Page 1 of 1
Speedo drive
Posted: Sat Dec 12, 2020 2:32 pm
by Liam86223
Hi guys I’ve got a 1.8 gt-2 5 speed and when driving it seems to show 5 mph slower than it’s displaying, so I found out it has a white speedo drive and when looking online it’s supposed to have a red one.
I’ve bought a circlip and a red drive but the new drive won’t stay on the end of the cable and it won’t fit with the circlip so I’m stuck.
Any suggestions would be really appreciated.
Re: Speedo drive
Posted: Sat Dec 12, 2020 4:13 pm
by Kdc169
You have to get the circ clip, in the groove first, then push the cog over it.. try a bit of grease.. soak the cog in warmish water to help it pass over the circ clip. Cold days dont help.
Still even with different drive you may find discrepancies in speedo, due to wheel and tyre ratios. See attached.
End of the day if shows 75 and your doing 70 on motorway you keep your licence. 1 of the reasons why 10% +2mph rule was there, due to mechanical measurement, now you just plug in to live OBD and can see speed,done by ECU. Depending on quality of GPS you may also find difficult to check calibration, so i guess rolling road or MOT bay.
speedo.jpg
speedo 1.jpg
Re: Speedo drive
Posted: Sat Dec 12, 2020 5:25 pm
by C 20 CCO
Haynes manual shows what needs to be done, if you have one. I swapped my drive gear many moons ago and managed it with no problem.
Re: Speedo drive
Posted: Sat Dec 12, 2020 9:21 pm
by Liam86223
Thank you for the advice I’ve got the circlip but when I push it on it doesn’t seem to want to go all the way it has a nipple in the middle of the circlip, unless I’ve bought the wrong one
Re: Speedo drive
Posted: Sun Dec 13, 2020 12:14 pm
by Blueshark
Re: Speedo drive
Posted: Sun Dec 13, 2020 4:49 pm
by mark1gls
Most VWs speedo over read by about 5 mph, I’ve had a 2002 vw polo over read as did a 2005 VW Touran, 3 different transporter vans all over read... I guess it’s a bit like VWs claims of fuel economy... just a little out
Re: Speedo drive
Posted: Mon Dec 14, 2020 11:32 am
by GT_II
This is not just a VW thIng. Speedos are allowed to over-read by up to 10%, so most are designed to over-read by around 5% to provide a safety margin. Add in a couple of % for tyre tread wear and you're over-reading by 5 mph at 70 mph.
Re: Speedo drive
Posted: Fri Jan 29, 2021 7:02 am
by RussGLAuto
The GL was 8 MPH over reading when I first got it. The tyres were 20 years old. Changed them for new and guess what, now back to VW 'standard' 5 MPH over reading...
Old perished rubber makes a difference...