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I just returned today from the Blueridge Parkway, first real trip I've taken on my ST3, about 2,000 miles. On my trip back to New York I was averaging around 80mph. My bike is a 06 ST3 with stock gearing, now my question, How much is the speedometer off? I assume it's optimistic.
 

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most speedos are optimistic.
The variance varies with tire wear too. Less rubber, smaller circumference, higher indicated speed.
Next time you find one of those speed guns trailers from the cops that indicate speed, try to get a reading off that and compare it to your indicated speed; that's the % of variance.
I find it that it's not worth trying to figure out. It's close enough for me.
 

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A lot of people claim about 10% error. Best way to verify, I think, is with a GPS. Place it in your tank bag map case, and glance at it while holding a steady speed on the freeway.

FWIW, my old ST2 was spot-on, my recent ST4S reads 10% high.
 

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I've learned to not trust motorcycle speedometers, they're wrong up or do somewhere. My ST UNDER reads by about 5mph at highway speed. Keeps my hand from getting too happy w/ the throttle.
 

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It will usually read from 4-8mph higher than your actual speed. That's my experience comparing to my GPS.
 

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My odometer is off as well.

Went on a Poker run where the directions were mapped out with distances. At the beginning we had to reset the odometer. After the 70.2 miles were over I was showing about 75 miles.

When I go thru the stationary radar indicators I'm a little higher than it says. I wonder if there is an adjustment to get it correct? Good question.
 

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My ST2 is a real worry, the speedo is in 20kms increments, so when I travel on highways, the speed limit is 100km/h, but to stick with traffic and not hold anyone up I have to do just under 120km/h indicated.

If I come across a real nasty policeman, I could be in real trouble.
I don't know how DUCATI got these things approved for road use when the speedo's are so inaccurate.
How could you accurately do 110km/h when there is no mark on the gauge face? All I can do is try to hold the needle roughly between 100 & 120 kmh.

That is 20% difference, and the police generally only give you 5% if your lucky.

Anyway, I have never been booked on my Ducati (touch wood), but worth warning others about.

Ride safe,

Craig
 

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My MY02 St4s is 10% optimistic at all speeds , and that is significant when you want to cover ground quickly 100 mph is actually only 90 mph and 130 mph drops to 117.
So to reach the average top speed for a 4s you would need to see 170 mph on the dials !
Strangely the trip meter is accurate to within 2 %
Both readings checked against my Zumo.

In the UK it is illegal for a speedo to under-read but you are usually allow 5% before you will get a ticket and the police rarely give a ticket 80 mph on DCW's providing the conditions allow it.
 

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My GPS and my speedo read the same speed so either they're both right or they're both wrong.
 

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I don't know how DUCATI got these things approved for road use when the speedo's are so inaccurate.
Most countries require manufacturers to have speedometers that read between the actual speed and 10 or 11% too fast. If the speedometer is 1 mph too slow it does not meet the standards so manufacturers err on the fast side.

How could you accurately do 110km/h when there is no mark on the gauge face?
It might not be labeled but I bet there is a hashmark for 110 kph.

My 2002 ST4s is 10% fast to about 50 mph, then it gradually trends towards 5% fast at around 105 mph and by 140 mph it is only 2% fast. But they are mechanical devices so they are all a bit different. I don't worry about it though, I just make sure I am going faster than the traffic :D
 

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Most countries require manufacturers to have speedometers that read between the actual speed and 10 or 11% too fast. If the speedometer is 1 mph too slow it does not meet the standards so manufacturers err on the fast side.



It might not be labeled but I bet there is a hashmark for 110 kph.

My 2002 ST4s is 10% fast to about 50 mph, then it gradually trends towards 5% fast at around 105 mph and by 140 mph it is only 2% fast. But they are mechanical devices so they are all a bit different. I don't worry about it though, I just make sure I am going faster than the traffic :D
Hi Mike,

Yes, there is a mark for 110kmh, but it is so small and almost hidden on the outside ring of the speedo.
I had to get a torch and double check it was there, I'm not sure you could easily see it while riding.
And yes I do like to stay ahead of the cage drivers too.:D

Thanks,

Craig
 

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<snip>...at around 105 mph and by 140 mph it is only 2% fast.<snip>
Er.. All in the name of science... uh...honestly officer, this is all theoretical...

Ha! You're right Mike. Seems more accurate as the needle gets "clockwise".
 

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My speedo is also out, but I know that at 5000 rpm in top gear with my gearing I'm doing 120kmh... I kinda work off the tacho more than the speedo..
 

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My speedo is also out, but I know that at 5000 rpm with my gearing I'm doing 120kmh... I kinda work off the tacho more than the speedo..
What gear are you in?

I'm not a f**king mind reader:D

Craig
 

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That's good, glad we cleared that up.

Means nothing to me anyway, I've got an ST2 with 15 - 42 gearing.

Just keeping you on the ball!

Craig :D
 

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One of my buddies had his ST4S speedo "calibrated" at some shop on the left coast. He also had one done prior, for an old R100RS (they also read 10% high). He mailed it out there, they do their magic, and then they mail it back to you.

No sure of the name of the place, but I can find out if you'd like.
 
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