How to correct speedometer for taller tires

dlhovland

Well-known member
Joined
Jun 17, 2012
Location
Yakima
TDI
2015 golf Tdi manual transmission. Wife's car a 2014 toured v6 Tdi
I currently have 225 45 17 tires on my 2013 JSW TDI. I am going to 225 55 17 tires this week. The tire guid shows my speedometer will be of by 5 miles per hour at 70 miles per hour. Can I adjust this with my Ross tea. Thanks in advance.
David H
 

JELLOWSUBMARINE

Veteran Member
Joined
Mar 3, 2014
Location
yes
TDI
2011 Jetta Sportwagen, 6M, red/tan, navi, pano, 83 5m diesel pickup, 82 p/u trailer,.04 5.5 TDI Passat wagon (gone), 80,81,82 diesel p/u (gone), 80,82 sportruck (gone), 59 passthru bus (long gone), 79&87 westy (gone), 57 baja bug (long gone), 73 914
No sure if your 2013 is the same as my 2011, but on my dash display it gives the option for 5% larger tire adjust.
 

dlhovland

Well-known member
Joined
Jun 17, 2012
Location
Yakima
TDI
2015 golf Tdi manual transmission. Wife's car a 2014 toured v6 Tdi
Your speedo is probably already reading "too fast" at 70mph, and "even more too fast" at 80 and 90, so bigger tires will make your speedo more accurate.
My digital speedometer reads one mile per hour fast at 70 miles per hour. Checked with gps.
my turbo diesel site has a write up on this if any body need help with this
David
 

TurboABA

Veteran Member
Joined
Jul 24, 2010
Location
Kitchener, ON
TDI
2010 Jetta 6spd MT, 2014 Touareg Execline
I currently have 225 45 17 tires on my 2013 JSW TDI. I am going to 225 55 17 tires this week. The tire guid shows my speedometer will be of by 5 miles per hour at 70 miles per hour. Can I adjust this with my Ross tea. Thanks in advance.
David H
 

Jetta_Pilot

Top Post Dawg
Joined
Apr 14, 2005
Location
West Hill, Ont. Nov.2nd in Mexico till April 27th
TDI
2015 Passat Highline TDI Candy White (SEL Premium) long gone 2002 Jetta TDI
VW for some reason, ostensibly to avoid speeding tickets, makes the speedometer read for example 60 Mph when you are really going less, up to 5% less at Kph or a different percentage at Mph, but your odometer will be correct.
When you install larger tires, as I have also done, the speedometer will be closer to accurate but now your odometer will be off.

To the best of my knowledge there is no way to adjust for that.
 

hskrdu

Top Post Dawg
Joined
Oct 17, 2003
Location
Maryland and New England
TDI
2003 Golf GLS 4D 5M, 2015 GSW SE 6M
It's not a exactly VW issue. As has been discussed in prior threads, VW follows the Euro Union regulations (#39) which (in fewer words) states that the speedo can never read slower than actual speed. The end result is an odometer that is spot-on, but a speedo that reads high. It does seem more pronounced for German manufacturers, but that may be anecdotal. IME, it seems more notable in later year cars, but that may be a result of higher speeds than when I had a Rabbit or an air cooled Beetle.
 
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