Speedo WAY off...

[Rollque]

I have an 04' GS Adv....Ive put 5400 miles on it and just the other day installed my Garmin GPS. The GPS tells me MPH to the tenth of a mile and is extremely accurate (since ive taken it in 4 other vehicles and its within 1mph in all of them).

The problem is my bike is off by 6 1/2 mph at 70...meaning when the speedo says 70, Im actually going 63.5mph.

Is this common? I cant imagine it is..has anyone ever adjusted theirs? Most likely I will take it back to the dealer and have them fix it along with the recalls.

Just thought I would ask if theres anything I should know...

Aaron

[jdiaz]

You can get a different speedo drive for the front wheel which will get it closer. Do a search on the pages at advrider.com for it.

[cgarr]

Yup,
My '04 GS has the same affliction. It is in the neighborhood of 5MPH off at 50-70MPH, at lower speeds the offste is smaller, and at higher speeds it increases. Another friend with a GS has the same issue. So from my perspective it is a very common problem.

[Rollque]

There must be some kind of standard that the manufacturer must abide by? At some point this becomes a safety issue (or financial if you get tickets) and BMW would have to address this...

[Cliffy777]

Owned 2 Hondas and a Kaw and two Beemers. I just figure all bike speedos are off by 7-10%. I thought the makers did it so that we THINK we are going faster than we are.
I figure it might save me tickets - if I think I'm going 80 and it is really more like 72-75 then I am less likely to earn a performance award.

[Colt03]

I changed the hub on my 04 GS I can look up the part but either I changed it from a 3.0 hub to a 2.9 or visa versa. I can get you the part number of the part if you need it. Anyway the ODO is now spot on and the Speedometer is about 2 mph high at 75.

Plus if you change the hub early you warranty actually lasts the stated amount.

HTH

Craig in Ct

[DaveBell]

my 2004 Rockster is off by the same amount. My buddy, more knowledgeable about bmw, says they're all off about the same amount. checked mine with gps too. what's that part #? I'd like to fix mine.

[BradfordBenn]

I just learned the common speeds on the speedometer are. So I know that if I want to do 75MPH in North Dakota I shoot for 85 MPH as pretty close, 55 is actually 64. 25MPH shows as 30MPH...

well you get the idea.

[GSTom]

If you are concerned about speedo (and Odo) accuracy, for about $35 you can install a handlebar mounted bicycle computer (Sigma or other) that is programmable to the exact circumferance of your tire.

You need to buy a couple of rare earth magnets at Radio Shack to enhance the "pick-up" of the sensor at the wheel. Epoxy them to a spot on your front brake disk. The whole procedure is described on the IBMWR tech pages as well as other sites on the web. I did this on my innaccurate K100LT (1988) and am extremely pleased with the result. It gives you an additional trip odometer, a miles per hour average trip speed, miles per day, count up timer, etc.

These small units can easily be re-programmed at any point when your tire diameter changes, due to wear or replacement.

[donkey doctor]

Hello; I have a 77 R 100/7 that has an inaccurate speedo, I solved the problem with the use of a bicycle speedo/computer. I simply mounted the magnet provided to the spoke on the front wheel, bent up a bracket and mounted it up the the fender mount bolt.

I have never used a number type speedo before, as opposed to a dial with a needle, so I'm getting used to waiting a second or two to get a steady speed. Now I know exactly how fast I'm going, in kms. or miles per hour. I haven't tried out any of the other features of this device, but I don't want to know a lot of that stuff anyway.

A little tip if you decide to try this; Make sure there is enough wire to reach from the dash to where the pick-u must mount, some of the makers are very cheap with this stuff. I found I couldn't use the first one I bought for that reason.

[jody]

On a recent ride on the slab with mile markers, several timed miles (kitchen timer taped to top of tank) at indicated speed of 80 mph gave actual speeds of 77 to 78 mph. 2004 R1150RS with Metzeler Z4s with about 2000 miles on them, set cold at 32 psi front, 36 psi rear. Ambient temp 86F. This is a smaller error than I am used to seeing on this and other DBs, and may represent just one data point showing the unit-to-unit variability of our speedos. I will repeat this measurement from time to time with changes of tires, mileages, pressures, and temperature. YMMV.

[Colt03]

The correct part number to change your front hub is
62-12-2-306-532. This is the 2.9 ratio Hub. The stock one that is on is a 3.0. Order the part, change it out at your convienence or the next time you put a new tire on.

HTH

[Mr. Frank]

Originally posted by Rollque
There must be some kind of standard that the manufacturer must abide by? At some point this becomes a safety issue (or financial if you get tickets) and BMW would have to address this...

Don't assume that all BMW's are off the same amount, even the same year and model. I've had three BMW's. One was off about 7%, one was off 5%, and my current bike is off about 3% at highway speeds. It also seems to be off a greater percentage at low speeds than at high speeds.

[BradfordBenn]

My understanding from when I got a ticket way back when, like 15 years ago, is that the manufacturers are only required not to be slow. So that if you are going 60MPH the speedometer can not read 59MPH.

[donkey doctor]

Hello; Here's an update; now that I've had a few tanks worth of miles with the bicycle computer.

The inaccuracy in the BMW speedo wasn't linear; 30 was 35 50 was 65, 70 was 72, and 100 was dead on at 100. Beyond that speed the needle just takes off, as does the tach needle. I did register 187 kmh on it as top speed. The bike seemed to be running sweetly and pulling strongly.

Some of the other features have been handy. It automatically resets the trip meter while saving the previous number. It has a time of use function, a top speed during trip save feature. It calculates average speeds per trip or overall averages, it has a 3 year warrantee. All this for $24

There are conditions where the LCD face is hard to read, I'll have to find the right angle. My Polaroid sunglasses make it hard to read, and it isn't lit.

[kbasa]

Originally posted by Rollque
There must be some kind of standard that the manufacturer must abide by? At some point this becomes a safety issue (or financial if you get tickets) and BMW would have to address this...

My R12GS is only off by 1%

[YB in IN]

I hate to admit it, but my old 86 R80's speedometer was dead on in comparison to my K-Bike. That according to the LEOs anyway. :dunno

[Fang]

Originally posted by Colt03
The correct part number to change your front hub is
62-12-2-306-532. This is the 2.9 ratio Hub. The stock one that is on is a 3.0. Order the part, change it out at your convienence or the next time you put a new tire on.

HTH

Will that work on a 2004 R1200CLC? If not, do you know anything that will?:dunno

[Mr. Frank]

Originally posted by donkey doctor
There are conditions where the LCD face is hard to read, I'll have to find the right angle. My Polaroid sunglasses make it hard to read, and it isn't lit.

You may wish to rethink the use of Polaroid lenses on a motorcycle. Some people say their ability to screen out glare can mask liquids on the road surface and changes in the nature of the road surface.

[donkey doctor]

Hello; There have been a few other things I have noticed using poloroid sunglasses, combined with the visor on my helmet certain trees glow with a diamond blue. My one eye might see a wet patch that my left eye doesn't. Skid marks were invisible in one eye too. I was going to try to get someone else to try my glasses with my visor, to see if they noticed the same differences, the opportunity hasn't come up yet.

I recently did a 2000 mile trip with them, so I got used to the help pertty quickly. Going into the snow sheds on Rogers pass was like driving into pitch darkness from bright daylight.

The type I have attach to my glasses with little magnets, they are not easy to remove and replace, specially inside a full face helmet.

[BradfordBenn]

I think you mean POLARIZED, not Polaroid.

Anyway, putting two polarized items together is bad. Try looking at a cell phone or gas pump display with the sunglasses on (most are usually polarized) and you will see some interference. This interference can also occur with the visor, as they are some what polarized due to the scratches and dings from wear and the bend process.

For me, I use polarized sunglasses and clean my visor often, that seems to do the trick. For me it is the difference between eye fatigue and no fatigue. However YMMV everybody is different.