[ThunderCruiser]

After the latest update, mine seems to be 5-7 mph off. According to other sources, these ecm’s are locked for what that is worth. Have been wondering about dropping 1 tooth on the rear sprocket. Doable? Would that percentage about drop it right on the spot?

 

[zolo]

After the latest update, mine seems to be 5-7 mph off. According to other sources, these ecm’s are locked for what that is worth. Have been wondering about dropping 1 tooth on the rear sprocket. Doable? Would that percentage about drop it right on the spot?

Hi ThunderCruiser

Speed readings come from the ABS/wheel speed sensor. Dropping a tooth on the rear sprocket is just going to make your gearing slightly taller, reducing low-end torque and increasing top-end speed for each gear. It wouldn't affect the speedo at all.

Zolo

 

[STroadster]

As Zolo says the speed is almost certainly taken from the rear ABS sensor ( pulse ring in the parts book). So you could either find or make a pulse ring with fewer holes or you could fit a bigger diameter wheel and/or tyre. It might also be possible to fill in one or more holes on the ring but using heat would probably distort it and anything else could risk very big and expensive damage and it might trigger a fault code anyway.

 

[dawsonstaffs]

How come the speedometer is off by upto 10% but the odometer is always spot on? Don't they both go off the same sensor?

 

[mglax13]

I was at the dealer this week to have them take a look at the Shift Assist (shocking, I know) and mentioned the speedometer issue. The service writer asks "well how do you know that the speedometer is off?" so I explain to him that I compared it to the GPS speed on my phone and a Garmin, but to be sure, I had the guys at work shoot me with a LIDAR gun at several different speeds, and it confirmed the GPS readings. His reply? "Well your lasers are wrong".

Yes, thats right, 3 different sources, including a laboratory calibrated laser that's admissible in court and has a margin of error of +/- 1 mph at 100 mph, are all wrong, but the speedometer made by the same company that can't manage to build pannier racks that don't block their own center stand, is right.

This is why people hate dealerships...


Sent from my SM-G991U using Tapatalk

 

[CafRacer]

How come the speedometer is off by upto 10% but the odometer is always spot on? Don't they both go off the same sensor?

Just different calculations in the ECU, they could make both readings as accurate or otherwise as they want, within the limits of different tyre size's, tyre growth etc.

 

[Dr.Shifty]

How come the speedometer is off by upto 10% but the odometer is always spot on? Don't they both go off the same sensor?

The speedo is deliberately set to read high as a 'safety' measure. If it read low you could be booked by a speed camera through no fault of your own. Setting it high means you are always a bit under.

Here in Australia the design regs say it can read up to 10% high but zero low. My previous Toyota read 5kph high on everything, my Outback is 5% high, my Husqvarna bike is about 3kph high (new bike and I haven't checked it out much), but a Kawasaki I had was almost 15% high - that was a real pain to keep in mind, 110kph motorway I was showing 125kph..

I was out touring for two weeks on the Triumph recently and whenever we matched our daily distance it was always within a few km across all bikes - Indians, BMWs and my Tiger. However, the speed we had to set on cruise control to match the leader was always different and mine was the most inaccurate.

I often use a phone app called DigiHUD that gives me a gps speedo. That means moving between different speed zones is not so much of a headache.

 

[Dr.Shifty]

I had the guys at work shoot me with a LIDAR gun at several different speeds, and it confirmed the GPS readings. His reply? "Well your lasers are wrong".

Obviously he's a Storm Trooper who has never seen a properly calibrated anything.

 

[DamonYVR]

My 2017 V-Strom was about 6 - 8% fast, and my 2017 BMW F800GS seemed about the same. Lots of complaints on the Stromtrooper forum about it. That is based only on comparing GPS speed indications with the speedo reading. Though the roadside radar signs that show 'your speed' show the same difference. I think it is very common for speedometers to read higher than actual, and it is a liability issue. Indicating a speed below the actual speed is a legal problem. Showing more is the safety margin for the manufacturers. It is annoying but I think it is very common.

Interestingly, our Mercedes B250 shows an indicated speed that matches the GPS very closely, basically within the width of the needle on the dial face.

 

[strych9]

My 2021 Rocket 3 is off by 6.75%. Dealer says it's within specs, but has agreed to update the bike modules' software just in case. I can confirm that TuneECU has no provision for adjusting the speedo calibration on this bike. The setting is absent from the OEM stock map. Bummer.

 

[raysdiving]

The GT Pro is mys first Triumph and I know nothing of Tune ECU apart from snippets mentioned on here.

The speedo is very optimistic and at highway speeds it shows about 10% above real speed. If I have the GPS speedo showing 110 kph, the bike shows 120 kph. This is the limit allowed by Australian design specs but is a nuisance if i don't have the GPS mounted on the bike.

Is there a setting that can adjust this? On my previous Indian I could adjust the accuracy and flash the computer.

We have two 850 tigers wife and i and we both have same thing with two different GPS running. Having worked in the car industry customers would complain and the dealer gave them the same answer no you cant change the speddo setting by law. Good luck with the dealer i dont like your chances. I love the bike but the whole tft is naff not a fan inc the biggest whinge is the Tach its ****.

 

[Rusty_Shackelford]

Triumph cheated with the speedo to cheat on the fuel economy number. Basically they made 65 mph show when the bike is going 58 and measures "highway" fuel economy at a lower actual speed. Both Ford and VW were hit with fines in the USA for doing something similar to this. No one has filed a lawsuit yet as far as I know. If you fix the speedo error, the highway mpg turns into about 44mpg rather than the falsely advertised 48mpg.

Edit: By fix I mean doing the math with your GPS. Speed is collected by the ABS system (Bosch) and is modified by the main ecu. Speed healers do not work.

 

[grantcoll]

Triumph cheated with the speedo to cheat on the fuel economy number. Basically they made 65 mph show when the bike is going 58 and measures "highway" fuel economy at a lower actual speed. Both Ford and VW were hit with fines in the USA for doing something similar to this. No one has filed a lawsuit yet as far as I know. If you fix the speedo error, the highway mpg turns into about 44mpg rather than the falsely advertised 48mpg.

Edit: By fix I mean doing the math with your GPS. Speed is collected by the ABS system (Bosch) and is modified by the main ecu. Speed healers do not work.

Excellent point

 

[grantcoll]

The GT Pro is mys first Triumph and I know nothing of Tune ECU apart from snippets mentioned on here.

The speedo is very optimistic and at highway speeds it shows about 10% above real speed. If I have the GPS speedo showing 110 kph, the bike shows 120 kph. This is the limit allowed by Australian design specs but is a nuisance if i don't have the GPS mounted on the bike.

Is there a setting that can adjust this? On my previous Indian I could adjust the accuracy and flash the computer.

I had a 900 GT PRO and found the same thing. Speedo reading aboiut 7km/h higher than GPS. Dealer said it is within limits. I now have a 1200 GT PRO and have the same GPS mounted. The Speedo reading is only about 3 to 4 km/h high. I feel that is more acceptable.

 

[459084]

Just for reference, I used to have a Ford Ranger & Everest and had the Forscan software. This allowed me to adjust the wheel diameter by a couple of MM. This essentially adjusted the speed by changing the distance the wheel travels in the computer. I had mine down to within 1km/h of GPS speed. Even after tyre wear, it's worst readout was 2km/h out.
I am aware this will also affect fuel economy readouts but it's so negligible I wasnt concerned.

If I could do something similar with the bike I'd do it again.

 

[Mystic]

Interesting discussion. I have been riding my MY23 900 GT Pro for about a month now and had always felt as if my other group riders were closing in on me very quickly. Never paid too much attention. I installed the Garmin GPS last week and have since noticed that the GT Pro is at least 10% higher compared to the Garmin. I have had this Garmin bit for about a year and used it on my T120 previously and it was always spot on with the T120 speedo. So I don't doubt the Garmin GPS.

Went for the first service 2 days ago and mentioned the speedo issue to the dealer. Same old stuff like, it is meant to be high, but when I said about 10%, they said the Garmin GPS is wrong. I insisted on it being checked by the service engineer as opposed to the quasi-front-desk-service guy. Collected the bike couple of hours later and enquired and the quasi guy said, nothing can be done. No adjustments on the bile for the speedo apparently. Software has been updated so hope for the best.