Mazda 3 inaccurate speedometer reading

[lodi228]

My new Mazda 3s speedometer reading is out by 2 to 3 ks at 60 kph..and 4 to 5 kpm at 80, seems like the higher speed you go the more it is out.
I complained to my dealer but he said it is " in the variation range" and as long as its not reading slower its ok.Anyone else have this problem ?

 

[JEB83]

hi

How did you test your speedo? Just curious.

 

[Cloudland]

thought every car has some speedo error

NZ Autocar use a device called VBOX to test cars, 9 out of 10 cars they tested got it wrong, most shows 100 in the speedo, but actually travelling at 95~99 KM

 

[twilightprotege]

lodi - another new member???? introduce and tell us a bit about yourself

with speedo readings, you'll find that all cars read slightly faster than what they are actually doing. 2-3kph is nothing really, but at 60kph it's a little more than usual. it's normally only 2-3kph at 100kph

 

[NJP5Guy]

Look at it this way...your car has a higher top speed than everyone elses. (2thumbs)

 

[twilightprotege]

maybe not :evilgrin: hehehe

 

[ahb11m]

its normal, if you want it dead on, there are places that will correct this, but mazda will refuse

 

[lodi228]

In Answer...

How did you test your speedo? Just curious.

Jeb,
We first noticed the problem when we were driving the vehicle, it was very noticeable that the car wasnt travelling at the speed that it was indicating.I then had two other cars [ VT Holden & Nissan sedan] travel behind me at speeds of 60ks and 80ks, and they clocked my speed at 2 to 3 under at 60ks and up to 5 under at 80ks, so logically, at 110 ks I would be going quite a deal under what is indicated, another point is that if as stated on here by other posters that all cars are a little under then mine must be accordingly slower than theirs again.
It may not seem a big deal but having to constantly re-calculate your speed is certainly an undesirable situation in a brand new car.
Any suggestions on how to resolve this would be welcome...Cheers !

 

[twilightprotege]

the other cars - were they using the same spec tyres are original and how was their tred? for example, if the commonwhore had 225/50/16 with full tread, it has a diameter of 631mm. if it had 1/2 tread, it has a diameter of 622mm (assuming 9mm thread depth). that can make a bit of difference!

 

[lodi228]

Mazda speedometer reading

Twilight,
Im not a specs or tech-minded person so going into the intricate world of tyre size and tread wear on the other cars that I tested the Mazda against is something that I wont attempt, but thanks for the suggestion !.
But rest assured that the vehicle is indeed showing way over the speed that its actually travelling at....its glaringly noticeable to everyone who has been in the car. Just a sidelight but I have noticed other Mazda Neo 3s travelling below the speed limit and the general traffic flow speed..call that a coincidence maybe but Mazda do most certainly have an issue to address in this particular vehicle...all the service manager I spoke to wanted to do was fob me off with technical jargon ...eg ... after telling me that the allowable variation was up to 10 % ! ...he then rambled on about the precision of the speedometer equipment until I asked the quintessential question .." if they are so precise then how come theres a 10% variation??".
So there you have it...I am currently in a 3 way triangle with myself,Mazda and the dealership///the latest plan is for them to send a rep out and test the car with a GPS system....I trust the GPS doesnt have a 10 % variation !.
I will let you know the results.
Cheers.

 

[twilightprotege]

which dealer have you been dealing with?

i would say that there is what is called a technical service bulletin out about it. it's an unofficial recall. if the customer complains about it then they fix it, otherwise they never mention it to the customer.

i would suggest talking to the sales manager rather than the service ppl. you'll probably get more done if you make a scene in the sales area, esp on busy days like saturday mornings!

 

[Ron3KL]

Us too...

My wife has an SP23 that also seems very s l o w.

After reading lodi228's post, I took it out on to a nearby section of freeway that has 5km marked section for checking speedometers. Travelling at a constant speed and using a stop watch I checked the accuracy of the speedo over several runs. Not as sophisticated as using a GPS perhaps, but both methods rely on the accuracy of the ability of the driver to maintain a constant speed anyway.

The freeway is a 100 km/h zone by the way. So the 5km marked section should take 3 mins, or 180 seconds, at a constant 100 km/h if the speedo is dead accurate. Speed in KPH = Distance(km) / Time Taken(secs) * 3600

At 100 km/h indicated, the SP23 took 191.34 seconds for run 1 and 191.84 seconds for run 2 , in the opposite direction. That's an average speed of 93.9 km/h, or around 6% error.

At 90 km/h indicated, the SP23 took 212.32 seconds for run1 and 212.2 seconds for run 2. That's an average speed of 84.8 km/h, again around 6% error.

I didn't do any slower runs as even at 90 km/h I was being a nuisance in the traffic! (sleep). (And I didn't do any faster runs 'cos there was a radar unit at one end of the run...)

Anyway I think we will be taking this up with our dealer. A 2-3 km/h difference at 100 km/h is acceptable, a 6-7 km/h difference is not.

 

[twilightprotege]

well welcome to the site

yeah that definately doesnt sound good. that's a fair bit out.

another way to double check - how far out was the distance on your speedo compaired to the signs?

 

[Ron3KL]

Good point. What with watching the speedo, the traffic, the signs and starting and stopping the stopwatch I didn't note the odometer...

Next time.

 

[twilightprotege]

with my car i have slightly smaller tyres (by 1.9% - that's the difference between 195/50/16 and 205/45/16) and it's now perfect. 5km of signs, 5km distance travelled according to the odometer. love it.

 

[ahb11m]

hmm yeah, but to check by the odometer, or by the watch its best you have a perfectly straight bit of road, your in the highest gear (which i'm presuming you did) and also no other outside influences.... ie try and find yourself a vacumm...

 

[Ron3KL]

hmm yeah, but to check by the odometer, or by the watch its best you have a perfectly straight bit of road, your in the highest gear (which i'm presuming you did) and also no other outside influences.... ie try and find yourself a vacumm...

That's partly why I did the runs each way, to compensate for those factors. For these purposes I don't need to be super accurate - a 6% error is big enough to be quite noticeable. Around the 'burbs sitting on whatever the current speed limit is in the SP23 attracts a tailgater almost immediately. Slow.

 

[coldie123]

vacuum... lol!

yup like what twilight said, you can adjust your speedo readings by getting bigger or smaller diameter rims/tyres. if you are actually travelling slower than what your speedo is indicating, then get larger diameter tyres. plus it'll look better and help reduce fender gap

mine are 2.5% larger and just within the legal limits of 15mm difference from the stock diameter.

 

[old skool style]

The speedo could be faulty or if it compares to be the same with other cars of the same specs then it is a factory setting. All car manufacturers usually set the speedo to read up to 5 km less than the actual speed of the car. I have no idea why probably to prevent the driver from going over the limit by a few k's because most people drive with the needle right on the marker.