Speedometer error

[ruddy]

I'm old to motorcycling but new to Beemers, so I'll have some typical newbie questions from time to time. Here's one: what's the typical speedometer error for the R1150Rs? I'm used to Japanese bikes with their 10% or more above your actual speed. I'm going to be taking off on a 1,200+ mile trip in a few days, and I may not be able to figure it out before then.

Thanks.

[ASQTec]

When my speedo says 60 MPH, the GPS says 57
When my speedo says 80 MPH, the GPS says 79

Overall, I would say no more than +6%.

[ErikU]

Mine is off 5 - 8mph at highway speeds....

[Boxer]

When my speedo says 60 MPH, the GPS says 57
When my speedo says 80 MPH, the GPS says 79

Anthony, something is wrong with your speedometer. It is too accurate. On most every Roadster I've seen the error is at least 5 mph off. At 70 indicated my GPS says 65...or thereabouts. So what I do to travel at 9 over the limit to avoid tickets is this: If the speed limit is 70 and I indicate 65 then I go 84 so that with the error I'm actually going 79.

[ASQTec]

Anthony, something is wrong with your speedometer.

Either that or my GPS.

[RonBomb]

I read on another BMW website somewhere that the error is 10% plus 1 1/2 mph. That fits with my general observation.

RonBomb

[Beemeridian]

5764

[Boxer]

Someone, puhleeezzee! tell me that there is an adjustment screw, or drive gear change kit, or some way that BMW, in it's herein readily acknowledged superiority in all matters of moving parts--that we can easily calibrate these analog-license-protectors.

You must take the speedometer off and remove the glass cover. Then with a white marker of some kind cross out the numbers and write them all 5mph slower.

[socalrob]

My RR speedo is just shy of 9 percent too fast (72mph when indicating 80mph). The speedo on my suburban is about 10 percent slow (88 mph when indicating 80mph). Let me tell you, sometimes I forget to slow down in the suburban (I only put about 100 miles per month on it) after riding the bike so much. For the longest time I used to wonder why the traffic was going so slow whenever I drove the truck.

Is it really that hard just to make a decent speedo????

[ken k]

That is bizarre. When we were riding to VT we were often over 90 mph (on our speedos) and yet cars were passing us. I figured there was no way we could have been going that fast.

Does that mean that the odometer is about 10% off also?

There are some weird things with this bike. the other is the lack of self-canceling turn signals. My '73 yamaha had them for cryin out loud.

ken k

[MIXR]

Yep - The odo is also out. Bit of a trap when you think you have a 350 km range but it falls short by a few 'real' kms in distance. I'll post some shots from my round Aus trip tonight. Shows the speedo against the GPS. I think there are three shots at different speeds. Mick.

[MIXR]

Some shots that show the common error on these bikes. Interestingly, my mates GSX1400 had a similar speedo error, but his odo was much closer to the GPS! Explain that one (unless it's a different pickup on the Suzi). I'll try and check an enlarged shot, but have indicated what I think is the right variation (about 6 km/hr in each case)


101 is 107 (6)

104 is 110 (6)

130 is 136 (6)

Look closely for the speedo reading and compare to the GPS. Also remember that both instruments do have a bit of lag time, but not much, so the error is within a km/hr or two at most.

And before you ask, the other instrument is a simple dial thermometer that gives me a rough guide to the 'ride temp' being sensed.

[Beemeridian]

786

[peterbulgar]

At an indicated 70 mph on my bike a GPS shows a true 66 mph. This 6% optimism is slightly more accurate than most riders report. The odometer is 3.5% optimistic. Over a 100 mile stretch of road (based on mileage markers - I figure that they are fairly accurate over that distance) the bike's odometer showed 103.5 miles.

MCN shows speedometer error in their road tests. FWIW The Harleys are always spot on or very close.
Peter '73 R75/5, '04 R1150RA

[jon pierce]

ALL speedos coming from Europe tend to over read by about 10%. It is intentional. It is done to cover any errors that might occur from poor manufacture or wear. It is also an attempt to slow us down - and when the cop does pull you over for doing a 100mph he knows that you thought you were doing a 110mph - so he will be cross with you! The subject matter has been covered many times in the UK with all manner of vehicles.

Incidently you should find that the distance measured by the oddo is correct despite the 'inflated' speed reading.

Here in the US (possibly due to litigation!) speedos are very accurate. That way both parties (you and the authorities) know what speed you were doing.

So, you can speed a little bit and keep on the right side of the law - just remember what vehicle you are in at the time so as not to make a mistake

[Beemeridian]

543

[ken k]

Here in the US (possibly due to litigation!) speedos are very accurate.

[jon pierce]

Here in the US (possibly due to litigation!) speedos are very accurate.

What gives

[ruddy]

Wow, this is news to me! Why then have I experienced at least seven or eight motorcycles with significantly high reading speedometers? Let's not forget car speedometers, either. Haven't we all seen test reports that list speedometer error in the results? When was the last time you saw one that didn't indicate higher than actual speeds?

[NCPadgett]

MAYBE, JUST MAYBE, the spedos are right and the GPS' are wrong