speedometer question
Thread Starter
Junior Member
Joined: Jan 2006
Posts: 41
Likes: 0
From: NYC
2006 E55, 2007 R350
speedometer question
Quick question: Does anyone know how is our E55's speed being measured? Is it based on wheel rotation or is it based on transmission rotation?
Thinking about changing the size of tires on my car (wider), I want to make sure I won't screw up the true speed/distance by too much so I won't travel much faster in reality than what the speedo indicates. If the speed is measured base on transmission rotation, doesn't a wider rear like a 275/35/18 or 285 make the car go faster than the speedo indicates? How do you solve the problem or just ignore it?
Thanks for all your help.
SAC
Thinking about changing the size of tires on my car (wider), I want to make sure I won't screw up the true speed/distance by too much so I won't travel much faster in reality than what the speedo indicates. If the speed is measured base on transmission rotation, doesn't a wider rear like a 275/35/18 or 285 make the car go faster than the speedo indicates? How do you solve the problem or just ignore it?
Thanks for all your help.
SAC
Senior Member
Joined: May 2006
Posts: 425
Likes: 15
Originally Posted by sac73
Quick question: Does anyone know how is our E55's speed being measured? Is it based on wheel rotation or is it based on transmission rotation?
Thinking about changing the size of tires on my car (wider), I want to make sure I won't screw up the true speed/distance by too much so I won't travel much faster in reality than what the speedo indicates. If the speed is measured base on transmission rotation, doesn't a wider rear like a 275/35/18 or 285 make the car go faster than the speedo indicates? How do you solve the problem or just ignore it?
Thanks for all your help.
SAC
Thinking about changing the size of tires on my car (wider), I want to make sure I won't screw up the true speed/distance by too much so I won't travel much faster in reality than what the speedo indicates. If the speed is measured base on transmission rotation, doesn't a wider rear like a 275/35/18 or 285 make the car go faster than the speedo indicates? How do you solve the problem or just ignore it?
Thanks for all your help.
SAC
If you change only the breadth of the tires, you don't have a 'problem'! But have also an eye on the height against the breadth of the tires!
But, bigger wheels means more distance with lower milage in my calculation and the factory builds a higher score of more or less 5 % (that's obliged)! So I don't really see a problem for you even if you put 20" wheels on it!
