speedo error

[purplefalcon]

i have a '98 firebird and a '01 gmc yukon, both have electronic speedos, both vehicles speedos and odometers are deadly accurate.

i just traded a '00 zx12r for a '04 'busa, both bikes speedos were off about 7-10 %, therefore so are the odometers.

if the big 4 japanese builders sell, say, 200,000 new units each year, each unit having an average 8% error, how many warranty dollars do they save due to prematurely expired warranties ? how many excelarated depreciation dollars do the owners lose ?

i am really disturbed that i should have to buy a yellow box or whatever to be able to know how fast (or how slow) i am going. not all riding is at warp speed on the freeways.

that's it, just wanted the world to know that i'm very unhappy about this matter.

 

[NearDeath]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

 

[NearDeath]

by the way... I bet your fire bird or your yukon don't register 180MPH.

If you compare the vehicles at the max. speed the slowest vehicle can produce, I don't think you will be that far off...

 

[purplefalcon]

my speedo on the bike shows 85 when i am really doing 75-77, or there abouts, dude. 100, 180, whatever. do you know how fast you going through a school zone ?

the point being, the speedo in my car and truck are correct, as they should be, the speedos on bikes are not. if the fuel mapping was off that amount the bike wouldn't run. if the alignment of the critical chassis members where off that amount, the bike would be unrideable.

wouldn't it be nice if the speedo worked as well as the rest of the bike ?

 

[RaiderDm]

Well let me set your mind at ease. Your odometer is electronic...And Accurate.
Your Speedo is electronic...And inaccurate...on purpose.
I know this because I work with a DMI thats accurate and can be calibrated.
I've run the busa for 50 miles side by side with the calibrated DMI
Always spot on. The DMI is accurate to the 3rd decimel place (0.000)

Your speed process the electronic signal differently than the ODO and is off by as much as 10% at higher speeds.



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[WWJD]

I don't know exactly how accurate my GPS really is but it shows around 10% off on speedo uphigh: 170ish - really around 155, and the odo off around 3% which I recorded serperately. I'm sure tire pressure, turning, treadwear, ozone, sunspots, dust mites, invisible Aliens, teh number 7 and the space time continuem all affect the Busa speed/mileage info.

Interesting point about the warrenty plans though. Sounds like a good plot for the X-Files!

 

[justintime2]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Sorry cloud9, your wrong on this one. About 10% off from top to bottom. Reads high.

 

[NearDeath]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Sorry cloud9, your wrong on this one. About 10% off from top to bottom. Reads high.

okay man... I will stand corrected

 

[MET]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Depends what you classify as very little. It is a fact that the speedo on a Busa is 7% off from about 68 on up.

 

[MET]

I don't know exactly how accurate my GPS really is but it shows around 10% off on speedo uphigh:  170ish - really around 155, and the odo off around 3% which I recorded serperately.  I'm sure tire pressure, turning, treadwear, ozone, sunspots, dust mites, invisible Aliens, teh number 7 and the space time continuem all affect the Busa speed/mileage info.  

Interesting point about the warrenty plans though.  Sounds like a good plot for the X-Files!

A good GPS unit, and most are good this days, includig the watch GPS units. With in 15 to 20 feet. Which once locked on is about 1/2 percent off. They are not good for doing 60 ft. trap reading though.

 

[MET]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Sorry cloud9, your wrong on this one. About 10% off from top to bottom. Reads high.

Actually es he was wrong but so are you. The eading is .075% off across the board, unless yo7 change your gearing to !16T which is off 10-12% off o 18T which is off 3-4%

 

[justintime2]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Sorry cloud9, your wrong on this one. About 10% off from top to bottom. Reads high.

Actually es he was wrong but so are you.  The eading is .075% off across the board, unless yo7 change your gearing to !16T which is off 10-12% off o 18T which is off 3-4%

That's why I said ABOUT 10%. Everyone seems to report varying degrees of innacuracy but it always seems to be between 7-10%. That's what it was with mine. This brings up and interesting Q though. If Radierdm is correct on the ODO being accurate and the speedo being off this makes the SH or Yellow-B a mixed bag. If the speed signal going into the gauge is dropped by 10% to correct the reading and the ODO is already accurate, then this will change the ODO to read 10% less miles as well.

 

[Juggler]

This speedo error is a pain. I've got a SpeedoHealer which does a good job, but unfortunately, the device can only correct for constant error instead of linear error.

I did a couple of linear tests on my bike, and besides low speed (under 35), it was very linear.

Even with a YellowBox or SpeedoHealer, you're not going to get 100% accuracy. You'll have to pick a speed (or speed range) where you want your speedo to be "dead on". Below that level, your speedo will read slow, above that level, the speedo will run high.

I've been thinking that it would be a cool feature if a device (like a YB or SH) could have a correction value for a given speed. So for each 5mph range (or smaller), you could specify a specific correction value. That way you would be extremely accurate at most speeds. Of course, you'd have to measure against a GPS or something to determine the error, but it could be useful.

BTW, I highly recommend the SH (www.speedohealer.com) if you want to correct some of the stock speedo error, or if you're going to re-gear.

 

[MET]

first of all dude...

the speedo is VERY accurate at all speed limits for the most part. Now if the speedo is a little off at 180, you can live with it...

I do feel you though on the frustration.

Sorry cloud9, your wrong on this one. About 10% off from top to bottom. Reads high.

Actually es he was wrong but so are you.  The eading is .075% off across the board, unless yo7 change your gearing to !16T which is off 10-12% off o 18T which is off 3-4%

That's why I said ABOUT 10%. Everyone seems to report varying degrees of innacuracy but it always seems to be between 7-10%. That's what it was with mine. This brings up and interesting Q though. If Radierdm is correct on the ODO being accurate and the speedo being off this makes the SH or Yellow-B a mixed bag. If the speed signal going into the gauge is dropped by 10% to correct the reading and the ODO is already accurate, then this will change the ODO to read 10% less miles as well.

Yes and the speed will still be off at certain speeds. That is why I never changed to a Box and use a GPS when I want accurate readings.

 

[sweeper]

I've never understood the metric speedometer mystery. Most are off by differing amounts. You see this discussed ad nauseum on a lot of forums. Believe it or not there are a lot of people who contend that they are off on purpose by the manufacturers to save us speeding tickets.

I just don't understand why the Harley speedos are always dead on but the metrics are always off. My 1800 reads about 3.5 to 4 mph off up to 120 (GPS verified). The Busa on the other hand is depressingly off at high speeds. 5 mph off around 60 then gets larger as speed increases. I wish I knew the real reason.

 

[MET]

I've never understood the metric speedometer mystery.  Most are off by differing amounts.  You see this discussed ad nauseum on a lot of forums.  Believe it or not there are a lot of people who contend that they are off on purpose by the manufacturers to save us speeding tickets.  

 I just don't understand why the Harley speedos are always dead on but the metrics are always off.  My 1800 reads about 3.5 to 4 mph off up to 120 (GPS verified).  The Busa on the other hand is depressingly off at high speeds.  5 mph off around 60 then gets larger as speed increases.  I wish I knew the real reason.

same percentage at low speeds and high, which tells you most lkely it is built into the bikes.

Off 4.5mph @ 69 = 7%
Off 14 miles per hour @199mph =7%

 

[purplefalcon]

well, now that everyone has proven beyond a doubt that they all have great skills in math and the written word, the point still remains that suzuki has not fulfilled their contract with us as buyers.

the speedos and odos are both off and it is by design (or lack of). period

 

[RaiderDm]

Its because the law REQUIRES it. German law is even toughter than ours.

Sport Rider, Motorcyclist & MCN all have articles that go into this in more depth.



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[mzrsq]

So why doesn't the industry, including the auto industry devise their sppedo's to work from a GPS type reading. It honestly couldn't cost that much more. That way (even in the cage) regardless of gearing or tire size or tread wear, or the weather that day, your speedo would always read correct.

Or am I just dreaming here?

 

[Juggler]

So why doesn't the industry, including the auto industry devise their sppedo's to work from a GPS type reading.  It honestly couldn't cost that much more.  That way (even in the cage) regardless of gearing or tire size or tread wear, or the weather that day, your speedo would always read correct.

Or am I just dreaming here?

mzrsq,
I was thinking it would be a relatively straightforward thing to take the output from a GPS (it's essentially serial data), and use it to drive the speedo directly.

I think the only downside to this would be if the GPS in question can't find a satellite (riding in the forest), or if update isn't fast enough (my Geko updates once a second -- I think).