Hi everyone,

So a few weeks back I decided to get a 520 conversion chain/sprocket kit from Thrust Company/Moto-heaven. They come with an ek gold quad link chain and what looks like a good quality t6 hardened rear sprocket. Anyways I changed my gear ratio by going +4 on the rear and leaving the front stock, so its not quite as extreme as the popular -1/+2 choice. Regardless though, it did throw off my speedometer and odo. Now alot of people reccommend speedohealers, and I have no doubt they work great. But unfortunately I am a poor college student and couldn't afford to shell out the $150ish it costs. I did some searching and decided to install a Sigma bike computer intead. You can find how-to's on the web and plus its very straightforward. The hardest part for me anyway was measuring the exact circumference of your front tire. but once you get that and input it into the computer you have a very accurate and relatively cheap speedometer/odometer. My stock speedo was about 12 mph faster than reality. Just be sure to check the specs on different brands because many of them aren't accurate past 100 mph or 120 mph. Sigma's are accurate to 185. Just wanted to pass the knowledge on to all of you with q/a kits and thrown-off speedos/odo's on your bike. Let me know if you have any questions.

Oh and btw the model I purchased was the BC1606L. about $30 with lots of features and a backlight to boot.

 

it shouldnt be 12 mph off all the time...should be a percentage cause when your going 13 you def. are not going 1 mph..

does the one you have correct speeds based on a known point and percentages?

 

Your right its not off by 12 mph all the time, that's just my guestimation based off of comparing the analog speedo on the bike and the digital readout on the computer going between 35-65mph. And as for how the computer calculates speed/dist etc, i believe it relies on the number you input that is the circumference of the front tire (in mm). So as long as that is accurate your speed should be too. And as a double check you can check your trip meter against those mile markers on highways to see how close you are. Did that answer your question?