Not going as fast as I thought!

[hueco]

Got the GPS hooked up. Rode to work. Man. What a bummer. GPS shows I am going 5mph slower than the speedo reads. Example. Speedo reads 75 mph. GPS reads 70 mph. And so on. Man. All these years I thought, I am really getting by on these cops. And, why am I having to go so fast to pass these cages?    Now I find out I am the bitch. Gas mileage goes down if I run actual mph. Wish I would not have put GPS on. Ignorance is bliss. I just killed Santa Claus.

[scarylarry]

do you have stock size tires?

[KY,Dave (AKA Misunderstood)]

That's standard for most bikes........

[redflash]

Which translates to .933% on the odo as well So I've only ridden her ~73,250 instead of the indicated 78,500 bummer! And I ususally ride 85mph indicated and get barely 32mpg.

[Jabba]

Which translates to .933% on the odo as well So I've only ridden her ~73,250 instead of the indicated 78,500 bummer! And I ususally ride 85mph indicated and get barely 32mpg.

That ain't true.

My speedo's are off like everyone elses.  My ODO's are spot on.  I rode over 1200 miles with my bud with a GPS.  over 1200 miles I was off by 3 miles.

That's only 0.25% error.  Pretty spot on if you ask me.

Yes they run off the same cable... but we have all decided that the speedo mismatch is deliberate, and therefore uses a different algorithm.

Jabba

[redflash]

well that's good new Jabba, I'll take it!

[Toledo Mark]

Same as Jabba here.

[dreamaker]

Got the GPS hooked up. Rode to work. Man. What a bummer. GPS shows I am going 5mph slower than the speedo reads. Example. Speedo reads 75 mph. GPS reads 70 mph. And so on. Man. All these years I thought, I am really getting by on these cops. And, why am I having to go so fast to pass these cages?    Now I find out I am the bitch. Gas mileage goes down if I run actual mph. Wish I would not have put GPS on. Ignorance is bliss. I just killed Santa Claus.

I understand what you are saying, that really sucks!!!!   We got cheated out of all those speeding tickets. We could have had a nice collection of them and they ripped us off because to the speedo showing faster then we should have been. You can't trust any body these days.



LOL

[Hef]

I agree with Jabba as well. My speedo is off by 5 mph and any Valkyrie owner I have talked to says the same. However the odometer is very close to actual according to my GPS.

[Hoser]

The manufacturers have been doing this for years,  I have never owned a bike that read less than five mph fast.  I ain't griping, just thinking about all the tickets I didn't get.  Got more than my share anyway, always wondered why they were less than I thought they would be, until I figured it out.      hoser 

[Jabba]

I always correct for the speedo mismatch in my head anyway. 

I have only ever had 1 ticket on the Valk.  I have gotten out of 2.  I have a pretty good driving record, so I got to do a deferral on it.  Cost me $250 but no record and no points. 

Jabba

[Willow]

My speedometer reads about 3-4 mph fast at 75 indicated.  My odometer reads 3% low at 75mph indicated.

I don't honestly believe a mass produced mechanical speedometer/odometer can be accurate.  There are too many subtle variables.  I believe manufacturers in general attempt to err on the safer side as litigation insurance.  That's just my guess.

Now for my question.  It always puzzles me to hear someone say his speedometer reads xx miles fast or slow as if they expect that to be constant.  Since the speedometer or odometer is representing revolutions of the wheel as a speed or distance traveled shouldn't it vary with the rate of the revolutions?

[Hoser]

I think it does, mine is spot on five over at 65 indicated.  It is still different at other speeds.  I'm usually running about 65 indicated in5th gear, so that's the one I notice the most.  3000 rpm at my indicated 65. It is 2000 rpm at 45 mph indicated, in 5th gear. Hoser

[JetDriver]

When I am sitting at a stoplight, my speedo matches my actual speed exactly!   By the time I get to 75, it's reading 5 mph faster than I'm actually going.  Depending on how fast or slow my speed is, if my speed is between 0 and 75, my speedo error has to be somewhere between 0 and 5.   It'll vary.

[Moonshot_1]

My speedo is dead on accurate. Or so the Iowa State Patrol tells me so. Gave me an award too.

[BIG--T]

Wow, so in 5th gear the speedo shows 65 and I'm actually running 60 @ 3000 rpm?

[Bone]

When traveling highways I always run 5-7 mph over the posted speed.
Have never been stopped.

[valkyriemc]

Speedos' being off is so common you can purchase a device to correct it, or get it real close.

http://www.healtech-electronics.com/

Click on "Speedohealer"

[BradValk48237]

Gosh... I always thought it was 15 mph off.......... 

[Fudd]

Speedos' being off is so common you can purchase a device to correct it, or get it real close.

http://www.healtech-electronics.com/

Click on "Speedohealer"

For "non-cable driven speedo's"

[vicrider]

Got the GPS hooked up. Rode to work. Man. What a bummer. GPS shows I am going 5mph slower than the speedo reads.

Having spent years around bassboats and other boats I've always joked how such a little bitty lightweight thing like a GPS can slow a boat down so much. Boat speedoes are notoriously more optimistic than even bike speedoes. When guys with their 75mph bassboats find out they're actually running 68 it really knocks their machismo down.

I've GPS'd my Vic with 2 different units because of arguments with so many other riders I ride with. They always tell me I'm running too fast because of their speedoes. Mine is dead on at 65, 75, and 85. What is off is my odo. When we do 100 miles on everyone elses odo mine will be 93 or 93. Good part is I think the 49K on odo is really like 52 or 53K but looks lower mileage than it is.

[vicrider]

ps...depending on where you live a GPS is NOT accurate for total mileage. It only figures mileage as the crow flies. I try to explain this in our hilly country in western OK that if you laid a string up and down the hills from point A to point B, the GPS only measures that distance. If you pull that string out straight it will be a whole longer than from A to B. The only place I can think of where a GPS might be dead accurate for miles traveled is Kansas.

[hueco]

do you have stock size tires?

Yes. Dunlop E3 front and rear. My 2007 HD Ultra is 3 mph off  the same way using the same Garman GPS. Que Sera,Sera.

[Hoser]

ps...depending on where you live a GPS is NOT accurate for total mileage. It only figures mileage as the crow flies. I try to explain this in our hilly country in western OK that if you laid a string up and down the hills from point A to point B, the GPS only measures that distance. If you pull that string out straight it will be a whole longer than from A to B. The only place I can think of where a GPS might be dead accurate for miles traveled is Kansas.

You got that right!    hoser

[dallastar]

+1   

That's standard for most bikes........

[Ferris Leets]

ps...depending on where you live a GPS is NOT accurate for total mileage. It only figures mileage as the crow flies. I try to explain this in our hilly country in western OK that if you laid a string up and down the hills from point A to point B, the GPS only measures that distance. If you pull that string out straight it will be a whole longer than from A to B. The only place I can think of where a GPS might be dead accurate for miles traveled is Kansas.

Not true.  the GPS takes readings every X seconds and that distance traveled is how the distance is calculated.  My GPS takes a reading approx every second.

[MP]

Federal law REQUIRES that speedos read actual speed, or faster.  They are NOT ALLOWED to read slow.  Therefore, to avoid any risk in a speedo being low, they make them read a little fast to protect themselves.

The odometer is VERY close.

The GPS  reads every second or so, so windy roads do add up.  To test it, find a block where you can go around and around.  Go around several times, and stop where you started.  If you have any miles shown on the GPS, it is reading distance every second or so.

MP

[Walküre]

Hmmmm....on a lark, I checked mine with I first got the "dedicated" bike GPS, and it was just about dead-on, as close as I could tell with the analog speedo (standard). Does that mean my odometer is probably off?

I've only had the GPS on the bike once - I'll have to drill down and see if it has mileage covered.

R

[Mildew]

Who knows what's accurate. My speedo vs gps shows a 6 mph difference but my 19 over ticket was faster than my speedo showed. The size of the vehicle make a difference on the radar also. I guess the best way to check is by using a stop watch betwween mile marker numbers, then who's saying the mile marker numbers are correct.

[Farther]

I doubt your stop watch is going to be more accurate than a GPS unit.

[Willow]

The odometer is VERY close.

Not necessarily so.  My odometer (on my Standard) consistently reads 3% off (That's 97 miles recorded for every 100 traveled) while my speedometer reads about 4 mph fast at 75 mph indicated.

[Cruzen]

What speedometers are you guys talking about.  The ones used on the Standard/Tourer or the Interstate?  I've had my IS tracked by a state system and two different radar guns and yes it is off but by 2mph at 75mph.  That's nothing to even consider.

However don't bet anything on those commercially available GPS units.  About two years ago some of the guys who work for my company's survey team, which is one of the largest survey teams in Arizona, took three of the commercially available GPS units out with them.  They compared the accuracy of the three they had with our professional equipment.  At the time of this test, the commercial units were in the $300-500 price range.  Our professional equipment runs about 18K and is calibrated to federal specs.  They found the three commercial GPS units to be off by 3-5% when compared to our professional equipment.  Not too bad considering the price differential.  This info was distributed to employees in the company who were considering buying GPS units.  

That 3-5% variation could easily account for all or a portion of you speedometer deviation.