Have you asked the Triumph dealer, would be interesting to see what they say. How do you know if your GPS is reading accurately?

 

So far I assume it's accurate as the GPS calculates distance over time where the bike reads an internal sensor and assumes the tyre diameter remains the same no matter the wear or profile. Now that you've put my mind to work I'll check it - I have one Garmin unit, gps on my phone, and a cycling computer with gps. I'll set all three of them on the bike and see how they compare.

 

I have exact same issue on my Rally Pro. 10% off on speedo (USA...MPH)
I remember reading somewhere that you can change the speedo "accuracy" using Tune ECU at a plus or minus % value .... BUT.... when you change the MPH/KPH setting is also affects (due to brilliant Triumph programing technology) the odometer. In most parts of the USA this would be borderline illegal as tampering with the odometer and would be considered an unacceptable practice.

I would imagine the Triumph dealer will state that "it meets standards" . Please post you experience(s) with dealership and Tune ECU.

 

Supposedly yes. You could on the old windows version although I’m not seeing it as a function on the tests and adjustments in the manuals.

Read these. There is currently an issue with registering Tuneecu but this will be resolved.

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Supposedly yes. You could on the old windows version although I’m not seeing it as a function on the tests and adjustments in the manuals.

Read these. There is currently an issue with registering Tuneecu but this will be resolved.

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Those links take me to a page which tells me to log into facebook. I'm logged in to fb but they don't see it. Is there a different site or link for the info. I've no experience with TuneECU at all.

 

My research suggests this cannot be done via the ECU because its now driven from the ABS computer and I don't suppose anyone would risk messing about with ABS firmware. It might be tempting to replace the sensor ring for one with fewer holes.

 

get a smaller tire.

 

No get a bigger tyre. A smaller one would read even faster.

 

I had a KTM LC motorbike. When i swopped over from offroad wheels to smaller Moto road wheels I would alter a value in the sub menu. Took a couple of button pushes only. Maybe Triumph have this in a sub menu ?

 

I have the same issue with the speedo being off. I was comparing it to the GPS speed on my phone, but to make sure, I had the guys at work shoot me with a LIDAR speed gun while I rode past and the GPS was dead on. The speedometer, as we suspected, was off by about 10-12%

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The Speedo on the Rocket was 6% low. I think all bikes are set low although I’ve only seen it on Triumphs.

 

I have just tested the new 850 sport using both instantaneous GPS speedo and also GPS average at constant speed and the bike speedo does unfortunately read about 8% high so with a worn rear tyre it will probably be even worse. This is within regulation limits in the UK but I thought the US regs. required greater accuracy. Maybe it only applies to cars but the figure of +2% has been suggested before.
Perhaps someone could make an ABS sensor ring with one less hole to see if that fixes it. There might even be a genuine Triumph part for another model which will fit. If someone would like to get on their hands and knees in a dealers showroom and start counting you could be an instant hero. Might need to explain what you are doing though!

 

I have just tested the new 850 sport using both instantaneous GPS speedo and also GPS average at constant speed and the bike speedo does unfortunately read about 8% high so with a worn rear tyre it will probably be even worse. This is within regulation limits in the UK but I thought the US regs. required greater accuracy. Maybe it only applies to cars but the figure of +2% has been suggested before.
Perhaps someone could make an ABS sensor ring with one less hole to see if that fixes it. There might even be a genuine Triumph part for another model which will fit. If someone would like to get on their hands and knees in a dealers showroom and start counting you could be an instant hero. Might need to explain what you are doing though!

I thought they did it on the Rocket to help us not get speeding tickets. They’re obviously doing this intentionally. It’s not a design flaw.

 

I reported the +10% inaccuracy to my dealer and they said its within spec. So... I just ride 10MPH faster. Or 15... 20...

 

You could Adjust the Spedo accuracy with TuneECU on the Tiger 800 as I had to do it when I cahnged the front sprocket to a 14t, Though not sure that TuneEcu can access everything on the 900 yet

 

Speed adjust was available on the earlier Tiger 800 but not the most recent. It isn’t available on the Tiger 900.

 

From what I have found, motorcycle speedos can read up to 10 mph high, but cannot read lower than actual as per DOT. First time I had mine on the interstate, knew something was up because I knew not that many Semis run 80 MPH... I would certainly like it to be much more accurate.

 

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

 

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.

 

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.

 

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...


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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.

 

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.

 

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.

 

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 ****.

 

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

 

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.

 

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.

 

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.