that regardless of what a "$60K dyno" May or may not say that the Busa's speedo is horribly inaccurate. Hundreds of times over the last years we've all come across the "speedo said 180 and the GPS said about 155-160". Not a lot of room for argument here, it's not one or two folks, it's magazine tests, and countless GPS runs.
Don't put too much stock in speed runs on a Dyno and how it relates to what the speedo says. Remember dyno's are only relevant to themselves on that particular day, they are hardly finely tuned empirical measuring devices. Factors like Air Temp, Operator, Humidity, Altitude, etc can all have a dramatic effect on the output. According to the dyno Tru-Wrecks Corvette would run 220MPH or something like that, but we know it won't that's just how fast it can spin that little drum...
Now Revlis, before you get your panties all wadded up and throw out any more generalizations and presenting them as facts, or throw out any more feble attempts to insults someones intelligence, spend a little time learning to read and COMPREHEND!
Look at your above post, I inserted "In my Opinion". I'd think you would understand this not to be a factual statement, simply "My Opinion"!
My first thread says "My experiment has "ME" convinced"! Not you or anyone else, only me. The only facts I have presented is the dyno speed and my busa's speedo were very close at reading speed. I never once said the busa's speedo was accurate.
Look at your above post, I inserted "In my Opinion". I'd think you would understand this not to be a factual statement, simply "My Opinion"!
My first thread says "My experiment has "ME" convinced"! Not you or anyone else, only me. The only facts I have presented is the dyno speed and my busa's speedo were very close at reading speed. I never once said the busa's speedo was accurate.
Warchild
Banned
GPS man. I changed the rear sprocket to a 38 and came close to correcting my '06, at normal speeds anyway. At the max I'm about 3 MPH off now, max being 180 MPH GPS
TufBusa
It is possible that your speedometer is accurate on your bike and most bikes are not. I've seen 5-10% error on most bikes but that does not mean the calibration of your speedometer head might be "off" causing it to read correctly. I have ran one of my gps units with radar in a patrol car and it was spot on. While I have seen them bump a high number with restricted signal, a constant ready is true in my books.
Also a GPS will adjust for altitude and even tell you the correct altitude. If I remember correctly they are accurate within +-30'. I've read specs on the GPS speed accuracy being between .1 and .5 mph.. Garmin is quoting velocity accuracy at .05 meters per second which converts to 0.1118468146027 mph.
It is possible that your speedometer is accurate on your bike and most bikes are not. I've seen 5-10% error on most bikes but that does not mean the calibration of your speedometer head might be "off" causing it to read correctly. I have ran one of my gps units with radar in a patrol car and it was spot on. While I have seen them bump a high number with restricted signal, a constant ready is true in my books.
Also a GPS will adjust for altitude and even tell you the correct altitude. If I remember correctly they are accurate within +-30'. I've read specs on the GPS speed accuracy being between .1 and .5 mph.. Garmin is quoting velocity accuracy at .05 meters per second which converts to 0.1118468146027 mph.
Geosynchronis Positioning System is used by aligning a minimum of 3 satellites constantly sending out a time stamp. If you want elevation as well to show up on your receiver then you will need a 4th satellite.
The receiver takes the times given by the satellites and with triangulation figures out exactly where you are (civilian use gps accurated to within 9 meters and military to 3). For speed correction it just figures out how much time has elapsed between point a and point b.
While I was military this is just one of the systems that I worked on. A receiver may be faulty but when you have multiple people all showing the same results with individual units that pretty much makes it proven. GPS is accurate.
'nuff said
The receiver takes the times given by the satellites and with triangulation figures out exactly where you are (civilian use gps accurated to within 9 meters and military to 3). For speed correction it just figures out how much time has elapsed between point a and point b.
While I was military this is just one of the systems that I worked on. A receiver may be faulty but when you have multiple people all showing the same results with individual units that pretty much makes it proven. GPS is accurate.
'nuff said
You're all right.. and all wrong at the same time.. it's just production tolerances folks.... some are fairly accurate, some arent... at the shop we are told by Suzuki to expect up to 10%.... we've replaced speedos that were 11-15% off and we've tested machines that were almost spot-on! We've ordered speedos for customers that were near the 10% cut-off only to have to send the new one back for being even worse!.. some 'Busas make 165hp.. some make 150.. take 5 stock bikes to the dyno and get 5 different numbers.... it's just the way it goes.. some speedos are more accurate than others.. no need to fight!
I own a Zumo and use it in all my vehicles. All motorcycles have a ram ball.
earlgpz750
Registered
wow...lots of heat and debate here...phew...i definatly understand what you are saying regarding your views on the Dyno and as you stated it is your opinion. And as heykenny said..it could be "You're all right.. and all wrong at the same time.. it's just production tolerances folks" which makes a lot of sense IMO.
But really what it comes down to:
1) We all have damn fast sexy bikes!
2) We like to go fast (once in a while..shhhhh!!!)
3) When the police tags a bike with a gun, hes going to use what he sees and you all know the rest.
Now I feel that a GPS is very accurate, but when someone gets yanked being taged at 75MPH (radar) in a 65MPH zone, but we are seeing on our Speedos at 70MPH but our GPS says 65MPH.....what does one do then???
That was just a thought question gang...
As long as i can pull the data from the GPS for the time of the incident, that may hold in court that the GPS is accurate and Radar is not.
But regardless of what DYNO says or GPS says...we go pretty damn fast pretty damn quick!!!
But really what it comes down to:
1) We all have damn fast sexy bikes!
2) We like to go fast (once in a while..shhhhh!!!)
3) When the police tags a bike with a gun, hes going to use what he sees and you all know the rest.
Now I feel that a GPS is very accurate, but when someone gets yanked being taged at 75MPH (radar) in a 65MPH zone, but we are seeing on our Speedos at 70MPH but our GPS says 65MPH.....what does one do then???
That was just a thought question gang...
As long as i can pull the data from the GPS for the time of the incident, that may hold in court that the GPS is accurate and Radar is not.
But regardless of what DYNO says or GPS says...we go pretty damn fast pretty damn quick!!!
Bingo!You're all right.. and all wrong at the same time.. it's just production tolerances folks.... some are fairly accurate, some arent... at the shop we are told by Suzuki to expect up to 10%.... we've replaced speedos that were 11-15% off and we've tested machines that were almost spot-on! We've ordered speedos for customers that were near the 10% cut-off only to have to send the new one back for being even worse!.. some 'Busas make 165hp.. some make 150.. take 5 stock bikes to the dyno and get 5 different numbers.... it's just the way it goes.. some speedos are more accurate than others.. no need to fight!
As a vetran land speed racer we spend a fair amount of time doing research on gearing, speed measurment etc and over the years I have used dynos, GPS, laser timing lights accurate down to .00001 mph as well as speedos and other gps based devices from other forms of land and water speed racing.
First all I have to agree that the Dynos are not very accurate for actual measurement. We have ran bikes to redline on the dyno and acheived X Mph in 6th gear then do the same thing at the land speed venues and they speeds are not that close. I also routinely outfit my bikes with a GPS while land speed racing and find them to be VERY accurate for gathering speeds of bikes, sail boats, airplanes and even world record holding dirt based "sail boats"
I have not specifically checked out the 08 busa yet but to me Warchilds meaurements look to be the best and most accurate method and results that I have seen so far. I appericate the effort that went into the dyno study and it was a good study but the dynos in general are not accurate enough to be used for speed. Leave them for Hp estimates.
And as far as the GPS goes it doesnt matter if it is a $400 unit or a $100 unit the speed measurements in my experience seem to be shockingly accurate ever at speeds over 200mph as I have checked many times.
Don
First all I have to agree that the Dynos are not very accurate for actual measurement. We have ran bikes to redline on the dyno and acheived X Mph in 6th gear then do the same thing at the land speed venues and they speeds are not that close. I also routinely outfit my bikes with a GPS while land speed racing and find them to be VERY accurate for gathering speeds of bikes, sail boats, airplanes and even world record holding dirt based "sail boats"
I have not specifically checked out the 08 busa yet but to me Warchilds meaurements look to be the best and most accurate method and results that I have seen so far. I appericate the effort that went into the dyno study and it was a good study but the dynos in general are not accurate enough to be used for speed. Leave them for Hp estimates.
And as far as the GPS goes it doesnt matter if it is a $400 unit or a $100 unit the speed measurements in my experience seem to be shockingly accurate ever at speeds over 200mph as I have checked many times.
Don
During rapid acceleration/deceleration don't rely on a gps for instant speed display...........depending on the processor speed of your unit, you may have a lag time before the true speed is calculated and displayed. Give it a few seconds to catch up.
We also datalog RPMS etc in our land speed racing and on most bikes the last 2-4 seconds the bike spends fighting against aero drag at or near its peak speed for the standing one mile course I compete in so rapid acceleration is no longer an issue. The gps that I have used refresh once a second, the speed based versions made for this refresh every .1 seconds.
Yorad
Registered
Not to add more confusion, although I think we have come up with a great deal of evidence to clear up the issue, but I also have 2 different accuracy settings on my new Garmin Nuvi 650. I forget the name and I don't have it with me today, but basically there is a setting I can toggle on and off that increases the accuracy of the unit significantly, but also uses more battery life when turned on.
I'm not sure what the net effect on speed calculations would be, and I'm sure it's highly accurate in both modes, but I'm curious if anyone knows more about it than me since we seem to have caught the attention of some gurus.
I'm not sure what the net effect on speed calculations would be, and I'm sure it's highly accurate in both modes, but I'm curious if anyone knows more about it than me since we seem to have caught the attention of some gurus.
Yorad,
Are you talking about ground based WAAS?
Most GPS units made in the last 8 years will receive signals from 12 birds at one time. Usually they don't hit that many but with an antenna I have seen mine lock on 10 at one time. The more satellites it locks in on the more accuracy to a specific point. The accuracy to the point is about 30-50 feet. This is the reason, most gps units have the ability to lock the path of travel down to the road you are traveling.
When I first started playing with personal owned GPS units in 99 there was something called SA enabled. I think it stands for selective availability but selective accuracy may have been a better term. It allowed the government to control the accuracy of the signals that were sent from the bird which affect the position the GPS gave us. I think the accuracy with SA enabled was about 300-400'. Fine for navigation but you don't want to do surveying with it! It was turned off in 2000 (I'm pretty sure it was then) and allowed use to get to 30-40 feet.
WAAS is ground based and allows for correction to under 5 feet. The corrections are necessary because of atmospheric changes. It is an initiative from the Federal Aviation Administration to help with flight landings.
While it greatly affects location, it does not really change the accuracy of the MPH reading. Basically if it shows an error of 30' in the North West direction, it will show that same error in your immediate path. Therefore accuracy in relationship to velocity is not changed much with WAAS.
Ohh and Surveyors use other land based equipment in conjunction with GPS. If I remember correctly it was GNSS. I was involved in supporting some applications that used it for surveying purpose in 95-97"¦.mainly to document utilities and current construction. It peaked my interest in GPS units. I think the equipment they were using then was in the $50K range and the user had to wear it in a rather large backpack.
Are you talking about ground based WAAS?
Most GPS units made in the last 8 years will receive signals from 12 birds at one time. Usually they don't hit that many but with an antenna I have seen mine lock on 10 at one time. The more satellites it locks in on the more accuracy to a specific point. The accuracy to the point is about 30-50 feet. This is the reason, most gps units have the ability to lock the path of travel down to the road you are traveling.
When I first started playing with personal owned GPS units in 99 there was something called SA enabled. I think it stands for selective availability but selective accuracy may have been a better term. It allowed the government to control the accuracy of the signals that were sent from the bird which affect the position the GPS gave us. I think the accuracy with SA enabled was about 300-400'. Fine for navigation but you don't want to do surveying with it! It was turned off in 2000 (I'm pretty sure it was then) and allowed use to get to 30-40 feet.
WAAS is ground based and allows for correction to under 5 feet. The corrections are necessary because of atmospheric changes. It is an initiative from the Federal Aviation Administration to help with flight landings.
While it greatly affects location, it does not really change the accuracy of the MPH reading. Basically if it shows an error of 30' in the North West direction, it will show that same error in your immediate path. Therefore accuracy in relationship to velocity is not changed much with WAAS.
Ohh and Surveyors use other land based equipment in conjunction with GPS. If I remember correctly it was GNSS. I was involved in supporting some applications that used it for surveying purpose in 95-97"¦.mainly to document utilities and current construction. It peaked my interest in GPS units. I think the equipment they were using then was in the $50K range and the user had to wear it in a rather large backpack.
Yorad
Registered
Thanks Professor! WAAS is exactly what I was looking for. More info here in case anyone else is interested: http://www8.garmin.com/aboutGPS/waas.html
Not much more though, you covered it pretty well!
Not much more though, you covered it pretty well!
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