Speedometer Accuracy

[harveyrawn]

I've been spoiled by the great accuracy of the speedometer on my old R80, where its speed reading seems dead on.

The speedometer on my R1150R seems to register about 10% higher speed than actual. Is that typical?

[dmk]

I've noticed the same thing when comparing it to my GPS - about 7-10% too high.

[towerworker]

While running at 70 mph (indicated) on my '04 my gps reads 66 mph. My tires are not new but have probably 50% tread life remaining.

My previous '03 had similar speedo error.

Wayne

[harveyrawn]

While running at 70 mph (indicated) on my '04 my gps reads 66 mph. My tires are not new but have probably 50% tread life remaining.

My previous '03 had similar speedo error.

Wayne

That's about 6%, close to a "normal" 5% for speedometers. Mine seems about double that, and feels strange. I'll adjust to it, as most German machines demand.

[RGuy]

Mine is ~7% fast - compared to my GPS and also confirmed by timing the distance between mile marker signs on the interstate.
Speedo Indicated 70 mph = Actual 65 mph.

[maduko]

Ditto... mine is about 10% optimistic.

[riceburner]

Pretty much ALL bikes are like that.

IE the err correct on the "safe" side.

The reason goes that if you're doing an "indicated" 70 you're definitely doing less than 70. So you can definitely say you are NOT breaking a 70mph limit.

If they were allowed to err the other way, then you could be doing 75mph, but think you're only doing 70, and such break the speed limit by accident - and then you would have a good excuse for it. By law speedos in most countries have to allow for 10% error (IIRC) - and for the reasons above the manufacturers make the error as speed+10, speed-0.

[gregor]

Did I imagine it or is there not some way to adjust the speedometer reading?

[towerworker]

I've never heard of any method of adjusting the accuracy of the speedometer. I know tire size (tread depth) which changes tire circumference will have an effect on speedo accuracy (although I think it is minimal--may be a reason for possibly designing in some inaccuracy)

[ASQTec]

I've read about the Speedohealer from http://www.healtech-electronics.com/, but have never seen one firsthand. My speedo being off has never really bothered me enough to do something about it.

When you sell your bike, just tell the prospective buyer that it actually has less mileage than the odometer states. Then you can ask for book value.

[CRazyCam]

For anyone who feels strongly enough about having an accurate speedo reading, the quick/cheap option is to get a push bike trip computer, fit it and then calibrate it correctly.

regards,CrazyCam