Speedometer Error on EFI models

Check out the new Gallery

wicked red 1100
by mag10, August 21

first ride
by NemoJr, April 1

Steve McQueen inspired
by Feral, November 28

GaRally22
by chy, September 18

Print Thread

Speedometer Error on EFI models #514965 03/20/2013 1:37 PM
Joined: Mar 2013 Posts: 124 Fredericksburg, VA tdragger OP Adjunct
OP tdragger Adjunct Joined: Mar 2013 Posts: 124 Fredericksburg, VA	We have found on the Rocket III that Triumph has built in calibration error in the ECU for the speedometer. It is our experience that the speedometers will read about 7% higher than your actual speed. I know that mine does it. My question to the forum is does the EFI models of the America/Speedmaster have that same built in calibration error? If the speedo shows that you're running 60 mph, are you really only going 54-55? We have an older bike with a mechanical speedo and it is spot on with my GPS but my Rocket is not. I haven't had a chance to take the new Speedy out with the GPS to see.

Re: Speedometer Error on EFI models tdragger #514966 03/20/2013 2:28 PM
Joined: Feb 2007 Posts: 23,194 Likes: 56 NE PA USA The_Dog33 Fe Butt
The_Dog33 Fe Butt Joined: Feb 2007 Posts: 23,194 Likes: 56 NE PA USA	I think they all have that, old, new, doesn't matter. I learned all I need to know about life by killing smart people and eating their brains. Eat right ,Exercise ,Stay fit, Die Anyway!

Re: Speedometer Error on EFI models tdragger #514967 03/20/2013 3:02 PM
Joined: Jun 2011 Posts: 407 Likes: 2 NW Florida, USA MattyMo Adjunct
MattyMo Adjunct Joined: Jun 2011 Posts: 407 Likes: 2 NW Florida, USA	Quote: My question to the forum is does the EFI models of the America/Speedmaster have that same built in calibration error? If the speedo shows that you're running 60 mph, are you really only going 54-55? On my 09 (EFI w/mechanical speedo) the speedometer over reports compared to my GPS. It's off by ~3MPH almost across the dial. 45MPH on the dial = 42MPH on my GPS, 78MPH on the dial = 75MPH on my GPS 09 America, some modifications

Re: Speedometer Error on EFI models MattyMo #514968 03/20/2013 3:19 PM
Joined: Jan 2008 Posts: 513 South Central Mississippi, USA Preacher Adjunct
Preacher Adjunct Joined: Jan 2008 Posts: 513 South Central Mississippi, USA	I'm sure that error has kept me from several tickets or else our Mississippi Highway Patrol troopers are sympathetic to bikers on cruisers Its more fun to be ridin'! I'm still ridin

Re: Speedometer Error on EFI models Preacher #514969 03/29/2013 2:27 PM
Joined: Mar 2013 Posts: 124 Fredericksburg, VA tdragger OP Adjunct
OP tdragger Adjunct Joined: Mar 2013 Posts: 124 Fredericksburg, VA	I took the Speedy out for a spin and reached a ton but was interested in the true speed.

Re: Speedometer Error on EFI models tdragger #514970 04/01/2013 2:51 PM
Joined: Jan 2008 Posts: 1,172 Likes: 15 Wisconsin mag10 Learned Hand
mag10 Learned Hand Joined: Jan 2008 Posts: 1,172 Likes: 15 Wisconsin	I recalibrated the speedometer on the 2012 SM using TuneECU. As the error was mostly due to my changing the counter shaft sproket from 18 T to 16 T it was a rather large error. the correction value (%) was calculated and the actual was checked against a GPS. I seem to recall that the OEM setting was within 2% of the GPS reading. 05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter

Moderated by bennybmn, chy, mert

Link Copied to Clipboard

2025 Arkansas Rally
by roadworthy - 04/24/2025 7:57 PM

Bonneville America Forums Forums Technical Forums General Tech Speedometer Error on EFI models