675 How Off Is Your Speedo?

GPS speed is reliable over distance but has variations at an instant Reading. I found my Speedmaster speedometer is 5-6km/hr higher than actual speed, which is std for modern vehicles

 

It can be +or -10%, which you are within , so it’s normal.
You may be able to find someone who can calibrate it for you, then it will be accurate at all speeds, and certified thus. It was the case with the “old” speedometer with a needle, not sure about digital/electronic ones.

 

We talk about +/- 10% in this country (UK) but is that a standard accepted tolerance everywhere? I suspect it is otherwise we'd all benefit from whomever has the most stringent rules, and they'll all read high as a safety margin. I've never seen one read under. I noticed the other day that my Ducati is about 2-3mph over at around 50mph. I haven't checked at different speeds.

 

Apparently, according to European Guideline 75/443/EEC: 1)The shown speed must be higher than the real speed. 2) the shown speed must be lower than 1,1 times the real speed + 4kph.

At 100 kph mine shows roughly 110.

 

Trust the EU to have a rule for it. I'm surprised we don't see more GPS speedos on bikes these days. Are there any and if not, is there a reason other than cost?

 

I'd imagine that would be because of reception issues - no reception, no speed readout?

 

GPS speedos will only read accurately on level ground, going up hill or down hill there will be errors due to having to travel an increased distance on the road compared to what the satellites can see and read.

Speedos are not supposed to read slower than the vehicle is actually travelling so it cannot be used in the defence of a speeding charge.

 

Usually about 10 percent go up one tooth on the front sprocket and it'll read closer to the real speed

 

Oh yes, hadn't thought of elevation changes, or tunnels. The things you learn around here.

 

The basic rule of thumb is that you are never going quite as fast as your speedo says. The Doppler radar speed signs are quite accurate and clock me doing 39mph at an indicated 42mph. Beyond that, the calibration is for new tyres at maximum circumference. Throw in a little wear and the over estimation creeps up.

 

My 2010 speed triple is at least 10% out. Over reading that is.

 

All the bikes I have owned In recent years have shown a Speedo faster than my satnav. As has been said this is normal.

 

I haven't checked the Bonnie yet, but most bikes I've owned have been 8-9% fast. The V2K was spot on and so is the Goldwing.

 

Just been to France and covers about 1400 miles mostly with sat nav, Speedo read 2mph faster than sat nav at all speeds above about 30 mph. This was on my Speed triple RS. I have 20 inch wheels on my transit and Speedo is exactly the same as day nav.

 

Wondering, if they are inaccurate with the speed may be they get the mileage wrong too? Anyone measured?

 

I agree with the tunnel theory but elevation changes?
That’s like going to the bottom of the garden to get a closer view of the moon init?

 

Surely, top of the garden for a closer look? lol

 

https://www.healtech-electronics.com/products/sh/
This might cure your anguish!
Personally, I’d rather it be reading over speed than what I’m actually doing due to the cameras!