Speedo inaccuracy
#1
06-13-2009, 07:40 AM
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Location: Andover, Kansas
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Speedo inaccuracy
What kind of inaccuracy do you see on your speedo? I followed my wife, in our car, down the highway last night. Her cruise was set to 74 mph. The speedo on my 90 cbr 1000f registered 83 mph. My sprockets are stock values. Delta could be a combination of error in the car speedo and my CBR. I don't have a gps with speed. Just curious about other riders' experiences.
#2
06-13-2009, 07:47 AM
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Never actually checked mine against another vehicle properly.....but when cruising at 60mph/100 klm per hr the traffic seems to be sitting with me at the same speed limit...
As a rule though , most factory speedo's are set a little high to be on the safe side ... but 9 mph sounds a bit high ??
What profile front tire do you run ??
As a rule though , most factory speedo's are set a little high to be on the safe side ... but 9 mph sounds a bit high ??
What profile front tire do you run ??
#4
06-13-2009, 08:32 AM
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#5
06-13-2009, 02:42 PM
#6
06-13-2009, 05:23 PM
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Even though the drive is from the counter shaft on a 90 ....if the rear wheel dia is reduced with low profile tires , or the gearing is lowered, the engine will rev a little higher to get the wheels to cover the same amount of ground (actual speed)... and then because the rotations of the counter shaft are then higher and are fixed to the engine rotation (darr)....the speedo will register a slightly out(higher) reading due to the few extra revs required to get her up too 100klm per hr (60mph)...
Similar chit that is caused by sprocket changes too....
#7
06-13-2009, 10:04 PM
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#9
06-16-2009, 06:33 PM
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Hey guys, haven't been here in awhile saw the discussion of speedo errors & decided to chime in. lol! I'm running a 17/46 sprocket with a Dunflop(lol)Qualifer 180/55/17 rear & a 120/60/17 front. So when I'm at about 9800 to 9900 rpms my speedo reads 175 mph. My conclusion is yes its off quite a bit, but how cool it looks reading 175. Dat's my story & I'm stickin to it! lol!
Ps: Hiya Steve & Pete, sorry for my absence on here. lol!
Ps: Hiya Steve & Pete, sorry for my absence on here. lol!
