In article ,
Mrcheerful wrote:
The mileometer is usually quite accurate because it is directly pulse or
cable driven, whereas the average analogue speedo has a flappy needle
which is safely adjusted to overread. so putting big wheels on will
often make the speedo closer but put the (previously accurate)
mileometer out.

I'll take your word for it in general but it's not universal. BMWs over
read in both speedo and odometer. Buy roughly the same amount.

--
*Beauty is in the eye of the beer holder *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 30 Jan 2010 00:29:45 +0000, Dave Plowman (News) wrote:

In article ,
Mrcheerful wrote:
The mileometer is usually quite accurate because it is directly pulse
or cable driven, whereas the average analogue speedo has a flappy
needle which is safely adjusted to overread. so putting big wheels on
will often make the speedo closer but put the (previously accurate)
mileometer out.

I'll take your word for it in general but it's not universal. BMWs over
read in both speedo and odometer. Buy roughly the same amount.

Yep, that's what prompted my question; both the Focuses I have had were
4% out in both speedo and mileometer when compared to sat nav.

Chris

--
Remove prejudice to reply.

"Chris Whelan" wrote in message
...
On Sat, 30 Jan 2010 00:29:45 +0000, Dave Plowman (News) wrote:

In article ,
Mrcheerful wrote:
The mileometer is usually quite accurate because it is directly pulse
or cable driven, whereas the average analogue speedo has a flappy
needle which is safely adjusted to overread. so putting big wheels on
will often make the speedo closer but put the (previously accurate)
mileometer out.

I'll take your word for it in general but it's not universal. BMWs over
read in both speedo and odometer. Buy roughly the same amount.

Yep, that's what prompted my question; both the Focuses I have had were
4% out in both speedo and mileometer when compared to sat nav.


not what I have seen, so obviously whatever is done it will be worth
checking on a motorway journey with a satnav as to accuracy. and in this
case YMMV !!

Look....The easiest way to change the overall gear ratio is to change the gears in the differential. In some cases, aftermarket suppliers offer the necessary parts and often the vehicles' manufacturer has an excellent selection available. If you are on a budget, a little research will probably reveal that your vehicle was available with a number of differential ratios....