Speedometer Accuracy?

[REDUC]

So, if my "friend's" S4RS, with the full Termi exhaust, chip, and intake "happened" to hit 160 MPH indicated, still pulling with about 9,750 on the tach (stock gearing), how fast would I (i mean "he") really be going?   [moto]  Remember, with the DP ECU, there's an extra 1,000 rpm before the rev limiter shuts down the party, and "my friend" tells me that the bike felt like it would easily pull the whole gear...Anybody throw a GPS on their bike to verify their speed and do something this foolish? 

[Speeddog]

Your friend would be going about 155mph, assuming the tach is accurate.

IIRC, the speedo on my S4 reads about 5mph high at 70mph or so, according to my Zumo GPS.

[Kerry Blue]

From 0 to 60 kilometers per hour the gps and bike are about the same. At 110 indicated the gps reads only 99-100.

[herm]

my gps shows me to be 6-7 mph slower than the tach reads
i have also had an LEO quote me 8mph slower than the tach read when he took the reading

[yotogi]

I don't think that I have ever had a speedo that correctly reported the speed. Almost always 5MPH off on the "safe side"...

Of course I take that into account when I ride so...

[Duck-Stew]

5-10% of the actual speed depending on too many variables to mention.  Likely you were at least 150mph but no higher than 155.

[Takster]

My owners manual says that the speedo number is +8% of actual.  Why in the world would they make this a feature?

[mmakay]

My owners manual says that the speedo number is +8% of actual.  Why in the world would they make this a feature?

No shit?  It actually says that in the manual??   

[Takster]

No shit?  It actually says that in the manual??   

To quote:
"Speed” indicator
This function enables display of the motorcycle speed.
The dashboard receives actual speed value (expressed
inkm/h) from the control unit and displays the value
increased by 8%.
The maximum speed that can be displayed is 299km/h
(186mph).
Over 299km/h (186mph) the display will show a series of
dashes “- --” (steadily lit - not flashing)vs. EU
- p.19 of '09 M696 owner's manual

[link] http://www.ducati.com/en/bikes/service/manuals/2008/pdf/M696-08_en.zip;jsessionid=J3CA3G4FOSLZWCRNCB3CFFIKFUIHSIV1 [/link]

...so anybody seen dashes yet?

[IdZer0]

Wouldn't the 8% tollerance just be to account for difference in wheel+tire radius between upright and in-lean positions?

[herm]

To quote:
"Speed” indicator
This function enables display of the motorcycle speed.
The dashboard receives actual speed value (expressed
inkm/h) from the control unit and displays the value
increased by 8%.
The maximum speed that can be displayed is 299km/h
(186mph).
Over 299km/h (186mph) the display will show a series of
dashes “- --” (steadily lit - not flashing)vs. EU
- p.19 of '09 M696 owner's manual

[link] http://www.ducati.com/en/bikes/service/manuals/2008/pdf/M696-08_en.zip;jsessionid=J3CA3G4FOSLZWCRNCB3CFFIKFUIHSIV1 [/link]

...so anybody seen dashes yet?

hahhahahaha, funny...

you were kidding....right?

[REDUC]

I think next time I'll borrow a GPS and focus on maxing out the tach, as the speedometer only goes to 165 mph, and I'm pretty sure that I can bury that damn needle. (no "dashes" available on theis "Old School Monster")

[LA]

At about 155 mph you are at the aerodynamic limits of the bike.  The resistance is a cube root function so that the only way the bike would go any faster is if you're not on it. Not weight, but aero drag. 

You'd have to be under the paint to hit 155 already.

LA

[RichD]

...Why in the world would they make this a feature?

Because that is the law!  DOT requires it...

Ask them why! (I don't know either...  )

[Takster]

Because that is the law!  DOT requires it...

Ask them why! (I don't know either...  )

Wow.  I learn a dozen new things a day here.

BTW, pugglepod 9000 is the coolest thing ever! Good work!