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+6 mph???

26667

26667

the Wizard of Oz
It's probably been answered before, but just passing thru a construction zone with the lighted sign that tells "Your Speed" and of course my R11RT is 6MPH optimistic. My '82 R100 was exactly the same. I've found the same to be true when I ride with GPS; it's always +6

Why!!?? Why? Why?:scratch Why 6? Why not 2?....Why not right on????:violin
 
So, if the work zone is rated at 30 mph, your speedo reads 36 mph? If the zone is rated at 45 mph, your speedo reads 51 mph?

For the Airheads, a service bulletin was released that indicated what the max permissible error was. That error could be no greater than your actual speed times 10% plus 2.4 mph. So, 55 mph actual speed would be displayed somewhere between 55 and 62.9 mph...that difference could be as high as 7.9 mph. So, the amount off wasn't a fix number but would depend on the actual speed.
 
We did a whole thread on this a couple of months ago. It was informative. Bottom line, the speedos are up to 10% higher than actual speed by design.
 
1992 K1100 is almost 10 mph off.... when I look at it. I tend to use GPS speed if I need a precise reading. Guess I've just accepted this and really don't think about it any more. (my old /5 gives no reading at all and doesn't have a gps. Lot of 'guessing' going on there) - Bob
 
Interesting. I recently set a personal best on my RT. And the speedo reading was 6 MPH higher than what the Nav 5 recorded as the max.
 
Not sure if it's just EU, but the OEM didn't want any reason for an owner to sue them for getting a ticket if the speedometer was inaccurate the "other" direction.
 
rangerreece said:
We did a whole thread on this a couple of months ago. It was informative. Bottom line, the speedos are up to 10% higher than actual speed by design.
Click to expand...

This is to save our ignorant asses from ourselves. On the Interstates, I tend to run my Airheads just as fast as they will go. The actual values are meaningless. I tend to run in the range where" arrest driver-impound vehicle " is the rule.
 
James.A said:
This is to save our ignorant asses from ourselves. On the Interstates, I tend to run my Airheads just as fast as they will go. The actual values are meaningless. I tend to run in the range where" arrest driver-impound vehicle " is the rule.
Click to expand...

My train of thought went there too but then tended to gravitate more towards the more likely corporate scenario of running through warranty mileage quicker potentially saving the company billions in warranty claims over a given period of time.

Personally, I'm an accuracy guy. I don't feel there is any excuse for an engineering leader not to be able to incorporate accurate GPS speed in to the bike's cockpit instrumentation. The engineers already figured out how to pull accurate GPS time and update the bikes clock.
 
1. Was there not a time during the Carter administration where 85 mph speedometers were required? I believe that same law dictated a certain degree of accuracy which was less than 5% off.

2. The speedo on my R1100S , is almost dead accurate. The odometer is 5% low.
 
James.A said:
This is to save our ignorant asses from ourselves. On the Interstates, I tend to run my Airheads just as fast as they will go. The actual values are meaningless. I tend to run in the range where" arrest driver-impound vehicle " is the rule.
Click to expand...

:rofl True

It's also why some folks think every other yoyo on the road is speeding by their BMDubya
:whistle

The LEO's are thinking we are being speed cautious and responsible doing 50 in a 55.
 
Speedo Error

26667 said:
It's probably been answered before, but just passing thru a construction zone with the lighted sign that tells "Your Speed" and of course my R11RT is 6MPH optimistic. My '82 R100 was exactly the same. I've found the same to be true when I ride with GPS; it's always +6

Why!!?? Why? Why?:scratch Why 6? Why not 2?....Why not right on????:violin
Click to expand...

Good news, at least some of the newer ones are more accurate. My 2010 RT is only +3 at freeway speeds.
 
I think we would all like our speedometers to be accurate or very slightly fast. And I had one on my 1987 K75. Hold the speed at 60 mph and watch told me it took exactly one minute to pass each mile marker. My current bike (K100RS) DOES have an accurate odometer but the speed reads quite high. So odometer readings and speed readings are not necessarily connected. My VW Passat also seems to have an accurate odometer but read high with the original size tires. No telling about the speed or odometer readings on winter tires since I got (unknown to me at the time) winter tires and rims an inch smaller.

I think it would be a good idea to know how fast you are going rather than having to guess. But I just try to follow the speed of traffic - which I am sure is sometimes WAY above the posted speed limit. Safety first. Legality - well don't be the fastest one down the road.
 
Probably a good thing mine reads about 4% fast yesterday when a country LEO was behind me for 15 miles...

Found something online from BMW where they only claim ±2% for the RT-P speedo. The same notice said difference between new and worn tires could be that much. Even though I saw it on the internet so know it's true, I don't think I'd argue the point if I had an opportunity to discuss it by the side of the road.
 
At 135 mine is off 6-7 mph. GPS = 135 Speedo = 141-2. sort of a guess since I didn't want to take the time to accuaretly figure out the speedo.
 
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