06 ST1300A, speedo shows wrong speed by about 5 kph (3 mph)

r2c9y

Joined
Nov 19, 2024
Messages
1
Location
Europe
Bike
06 ST1300A
As in the title: 06 ST1300A, speedo shows wrong speed by about 5 kph (3 mph). Brand new tires and correct air pressure doesn't help.

When my navigator (navigators because I have tried multiple) says I'm doing 80 kph, the speedo on the bike shows about 85 kph. This goes for "all speeds" it's always showing 5 kph more than the real speed.

Does anyone have some good advices for fixing this? It's only an annoyance, I know, but I would like it fixed regardless if possible.

Thanks :-)
 
If its really that important, seach for SpeedoHealer, i.e.:


all vehicle speedos are on the optimistic side... by (EC) law: 10% + 4kph permitted...

interestingly is the instrument on my 'ol ST1100 pretty accurate... :unsure:
due which I always have to be careful when changing from my trusty Toyota (showing +12kph) to the ST (showing +1kph)... ;)
 
r2c9y said:
speedo shows wrong speed by about 5 kph (3 mph). Brand new tires and correct air pressure doesn't help.
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This is pretty standard for the STs. The faster I go on mine the slight bigger the error. The SpeedoHealer will fix that but you loses something else in the bargain. I don't recall what that is but somebody will.

I'm find with it myself. It keeps me from needing a radar detector. If I use it to drive the speed limit I know I won't be over. I'm not a member of the "This detector saved my bacon 147 times!" club.

I did have a detector once upon a time because I thought ECM was cool and it sounded like a SAM growler and had a cool LED display. But it just got annoying so I removed it.

From time to time I put my phone in a cradle with a speedometer app that pretty much filled the screen. I saw there wasn't enough difference for me to think twice about.
 
I first noticed an error at low speeds in marked construction zones. Many have speed monitors that flash your speed. About 3mph lower than my speedo indicates at every one I've encountered.
Given the 'speed creep' I seem to have....few of the usual indicators like wind noise, engine noise, engine vibration...... I once caught myself doing near 90mph in along a marked 70mph rural stretch. So I usually run along with the majority of traffic or glance at the speedo frequently in light traffic.
 
I usually run with a GPS on my bike……well all the time really. That usually gives me a rather accurate speed, which I rely on. I have installed cruise control, and that makes maintaining the posted speed limit within the accepted tolerance that police with radar devices accept but not speed cameras. ;)
 
Yeah, it's known. I just used the gps as a speedo. When the speedometer said 80mph the gps said 73mph.

I had a friend that insisted on going the speed limit as indicated on the speedometer while in the fast lane and was almost the victim of road rage several times...
 
Every Honda I have owned has read Higher, has saved me many times going through speed traps, in fact Yesterday was one such example. Odometer is accurate mind you. G
 
r2c9y said:
Does anyone have some good advices for fixing this? It's only an annoyance, I know, but I would like it fixed regardless if possible.
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All st1300 speedometers read 7 or 8% higher than actual speed. There are only two ways to fix it. One is an electronic device like the SpeedoHealer, which interrupts and alters the signal between the speed sensor and the speedometer. The other is to physically move the speedometer needle on its pivot so that it more closely reflects the actual speed. You will have to pick what speed range is the most important for you and set the needle at that speed. The speedometer will still be off by the same 7 or 8% at other speeds but it will be accurate at the speed range that you set it for.
ST1100Y said:
interestingly is the instrument on my 'ol ST1100 pretty accurate...
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I have had two ST1100's- a 1999 and a 2000 model year. Both of them were accurate to within 1 or 2 KM/h compared to GPS and roadside radar speed signs. My 1992 Shadow was also this accurate. So have been most of my other vehicles that I have ever checked. My current truck is within less than 1 Km/h of these signs. In my opinion there is no good reason or excuse why Honda did not ensure that the ST1300 speedometer is more accurate.
ST Gui said:
The SpeedoHealer will fix that but you loses something else in the bargain. I don't recall what that is but somebody will.
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What is given up is accuracy in the odometer. The speedoHealer will improve the accuracy of the speedometer and decrease the accuracy of the odometer by a corresponding amount.
 
I've owned several cars, SUVs, bikes and only 3 have ever had an accurate speedometer.
It is actually well known that car/truck speedos are typically 3-6% off set to read higher than actual. Bike speedos in my experience typically run 6+% higher than actual. I've had only one bike that was accurate and 2 cars that were accurate. 2 of my bikes showed 11% higher than actual. It is actually Federal law in the USA that imposes strict penalties if a speedometer shows anything under actual so most vehicle makers go high (unless they are a high dollar priced vehicle and even then may not be accurate).

Since GPS systems calculate speed from changes in satellite positioning they are typically far more accurate than vehicle speedometers. Navigation systems for consumers are usually around 0.3% accurate. IOW- if you are going 100 then the Sat-Nav will show 100.3 at the worse. Really not enough offset to even consider unless you are extremely anal.

I'm good at math so I have no issues just knowing what number I see on the speedometer and what actual speed that really is... within +/- 0.5. I don't have a need to spend any money on a SpeedoHealer.

Oh, and I can really tell when a driver in front of me thinks their speedo is accurate since they are consistently going slower than the speed limit by a very small percent... always.
 
Huh. This explains it. When I did my run out to Calgary and back a week or so ago, I noticed that the speed registering on the speedo was below that on the Waze app on my phone and on the gps, as well as various road work speed monitors. Purely hypothetically and only as an example, if the speedo read 130 kph for example, the Waze app and the gps (might have) said 122 kph or so.
 
That is quite usual. Speedos are designed to ensure that they will never show a speed that is slower than your actual speed.
There is a manufacturing tolerance and there is the effect of the change in diameter of the tyres as they wear down (about 2%) change, and the effect of tyres heating up and cooling down.

A speedometer will never say show that you are traveling at 70 mph when you are actually traveling at 71 mph. But it may say that you are traveling at 77mph when you are only traveling at 70.

At the time that I checked this out (2014) the tolerance for the speed shown by a speedometer was anywhere between the actual speed and 10% + 5mph. So at an actual speed of 70, the speedo could legally read any value between 70 and 82 mph. On average half of the speedos could therefore be reading above 76mph. A very few will be spot on with overinflated, hot tyres. (The bike travels further per revolution in this situation, and speedos are tested with hot, overinflated tyres).

The difference between the reading and true speed is never fixed at (say) 5mph. It varies with speed.

I used to get a mental calibration using the satnav. Open straight road, clear view of the sky, no heavy traffic or tall buildings. Tyres warmed up, Constant speed, straight road, Compare the satnav speed with the speedo and check that the satnav and the speedo are both reading a constant value. Mine would often read 76mph at a true 70mph. Sometimes it would read (say) 74.

You cannot rely on the satnav for an instant readout. It calculates the speed that you have been traveling over the last few seconds, it does not show the speed you are traveling now. Hence the need for a straight road and constant speed.

If you use a speedo healer, it will sometimes be showing a slower speed than you are traveling, and your mileage will be wrong.
 
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jfheath said:
There is a manufacturing tolerance and there is the effect of the change in diameter of the tyres as they wear down (about 2%) change, and the effect of tyres heating up and cooling down.
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This changing tire diameter is something kids and some adults never consider when they change the tire diameters for various effects. A larger than factory tire diameter will lower the speed indicated by the speedo. Decreasing the diameter below the factory spec will raise the speed indicated by the speedo. The delta of either will depend on the significance of the changes.

Aside from speedo accuracy tread life increases with an increased diameter and decreases with a smaller diameter. I put larger wider tires on a previous car and was careful to check the speed error and live with it. There were (are?) shops that would/will adjust a speedo for accuracy but I never bothered. It never bit me either.
 
ST Gui said:
Aside from speedo accuracy tread life increases with an increased diameter and decreases with a smaller diameter.
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This and that a vehicle (car) is homologated for a variety of tire/wheel dimensions and manufacturers are likely the reason for that legal "optimistic" indication of speed over ground...
Even (modern) cars with their embedded satnav and whatnot (AKA rolling tablets), which technically could indicate 99% accurate speed due their GPS, maintain above mentioned indication inaccuracy...
 
As best I can remember, every vehicle I've ever owned, including two modern EVs, has reported faster than actual speed. The one exception is the ST-1300P (police), which is pretty accurate. Go figure.
 
The one exception is the ST-1300P (police), which is pretty accurate. Go figure.
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It has to be if it will be used in police duty service. In many jurisdictions police are authorized to use the speed that their vehicles speedometer indicates as a means to determine if other drivers are speeding and use that data to issue a fine. Most jurisdictions would require that the police vehicles speedometer have current calibration certification to be authorized for this purpose.
 
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