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Main Area => General GS500 Discussion => Topic started by: TheDrunknmonky on September 06, 2010, 08:51:08 PM

Title: Speedo giving wrong speed.. 5-6 mph over actual
Post by: TheDrunknmonky on September 06, 2010, 08:51:08 PM
Went riding with a few friends the other day. have now been informed that my speedo reads 5-6 mph higher than actual (says 45, doing 40).  Hoping this is a simple cable adjustment issue. Advice please and thank you.

06 F w/6100 miles and a stock f/e and wheel.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Paulcet on September 06, 2010, 08:52:58 PM

:o













That's perfectly normal
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: adidasguy on September 06, 2010, 08:58:42 PM
I've hear that, too, that the speedo is 5 to 7% high. I've experienced the same thing driving past those "Your Speed Is XX" electronic signs.

I guess that means mile and mileage calculations are also about 5% high. 63mpg did seem a little high after one trip.

Look at it this way: if you normally drive 5 to 10 miles over the limit, then based on your GS speedo, you're driving the speed limit hence no more speeding tickets !?!?! LOL?!?!?
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: ojstinson on September 06, 2010, 09:46:30 PM
That's it, a built in safety and anti ticket feature at no extra charge. Kinda like setting your watch ahead so as not to be late for work.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: LetsBeFriends on September 06, 2010, 10:16:37 PM
my 04 F does the same thing.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: mister on September 07, 2010, 12:48:35 AM
Quote from: adidasguy on September 06, 2010, 08:58:42 PM

I guess that means mile and mileage calculations are also about 5% high. 63mpg did seem a little high after one trip.


Not necessarily. Passing one of those Speedo Check things on the highway with a mark each click for five clicks, it ticked over pretty well spot on on My bike. But have had people tell me the speedo is wrong - but only people on non-Suzukis.

Michael
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: burning1 on September 07, 2010, 12:54:14 AM
Most motorcycle speedos read 5-10% high. IMO, it's intentional.

On my K1300GT, the speedometer reads about 5 MPH high at freeway speeds, and yet the reported average speed from the trip computer is spot on.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: twocool on September 07, 2010, 04:16:56 AM
Quote from: mister on September 07, 2010, 12:48:35 AM
Quote from: adidasguy on September 06, 2010, 08:58:42 PM

I guess that means mile and mileage calculations are also about 5% high. 63mpg did seem a little high after one trip.


Not necessarily. Passing one of those Speedo Check things on the highway with a mark each click for five clicks, it ticked over pretty well spot on on My bike. But have had people tell me the speedo is wrong - but only people on non-Suzukis.

Michael

Yes my findings too..........remember the speed needle, and the odometer are two different mech's......distance can be spot on, while the speed is 7% conservative!

My distance usually agrees pretty well with the gps, while the speed does not....

Almost every automobile review I have read in magazines gives some sort of chart for speedo error


Cookie
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Elijafir on September 07, 2010, 02:42:26 PM
Supposedly automobile manufacturers are required by law to set the speedometers 5-10% fast to help eliminate law suits involving "incorrect" (reading too slow) speedometers.  As previously stated the speedometer and odometer are run by different mechanisms.. so while the speedometer may be 5-10% off.. the odometer can be completely accurate.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: twocool on September 07, 2010, 02:50:03 PM
Quote from: Elijafir on September 07, 2010, 02:42:26 PM
Supposedly automobile manufacturers are required by law to set the speedometers 5-10% fast to help eliminate law suits involving "incorrect" (reading too slow) speedometers.  As previously stated the speedometer and odometer are run by different mechanisms.. so while the speedometer may be 5-10% off.. the odometer can be completely accurate.

Sorta makes sense, in this sue-happy society........we call this "known error".

My 1984 Honda Scooter had a digital speed readout........it was right on, exactly matched the GPS!

Also explains that when I used to do really long drives...NJ to FL.......I would keep the speedo on like 70 but time vs distance (on the odo) I only seemsed to average like 60 MPH......

Cookie




Cookie
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: GI_JO_NATHAN on September 07, 2010, 06:32:14 PM
Yep only way to really calibrate it on the GS is to change your front tire size, But then you also may effect the odo. With my 120/60 front tire, at 40-55 it's about 5 over, at 60 it's 6, at 70 it's 7, and 80 and up it stays about 10.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Suzuki Stevo on September 07, 2010, 06:52:21 PM
My Speedometer is roughly 7-8% high while my Odometer is spot on (Garmin GPS)
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Pigeonroost on September 07, 2010, 07:11:41 PM
Mine is more than 10% in error.  I use a bicycle computer device that I found mentioned on this board and calibrated it using the suggested numbers from the post and verified by using my GPS.  Spot on, inexpensive, and a bit complex to program.  Honda just started correcting the calibration of their street bikes for 2010; previously they were also 10% or so off.

prs
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Twism86 on September 07, 2010, 08:36:20 PM
Mine is just under 10% high. Im doing "80" and i look over at my Dad and his gps reads 73/74.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: Chuck500 on September 10, 2010, 05:30:17 PM
I have read on another forum that DOT requires that 0% of speedometers read pessimistic, i.e., vehicle is going faster than indicated.  To assure compliance manufacturers calibrate them from 5% to 10% optimistic, i.e., vehicle is going slower than indicated.

Keep the shiny side up (and tickets down),

Chuck
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: burning1 on September 12, 2010, 02:30:12 AM
Quote from: GI_JO_NATHAN on September 07, 2010, 06:32:14 PM
Yep only way to really calibrate it on the GS is to change your front tire size, But then you also may effect the odo. With my 120/60 front tire, at 40-55 it's about 5 over, at 60 it's 6, at 70 it's 7, and 80 and up it stays about 10.

I think you have it the wrong way round. The larger the front tire, the lower the speedo/odo reading. For bikes that read off the counter-shaft sprocket, shorter gearing will tend to increase the error, where taller gearing will decrease it.
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: GI_JO_NATHAN on September 12, 2010, 05:12:53 AM
Quote from: burning1 on September 12, 2010, 02:30:12 AM
Quote from: GI_JO_NATHAN on September 07, 2010, 06:32:14 PM
Yep only way to really calibrate it on the GS is to change your front tire size, But then you also may effect the odo. With my 120/60 front tire, at 40-55 it's about 5 over, at 60 it's 6, at 70 it's 7, and 80 and up it stays about 10.

I think you have it the wrong way round. The larger the front tire, the lower the speedo/odo reading. For bikes that read off the counter-shaft sprocket, shorter gearing will tend to increase the error, where taller gearing will decrease it.
Yeah not sure how that's wrong, what I was saying is that changing the front tire size on the GS is the only way to change the speedo...
Title: Re: Speedo giving wrong speed.. 5-6 mph over actual
Post by: gsJack on September 12, 2010, 05:56:49 AM
I found the speedometers on both my previous 97 and my current 02 GSs to be 10% off at lower speeds.  Holding them right on 40 mph indicated gave a very consistant reading of 36 mph passing one of those police radar carts that flash your speed when I was running a stock 110/70 front tire.  A 110/80 front tire would cut the error to less than half of that 10%.

At higher freeway speeds of 75-80 mph indicated the speedo error seems to be less than 10%.  That indicated 80 mph showing about 73/74 on a gps reported by Twism86 above sounds about right to me.  I think the centrifical growth in dia of the tire at speed would account for the difference.

Since the speedo is more accurate and my local dealer almost always has a 110/80 tire in stock but not a 110/70 I have settled for a lot of 110/80 front tires for my GSs over the years.   :icon_lol: