BMW M5 Forum and M6 Forums banner

3.45 gears and speedo

815 Views 4 Replies 5 Participants Last post by  gsfent
Delete

thanks
1 - 5 of 5 Posts

· Registered
Joined
·
286 Posts
Ryan,
Doesn't the speedo based its measurement off the wheels/tires so the size of tires will affect it. But with a different diff ratio your rpm's would just be higher for the same speed and therefore should not affect the speedo reading. Typical error between speedo reading and actual could be 3% easily according to BMW.
-Roberto
 

· Registered
Joined
·
2,382 Posts
use a gps unit and see how much you off ...
 

· Registered
Joined
·
771 Posts
The gearing will increase the rpms of your engine by about 500. I don't believe it will affect the speedometer. So when in 6th and cruising at 80 mph my tac would normally read 2500 rpms. Now with the 3.45:1 diff, I am reading 3000 rpms. Hope this helps.

Mike
 

· Registered
Joined
·
13,187 Posts
The gearing will increase the rpms of your engine by about 500. I don't believe it will affect the speedometer. So when in 6th and cruising at 80 mph my tac would normally read 2500 rpms. Now with the 3.45:1 diff, I am reading 3000 rpms. Hope this helps.

Mike
+1.
Regards,
Jerry
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top