Mileage Meter Off with different tires
- Thread starter NViejeP
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qballjr13
New member
Check out this site and enter in the stock size tires, then enter the size of the new tires and they will compare them and tell you the difference between them....great site to keep for future reference.
http://www.1010tires.com/TireSizeCalculator.asp
http://www.1010tires.com/TireSizeCalculator.asp
Expat
Banned
animator said:
GPS will give you the actual speed based on your movement and the triangulation of several satellites which you can compare to your indicated speed.
With my MTR's my GPS speed (actual) as an example, can be 80mph whereas my indicated speed (speedometer in car) shows 76mph.
Problem is, I don't know how accurate the GPS is. As an example mine is supposed to be accurate within 20ft of location but I don't know how this translate to speed differential.
I do know that before I changed tires, my GPS and speedometer read within 1mph difference.
ovrrdrive
New member
Expat said:
I think he was questioning this part:
The percentage difference my vary at different speeds.
And I'm not sure if that's possible. I think the larger tires will change the final drive ration and it will be a linear percentage difference from 0-what ever top speed is.
I took off the stock 28's on my truck and replaced them with 32"'s and my speedo is off about 5% across the board. I have driven with a GPS to verify that too.
A GPS is the only way to figure out how much it will be off.
animator
New member
ovrrdrive said:
Yep, that's the part I'm wondering. The only way the percentage would be variable would be if something in the system was variable, such as the tires getting larger or smaller while driving or something.
On my truck, I went from 32" to 35" and used an online calculator to determine how bad the speedo is off. I wrote down the more common road speeds and their conversions on a piece of paper and taped it to my dash
When someone gets in my truck for the first time, always the first question is: what the hell are those numbers for?? ha
tekcru
New member
When Changing tire size the percentage difference is linear. When I went from stock 265/65r17 to 265/70r17 the difference is aprox. 5% based on my GPS. This means that when my speedo says I'm going 100km/h I'm really going 105km/h and when it says 50km/h I'm really going 52.5km/h.
The difference between your speedo and your actual speed will depend on the size of your tires. The calculator form 1010tires mentioned earlier in this thread will give you a rough idea of that difference until you can check it against a GPS or another vehical.
The difference between your speedo and your actual speed will depend on the size of your tires. The calculator form 1010tires mentioned earlier in this thread will give you a rough idea of that difference until you can check it against a GPS or another vehical.
