Greg,
Well if you feel even with 16" wheels you won't achieve an accurate speedo, then for arguments sake, that may bring into question the accuracy of GPS technology, given my speedo reads the same speed as the GPS digital readout running 15" wheels with a worn diameter of 706mm.
My original 14" Michelin X tyres are 676mm worn, an exact diameter difference of 30mm from the above 15" wheels. I accept the speedo would read fast with the 14" wheels and my 15" wheels appear to attain a correct speedo reading ... or else the speedo is still wrong if one can't believe the GPS readout.
Begs the question ... if one accepts that GPS readout is accurate, how come you are having difficulty getting accuracy even with 16" wheels (assuming the O/A diameter is larger)? What's so different about your syncro setup to cause this dilemma?
Cheers.
Ken
To: Syncro_T3_Australia@yahoogroups.com
From: gregespo73@yahoo.com
Date: Thu, 30 Dec 2010 14:10:13 -0800
Subject: RE: [Syncro_T3_Australia] Instrument Cluster
Ken as has already been pointed out a manufacturer will always make there speedos read high to avoid litigation. I do not know the VW equation of the top of my head but the BMW one is @ 100kmh minus 7kmh then plus or minus 4kmh. So your speedo is good if at 100kmh true your speedo reads 89kmh to 97kmh. Japanese cars tend to be more accurate at around 3 to 4kmh low. My bus reads a whole 10kmh fast with tyres slightly larger than stock. Even when I fit 16"s I wont bridge this gap, unless of course I cut out the guards, fit BIG tyres and a 3.0L tdi!!! Greg E
--- On Thu, 30/12/10, Ken Garratt <unclekenz@hotmail.com> wrote:
From: Ken Garratt <unclekenz@hotmail.com>
Subject: RE: [Syncro_T3_Australia] Instrument Cluster
To: "Syncro _T3_Australia forum" <syncro_t3_australia@yahoogroups.com>
Received: Thursday, 30 December, 2010, 10:43 PM
Les,
Just love opening cans of worms .....
re: "This further means that anyone who has fitted a larger wheel/tyre size can get a correct speedo reading by fitting the gear appropriate to the wheel/tyre size."
Case in point, my present tyres are a slightly larger diameter than the BFG T/A 215 75 R15s.
So from what you say above I can only assume but find it very hard to believe, that a previous owner of my syncro had the speedo drive gearing changed to suit 15" wheels and tyres, given it is my experience that my GPS readout and the speedo read exactly the same whilst travelling.
So given I find it hard to believe the gearing was changed and knowing the syncro originally had 14" wheels and michelin tyres, why is my speedo reading correctly?
A happy new year conundrum.
Cheers.
Ken
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