My speedo seems to read high

[gmcjetpilot]

I have not done a timed distance but speedo is about 3 to 5 mph high vs GPS. Let's assume the GPS is off +/- 1 mph.... I am still reading fast.

 

Is this common. Is there a fix.  Of course a 2004 has cable driven speedo.

 

I am sure the watch works inside the speedo can be tweaked by a little old Bavarian man in Berlin.  However not being that, is there a DIY fix?

[Hosstage]

Stock speedometers in almost all vehicles read a bit high, it eliminates lawsuits from people who get speeding tickets and try to blame the automobile/motorcycle manufacturer.

New cop cars get calibrated. In the old days they would have a sticker next to the speedo with the conversion from speed shown to actual.

[dirtrider]

14 minutes ago, gmcjetpilot said:

I have not done a timed distance but speedo is about 3 to 5 mph high vs GPS. Let's assume the GPS is off +/- 1 mph.... I am still reading fast.

 

Is this common. Is there a fix.  Of course a 2004 has cable driven speedo.

 

I am sure the watch works inside the speedo can be tweaked by a little old Bavarian man in Berlin.  However not being that, is there a DIY fix?

Afternoon gmcjetpilot

 

Almost all the BMW 1150 bikes (except RT-P with approved police tires) will be about that high, most of my old 1150RT's were 9-10 mph high at 100 mph.

 

A new tire inflated to max-approved will usually bring it down a little but not that much. 

 

You can buy a police (calibrated) speedometer off of E-Bay  & that will help a lot, then install a front police approved tire & it will then be darn close. 

 

Most older BMW motorcycles were that way as they absolutely could not read slower than travel speed. When electronic speedometers came into use the compliant window was adjusted so they could read closer to actual. 

[Skywagon]

My 79 R100Rt and 73 R90 was pretty far off.  My 1150RT was pretty close until about 50; By 70 it was off 5mph and got worse the faster I went.  My 1200RT wet is pretty much dead on with the GPS below 85.  Above 85 it will read 2-3 mph fast.  I'm ok with that as it is a cushion.  I rarely look at the speedo anyway, I prefer the GPS.

[King Herald]

Mine reads 35mph at 30, and about 77 at 70, comparing to GPS.

Legally, in the U.K. anyway, speedos must read high, and can be as much as 10% over in a new vehicle. I know how far it is out and adjust my velocity to suit, and not get busted for speeding. 

[RadioFlyer]

If you Google this you will find a great many posts stating that this is deliberate and the rationale for it.

[gmcjetpilot]

Thanks community. I'm good with that. Good to know it's normal. Yep my GPS blocks some of my Speedo so GPS is my primary speed indicator.

[wbw6cos]

Besides, which number are you going to use when you are in the hotel parking lot at a BMWST gathering?   

[RPG]

21 hours ago, gmcjetpilot said:

I have not done a timed distance but speedo is about 3 to 5 mph high vs GPS. Let's assume the GPS is off +/- 1 mph.... I am still reading fast.

 

Is this common. Is there a fix.  Of course a 2004 has cable driven speedo.

 

I am sure the watch works inside the speedo can be tweaked by a little old Bavarian man in Berlin.  However not being that, is there a DIY fix?

You can do what I did. Get a Police speedo. It perfectly matches my GPS mph reading (at least to 115mph....LOL)

 

[9Mary7]

US regulations allow for up to 10% error on speedo readings......Manufacturers go high on the side of caution as well as getting you out of warranty faster by that same 10%.

I just rescued a 35 year old Honda M/C and, after making it roadworthy, I find that it reads exactly +10%, as it did when new.

[gmcjetpilot]

I am not going to get Police accurate speed-O..... Why? So when I get a ticket clocked doing 90 mph, I can go to court and tell Judge, "Your Honor, I was not doing 90MPH Sir. I was doing 98 MPH.... " Ha ha. 

[Bluenoser]

My R1100RT speedometer is about 9% high compared to GPS.  The concern for me is that the odometer is also about 9% high which means at 90,000 km there actually only about 82,000 true km on the bike.

[ADulay]

My last three RTs all read 2 mph fast on the speedometer.

 

So does the new one.

 

AD

[Brodiepunker18]

I was wondering about this after I got my gps mounted and noticed it wasn’t reading correct…I wasn’t sure if it was the gps being wrong or the actual speedo…

 

 

[dirtrider]

1 hour ago, Brodiepunker18 said:

I was wondering about this after I got my gps mounted and noticed it wasn’t reading correct…I wasn’t sure if it was the gps being wrong or the actual speedo…

 

 

Morning Brodiepunker18

 

On a level straight road the GPS is usually pretty darn close, on a road with a lot of tight curves the GPS is not as close but still better than most BMW cable drive speedometers, going up or down a steep hill again the GPS is less accurate, but still more accurate than the BMW cable driven speedometer.

 

[BerettaRacer]

Yeah, my speedo seems to read a bit high too.

 

But MY issue seems to be associated with my right wrist. When I twist my wrist the speedo reads HIGH, as soon as I release my wrist the speedo seems to come back to normal. 

 

LOL

[Redfoxx]

On 7/18/2023 at 10:27 AM, Hosstage said:

Stock speedometers in almost all vehicles read a bit high, it eliminates lawsuits from people who get speeding tickets and try to blame the automobile/motorcycle manufacturer.

New cop cars get calibrated. In the old days they would have a sticker next to the speedo with the conversion from speed shown to actual.

Todays squad used to say certified printed right on  same plate the numbers are printed on.

[Redfoxx]

On 7/21/2023 at 8:03 AM, dirtrider said:

Morning Brodiepunker18

 

On a level straight road the GPS is usually pretty darn close, on a road with a lot of tight curves the GPS is not as close but still better than most BMW cable drive speedometers, going up or down a steep hill again the GPS is less accurate, but still more accurate than the BMW cable driven speedometer.

 

My goldwing was electronic sensor and speedometer. It too read about 5 mph fast. 

[dirtrider]

1 hour ago, Redfoxx said:

Todays squad used to say certified printed right on  same plate the numbers are printed on.

Evening RF

 

Not all tires are the same circumference. That certified is only certified when using police tires, but they are usually closer than a stock  (non- RT-P)  speedometer even when using new non-police tires.

 

Even then, a worn front tire changes the distance covered per revolution.

[Redfoxx]

54 minutes ago, dirtrider said:

Evening RF

 

Not all tires are the same circumference. That certified is only certified when using police tires, but they are usually closer than a stock  (non- RT-P)  speedometer with new tires, even using non-police tires (but even then, a worn front tire changes the distance covered per revolution).

DR:

State patrol could and would recertify our speedometers. used radar units and actually drove certain speeds, up to high speeds. 

 

RF

[dirtrider]

49 minutes ago, Redfoxx said:

DR:

State patrol could and would recertify our speedometers. used radar units and actually drove certain speeds, up to high speeds. 

 

RF

Evening  RF

 

I can see a check or recertify but what tires were you running.

 

There is more to it that just checking the actual speed against the speedometer, it needs to remain in spec at all speeds. 

 

The company I work for is very critical of indicated vs actual as a number of our tests depend on accuracy of both actual speed & distance traveled. 

 

With the difficulty in correcting the speedometer as well as also correcting the accuracy of the odometer we just run a constant speed over an EXACTLTY measured 1, 2 or 3 miles then plug the measured time (out to hundredths) into a chart for the corrections, we also do this at different speeds to get a correction curve. 

 

Then we just print out a correction sticker then place it in the upper left of the windshield. 

 

If we really want extreme accuracy of speed & distance we clamp a 5th wheel on the rear then tow that along, or use a speed/distance laser reflecting off of the road surface. 

 

The three (time vs speed over an "exact" mile) that I like to remember is:  70.0 mph= 51.43 seconds ,  80.0 mph= 45.0 seconds & 100.0 mph= 36.0 seconds

 

[Redfoxx]

3 hours ago, dirtrider said:

Evening  RF

 

I can see a check or recertify but what tires were you running.

 

There is more to it that just checking the actual speed against the speedometer, it needs to remain in spec at all speeds. 

 

The company I work for is very critical of indicated vs actual as a number of our tests depend on accuracy of both actual speed & distance traveled. 

 

With the difficulty in correcting the speedometer as well as also correcting the accuracy of the odometer we just run a constant speed over an EXACTLTY measured 1, 2 or 3 miles then plug the measured time (out to hundredths) into a chart for the corrections, we also do this at different speeds to get a correction curve. 

 

Then we just print out a correction sticker then place it in the upper left of the windshield. 

 

If we really want extreme accuracy of speed & distance we clamp a 5th wheel on the rear then tow that along, or use a speed/distance laser reflecting off of the road surface. 

 

The three (time vs speed over an "exact" mile) that I like to remember is:  70.0 mph= 51.43 seconds ,  80.0 mph= 45.0 seconds & 100.0 mph= 36.0 seconds

 

DR:

We would normally do a speed run, the radar units where  special vs standard Law enforcement radars which round down,  these measured our ground speed.  We would run up to 100mph and compare speed every 10mph. if there was a error it seamed after about 50mph it would stay consistent up 100 mph.  one of my first cars I had ran it to 130mph no speedo error. I had one  with only a 1-2 mph off on certified speedo, guessing tire wear.  We had cars with non-certified towards my end due to vehicle manufacture shortages, and we then ran Dodges and they had emission issues so they had swap transmissions and differential to pass Federal emissions, so the vehicles came with more civilian parts than police. They were maintenance nightmares. Kind of like my BMW with June 18th 2003 manufacture, right at change over. 

 

RF

[RPG]

On 7/18/2023 at 11:24 AM, gmcjetpilot said:

I have not done a timed distance but speedo is about 3 to 5 mph high vs GPS. Let's assume the GPS is off +/- 1 mph.... I am still reading fast.

 

Is this common. Is there a fix.  Of course a 2004 has cable driven speedo.

 

I am sure the watch works inside the speedo can be tweaked by a little old Bavarian man in Berlin.  However not being that, is there a DIY fix?

 

It is common. My '74 R90s reads about 4mph high at 70mph.

My 2004 RT is pretty similar. I found a nice police speedo and installed it on the RT and it now matches my GPS at any speed. A Police speedo will have 2mph gradations between the main numerals and only go to 120. I also updated my R90s speedo by adjusting the pickup cup distance to change the eddy current strength and it's now pretty accurate also.