True speeds

[Huambo81a]

Heres a question, how 'off' are bike speedos in general, are some manufacturers more reliable than others?

I saw 160 on my ZX6r on the motorway the other day (indicated) As people say that my bike will do 161 ish top, what was i actually doing? and what would have to be indicated before i was doing a true 161mph? lol 180?

It begs the question, why are digital speedos off at all?
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Present: 2017 KTM Super Adventure S
Past: 97 Bandit 600 / 05 Bandit 1200 / 03 ZX6-R / 2006 Tuono R / 2001 VFR 800 / 2010 Street Triple R / 2013 Speed Triple S / 2017 S1000XR

[numark1]

My zx6r would read just under 180. So probably a real 160.

[Kickstart]

Hi

For an idea of accuracy, on a top speed run the Bandit was doing 154mph when the needle was on the final mark on the speedo of 170mph.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[craigs23]

10%ish, guess it depends from bike to bike. Is it Aprilia that have the most accurate speedos?

[Silver]

An indicated 186mph on my GSX-R750 was a real 171mph.

[G]

[Kickstart]

[G]

My RS250 read about 10 under the real speed, from what I could work out; may have been worse than that.

[Kickstart]

Hi

Don't really think digital speedos are any more accurate than analogue ones. They just give you the same old crap in a decimal format.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lawnie]

Buy a cheap GPS with a handlebar mount.

[matt89]

dont know about bike speedos but weve got both digital and analogue speedos in our car aswell as a roadangel. our speedos were showing 125 and the road angel was going between 112-115mph so they were only 10% out but i think that all speedos go about 10% out.

Matt

[Sephiroth]

Where can you get a cheap GPS and how much are they roughly?

[G]

Ebay.

From around £50 for a basic one.

[Lawnie]

Something like a Garmin Etrex, very simple to use (I have one).

[Sephiroth]

Ahhh expensive!

[Black Knight]

Honda Blackbird 02.

GPS 30 - Clocks 33

Gps 70 - Clocks 77

GPS 100 - Clocks 92

GPS 128 - Clocks 140.




Readings taken on a Blackspot Road angel.
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Where does a turn end? 'Where you can do anything with the gas you want to, where you are brave again, where your attention is free from the turn, where you are sure you can do it better next time; that's the end' - Keith Code.

[Sephiroth]

It's the fact that the clocked 30 is actually faster than it appears! Beware of scameras! Ahh

[MikeH]

I'm sure I read somewhere that GPS can be inaccurate too at high speeds. Something to do with it can't process the sats positional info quick enough to calculate totally accurate figures, dunno I'm no expert.

To be honest though if I'm running at three figures+ I don't tend to be looking at the speedo there are to many hard metal objects to worry about hitting, especially those with blue lights on

Mike
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Busa Junkie

[Sephiroth]

Blue lights eh?

[Lawnie]

[Black Knight]

Sorry, updated 30mph reading.

The gps systems are inacurate measuring acceleration due to the time it takes to pick up a reading and process it.

In the cases of my measurements above I sat at a constanst speed for at least 10 seconds allowing for an accurate measurment.
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Where does a turn end? 'Where you can do anything with the gas you want to, where you are brave again, where your attention is free from the turn, where you are sure you can do it better next time; that's the end' - Keith Code.

[Lawnie]

Yes, GPS can only update as fast as one second due to the satellite transmission. I thought this thread was about speed, not acceleration.

[garth]

bandit is geared for 119

can still get 128~ on the clocks
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