2019 Tracer 900GT Speedometer 8,33% off the speed.

[ktm670]

Hi Guys. 

I recently brought my first non Ktm bike from the last 20 years and I like it very much so far ! 

This is a Tracer 900 Gt that was almost brand new with 3000km (1864mi)

I did change the bad Oem Dunlop tire on it for the new Bridgestone Battlax T32 that complete change the bike agility. 

Last week i did a nice 1000mi trip on 36 hours so I use my GPS. 

I was choc to see how much off my speedo is. At 130 km/h (80.78 mi/h) on the speedometer I was at 120 km/h ( 74,57)on the gps witch make a 8,33% mismatch speed. That is by far the higher I did see. 

Of course I did use the same Tire size ( 180/55zr17 and 120/70Zr17)

Did anyone know how to correct that ? 

[bwringer]

That is pretty standard. Almost all motorcycles of every brand do this, and most read about the same: 8% higher than actual speed. Some are even worse.

No one really understands why they are so inaccurate, but it's been this way for many years. Odometers are usually pretty accurate, oddly enough.

-Some Tracer/FJ owners just ignore it and get used to it.

- Some just pay more attention to the GPS if your actual speed matters (it usually doesn't matter much).

- Some take care of this by having the ECU flashed. The first owner did this on my FJ-09, and the speedo is accurate, maybe 1 or 2% high.

Edited August 23, 2022 by bwringer

[Ride365]

My 20 is only 1 MPH off above 50 per GPS, most accurate speedometer of a bike I've ever owned.

[KrustyKush]

My 2021 GT seems to be pretty accurate.  I still assume the inflated reading, and so I jack it up a bit and end up cruising around indicated 82 mph most of the time.  This seems to me to be the natural cruising speed of this motor.  Oddly, I would say the same speed applied also to my 2014 FJR.  It gravitated to indicated 82.  I may be imagining this, though.

[duckie]

Funny…….I just ride…..

[Brock]

New guy to the forum but I thought I'd chime in on why I believe most but not all speedos read high.

Back in the pre-electronic era new speedos had a range of accuracy, lets call it 5% up or down from accurate, probably on a bell curve. If the speedo is reading high, no problem, if it's reading low however then there's the problem of manufacturer liability for traffic violations. Police vehicles had 'authority' speedometers installed which had been individually calibrated for accuracy. This was back in the 60's and 70's

Not so with the mass production, built down to a price. The manufacturers just printed the speed scale so the lowest reading speedos showed correctly and all the rest read high. In 56 years of owning vehicles I've never had a vehicle show a lower speed than accurate. The best was my 2004 Astrovan, reading a mere one MPH high, one of the worst was my 2000 BMW RT1100 (60 mph shown, 55 on gps). Most newer vehicles are better but still never read low. It's kph not mph now and the speedos

In support of this odometers have always seemed MUCH more accurate yet they're driven by the same cable or sensor.

I don't get my new 2021 Tracer 9 GT for another two months (it's a bit wintry here in February and March) but it's nice to know a flash can take care of it if I need to.

Cheers,

B

[Turd Ferguson]

The faster I go the more the speedo is off. Actually worse than mechanical speedos of yore.

[Wintersdark]

On 5/13/2023 at 1:51 PM, Turd Ferguson said:

The faster I go the more the speedo is off. Actually worse than mechanical speedos of yore.

This is how it always is on modern ABS equipped bikes.  The ECU is estimating your speed off of wheel revolutions measured by the ABS ring, with a theoretical wheel diameter.  As wheel circumference changes so does speedo output, as a result.  

Generally speaking, motorcycle speedometers are off by 5-10%, and always read high.  This is a liability factor; by having the speedo read a bit high, if you mount for example slightly larger wheels (thus travel further per revolution of the wheel) the speedo doesn't read too low... Which would encourage you to ride faster, risking danger and legal issues.  The cops don't care what your speedo says, only how fast you're actually going.  But the bike is basically assuming your speed = measured wheel RPM times a built in constant for wheel diameter.  As such, the faster you're going, the further off it will be in absolute terms.  

Say it's off by 10% (the wheel circumference - it's assuming you have is 10% larger than the wheel you actually have), at actual 50mph it'll read 55mph, at actual 100mph it'll read 110mph.  

My Tracer is about 6% off, my Tenere 700 is almost 10% off.