Speedometer Error with R1250RSs & TFT Screen

[Grumpy Goat]

As some of you might remember, one of my pet irritations with the R1200RS and the old analog speedometer is the speedometer error, which on my bike is up to 4 mph when compared to the BMW Navigator or the phone.

This large of an error might be acceptable to most / all but it is not to me ... and especially not on a premium marque. The speedo error on my Tracer is 1 mph and similarly on my 2014 Honda CB500RA before the RS. As a result, I have trained my eyes never to see my speedometer and that area to the left on the dash is largely a black blur. The speed readout is one of the main reasons I have my Nav VI.

Question to you R1250RS owners with the TFT screens - have BMW fixed this problem? What is the typical error on your bike?

[Lee]

On our R1250RSs the speedometer is off 2% to 3%.
At 60 mph (GPS) the TFT will read 61 or 62.
At 100 mph (GPS) the TFT will read 102 or 103 mph.
Both bikes are the same.

Speedometer error on our R1200RSs was 3 %
At 60 the dash showed 62.
At 100 to 110 the dash would read 3 mph higher than a GPS.

[Duckbubbles]

On our R1250RSs the speedometer is off 2% to 3%.
At 60 mph the TFT will read 61 or 62.
At 110 mph the TFT will read 102 or 103 mph.
Both bikes are the same.

Speedometer error on our R1200RSs was 3 %
At 60 the dash showed 62.
At 100 to 110 the dash would read 3 mph higher than a GPS.

Same on my current and previous R1200RS's. You'd think if they could make them uniformly inaccurate, they could make them uniformly accurate. I believe they never want the speedo to show lower than actual and I've heard the explanation that due to physical size differences in separate manufacturers tires they make them this way. True or not.

Things are better these days- My old K100RS was ridiculously inaccurate being 6-8 mph high at normal road speeds. I repositioned the needle and ilt is now within 1 mph at most normal speeds. Same for my Ducati. It used to be if you wanted an accurate speedometer, buy a Harley.

Frank

[Lee]

You'd think if they could make them uniformly inaccurate, they could make them uniformly accurate. I believe they never want the speedo to show lower than actual and I've heard the explanation that due to physical size differences in separate manufacturers tires they make them this way. True or not.

The UK guys on the RS forum argue it's that way by law over there.
I think it's a dumb law.

[Grumpy Goat]

On our R1250RSs the speedometer is off 2% to 3%.
At 60 mph the TFT will read 61 or 62.
At 110 mph the TFT will read 102 or 103 mph.
Both bikes are the same.

Lee, thanks - I do hope you mean "At 100 mph the TFT will read 102 or 103 mph."

A 7 - 8 mph difference would make me seriously reconsider the bike. Seriously. This issue is that unacceptable to me.

61 - 62 @ 60 is fine and even 103 @ 100 is OK but getting irritating. My 4 mph difference is at lower speeds, so more than 3% I think.

On my Tracer the 1 mph seems more or less constant, meaning as a percentage it is likely getting smaller / more accurate the faster I go which is better than the other way around.

[Grumpy Goat]

...
Things are better these days- My old K100RS was ridiculously inaccurate being 6-8 mph high at normal road speeds. I repositioned the needle and ilt is now within 1 mph at most normal speeds. Same for my Ducati. It used to be if you wanted an accurate speedometer, buy a Harley.

Hahah ... don't know if I want accuracy that bad.

I love the "reposition the needle" bit ... great solution.

[Grumpy Goat]

The UK guys on the RS forum argue it's that way by law over there.
I think it's a dumb law.

I have heard the same thing and personally I think it is anecdotal "inaccuracy", to put it in PC terms.

I seem to recall seeing a UK (?) statute that limits the error which is a far cry from setting forth some margin that speedos must be over by. I think I saw that the tolerance was biased towards overstating the speed and not understating it, which makes absolute sense. BUT there was nothing to say that it shall not be zero.

UPDATE - After typing the above I Googled "UK law regarding speedometer accuracy" and found the top hit being:

The law for car speedometers in the UK
A speedo must never show less than the actual speed, and must never show more than 110% of actual speed + 6.25mph. So if your true speed is 40mph, your speedo could legally be reading up to 50.25mph but never less than 40mph.Feb 11, 2022

I will go on record here - If any vehicle of mine, including my beloved RS, were to, by design (i.e. not be fixable) show me 50 mph when I am doing 40 mph I will fire it on the spot - no questions asked, no ifs and buts.

[Lee]

Lee, thanks - I do hope you mean "At 100 mph the TFT will read 102 or 103 mph."

Oops, I went back and corrected my mistake.

[Lee]

On my Tracer the 1 mph seems more or less constant, meaning as a percentage it is likely getting smaller / more accurate the faster I go which is better than the other way around.

Most of the time my steady cruising speed will be in the 60 mph to 80 mph range.
Even if my error is 3% my dash reading with be off a constant 2 mph. 1.8 to 2.4 mph.
I need to be going over 100 to see a difference.
Most of the time when going over 100 I'm accelerating to pass and not looking at my dash and GPS to compare.
If we go to Colorado this summer I'll do some more steady speed comparisons.

[MrVvrroomm]

Our TFT GS/GSA bikes are about 3 mph optimistic in our speed range. I don't believe there's any difference in speed sensors from TFT vs analog. The speed sensor is electronic either way.

[Lee]

Our TFT GS/GSA bikes are about 3 mph optimistic in our speed range.

80 to 150 ?

[Grumpy Goat]

Our TFT GS/GSA bikes are about 3 mph optimistic in our speed range. I don't believe there's any difference in speed sensors from TFT vs analog. The speed sensor is electronic either way.

That is my feeling also. Just that with a needle there is more "give" in the reading but with a big number on the TFT ... can't ignore it as easily.

[MrVvrroomm]

80 to 150 ?

Max speed of a '19 R1250GSA is 137 according to GPS, TFT was 142, at whatever elevation Gunnison is. LOL

[MrVvrroomm]

That is my feeling also. Just that with a needle there is more "give" in the reading but with a big number on the TFT ... can't ignore it as easily.

Here's what really messes with my OCD: TFT display shows current speed, current speed limit, current set speed of cruise control, Nav VI shows current speed limit (may actually differ from TFT), Nav VI shows true speed.

When glancing at TFT/Nav there are actually 5 numbers, usually the only 2 that match are cruise set speed and TFT speed.

[Lee]

80 to 150 ?

Max speed of a '19 R1250GSA is 137 according to GPS, TFT was 142, at whatever elevation Gunnison is. LOL

Max speed is probably over 140 at a lower elevation.
You need to try again

[Grumpy Goat]

Max speed of a '19 R1250GSA is 137 according to GPS, TFT was 142, at whatever elevation Gunnison is. LOL

That was very similar (same speeds actually) to my result the one and only time I had my R1200RS at WOT, loaded with panniers and top box in Big Bend National Park in 2016. I don't think it had much left with that load and with those "lumps" increasing the drag.

[Grumpy Goat]

Here's what really messes with my OCD: TFT display shows current speed, current speed limit, current set speed of cruise control, Nav VI shows current speed limit (may actually differ from TFT), Nav VI shows true speed.

When glancing at TFT/Nav there are actually 5 numbers, usually the only 2 that match are cruise set speed and TFT speed.

Oooh ... that would also mess with my OCD too. I only need to know two speeds - speed limit and [accurate] speed I am doing. I am more forgiving if there is a bit of a discrepancy between set CC speed and speed attained.

[darrell]

You guys are all so naughty riding on our public roads. Sitting here working on my 2022 travel plans and wondering where I can pick up a short term job to the cover the $0.08/mi fuel costs and $0.05/mi tire expense. As well as thinking I'm not sure my 2016 has ever been over 100 mph.

Anyway back to Speedometer error. My 2002 R1150GSA was 7 - 8% off from actual until I changed the speedo drive to the one used on police bikes and now nearly spot on compared to GPS.

[Duccrazydave]

80 to 150 ?

Max speed of a '19 R1250GSA is 137 according to GPS, TFT was 142, at whatever elevation Gunnison is. LOL

I can vouch for that

[TriangleRider]

https://www.cycleworld.com/sport-rider/h...emperature.

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