So just how inaccurate is the polo speedo??

[pomme]

100 came up as 92. I'll steal a gps off someone

[blutopless2]

This is a crap philosophy by VW, imnsho. It's much better to have an accurate reading so that you know what you are doing, rather than it being a guesstimate of something.

i agree... i have found that all we do is sit 5k's over the limit to compensate for it.

[Funkdancer]

Apologies for using the word that combines bull with manure, didn't mean to upset anyone.

Yep having to compensate for the speedo is a bit suboptimal, all manufacturers do it to some degree (e.g. my Accord is 4%) but in the Polo it has been taken a degree too far. When money and your license is on the line, we deserve to have proper information about the speed our vehicle is doing.

Another thing is that the odo will be displaying an over inflated figure, which will affect resales price.

How would we go about getting it fixed / adjusted?

[PoloGTi]

We could just send VW Australia an email asking why and by how much its out???? Might give us the real reason for doing it.

[ACTGTI]

all manufacturers do it to some degree (e.g. my Accord is 4%)

Hate to be pedantic, but my Peugeot 206 GTi180's speedo was 100% accurate at all speeds! So, not all manufacturers provide inaccurate speedos. This was apparently done by measuring speed at each wheel through the ABS sensors, then taking the average of all 4 wheels.

[Cygnus]

Does that mean we don't have to worry too much about an increase in wheel diameter when we get bigger rims?

[Funkdancer]

Hate to be pedantic, but my Peugeot 206 GTi180's speedo was 100% accurate at all speeds! So, not all manufacturers provide inaccurate speedos. This was apparently done by measuring speed at each wheel through the ABS sensors, then taking the average of all 4 wheels.

That's good stuff. However, how would it know about tyre inflation? Some system to correct for this?

The ECU of the Accord actually got it just about 100% correct at the current 36 PSIs. However if filled with less air, the ECU itself would be off.

In the Polo the ECU itself is 4% off at 36PSIs, which would probably be slightly improved by running a softer configuration. Then there's another few % between the ECU and the speedo.

[blutopless2]

Another thing is that the odo will be displaying an over inflated figure, which will affect resales price.

i have read posts on new beetle forums from the states saying that this is not the case... the odometer is actually a true reading whereas the speedo reading is altered.

i have not tested this theory and i dont know how they came up with this idea either.

[Funkdancer]

i have read posts on new beetle forums from the states saying that this is not the case... the odometer is actually a true reading whereas the speedo reading is altered.

i have not tested this theory and i dont know how they came up with this idea either.

It'd appear to me that the ECU data is what's going to the odo. The ECU is still off by about 4% (showing too high speed). However the ECU reading is not as bad as the actual speedo.

[ACTGTI]

That's good stuff. However, how would it know about tyre inflation? Some system to correct for this?

The ECU of the Accord actually got it just about 100% correct at the current 36 PSIs. However if filled with less air, the ECU itself would be off.

In the Polo the ECU itself is 4% off at 36PSIs, which would probably be slightly improved by running a softer configuration. Then there's another few % between the ECU and the speedo.

Don't know how it corrected for tyre inflation, but it was spot on for both 36 PSI and for 41 PSI anyway, I know that.