Speedo Error and Sprocket Change Questions

You said "Vee", so I'll assume you mean a DL1000 of some unknown vintage. On a Vee with the pickup on the front sprocket, lowering the gearing increases the error. Pretty much everyone lowers the ridiculously tall stock gearing, so we'll go with that scenario.

For example, I went from the 17/41 stock gearing to 17/43 on my 2002; a minor change, but I was very happy with the result. However, that increased the error from 7-8-ish percent to about 11%. I installed a SpeedoDRD and set it to 10% correction so I'd end up with speed reading only slightly higher than actual, same as what I'm accustomed to in my car.

The sucky part is that odometers are more or less accurate in stock form. So electronically adjusting the speedo like this means that the odo is now 10% low. This may or may not matter much to you, or it may be something to keep track of.

AFAIK, all years of the DL650 use a speedo pickup on the front wheel, so gearing changes don't affect the amount of error. They still come from the factory with a ridiculous amount of error built in, but changing the gearing doesn't make it better or worse.

The 1st Gen VStrom use four pulses per rotation of the output shaft via a Hall effect. A speedo healer usually reduces the number of pulses to the speedo in order to correct the indicated speed. I guess these devices could also add pulses as well...IDK...never had one.

Anyways, so bwringer....you had speedo error increase due to increasing the final ratio, which to me says that the correct method is to take the new drive ratio and divide by the OEM drive ratio...yielding a number greater than one; speedo error increased. This makes sense to me and is opposite of what I read on another site..which is what prompted my questions.
As I noted in my first post, my '08 DL1000 has a 17 / 42 ....the change was even less than on your '02. I have yet to compare my phone's GPS with the V-Strom's speedo. I have just been assuming it to be about 10% slow....have not been stopped by police....yet anyways. My Honda VFR750's speedo is about the same, so I am used to always adding that 10%.
I will likely be replacing the chain/sprockets in June which gives me the Spring to have far more seat time on the VStrom than I do now to determine if I want to change the rear to 43-45 teeth and of course deal with the speedo error.
Also have to clarify the statement I made above about replacing the speedo face with a corrected one....that only works with OEM 17/41 setup.

Thanks for the replies.

Yes, I've verified using my 2002 DL1000 and mile markers over a long distance (20+ miles) that with the speedo DRD correcting the speedo, the odometer reading is off by the same amount. Not much else to do on long flat straight interstates... A DRD or "healer" slows down the pulses coming from the pickup at the front sprocket by an amount you set.

I believe the root of the problem is that regulations allow for speedo readings to read high by any amount, but never low. Odo readings apparently have a lower error tolerance. Not sure, but no one has ever really figured out why almost every motorcycle on the planet has a speedo that reads 5-10% high, while cars are almost all within 1 or 2% high. Maybe it's some sort of performance perception arms race thing.

The "real" solution would be to either:

1) Juggle/reprogram the math used in the internal electronics and programming to keep the odo accurate while correcting the speedo. This probably isn't possible in the DL1000, at least the earlier ones. It is possible on some bikes that do the math in the ECU; on the Yamaha FJ-09/Tracer, for example, this is a pretty standard part of a common ECU flash to improve ridability. If you like, they'll re-flash the speedo math and leave the ODO math alone.

2) A custom speedo face would also be another way to keep an accurate odo while correcting the speedo. These used to be available for the DL1000, but the guy making them stopped long ago, and they weren't available in custom offsets; they came in one "standard" offset to match the most common situation. This was a great solution, but apparently having them made was kind of a pain in the ass, and the size of the market was not very large.