Speedometer Odometer calibration

[xltluxfx4nl]

My AWD FX4 Tow consistently reads 2 to 3KM faster than the street radars. Around here there are numerous street radars and while I would expect some inconsistency my truck speedometer reads 2 to 3 km faster. With 5k kilometers burned and after passing numerous street radars in different locations I have been monitoring the difference and find speedometer 2 to 3km faster at all speeds. This is somewhat concerning if calibrated too fast would this burn of warranty faster adding milage to the odometer? Checked tire size and same as sticker on door post so no reason to think wrong tire. Also fuel burn math tells me 9.5 to 10 liters per 100km while on board displays 8.5litres per 100 and I have seen it as low as 7. Wondering if anybody has had similar observations.

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[Naranjita]

My AWD FX4 Tow consistently reads 2 to 3KM faster than the street radars. Around here there are numerous street radars and while I would expect some inconsistency my truck speedometer reads 2 to 3 km faster. With 5k kilometers burned and after passing numerous street radars in different locations I have been monitoring the difference and find speedometer 2 to 3km faster at all speeds. This is somewhat concerning if calibrated too fast would this burn of warranty faster adding milage to the odometer? Checked tire size and same as sticker on door post so no reason to think wrong tire. Also fuel burn math tells me 9.5 to 10 liters per 100km while on board displays 8.5litres per 100 and I have seen it as low as 7. Wondering if anybody has had similar observations.

I added 245 All Terrain Tires and my speed is reading 1-3km slower than I was actually driving. So, upgrade your tires to 245's, and you'll be all good!

I'm sure you don't want to drop $1k-$2k on new tires. So I would go back to the dealer and explain the situation. No sense in burning through your warranty faster. I have heard enough warranty stories in my life of major failures right after expiration. You want every KM of your warranty!

Good luck!

 

[Johnkn]

More data needed, Faster at what speed?

If reading 2 faster at true 90 that’s ~2% and a nit. If 2 over at 10 that’s 20%

Check it against your phone gps speed at 90kph and report back

Good luck
.

 

[Dirtball]

I added 245 All Terrain Tires and my speed is reading 1-3km slower than I was actually driving. So, upgrade your tires to 245's, and you'll be all good!

I'm sure you don't want to drop $1k-$2k on new tires. So I would go back to the dealer and explain the situation. No sense in burning through your warranty faster. I have heard enough warranty stories in my life of major failures right after expiration. You want every KM of your warranty!

Good luck!

The 245 number on your tires is the tread width. Only reason you may have seen a speedometer change is the extra tread thickness from the A/T tires. Or if you went with /70 instead of /65.

edit* just noticed we have identical builds. Good man!

 

[Naranjita]

The 245 number on your tires is the tread width. Only reason you may have seen a speedometer change is the extra tread thickness from the A/T tires. Or if you went with /70 instead of /65.

edit* just noticed we have identical builds. Good man!

Yes, I'm aware. Just being lazy. I was referring to my tires as 245's as an abbreviation of my tire size. 65 and 70 are ratios of the first number and aren't good on their own either. I know it is not the 245mm causing my speedometer to change. Thanks for clarifying for others so they are not confused. Guess I figured everyone knows what I'm thinking.

 

[Dloder]

My AWD FX4 Tow consistently reads 2 to 3KM faster than the street radars. Around here there are numerous street radars and while I would expect some inconsistency my truck speedometer reads 2 to 3 km faster. With 5k kilometers burned and after passing numerous street radars in different locations I have been monitoring the difference and find speedometer 2 to 3km faster at all speeds. This is somewhat concerning if calibrated too fast would this burn of warranty faster adding milage to the odometer? Checked tire size and same as sticker on door post so no reason to think wrong tire. Also fuel burn math tells me 9.5 to 10 liters per 100km while on board displays 8.5litres per 100 and I have seen it as low as 7. Wondering if anybody has had similar observations.

Were you able to get this fixed?????
I have the same issue reading on my dash - 2 miles an hour faster than what I really am doing. I took mine to the dealer and told them that and they said they could not find anything wrong with it in other words we don't care.

 

[TheWizziard]

What is the expected accuracy of the street radars?

Could they error on the low side to get you to drive slower?

 

[raymaines]

An extra 2-4 MPH at all speeds is super common. The trip meter seems accurate in most cars though.

Just for the conversation: Wider tires are also larger in diameter and will effect your speedometer if the aspect ratio remains constant. i.e. 60% of 225mm is less than 60% of 245mm.

 

[MakinDoForNow]

The 245 number on your tires is the tread width. Only reason you may have seen a speedometer change is the extra tread thickness from the A/T tires. Or if you went with /70 instead of /65.

edit* just noticed we have identical builds. Good man!

Check the # rotations per mile not by size of tire but by exact # rotations per mile of the exact tire mounted. The OEM tires sometimes have less tread depth than the same aftermarket size. I will look mine up again.

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