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Hey, just want to start a general discussion about Speedo readings and actual speed readings verified using a gps device.

Now on my private test track i was able to achieve 165mph on the speedo (This was while wearing touring leathers/small rucksack.)

While the blades speedo said i had reached 165mph the GPS said i had only hit 150mph

Is this sort of speedo error normal?, Works out at about a 10% over-read? and is this sort of top speed out of a 1998 cbr900rr correct?

cheers
 

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Yours is closer then mine! My 98s speedo read over 185 and gps showed 144.4 was my top speed. I've asked the same question and have been told 10% is about normal for the speedo to be off
 

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my understanding is that the error % changes through the rpm band, so while it is 10% at 150, it may not be near as bad at 50. i don't know for sure though, and mine has a -1/+2 so it's WAY off, lol, and i don't have a GPS to check it.
 

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Hey, just want to start a general discussion about Speedo readings and actual speed readings verified using a gps device.

Now on my private test track i was able to achieve 165mph on the speedo (This was while wearing touring leathers/small rucksack.)

While the blades speedo said i had reached 165mph the GPS said i had only hit 150mph

Is this sort of speedo error normal?, Works out at about a 10% over-read? and is this sort of top speed out of a 1998 cbr900rr correct?

cheers


GPS is not perfectly accurate either.
In as-new condition the 900RR should be good for around 160mph.
Yes, speedo error at top speed can be huge.
 

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my understanding is that the error % changes through the rpm band, so while it is 10% at 150, it may not be near as bad at 50. i don't know for sure though, and mine has a -1/+2 so it's WAY off, lol, and i don't have a GPS to check it.


The error does increase but nothing to do with rpm.
The error increases as aerodynamic drag increases.
 
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