Built-in speedo error?

From the owner's manual:

Vehicle speed

The dashboard receives information about the actual
vehicle speed (calculated in km/h) and displays the
value increased by 5%

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In other words, a real life 60 MPH would display as 63 MPH.

Odd, I know speedometers almost always read fast, but this is the first time I've seen a manufacturer actually spell it out.

Anyone been able to verify the accuracy of the "5%" figure?

yup. can't verify it's EXACTLY 5%. more importantly, I've never heard a good reason for why.

nyandy said:

yup. can't verify it's EXACTLY 5%. more importantly, I've never heard a good reason for why.

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It's mostly about safety and avoiding lawsuits. If someone crashes because the bike is actually going faster than indicated, the manufacturer becomes [partly] liable. For the same reason (safety) it's also the law, at least for automobile manufacturers. Statutes describe the maximum error allowed.

Curiously, manufacturers benefit by making the speedometer indicate a too-fast amount, or at least they did back in the days of mechanical odometers. A 4-5% too high reading meant the warranty would expire that much sooner

luke said:

It's mostly about safety and avoiding lawsuits. If someone crashes because the bike is actually going faster than indicated, the manufacturer becomes [partly] liable. For the same reason (safety) it's also the law, at least for automobile manufacturers. Statutes describe the maximum error allowed.

Curiously, manufacturers benefit by making the speedometer indicate a too-fast amount, or at least they did back in the days of mechanical odometers. A 4-5% too high reading meant the warranty would expire that much sooner

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learn something new everyday. thanks Luke!

pg. 50 of the owners manual:

FYI, my streetfighter is +8%!

nyandy said:

yup. can't verify it's EXACTLY 5%. more importantly, I've never heard a good reason for why.

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zvez said:

pg. 50 of the owners manual:

FYI, my streetfighter is +8%!

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never caught that in the manual. wonder why the SF is 8%?

never could figure out why such a huge percentage, so when riding the sf, I have to think in my head how fast I'm actually going to keep being nailed for reckless driving/riding.

nyandy said:

never caught that in the manual. wonder why the SF is 8%?

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Ive used my gps to determine speedo accuracy on all my vehicles. The 1199 is right at 5% optimistic. I charted it up to 140mph and it is linear. This would mean that 60 is really 57.5 and 100 is really 95. Also at 187 when the speedo turns to the infamous --- you are only doing 178. It also explains why there is more left till redline at 186 indicated.

For reference my gsxr750k7 is 8% optimistic. My buddies 06 zx10 reads 82 when actual speed is 70.

So the faster you go the more the difference between actual and displayed speed but the error rate is always 5% on our 1199s.

The odometer is also impacted so at 1000 miles you have 950 miles. Since the warranty is 2 years unlimited miles this is not relevant. At resale I would say you'd need lots of miles for it to really impact sale price. But if it did we have the admitted discrepancy in writting from Ducati.

my M3 had a built in 5mph display error. shows 85 doing 80, 100 and your really doing 95. i called bmw to ask why, the answer was to make you think your going faster so you wont go that fast. i said so now that i know i just add that in so when i want to go 95 i go 100 thats just dumb. kind of like when you set your clocks fast once you know how fast you just subtract it out.

I have had 2 Yamaha R1s, both of them have had the same built-in error in the speedometer.

The built in error seems to be around 5-10%.. sometimes in streets by my house, cops place big speed sensors display showing the speed you're going at to discourage from speeding.. I've gone 30mph facing it and the display usually shows 27-28mph.

Does anyone know if changing the sprockets makes the error worse on this bike? Is it taking the signal from the wheel speed sensor or the gearbox? I'm wondering if a speedo healer will work on this bike or if its necessary. I will be doing sprockets shortly but I am concerned about making the error percentage worse.

I think this has been discussed here and there is no impact to speedo if you change your front/rear sprocket. I believe speed is read from the wheel.

gilesr6 said:

Does anyone know if changing the sprockets makes the error worse on this bike? Is it taking the signal from the wheel speed sensor or the gearbox? I'm wondering if a speedo healer will work on this bike or if its necessary. I will be doing sprockets shortly but I am concerned about making the error percentage worse.

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