Following on from Otheos' post on the TRUE mph you get per 1000 revs in each gear, you can work out how accurate your speedo is without buying a GPS device:-

On my 4x4 I've tried 3000,3500,4000, 4500 rpm in 4th and 5th, made a note of the displayed speed and then worked out what the speed 'should' have been shown as at each point.

Surprisingly, the speedo is more accurate than I expected:-

In 4th and 5th

3000rpm: 4th: 56; 5th 68 - Both are 3mph over true speed

3500rpm: 4th: 65; 5th 80 - 3 to 4mph over

4000rpm: 4th: 74; 5th 90 - 4 mph over

4500rpm: 4th: 83; 5th 101 - 4mph over

I'd expected the speedo to be over-reading by about 7mph at the higher 'speeds'.

So now you can work out your own- here's the gearing /1000rpm

from Otheos:-

-------4x4--------------------vRS----------------

Gear---Mph/1000rpm---Mph/1000rpm

----------------------------------------------------------------------

1st-----4.9-----------------6.2

2nd----8.8----------------10.5

3rd----13.4---------------15.6

4th----17.7---------------19.8

5th----21.6---------------24.3

:cheers:

Have you also checked against channel 16 on the Clima diagnostic screen?

Didn't check that as I remember it being a few mph out as well.

It is always handy to know (especially in the UK) how close the speedo is to your true speed !

By the way, I still think that the ride of the 4x4 estate is one of its best features - its really very good for blasting down bumpy, uneven roads - I bet its good for Greece ?!

:cheers:

I'll bring my GPS to the NEC on the 25th for anybody who wants to check their speedo.

Here's a very interesting one for you :1:

6300 rpm in 5th is an indicated 142mph :eek: or 136mph true

Goes to show that the 4x4 is near 'ideally geared'

6mph out on the speedo is very good at these speeds.

The Impreza was 11 out on the Bruntingthorpe runway at 138 true.

Did some of this myself this morning:

@ 3000 rpm

3rd - speedo: 69 kph, real: 64,8 - 6,4%

4th - speedo: 90 kph, real: 85,5 - 5,2%

5th - speedo: 110 kph, real: 104,7 - 5,0%

@ 4000 rpm

3rd - speedo: 91 kph, real: 86,4 - 5,3%

4th - speedo: 118 kph, real: 114 - 3,5%

5th - speedo: 147 kph, real: 139,6 - 5,3%

3rd @ 3000 rpm and 4th @ 4000 rpm are probably slight misreads!

So my channel 16 (over 10% under speedo) is very much off...

Nick - Please do bring along the GPS - I reckon since I got my new wheels, my speedo is reading more accurately. i.e increasing the wheel circumference by 3% has got rid of the true/read difference. I "believe" my speedo is better now, but this also has made me more aware of speed cameras, and I now make sure I'm doing 70, or even 68, through the one on the way to work every morning, just in case. (once through I, of course, do not speed back up to 90 cruising speed. Never!)

PS: Does anyone have the gearing/speed ratios for the TDI Fabia? I'd quite like to do a little test on my way home tonight. These kinds of threads have got me curious out my own car's speedo now.

Mattijs's results bear out my own observations - the Climate control channel 16 figures are far worse than the speedo.

Jason - don't forget that gearing is affected by wheel size. The gearing figures will be for the standard size wheels and tyres.

So the indicated 140- I got Sunday was better than I thought !!

140 :eek: !! Obviously on private road / track given that you live in Winchester - was down there for a wedding this weekend and I don't think ive ever seen a police force with such a wide variety of different makes/colours of unmarked cars. Have experienced this before and various members of our hockey side have been stopped by Hampshire police who have been driving 1) Red Scooby 2) Black Passat 3) Blue Golf vr6. Bloke stopped by the vr6 was most ****ed off as he had been complaining for the 10 minutes beforehand about this golf tailgating him so speeded up - oops!

WARNING! *dumb question alert* -What is a scooby? I've seen people referring to them in other posts, and I've only just plucked up courage to ask someone.

Subaru = Scooby

(The Impreza GT Turbo or WRX is usually implied, but the term will do for any Subaru.)

Skoda = Skud

And the UK Scooby fan site (or one of them at least) is at http://www.scoobynet.co.uk/

Hmm. I had a suspicion it was a Subaru reference as thats the only other quick car I can think of that sounds like Scooby. I'm quite surprise then, that the fuzz are using them as unmarked cars. The only vehicle I've seen used as unmarked patrol cars down here, is an estate Volvo. I guess the need for unmarked patrol cars is less down here? I can't see why. My mate got done by the aforementioned Volvo for doing a 20 mile average of 95mph. 20 miles? I thought that was hell of a long distance to to an average over!

Originally posted by Stuart_J in this post

So the indicated 140- I got Sunday was better than I thought !!

StuartJ

Stangely enough that makes two of us !

That would have made an interesting convoy. :drive:

Presuming your 4x4 is on 205/55-16s also, yup, an indicated 142 was a true 136 and still accelerating. I reckon the car would hit the redline abroad or on a long enough runway straight, which is just over a true 140.

Devon - there's a few of us previous owners still go on Scoobynet under different names to promote the Skoda cause !

Devon

The origin of 'scooby' is 'Scooby doo-Subaru' a bit of the old cockney rhyming slang!

We have a large stuffed Scooby Doo that we took on the Cannonball when we had the Scoob (hes even in the video & on the web site.

Hopefully if it all comes together he will be going on this years but hes now known as Skody doo, just need to find him a Skoda shirt & hat before October

yeh yeh yeh raggy :silly:

Was reading on the ford rsoc that a unmarked Vrs was blown away by a sapp cosworth. Does anyone remember the capri 2.8i pursuit car?

Aaah - bit of an apple and pears, sky-rocket type of thing. Ha! There are some quite amusing cockney rhymes out there. Going for a "gypsies" whilst out on the p*ss is a common event.

Originally posted by Dutch4x4 in this post

Did some of this myself this morning:

@ 3000 rpm

3rd - speedo: 69 kph, real: 64,8 - 6,4%

4th - speedo: 90 kph, real: 85,5 - 5,2%

5th - speedo: 110 kph, real: 104,7 - 5,0%

@ 4000 rpm

3rd - speedo: 91 kph, real: 86,4 - 5,3%

4th - speedo: 118 kph, real: 114 - 3,5%

5th - speedo: 147 kph, real: 139,6 - 5,3%

3rd @ 3000 rpm and 4th @ 4000 rpm are probably slight misreads!

So my channel 16 (over 10% under speedo) is very much off...

Bringing this thread back on topic, I did some GPS testing this evening with a friend's equipment and found that the above calculations, resulting in the speedo being some 5% off, are absolutely spot-on. GPS measurements lead to 5% as well.

Very interesting - as surprisingly the speedo error doesn't increase with the faster you go.

At an indicated 229kmh (143mph) the speed (manually) calculated from the gear ratios and tachometer was 218kmh (136mph) or exactly 5% - just like yours through the GPS.

So there we have it - 4x4 speedo error is 5% - I wonder if any vRS owners will have a go now ?!

By the way, I still think that the ride of the 4x4 estate is one of its best features - its really very good for blasting down bumpy, uneven roads - I bet its good for Greece ?!

Indeed, the ride is one of its best features especially here in GR and even more by summer time (beaches and "off road").

As for the accuracy of the speedo and tyre size, the numbers I posted were measured with a tyre size of 195/65R15 (the pre 2002 4x4), and while the 205/55R16 is equivalent, it's not identical size and it might give actually higher numbers (i.e closer to those indicated by the speedo) turning the error to lower values.

As for the accuracy of the speedo and tyre size, the numbers I posted were measured with a tyre size of 195/65R15 (the pre 2002 4x4), and while the 205/55R16 is equivalent, it's not identical size and it might give actually higher numbers (i.e closer to those indicated by the speedo) turning the error to lower values.

That's what I would have thought too, but to my surprise the 195/65R15 has a larger circumference than the 205/55R16, namely 1993.34mm v 1985.17mm. This equates to a difference of -0.41% and would be reflected in a (true) speed of 69.71mph for an indicated 70mph (assuming no speedo error with 195/65R15s). Those figures are courtesy of The Wheel and Tyre Bible here which should be accessible once our web links are transferred from the old site.

We live and learn........

Time to measure the dogs' circumferences........

Originally posted by DGW in this post

...but to my surprise the 195/65R15 has a larger circumference than the 205/55R16, namely 1993.34mm v 1985.17mm. This equates to a difference of -0.41% and would be reflected in a (true) speed of 69.71mph for an indicated 70mph

So if I understand you correctly and Otheos' comment, the 4x4 speedo seems to be surprisingly accurate (or at least what I've tried to measure) ?