Speedo vs GPS

[reaper.za]

I've ran a few test and so far it seems like my speedo is out by only 1-2%.

How are you guys finding it?

Attached, my clocks showed 297km/h and the GPS showed 293.
Another run my clocks showed 269 and my gps captured 265.

[yzfr1mike]

I tested my bike at 80 mph and the GPS read 78.

I have had to correct all my other bikes to get them within 1-2 mph at 100mph. I am not planning to change the BMW.

Mike

[reaper.za]

Originally Posted by yzfr1mike

I tested my bike at 80 mph and the GPS read 78.

I have had to correct all my other bikes to get them within 1-2 mph at 100mph. I am not planning to change the BMW.

Mike

Really like the way BMW do things!

[edchung]

I believe the BMW gauge is more accurate because it's reading wheel-speed using the ABS sensor, whereas most bikes calculate speed based on the gear-speed at the engine.

I'd assume that a non-ABS S1000RR has a less accurate speedo.

[zer0code]

I got a non-ABS S1k...

well fortunately i dl'd an GPS for my Nexus S. Tonight im gonna try it @ 120km/h and then report here what was the result.

[yzfr1mike]

I think the other bike manufacturers intentionally design the speedometers to read high to enhance their reputation for speed, and maybe to provide a margin of error for the rider when he encounters the local constabulary. The wheel speed sensor is capable of greater accuracy because changes to the bike's gearing don't affect the speedometer readings. However, changes to the tire diameter (thus circumference), will affect the speedometer accuracy.

Mike

[reaper.za]

Originally Posted by zer0code

I got a non-ABS S1k...

well fortunately i dl'd an GPS for my Nexus S. Tonight im gonna try it @ 120km/h and then report here what was the result.

Great. How did it go?

[reaper.za]

Originally Posted by yzfr1mike

I think the other bike manufacturers intentionally design the speedometers to read high to enhance their reputation for speed, and maybe to provide a margin of error for the rider when he encounters the local constabulary. The wheel speed sensor is capable of greater accuracy because changes to the bike's gearing don't affect the speedometer readings. However, changes to the tire diameter (thus circumference), will affect the speedometer accuracy.

Mike

My CBR600 was out by 20km/h. It irritated the hell out of me!
Interesting about the tire diameter. My tire is actually not looking to good after only 2000km's. I guess thats what 193 horses do when abused

[1000RR]

Originally Posted by reaper.za

My CBR600 was out by 20km/h. It irritated the hell out of me!
Interesting about the tire diameter. My tire is actually not looking to good after only 2000km's. I guess thats what 193 horses do when abused

I don't think many folks w/the stock tires looked too good after 2000km's... I ended up with ~2,400 miles on my K3's and switched out... and that was probably a hair more than the average from what I've seen on the forum.

As for the non-ABS bikes, I wouldn't be surprised if they were fairly accurate too... the only difference is they are pulling speed from the front sprocket instead of the rear ABS ring.

[chipset]

I am at 1988 miles and my Contis are about done. I might have a couple hundred more, but now I am on the hunt for tires.