sonny

Living Legend
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Henryetta Oklahoma
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Don't see it. Bike came from factory with a speed limit set at 135. odometer is off. You may think your going that fast but reality is a different story. More like 128 when the fat lady sings.
 

Dr.D

Octane Boost
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Tazewell TN
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Indians and the R3 2014 Roadster + TFC
Don't see it. Bike came from factory with a speed limit set at 135. odometer is off. You may think your going that fast but reality is a different story. More like 128 when the fat lady sings.
How does the bike know how fast it is going? The speedometer? Wouldn’t the ECU use the speedometer to tell the bike to shut down at 135 indicated? Certainly it does not an internal GPS to measure actual speed when the speedometer indicates another value. If it was limited to 135 mph it would stop gaining speed when the speedometer indicated 135 regardless of the actual speed determined by a more accurate measurement.

I thought it would shut down at the indicated speed of 135 but it does not. That’s why I want to get the truth from the factory in the UK. I do not doubt that the speedometer is inaccurate and overstating speed.
 

Steel

Resident Coonass
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Cut Off, Louisiana USA
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How does the bike know how fast it is going? The speedometer? Wouldn’t the ECU use the speedometer to tell the bike to shut down at 135 indicated? Certainly it does not an internal GPS to measure actual speed when the speedometer indicates another value. If it was limited to 135 mph it would stop gaining speed when the speedometer indicated 135 regardless of the actual speed determined by a more accurate measurement.

I thought it would shut down at the indicated speed of 135 but it does not. That’s why I want to get the truth from the factory in the UK. I do not doubt that the speedometer is inaccurate and overstating speed.
Download an app like Ulysse to your phone. It will record your max speed. You can also use it for 0-60, 0-100, & 1/4 mile times by GPS.
 

barbagris

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Wouldn’t the ECU use the speedometer to tell the bike to shut down at 135 indicated?
Be aware that whilst the ECU has a really good grasp of speed and mileage, the speedo under EU law cannot show a speed less than true. But the ODO has to be very close to real. They won't shut down - they simply will not get faster. The speedo is a display - not a sensor.

Actual speed varies with tyre diameter (and a close examination of mfrs specs will show they vary, as they do during teh course of their life) - so as a result speedos deliberately register fast. Usually 4-5%. True 135 with say 5% is about 142 indicated.

On old fashioned cable speedos the 5% bit only applied to a specific range - and I have seen older speedos read 10-15% high at speeds over 100mph. It may be that this also applies to stepper motor/digital speedos too. If so mfrs "may" exaggerate indicated top speeds.
 

barbagris

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I run an Independent GPS speedo on all my bikes - these days you can find pretty good ones fairly cheap. But a good GPS speed sensor will never be cheap. One could build a clever one using ublox's "dead reckoning" chip that takes GPS to calibrate the speed sensor input and auto compensates for tyre wear and all sorts - 500Euros a pop.
 

Boog

Traveling Story Teller
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Oct 17, 2013
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Dumfries, Virginia
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This is going back to old school methods, but find a measured mile such as State Troopers use from the air to time motorist on the highway. You simply start your watch at the beginning and stop it at the end. Be aware that this is just an average speed along the mile, but if you have helpers and a radio or phone coverage, they can get you at top speed at the start and its up to you to carry it though to the end. After, convert time into MPH. For example, if it takes you 30 seconds to cover the measured mile, your average speed is 120mph. Here is a link to the conversion to make it easier: Speed Distance Time Calculator
 

Dr.D

Octane Boost
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Tazewell TN
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Indians and the R3 2014 Roadster + TFC
Be aware that whilst the ECU has a really good grasp of speed and mileage, the speedo under EU law cannot show a speed less than true. But the ODO has to be very close to real. They won't shut down - they simply will not get faster. The speedo is a display - not a sensor.
Understood and I posed things as a question to initiate thought and response not because I do not understand. So I will ask this, how does the ECU obtain a really good grasp of speed and mileage? Going back to Sonny’s post I while expect the limiter to rely on knowledge gained from the speed sensors, which most likely are not accurate GPS sensors.
 

barbagris

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Understood and I posed things as a question to initiate thought and response not because I do not understand. So I will ask this, how does the ECU obtain a really good grasp of speed and mileage? Going back to Sonny’s post I while expect the limiter to rely on knowledge gained from the speed sensors, which most likely are not accurate GPS sensors.
Speed sensor in the gearbox (it is on the 2.3L anyhow) - This sends signals (electronic pulses) to the ECU. Triumph know the HOMOLOGATED tyre diameter range (new to worn - approx 5mm tread depth - which is approx 15mm/rotation difference over tyre lifetime - say 0.5%) - and they obviously can calculate how many pulses per km/mile ensue - a clock chip for timing is a really cheap. Other mfrs use other sources: my KTM uses the pulses from the front ABS ring - So @Steel would never run up mileage on the rearwheel. But tyre mfrs are allowed a rotational margin even of say a standard 240/50R16 - one might be 240/50.5 another 240/49.5. Not all mfrs publish the data.

Really GOOD GPS speed sensors are not cheap. SatNav sensors are usually pretty slow (5Hz was the norm) and not that precise (5-6 metres or more). A good speed sensor is 1 metre location accurate and will be at least 20Hz - many now are over 30Hz. I did investigate this stuff at depth about a decade ago - had some really good email exchanges with several chip and device mfrs.

Bear in mind that while GPS can be accurate you need clear access to sky. So GPS speedos do not and cannot work in tunnels and it is really easy to make even a good sensor read slow/fast with shielding on one side.

GPS is great for planes, boats and stuff like opencast mines. But crap in urban and alpine areas.
 

barbagris

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I will now add - Those of us running an E-Max - were now log less distance on the ODO than we actually do. And the speedo can theoretically read less than true. About 3.6% - And this is why it cannot legally be used in Europe.
 

Dr.D

Octane Boost
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Speed sensor in the gearbox (it is on the 2.3L anyhow) - This sends signals (electronic pulses) to the ECU. Triumph know the HOMOLOGATED tyre diameter range (new to worn - approx 5mm tread depth - which is approx 15mm/rotation difference over tyre lifetime - say 0.5%) - and they obviously can calculate how many pulses per km/mile ensue - a clock chip for timing is a really cheap. Other mfrs use other sources: my KTM uses the pulses from the front ABS ring - So @Steel would never run up mileage on the rearwheel. But tyre mfrs are allowed a rotational margin even of say a standard 240/50R16 - one might be 240/50.5 another 240/49.5. Not all mfrs publish the data.

Really GOOD GPS speed sensors are not cheap. SatNav sensors are usually pretty slow (5Hz was the norm) and not that precise (5-6 metres or more). A good speed sensor is 1 metre location accurate and will be at least 20Hz - many now are over 30Hz. I did investigate this stuff at depth about a decade ago - had some really good email exchanges with several chip and device mfrs.

Bear in mind that while GPS can be accurate you need clear access to sky. So GPS speedos do not and cannot work in tunnels and it is really easy to make even a good sensor read slow/fast with shielding on one side.

GPS is great for planes, boats and stuff like opencast mines. But crap in urban and alpine areas.
Alright this answer I can have confidence in. I thought that the ECU would consider the speedometer or rotating wheel counter to determine at what time to cut fuel and limit speed. Thanks for clear and logical answers.
 
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