Speedo Accuracy.
#1
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Speedo Accuracy.
Fitted an Origin B2 last night and I'm a little perplexed about how accurate the speedo on it is compared to the cars speedo and the "real" speed.
Car is an MY00 but has 17"alloys with 215x45 tyres - although I understand that it should be 40mm tyre depth to maintain the correct rolling radius - as a result, I was under the impression that the car is actually going slightly faster than the speedo indicates.
Now with the B2 installed - it always displays lower than the speedo - approx 10% less I calculate. I don't expect any system to be foolproof or 100% accurate but is likely to be the more reliable indication?
Car is an MY00 but has 17"alloys with 215x45 tyres - although I understand that it should be 40mm tyre depth to maintain the correct rolling radius - as a result, I was under the impression that the car is actually going slightly faster than the speedo indicates.
Now with the B2 installed - it always displays lower than the speedo - approx 10% less I calculate. I don't expect any system to be foolproof or 100% accurate but is likely to be the more reliable indication?
#2
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The difference between 205/50/16 and 215/45/17 is the 17's are approximately 43mm larger, because of this you should have been seeing the speed reading 71.6mph when you are actually going 70mph.
You will not normally get a speedo to be that accurate, they normally read over by a few percent on the standard wheel size, consider the GPS speed on the B2 to be accurate.
Thanks
Tebo
You will not normally get a speedo to be that accurate, they normally read over by a few percent on the standard wheel size, consider the GPS speed on the B2 to be accurate.
Thanks
Tebo
#3
The police had set up one of those "Your speed is" radar boards up the road from work the other week, I was suprised as I went past with speedo reading about 43MPH the radr board only put my speed at 38MPH. Did not expect a 5MPH difference at such a low speed?
#4
This is normal. Vehicle construction and use regulations require a vehicle speedometer accuracy to be in the range of -0->+10%. The implications are that it must never under-read - for obvious reasons - but may over-read. As the cost of manufacturing a speedometer with -0% error would be very costly they all over-read by a few percent without exception. Even if speed is measured correctly the display may not be accurate, so a speedometer error is allowed
#5
The Subaru seems to be very poor for accuracy.......On the 2 cars I have it has invariably overstated the actual speed by 10%......... now a few % would be fine but 10%!! - oh well when I eventually get caught speeding it might be a more pleasant surprise than it used to be - I can also sit at 90mph on the Motorway knowing that I'm doing nearer 80mph
I even had Protech check my km to mph converter as I was annoyed it overstated - I really noticed as I was clocking more mileage than was normal for certain routes......thats how I knew it was overstating.............
I even had Protech check my km to mph converter as I was annoyed it overstated - I really noticed as I was clocking more mileage than was normal for certain routes......thats how I knew it was overstating.............
#6
My car has 215/35/19 wheel/tyres on, its a jap import MY95 WRX with the speedo converted to mph, i was surprise/pleased to find out that with my new road angel gps my speedo was reading 90mph and the road angel was reading 89mph. On a private road of course..!!
Dan
Dan
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#8
My origin B2 reading is approx 5mph less than the actual speedo reading on my WRX MY03 with standard alloys/tyres.
And a 3mph difference on my BMW.
Funny how I tend to look at my Origin for speed reading nowadays.
And a 3mph difference on my BMW.
Funny how I tend to look at my Origin for speed reading nowadays.
#9
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SAme here on my MY03 WRX, i have a Road Angel and that is showing my speed as actually 4 mpg less than my speedo shows. But most cars are set up like that.
Speedo will always show faster
Speedo will always show faster
#10
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about 7mph @ 90mph ish difference here on my MY00 - the difference gets greater as the speed rises
seen some interesting speedo numbers compared to GPS @ SSo and Pod too
seen some interesting speedo numbers compared to GPS @ SSo and Pod too
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