Speedo error with 130/60R18 on front?

[HyperPete]

I installed the new 18" wheels and tires, and now the speedo seems to be way off. (No way am I going as fast as it reads!)

Can anyone help me to determine the percentage of error I am getting, and how to resolve it, running a 130/60R18 up front?

Thank you in advance!

 

[gamorg02]

my 130/70-18 is pretty close.

try this though:

http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp

with the 120/90 i had on years ago it was almost dead nuts on (to actual mileage)., so, by that the 130/60 is about 10% off and my 130/70 is 6%

if you wanted to go off stock, then they'd be closer as thats a 110/90.

 

[DMAN999]

The 130/60-18 (78 mm) is .8267 Inches (21 mm) difference in sidewall height than the Stock 110/90-18 (99 mm).
That correlates to about a 4.2% difference on the speedo or 96 mph when speedo reads 100 mph.
I used this calculator for that info:
http://www.miata.net/garage/tirecalc.html
I used 165/60-18 vs 155/55-18 (21.5 mm difference in sidewall, similar to your difference)

This gives very similar results using your Exact sizes (93.59 when speedo says 100):
http://tire-size-conversion.com/speedometer-calibration/

 

[HyperPete]

Whoa! Then I am impressed with this bike all over again! It gets up to warp speed FAST!

Thank you for the assistance. Now I need to tame my right wrist!