How far off is indicated speed from actual on a +2 rear sprocket?

[lonesoldier84]

+2 rear sprocket. Never speedo-healed from factory either.

Indicated speed 80kph. What is the actual speed?

 

[sublime0713]

Including original error, should be reading about 9-10% high. So actual should be about 72 kph. I used HealTech's calculator on their website.

 

[lonesoldier84]

link? and Ive heard it should be higher than that. Closer to 12-13% error?

 

[fzme]

link? and Ive heard it should be higher than that. Closer to 12-13% error?

Here's the site. Click on SPEEDOHEALER on the left, then under that, click on ONLINE CALCULATOR. You have to fill in pre/post sprocket size for front/back sprockets as well as rear tire size.

Based on the 180/55/17 tire, and the 16/48 gearing change (stock it 16/46) you have a -9.2% difference with +2 in the back. :thumbup:

HealTech Electronics Ltd. - Makers of the SpeedoHealer, GIpro, X-TRE, OBD Tool

 

[lonesoldier84]

but thats not including the amount it is off by from factory? wouldnt that add an additional 4% or so?

 

[fzme]

but thats not including the amount it is off by from factory? wouldnt that add an additional 4% or so?

Good question. I would borrow a friend's GPS if you don't have one, and compare the GPS speed with the speedo speed.

 

[sublime0713]

Sorry forgot the link earlier. The 9% is supposedly including factory error. The higher number (12 or so) is when you go -1 on the front as well as the +2 on the rear.

 

[Slug]

Mine was exactly 10% high as measured by GPS (that includes factory error).

 

[lonesoldier84]

Mine was exactly 10% high as measured by GPS (that includes factory error).

do you have a sprocket mod too? is that factory? if so, wow.

 

[Slug]

do you have a sprocket mod too? is that factory? if so, wow.

Yes, that 10% error is factory error plus the +2 rear sprocket.

 

[Kazza]

Just buy a speedo healer and check their calibrations. I just went down 1 on the front, and it changed by about 11.1%.

Programmed that into the healer - took her for a test - she's now spot on.

 

[heath_AU]

I have used this AWESOME site before.
Even has a STACK of factory OEM gearings preloaded!
Check it out

Gearing Commander: Motorcycle Gear Ratio Calculator for Sprockets RPM Speed Chain