I was curious if anyone ever clocked their bike against something to see how accurate their speedometer was. My bike seems as if the speedo is off by maybe 5 MPH or so. Either those cars on the freeway are hammer down or my speedo is advanced.
Quote from: Tuneforkfreak on June 22, 2016, 07:54:52 PM
I was curious if anyone ever clocked their bike against something to see how accurate their speedometer was. My bike seems as if the speedo is off by maybe 5 MPH or so. Either those cars on the freeway are hammer down or my speedo is advanced.
My '89 is off by about 5% to the upper indication. So I subtract that 5% for actual fuel mileage.
Quote from: Tuneforkfreak on June 22, 2016, 07:54:52 PM
I was curious if anyone ever clocked their bike against something to see how accurate their speedometer was. My bike seems as if the speedo is off by maybe 5 MPH or so. Either those cars on the freeway are hammer down or my speedo is advanced.
The speedo error on FJ's falls within normal limits. All car and bike speedos read fast by a similar margin, always have. Aprrox 5 mph at highway speeds is not unusual.
Noel
There are plenty of apps you can get for your phone that use GPS to calculate speed. From what I can tell my speedo reads true enough.
Compared with my GPS mine is actually quite accurate (1-2% too optimistic).
Back when mine would read steadily, it was a consistent 10%-ish off. 60 indicated was 55 or under on those "YOUR SPEED IS" signs, a bright-green 72 on the car next to me on the highway would show 80 or just under on my speedo when I was pacing him, etc.
Nowadays, the speedo varies wildly at some speeds (all the damping fluid has long leaked out of it) so I pretty much never look.
On mine, 100kmh on the speedo shows 98kmh on a GPS, accurate enough for me. I think different readings on some bikes could have something to do with the height of your front tyre. Some brands are wider than others of the same size, so maybe the aspect ratio on them is different as well. The higher the sidewall the slower it'll read, the lower the faster it'll read.
Quote from: Bill_Rockoff on June 23, 2016, 06:31:52 AM
Back when mine would read steadily, it was a consistent 10%-ish off. 60 indicated was 55 or under on those "YOUR SPEED IS" signs, a bright-green 72 on the car next to me on the highway would show 80 or just under on my speedo when I was pacing him, etc.
Nowadays, the speedo varies wildly at some speeds (all the damping fluid has long leaked out of it) so I pretty much never look.
I had no idea there was fluid in the speedo, or supposed to be any way. In any case, here in Ohio ( even lots of the back country roads) if you dont know your speed you will be reminded quickly. Any more it seems the po po are waiting behind every tree.
Quote from: Bones on June 23, 2016, 07:14:13 AM
.....I think different readings on some bikes could have something to do with the height of your front tyre.....
Sure, that'll do it, and for reasons I've never bothered with they also come from the factory, where all things are equal, with a varying error.
Noel
From what I have read from data from 1986 with the top three, kawi suzi and yamaha, the suzuki showed the most accurate then the kawi and the yamaha had the worst runout. They tested the speedo runout at max speed and of coarse the margin of error increases the faster you kookaloo.
Suzuki GSX-R1100 top speed was 156mph with the speedo showing 161mph
Kawasaki GPZ1000RX top speed 158.95mph with the speedo showing 168mph
Yamaha FJ1200 top speed 148.38 with the speedo showing 161 mph
On my 91 FJ, an indicated 60 mph is actually 56 on GPS.
On my '90, the speedometer is way far off of actual (like +15%) However the Odometer is only off 5% from GPS distance travelled..
We found Cap'n Ron's '92 Speedometer, and Odometer to be almost right on the money compared to GPS...... :unknown:
Like others have stated, it will vary from bike to bike.