Speedometer issue

[wildbillharley]

Have both a 2020 flhtk and a 2019 flhtk. Different size tires on them. The 2020 rides much better with 18s, front and rear, than the 2019 dies with its 17/16 setup. Same bikes and I put 18s on the 2019 and now the speedometer reads low. Reads 55 at 60 mph.
I talked to the Harley service manager and he was unsure why and how to fix it. Anyone have any knowledge that would help?

 

[joel]

Can the go into the BCM and change the tire profile like we can with trucks?

 

[Breeze3at]

The "why" is because a large diameter tire turns less to cover the same distance. Something that is above the technical level of most HD service managers. One way to fix is this link: https://www.dakotadigital.com/pdf/SIM-1.pdf. I have not used this but Dakota Digital has a pretty good reputation with HD electrical components. There may be several other mfg's., I just know of Dakota/

 

[gator508]

I found this on google, it may help if your speedo can be calibrated

How do I change my speedometer to match my tire size?

Press and hold the calibration button located on the speedometer, start the vehicle, and then release the button. Press that button again and then take the test drive. Once you have driven the distance needed, press the button once more and the speedometer will calibrate itself to accommodate the new tire size.May 10, 2019

good luck!

 

[wildbillharley]

Thanks for your reply’s, appreciate them and will check both out.

 

[wildbillharley]

Thanks for your reply’s, appreciate them and will check both out. Didn’t know

 

[wildbillharley]

I performed a stage one upgrade on both the bikes utilizing V&H products. Just checked and the FP3 says it can do the calibration using my smart phone. I will try that as soon as it quits raining and will post my results