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Discussion Starter · #1 ·
Hey guys, I just finished up with a customer of mine who has a C70 and looking to get into a XC70 and she told me that the only thing she does not like about Volvo is that they design the speedometer to read eight kph faster than you are actually travelling!??! Is this true? She took her car in after being on the freeway with her husband driving his car, and everyone was passing her including her husband. She phoned him on his cell to tell him to quit speeding, and he said he was on cruise(he drives Acura). She was on cruise as well. The service department told her Volvo does this because of safety? <IMG NAME="icon" SRC="http://www.vwvortex.com/zeroforum_graphics/screwy.gif" BORDER="0"> This makes no sense. I did not know what to say. Anyone heard of this before?
 

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<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Dill</b> »</i></TD></TR><TR><TD CLASS="quote"> design the speedometer to read eight kph faster </TD></TR></TABLE><p>Completely false!<p>EDIT: Typo <BR><BR>
<i>Modified by Copeland at 3:50 PM 8-30-2006</i>
 

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I can PROMISE you, that Volvo has not done this...<p>And you would be down right <IMG NAME="icon" SRC="http://www.vwvortex.com/zeroforum_graphics/screwy.gif" BORDER="0"> to think its true! Some sort of speed sensor is off on the C70 or her husband's Acura.
 

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Re: (Copeland)

a few time ago i got the carpc installed and started messing around with the gps. <p>The speedometer in my case was off by 2-3kph. There are a number of different things that influence this off reading:<p>- tire pressure<br>- temperature<br>- tire wear<p>The car has to give and aprox value of the reality and compensate for the factors mentioned above. No car has a 100% correct speedometer. it's normal to have a few km's discrepancy. I'd say about 5kph max.. <p>It's likely that the acura has the speedometer reading and aprox value so .... tell the lady to stop complaining <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/smile.gif" BORDER="0">
 

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My GPS does the same thing, but I think its the GPS.<p>I will ask one of my cop friends to clock me, and see the results while using speed control, GPS, and his radar.
 

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Re: Speedometer off (Dills)

That used to be true for many cars, but with the advent of the electronic speedo, it's no longer the case. Volvos are generally spot-on in my experience, within .5%.<p>You can check yourself, by resetting your trip odometer against highway mileposts. After 10 or 100 miles, check the error.<p>If you have changed your tires, it's possible for the dealer to tune the speedo by the way. There is a fairly wide range of adjustability, expressed in inches of travel per revolution.<p>Tom.
 

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Re: (Copeland)

You need to quit replying to my comments, you never have anything positive to say, I wasnt sure so I asked. You must know everything.
 

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What are you talking about, I answered your previous thread in the most kind way....as well as this thread..... <IMG NAME="icon" SRC="http://www.vwvortex.com/zeroforum_graphics/screwy.gif" BORDER="0"><p>I had also let you know that my intentions were not hostile.....<p>Previous Thread: <A HREF="http://forums.swedespeed.com/zerothread?id=64603" TARGET="_blank">http://forums.swedespeed.com/zerothread?id=64603</A>
 

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Another thread...<p><A HREF="http://forums.swedespeed.com/zerothread?id=64548" TARGET="_blank">http://forums.swedespeed.com/zerothread?id=64548</A><p>Sorry Dills, I wasnt aware that I was being negative in any of my responses.... <IMG NAME="icon" SRC="http://www.vwvortex.com/zeroforum_graphics/screwy.gif" BORDER="0">
 

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Re: (Copeland)

I have GPS speedo meter on my car and when driving about 100km/h in gps my S40 speedo has about 108. Sounds true to me.
 

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I've checked my S40 against the local PD "your speed is:" signs and it seems to be within a few mph. <p>If someone changed their tire diameter the speedo could be way off though. But obviously that's not Volvo's fault.<p>As a side note, many (almost all, as far as I know) motorcycles read about 10% high from the factory so it's not illegal or anything.
 

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Re: Speedometer off (Dills)

I've checked mine a number of times - against highway mile markers - up to 75 mile intervals to minimize error. Mine is 2% off, I get the same answer, within 0.2 % all the time. <br>But, mine reads such that I'm traveling faster than the speedometer reads (so I'm getting about 0.6 better mpg that I calc. from the odometer <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/smile.gif" BORDER="0"> ).<p>I have the 205/50R17 OE Michelin tires.<p>I was surprised. I beleive this much error is more that can be attributed to tire diameters being being different batch to batch.
 

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Re: Speedometer off (steve909)

The 16" OEM tires (836 revs/mile) vs the 17" (828 revs/mile) are off by about 1%.<p>I will guess that the speedo is calibrated for 16's, and not corrected for 17's at the factory. This accounts for the the ever-so-slightly higher reading of your car. Mine was spot-on (16's). Our XC90 was the same.<p><A HREF="http://www.tirerack.com/tires/Spec.jsp?make=Michelin&model=Energy+MXV4+S8&partnum=055VR6MXV4ES8" TARGET="_blank">Tirerack MXV 16" specs</A><br><A HREF="http://www.tirerack.com/tires/Spec.jsp?make=Michelin&model=Pilot+HX+MXM4&partnum=05VR7MXM4HX" TARGET="_blank">Tirerack MXM 17" specs</A><p>Tom.
 

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Re: Speedometer off (tmtalpey)

I know that the service techs can do something to your ECU based on your tire size because Volvo does offer OEM 16, 17, and 18" wheels and they want to be as accurate as possible. That being said....I would rather leave mine wrong so I always have a way to get out of a ticket <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/smile.gif" BORDER="0"><p>p.s. I have 18" wheels and have been pulled twice in the past 6months for going 78 in a 65 when the speedo read 74 in a 65 so.... Oh and I also noticed that I was never pulled when I had the 16" rims on....go figure <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/rolleyes.gif" BORDER="0">
 

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Re: Speedometer off (Tarheelvolvo)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Tarheelvolvo</b> »</i></TD></TR><TR><TD CLASS="quote">I know that the service techs can do something to your ECU based on your tire size </TD></TR></TABLE><br>Yes, I mentioned that above. It's actually a BCM parameter that is reprogrammed. The Brake Controller Module is what counts revolutions and converts to wheel speed. Many other systems watch this (e.g. the speedo, the engine, the geartronic, the AWD unit, etc), so it's semi-important that it be at least close.<p>Tom.
 

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this is def. NOT true. i have confirmed it with two GPS units.
 

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Re: Speedometer off (Tarheelvolvo)

Car and Driver did a story a while back about the optimistic speedos in European cars. According to regulation, European should <i>never</i> read low, even if the owner fit aftermarket wheels of different size that could alter speedometer accuracy. Hence they are made to read high. See below:<p><i><br>The European regulation, ECE-R 39, is more concise, stating essentially that the speed indicated must never be lower than the true speed or higher by more than one-tenth of true speed plus four kilometers per hour (79.5 mph at a true 70). Never low. Not even if somebody swaps a big set of 285/35R-18s for stock 255/45R-16s.<p>There's your explanation of high-reading European speedometers, with the highest readings on Porsches and BMWs that are most likely to lure owners inclined to fool with tire sizes. Of course, only the speedometer must conform. Trip computers are free to report average speed honestly. Try setting your BMW or Porsche cruise control and then resetting the average-speed function. Unless you've screwed up the tires, the trip computer should show a nearly accurate reading. Even General Motors, whose domestic speedometers are the best, must skew its readings slightly high on vehicles exported to Europe.</i><p>From <A HREF="http://www.caranddriver.com/features/1906/speedometer-scandal-page1.html" TARGET="_blank">http://www.caranddriver.com/fe....html</A>
 
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