Page 2 of 2 FirstFirst 1 2
Results 16 to 27 of 27

Thread: How Accurate is the Speedo?

  1. #16
    Registered User
    Join Date
    Sep 2012
    Location
    Lansing, Kansas
    Posts
    636
    Quote Originally Posted by jamo View Post
    Lee, I donít know how you got three percent, whether you measured it with a gps, but to me it seems more like the ten percent mentioned in the document. I have to be going 80 on the super slab just to keep up.
    Think about how fast one has to ride "just to keep up" out there in the Great Plains. Speed limits are frequently (usually?) your "keeping up" speed. I have driven so many miles at 85+ that I cannot even keep count.

    Good luck.
    Royce
    On the coast of Kansas
    2012 F800ST

  2. #17
    not so retired henzilla's Avatar
    Join Date
    Sep 2006
    Location
    CENTEX USA
    Posts
    10,253
    I led a club ride a few weekends back. One of my pre ride statements was the fact that most of the bikes displayed at least 3-5mph slower than actual speed. My point was if I was going 70mph at the front by GPS or knowledge of the bike I was on, to not think I was speeding It always comes up.

    Only the authority model RT's with a different gauge cluster is calibrated to actual speed...you know why they do that The faceplate on the RT Authority even has wording to that effect the last time I looked.

    Our KTM's are fairly spot on, none of our Beemers are. H is in the keeping pace mode anyways and she admits not a fixated on display person...works for her... I get to stop on the side of road and chat...she gets a pass
    Steve Henson-Mod Team and SABMWRA Prez

    Be decisive, right or wrong.The road of life is paved with
    flat squirrels who couldn't make a decision~unknown

  3. #18
    Registered User
    Join Date
    May 2008
    Location
    B.P., MN
    Posts
    1,142
    Run at 4K rpm, look at gps, divide speed by four, get mph/thousand rpm. Extrapolate. Mine is 16.8mph per thousand. Everything is taken into account. Tires, gear, etc. Warning, wait till yer stopped, off the bike, to do the division. Just saying, FWIW. Or just look at gps not the speedo.

  4. #19
    BMW MOA co-founder bmwdean's Avatar
    Join Date
    Mar 2003
    Location
    Tucson, AZ, & Madison, WI
    Posts
    1,358
    When i am riding at 50 MPH on my RT, my GPS records 48 MPH. Multiply by two and 100 MPH on the bike would actually be 96 MPH on the GPS.

    My 1967 R60/2 with a 3.5" rear tire at an indicated 50 MPH is dead accurate. With a 4" rear tire it is not accurate.
    Jeff Dean
    Tucson, Arizona, and Madison, Wisconsin
    Co-founder, 1972, of BMW MOA -- http://bmwdean.com/r1200rtw.htm
    R1200RT, R1250RT, 1967 R60/2 x 2

  5. #20
    Registered User WWeldin's Avatar
    Join Date
    May 2018
    Location
    Lilburn, GA
    Posts
    144
    Quote Originally Posted by 8ninety8 View Post
    Run at 4K rpm, look at gps, divide speed by four, get mph/thousand rpm. Extrapolate. Mine is 16.8mph per thousand. Everything is taken into account. Tires, gear, etc. Warning, wait till yer stopped, off the bike, to do the division. Just saying, FWIW. Or just look at gps not the speedo.
    I was told there would be no math on this thread.
    2000 R1200C, 2019 R1250RT

  6. #21

    aspeedo error

    It is law in most western european countries that the speedo by design can not read less than the actual speed. Due to differences in tire diameter in order for this not to happen they build an error into the speedo. In today's world it seems less than ideal as I get a reading from my GPS and the speedo so I know the actual speed. Do have to say that I have used different GPS and there speeds have varied by over 1mph.

  7. #22
    Debbie's Servant Lee's Avatar
    Join Date
    May 2003
    Location
    SW Iowa
    Posts
    5,945
    Quote Originally Posted by khafner View Post
    It is law in most western european countries that the speedo by design can not read less than the actual speed. .
    On the RS forum several UK members have mentioned this.
    Lee
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  8. #23
    Dress for fall & avoid it AlanColes's Avatar
    Join Date
    Aug 2013
    Location
    Bedford, Nova Scotia
    Posts
    1,012
    It is indeed BMW being driven by their lawyers. I'm aware of them having made compromises on performance and accuracy of various parts of their products since at least 1996.

    The issue is that there are some European Countries (and some US States from what I've been told) that have a zero-tolerance policy for speeding. If the speed limit is 60 mph and they catch you going 61-62 mph you get a speeding ticket.

    The lawyers say we can't have a speedometer that is registering 60 mph and have the vehicle actually doing 61 mph. If the person gets a ticket and then verifies that we were at fault we will get sued. Then we also need to take into consideration, tire wear, component wear, etc., etc., and we should have a safety margin as well. It is frivolous litigation and over-stringent companies that are driving this stupidity, not us.
    Regards, Alan - President BMWONS - MOA Charter Club #097, BMWMOA/BMWRA/BMWONS/Airheads
    Current: '14 R1200RT / '06 Ducati ST3s / '91 R100GS / '86 R80RT / '75 R90S / '73 850 & '70 750 Commando Prev: '04 R1150RT / '81 Honda GL1100 / '77 Suzuki GS750 / '73 Norton 850 Commando

  9. #24
    Rally Rat
    Join Date
    Dec 2006
    Location
    Sheboygan, WI
    Posts
    5,320

    Smile

    Quote Originally Posted by AlanColes View Post
    It is indeed BMW being driven by their lawyers. I'm aware of them having made compromises on performance and accuracy of various parts of their products since at least 1996.

    The issue is that there are some European Countries (and some US States from what I've been told) that have a zero-tolerance policy for speeding. If the speed limit is 60 mph and they catch you going 61-62 mph you get a speeding ticket.

    The lawyers say we can't have a speedometer that is registering 60 mph and have the vehicle actually doing 61 mph. If the person gets a ticket and then verifies that we were at fault we will get sued. Then we also need to take into consideration, tire wear, component wear, etc., etc., and we should have a safety margin as well. It is frivolous litigation and over-stringent companies that are driving this stupidity, not us.
    Oh my Lord - couldn't sleep at all last night, given that "..several states…" have a "...zero tolerance..." for speeding.

    Having only lived in the USA for 66+ years now, and ridden (on occasion 5-7 mph over) in all 48 contiguous states, I'm jealous that our neighbors to the north know so much more than I do about our law enforcement absolutes.

    Granted, certain villages, towns and 'burgs' will abuse 'letter-of-the-law' enforcement as a revenue stream, but "..several states..." are now involved?

    Sheeeesh! Let me know which ones you're referring to, so that I might crawl thru them @ 5 mph under this summer.

    Thanks.

  10. #25
    Dress for fall & avoid it AlanColes's Avatar
    Join Date
    Aug 2013
    Location
    Bedford, Nova Scotia
    Posts
    1,012
    Quote Originally Posted by greenwald View Post
    Oh my Lord - couldn't sleep at all last night, given that "..several states…" have a "...zero tolerance..." for speeding.

    Having only lived in the USA for 66+ years now, and ridden (on occasion 5-7 mph over) in all 48 contiguous states, I'm jealous that our neighbors to the north know so much more than I do about our law enforcement absolutes.

    Granted, certain villages, towns and 'burgs' will abuse 'letter-of-the-law' enforcement as a revenue stream, but "..several states..." are now involved?

    Sheeeesh! Let me know which ones you're referring to, so that I might crawl thru them @ 5 mph under this summer.

    Thanks.
    Kevin, I believe that I clearly identified that it was others, but didn't specifically state it was your countrymen, not your neighbours to the north that were the source of this, and that I did not say I was certain of it, only that I had been told that:
    Quote Originally Posted by AlanColes View Post
    ... some European Countries (and some US States from what I've been told) that have a zero-tolerance policy for speeding...
    Unlike you, I'm a neophyte at riding in the USA as I've only been riding in your country for 45 years and only managed to get to 40 of your lower 49. I have ridden/driven in all Canadian provinces, and somewhere around 20+ other countries. In the past 12 months I've only ridden in Canada and the US (about 6,000-10,000 miles per year between the two) but have ridden or driven in 8 additional countries which is a typical year for me (+/- 2).

    I try not to get speeding tickets but as I ride/drive at 10-mph over, or more, most every place (sometimes considerably more) I have gotten my share of tickets (half the Canadian provinces, in the US in too many states, from Maine to Florida, to California, to Washington, and in-between but only two European countries). West Virginia has proven to be the worst I've encountered for dirty "gotcha" enforcement and Hungary for enforcing zero tolerance. I typically ride 3,000-5,000 miles in the USA each year and ride/drive about 3,000 miles in other countries yearly.

    Just sharing my experience and sharing what riders in the US have shared with me, but provided the caveat that the US info was provided by others. Didn't realize that it was necessary to identify that they were US Citizens and how many miles they ridden and for how long. YMMV
    Regards, Alan - President BMWONS - MOA Charter Club #097, BMWMOA/BMWRA/BMWONS/Airheads
    Current: '14 R1200RT / '06 Ducati ST3s / '91 R100GS / '86 R80RT / '75 R90S / '73 850 & '70 750 Commando Prev: '04 R1150RT / '81 Honda GL1100 / '77 Suzuki GS750 / '73 Norton 850 Commando

  11. #26
    Quote Originally Posted by 1957mpd View Post
    It's not just a BMW motorcycle thing; every BMW auto I've had displayed the same speedometer variance from GPS-determined speed.

    Mark
    It's the same with my Mercedes Sprinter, speedo reads 5% high - and they wont adjust it! Must be a German thing...

  12. #27
    Dress for fall & avoid it AlanColes's Avatar
    Join Date
    Aug 2013
    Location
    Bedford, Nova Scotia
    Posts
    1,012
    Quote Originally Posted by txdaveski View Post
    It's the same with my Mercedes Sprinter, speedo reads 5% high - and they wont adjust it! Must be a German thing...
    Very much so.
    My new R1250RT and 2015 Touareg are (and 2 previous BMW M cars were) just as bad as my 2014 R1200RT was. While my 2019 Mustang and 2011 Lincoln are only about 1-2 high vs 3-5.
    Regards, Alan - President BMWONS - MOA Charter Club #097, BMWMOA/BMWRA/BMWONS/Airheads
    Current: '14 R1200RT / '06 Ducati ST3s / '91 R100GS / '86 R80RT / '75 R90S / '73 850 & '70 750 Commando Prev: '04 R1150RT / '81 Honda GL1100 / '77 Suzuki GS750 / '73 Norton 850 Commando

Similar Threads

  1. Replies: 29
    Last Post: 03-29-2013, 09:34 PM
  2. NADA values accurate?
    By manybikes in forum Airheads
    Replies: 16
    Last Post: 08-27-2011, 02:02 PM
  3. How accurate is your speedometer/odometer?
    By dhgeyer in forum Oilheads
    Replies: 55
    Last Post: 05-19-2009, 11:07 AM
  4. R80/7 Speedo
    By shakyone in forum Airheads
    Replies: 4
    Last Post: 02-27-2007, 05:07 PM
  5. Speedo v. GPS
    By Chrisrides in forum Oilheads
    Replies: 31
    Last Post: 04-28-2006, 08:27 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •