View Full Version : Speedo Calibration
Hi guys, long time reader... (great forum!)
Ive just had 17" wheels put on the car (from the stock 14") and i think its put the speedo out of whack, anyone know where i can get the speedometer re-calibrated?
Dont want to stand there arguing with the boys in blue about how i WASN'T speeding :P
Cheers guys
syncro
23-11-2006, 04:39 PM
Hi guys, long time reader... (great forum!)
Ive just had 17" wheels put on the car (from the stock 14") and i think its put the speedo out of whack, anyone know where i can get the speedometer re-calibrated?
Dont want to stand there arguing with the boys in blue about how i WASN'T speeding :P
Cheers guys
Check it first as it may be within limits.
They normally read about 5-10% fast.
How would i go about checking it? (forgive me ignorance :P)
i normally do about 550 nearly 600km a full tank and now im doing only 450 or so a tank? This happened immediately after i had changed the wheels. Would anything else be wrong?
golf3
23-11-2006, 04:59 PM
Heavier wheels = more unsprung weight = more power required to make them/the car move = more petrol = more $$$
Arhh, yes.. i thought about that, but these wheels are actually lighter and the car feels like its driving with greater ease
golf3
23-11-2006, 05:21 PM
Rolling diameter will be different every time you change tyres, even when still the stock size of 185/60R14. Tyres are all different. However, with 17's you should be running a 205/40R17 or similar to keep diameter to around the same...
However, with 17's you should be running a 205/40R17 or similar to keep diameter to around the same...
I am running 205/40R17's
But im pretty sure they're a larger diameter tyre, and that would make the difference im guessing/hoping, otherwise im baffled and my car is in desperate need of a tune-up
syncro
23-11-2006, 05:35 PM
Check your odometer on the M5 speedo check.
Drive next to someone and have a look at their speedo.
Drive really fast through a speed camera and wait for the photo.
Use a GPS.
golf3
23-11-2006, 06:19 PM
http://www.miata.net/garage/tirecalc.html
Using stock of 185/60R14 to 205/40R17
Speedo reading with non stock tyre is 3.2% too slow...
You are actually doing 61.9mph when the speedo reads 60
peedman
23-11-2006, 06:28 PM
It cant be out by more than 10kmph which is the legal boundaries by which ur speedo can be incorrect by. That might have changed tho.
syncro
23-11-2006, 06:52 PM
It cant be out by more than 10kmph which is the legal boundaries by which ur speedo can be incorrect by. That might have changed tho.
No it's 10%.
peedman
23-11-2006, 08:10 PM
Hehehe my bad. I really wouldnt worry about it, you would think that if u were doing 61kmph in a 60 zone the coppers wouldnt pull you over.
silverMK1
24-11-2006, 11:24 AM
im getting new tires put on my car and there 2cm smaller profile and the mechanic said my speedo would be out... sounds to me it wont be more than 10% so sould i get it checked out or dont worry about it:?
rayray086
24-11-2006, 01:21 PM
Try playing around with this program:
http://members.optusnet.com.au/~sthchan/tiresizer.zip
It's similar to the link that golf3 posted.
Another tyre sizer program thingy can be found at http://www.1010tires.com/TireSizeCalculator.asp?action=submit
All three are very useful, and should give you an idea of what size tyres you should really be using to keep the same overall diameter (or something close enough to it).
syncro
24-11-2006, 02:33 PM
Legally, replacement tyres should be no larger than 15mm more than any optional fitment.
A Dunlop 205/55x16 may not be the same diameter as a Toyo 205/55x16.
All good info!... however, this still doesn't account for my 80-100km loss per full tank of fuel.
According to a -3.2% differential with the new tyres - i should only be losing around about 25-35kms per tank..
hmm, well i've just refuelled again, we'll see how far this gets me
syncro
24-11-2006, 05:54 PM
The tyres may have more rolling resistance.
peedman
24-11-2006, 06:13 PM
Yeah I sorta agree. What tyre pressure you running? But 80-100kms is pretty high if its just bad tyres tho :?
Hoyhoy.
For a start legal tolerances are now only 3%.
So if you want to find your true reading, you will have to ring around in Syd. Look in the yellow pages under speedometers. I done this on the Gold Coast & on the third Ph. call found a bloke who would check the speedo with a mobile GPS plotter which is accurate. Got it in writing, cost me $30.00.
syncro
24-11-2006, 08:00 PM
Hoyhoy.
For a start legal tolerances are now only 3%.
I have never seen a speedo that is within 3%.
Read this thread;
http://forums.vwvortex.com/zerothread?id=2938451
I have never seen a speedo that is within 3%.
Read this thread;
http://forums.vwvortex.com/zerothread?id=2938451
Hoyhoy.
Try telling the cops.
syncro
24-11-2006, 08:44 PM
Hoyhoy.
For a start legal tolerances are now only 3%.
So if you want to find your true reading, you will have to ring around in Syd. Look in the yellow pages under speedometers. I done this on the Gold Coast & on the third Ph. call found a bloke who would check the speedo with a mobile GPS plotter which is accurate. Got it in writing, cost me $30.00.
Well how close was yours?
I have never seen a speedo that is within 3%.
Read this thread;
http://forums.vwvortex.com/zerothread?id=2938451
Hoyhoy.
The wife has a Mazda, not to old but the speedo is spot on.
I was told by the speedometer chap that the Japs & the Aussies have it pretty right, but the Euros are that bit different.
Well how close was yours?
Hoyhoy.
Mine was a 9% over-read, which I told VW who were not interested.
syncro
25-11-2006, 11:06 AM
I was told by the speedometer chap that the Japs & the Aussies have it pretty right, but the Euros are that bit different.
Are you sure he is not talking about odometers?
Are you sure he is not talking about odometers?
Hoyhoy.
This chap said that odometers aren't too far off. It's the speedos that are different.
bombsquad21
02-12-2006, 06:46 PM
Wayz, could it be that once you fitted your 17's your driving became more "spirited"? I know my fuel consumption certainly increased when i fitted mine ;-)
DubSteve
02-12-2006, 09:53 PM
Wayz, could it be that once you fitted your 17's your driving became more "spirited"? I know my fuel consumption certainly increased when i fitted mine ;-)
Yeah the car needs more power to take off.
Spirited yea, but nothing over the top (because my car isn't all the spirity to begin with :( ) hehe
but yes, the wheels are heavier and im sure it sucks more fuel because of that... but i would've never thought i would be getting 100km's less per full tank of fuel!???
i only put in 98ron and i used to get atleast 550km and now its a measley 450-470km's max!
thats harsh! :(
DubSteve
03-12-2006, 12:58 AM
Spirited yea, but nothing over the top (because my car isn't all the spirity to begin with :( ) hehe
but yes, the wheels are heavier and im sure it sucks more fuel because of that... but i would've never thought i would be getting 100km's less per full tank of fuel!???
i only put in 98ron and i used to get atleast 550km and now its a measley 450-470km's max!
thats harsh! :(
Thats still pretty good, Me out of a 60 litre tank I get 350kms :D :D
Thats still pretty good, Me out of a 60 litre tank I get 350kms :D :D
Steve, Is that the typical mileage out of a VR6????
Hope not, cos i wanna get my hands on a vr6! :(
DubSteve
03-12-2006, 06:16 PM
Steve, Is that the typical mileage out of a VR6????
Hope not, cos i wanna get my hands on a vr6! :(
It depends how you drive the car really;). If you drive on the freeway alot then its very fuel efficient, you can get it down to about 7-8 on the MFA. City driving is another story, you average about 12-13 on the MFA. But the car is very hard to drive conservatively because you just want to put your foot on the floor:D.
If you drove it like a learner then you will get about 400 - 450 don't quote me on that in the city i'm talking about. The car is more fun you don't worry about petrol just drive ;)
I drive the car hard usually because the power is great and I'm sure that other vr6 owners can vouch for that.
Haha... for sure mk3vr6!
400-450km for 60ltr tank is pretty good eh :D
but im still stuck on 550km from my 55ltr tank! :( and even more cut that ive spent $$$ on new wheels and gotten less efficiency :P
DubSteve
03-12-2006, 07:16 PM
Haha... for sure mk3vr6!
400-450km for 60ltr tank is pretty good eh :D
but im still stuck on 550km from my 55ltr tank! :( and even more cut that ive spent $$$ on new wheels and gotten less efficiency :P
Thats still heaps good on the fuel consumption alot more than what I get.
Golfer
03-12-2006, 10:21 PM
Ouch!!! With one trip to Brissie a week, then the rest driving to tweed and back (30 k's each way mainly city type driving) i get about 600ks out of my 55l tank. I once got close to 700k's (on the highway) and figured my best economy was about 6.1L/100Kms. Any other Gl owners vouch for this?
Golfer
03-12-2006, 10:34 PM
Mind you, i'm still running the VW steelies... I didn't end up getting my new 17's (A/C pain :mad: )
You'll find the increased rolling diameter puts more strain on the engine, and the load increase on the engine will pretty much ruin your economy... Upside is ur car will look cool :D
Cheers,
John :cool:
Ouch!!! With one trip to Brissie a week, then the rest driving to tweed and back (30 k's each way mainly city type driving) i get about 600ks out of my 55l tank. I once got close to 700k's (on the highway) and figured my best economy was about 6.1L/100Kms. Any other Gl owners vouch for this?
I'll vouch for that, even though im a CL owner!
Went from Sydney to Blue Mts then to the Hunter Valley and back to Sydney on one tank! :)
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