Hi there!! I bought recently my second Land Rover ando now is a Disco 2 mod 2000 v8 and has a few troubles. One is the speedometer witch doesn’t shoe the correct speed and goes slow. I looked the tyres are too big and I going to change it asap. Where I have to look for problems beyond the tyres?

 

Once you put factory correct sized tires on it your speedo will most likely be accurate again

 

No need to change the tires. Just do a little testing of the actual speed vs. what the speedometer shows and learn how to interpret what the speedometer is showing. You can time how long it takes to go a measured mile. Or, there are apps like Waze that will display a GPS-calculated actual speed.

 

my tires are 10% larger than stock, so I always add 10% to my speed. speedo say 40? I'm going 45. speedo says 70? I'm going 77. it's easy to get used to.

 

I'm also looking for button to slow down the reality.

But seriously folks... There are MPH/KPH apps on the market that work with the GPS in your device to read actual speed traveled. You can compare that to your speedometer, odometer, and OBD2 device to see the error factor in each.

 

My sat nav is more accurate then my speedo, the faster you go the bigger the difference, when driving and I go through a local smiley face speed checker my Sat nav is spot on with the speed checker, my speedo is always faster , so I drive on the Sat Nav whether its be on my GPS or phone, and I have not yet had a speeding ticket using one or the other you dont need to worry about the size of you tyres

 

Remember that an incorrect speedometer also means that your odometer is incorrect.

 

And therefore your MPG calculations are incorrect.