Infiniti Q50 Forum banner
1 - 20 of 30 Posts

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #1 · (Edited)
Hi all,

I've seen a couple of post skirting around this issue, but not really addressing it.

My 2018 Q50 RS is just under 10% out (too high) on the Analogue speedo -

  1. Various GPS units confirmed (first discovered when being followed by friends wondering why I was driving so much below the posted limit everywhere)
  2. Infinti have left the UK / Europe - My local Main-dealer Nissan garage confirm that CONSULT (?) console shows Transmission and Wheel Senor speeds are correct - Speedo is out
  3. Tyres are almost new and correct size
If I drive faster to compensate, I risk putting 10% more miles on my car over ownership? Unless the car takes mileage from Transmission / Wheel Sensors
It's really annoying as I'm never 100% sure of the speed I am doing
Nissan have no idea where to start to resolve this problem!

Any suggestions from you smart lot would be much appreciated

Bob
 

·
Registered
2016 Hybrid 3.5 SportTech RWD
Joined
·
942 Posts
If your speedo shows (too) low speed you'd go faster than allowed. I think your speedo shows more than real speed, 10% too high? Then it's additionally not good for you mileage if the source is the same (also 10% too high)...
 

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #3 ·
If your speedo shows (too) low speed you'd go faster than allowed. I think your speedo shows more than real speed, 10% too high? Then it's additionally not good for you mileage if the source is the same (also 10% too high)...
DeeCee! Well spotted! You are of course correct. I meant higher
I will edit my post now!

Just need to know how to fix it now
I have no issues as a speedo being a few % out... I know this is normal but at almost 10%, it's just annoying!
 

·
Registered
Joined
·
4,130 Posts
Do those new tires have the same revs per mile as the OEM ones? I'd think they would almost need to be a different size to be out by that much but check.
 

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #5 ·
Hi Rpiotro

The tyres on the car of the originals and only have a few MM wear so they are OEM
I've never heard of a rev per mile statement? As long as they are the same circumference, all should be okay +/- a % for wear

We know from CONSULT console that the Transmission Sensor and ABS Sensors are both correct - so the tyres are correct and the speedo wrong

Can the speedo be calibrated by software?

Bob
 

·
Registered
Joined
·
5,653 Posts
Hi Rpiotro

The tyres on the car of the originals and only have a few MM wear so they are OEM
I've never heard of a rev per mile statement? As long as they are the same circumference, all should be okay +/- a % for wear

We know from CONSULT console that the Transmission Sensor and ABS Sensors are both correct - so the tyres are correct and the speedo wrong

Can the speedo be calibrated by software?

Bob
On older cars you should have been able to adjust the speedometer, I've never performed the service myself however and I suspect
it would involve removing the gauge cluster if its a Analog readout.

If its Digital readout then you'd probably need a dealership level consult tool.
 

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #7 ·
On older cars you should have been able to adjust the speedometer, I've never performed the service myself however and I suspect
it would involve removing the gauge cluster if its a Analog readout.

If its Digital readout then you'd probably need a dealership level consult tool.
Thanks Clan!

My car is a 2017 and has an analogue dial only. The car is still under warranty so I think I will try and claim for a new component
The dealership say that in consult, they can see the Transmission and ABS Senors read the same and correct, but they too, were unsure of where to do next.
I said I would as all you super brainy types!

Bob
 

·
Registered
Joined
·
190 Posts
If you set the cruise control, does it put you at the right speed? Also the angle you are looking at the dash matters. At 6'5", the left half of the speedo looks slower than it actually is to me. If your seat is low/short driver it will appear higher instead.
 

·
Registered
Joined
·
5,653 Posts
Thanks Clan!

My car is a 2017 and has an analogue dial only. The car is still under warranty so I think I will try and claim for a new component
The dealership say that in consult, they can see the Transmission and ABS Senors read the same and correct, but they too, were unsure of where to do next.
I said I would as all you super brainy types!

Bob
Hmmm sounds like the Dial itself may just need to be calibrated, which I'm sure is possible if they remove the gauge cluster.
But it may just be easier to replace the unit, in any case good luck with the swap sir and let us know how/when they have it resolved.
 

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #10 ·
If you set the cruise control, does it put you at the right speed? Also the angle you are looking at the dash matters. At 6'5", the left half of the speedo looks slower than it actually is to me. If your seat is low/short driver it will appear higher instead.
Hi Call;

The Cruise control test is a good idea but at the stage I think it would just be another way of proving what I think I know.
I'm 6' 2" and my wife is 5' - we both can clearly see the speedo is about 10% out

My main dealer Nissan have also confirmed that the Transmission and ABS Sensor readings are the same and correct against GPS, but the speedo is out
They are stumped as to what to do and are suggesting a warranty replace of the speedo but they suggested or rather we agreed, to ask the forum to see if the Speedo can be calibrated via software?

Bob
 

·
Registered
2017 Q50 3.0 T Sport
Joined
·
83 Posts
Discussion Starter · #11 ·
Hmmm sounds like the Dial itself may just need to be calibrated, which I'm sure is possible if they remove the gauge cluster.
But it may just be easier to replace the unit, in any case good luck with the swap sir and let us know how/when they have it resolved.
Thanks buddy, will let you all know

Bob
 

·
Registered
Joined
·
3,635 Posts
Hi Rpiotro

The tyres on the car of the originals and only have a few MM wear so they are OEM
I've never heard of a rev per mile statement? As long as they are the same circumference, all should be okay +/- a % for wear

We know from CONSULT console that the Transmission Sensor and ABS Sensors are both correct - so the tyres are correct and the speedo wrong

Can the speedo be calibrated by software?

Bob
I don't think so but I would probably go with a bit larger tire instead, e.g. 255/40/19 all around. That or staggered with at least 275/35s in the rear.

I've had the OEM 265/35/19 on my previous RWD Q50 and it was off by 2mph @40mph vs radar and GPS reading (dragy). It also accumulated more mileage compared to my other 2 vehicles. Traveling the same distance, I think it was ~0.2 miles more per 8 miles. Just extrapolate that number and you'll see how sooner it'd reach the end of warranty mileage :)
 

·
Registered
Joined
·
5,653 Posts
I don't think so but I would probably go with a bit larger tire instead, e.g. 255/40/19 all around. That or staggered with at least 275/35s in the rear.

I've had the OEM 265/35/19 on my previous RWD Q50 and it was off by 2mph @40mph vs radar and GPS reading (dragy). It also accumulated more mileage compared to my other 2 vehicles. Traveling the same distance, I think it was ~0.2 miles more per 8 miles. Just extrapolate that number and you'll see how sooner it'd reach the end of warranty mileage :)
Huh it never really occurred to me that larger tires would increase the rate you accumulate miles, it makes perfect sense it was just never
a factor I would have considered.

Will keep that in the back of my mind if I ever have a car under warranty. XD
 
  • Like
Reactions: q50adix

·
Super Moderator
Newport, Oregon
Joined
·
12,829 Posts
The speedometer gets its speed signal from the ABS actuator and electric control unit which in turn is getting its signal from the wheel sensors. If you are not showing any DTCs for the ABS actuator and electric control unit, then the speedo is most likely the problem. I don't see any calibration procedure for the speedo in the service manual so it may be that it has to be replaced.
 
  • Like
Reactions: Call4God

·
Registered
2014 3.7, 14 Hybrid S, 17 Silver sport, 17 Red Sport, now 18 Signature.
Joined
·
1,875 Posts
Hey, Bob, I see what you are going through, I had the same problem when I had my Volvo 960, we tried a number of things and ended up changing the cluster, the speedo was faulty. Good luck, have you spoken to Infiniti, what have they said.
 

·
Registered
Joined
·
4,130 Posts
Hi Rpiotro

The tyres on the car of the originals and only have a few MM wear so they are OEM
I've never heard of a rev per mile statement? As long as they are the same circumference, all should be okay +/- a % for wear

We know from CONSULT console that the Transmission Sensor and ABS Sensors are both correct - so the tyres are correct and the speedo wrong

Can the speedo be calibrated by software?

Bob
Revs per mile and loaded radius are both good for comparison purposes. The usually correlate well but RPM is more accurate. I am used to using revs per mile in calculations of the necessary rear axle ratio for for the desired performance in heavy trucks (think 80K lbs GVWR).
Note RPM (revs per mile) on this one for example.

97564
 

·
Registered
Joined
·
3,635 Posts
Huh it never really occurred to me that larger tires would increase the rate you accumulate miles, it makes perfect sense it was just never
a factor I would have considered.

Will keep that in the back of my mind if I ever have a car under warranty. XD
Cool beans. Larger tires have lower rev/mile and effectively changes the overall gear ratio but shouldn't matter IMO. Besides, the 300hp version is already geared a bit taller than the 400hp RS.

I always reset the trip odometer whenever I stop at costco for gas. I noticed the stock tires 265/35s on the Q were logging 7.9-8 miles as soon as I park on my driveway. Whereas my two other vehicles logged 7.6 - 7.7 miles only. Difference was even larger on my daily commute to work.
 

·
Registered
Joined
·
5,653 Posts
Cool beans. Larger tires have lower rev/mile and effectively changes the overall gear ratio but shouldn't matter IMO. Besides, the 300hp version is already geared a bit taller than the 400hp RS.

I always reset the trip odometer whenever I stop at costco for gas. I noticed the stock tires 265/35s on the Q were logging 7.9-8 miles as soon as I park on my driveway. Whereas my two other vehicles logged 7.6 - 7.7 miles only. Difference was even larger on my daily commute to work.
Aye that's a pretty large variance for such a short distance, can't help but wonder if that's one of the reasons why larger and larger tires are on offer
when it was pretty clearly confirmed a few years ago by C&D that after 18in there is few performance benefits.
 
  • Like
Reactions: rpiotro

·
Registered
Joined
·
3,635 Posts
Aye that's a pretty large variance for such a short distance, can't help but wonder if that's one of the reasons why larger and larger tires are on offer
when it was pretty clearly confirmed a few years ago by C&D that after 18in there is few performance benefits.
It may be the same reason why NBA shorts are now longer than they used to in the 70s/80s.
 
1 - 20 of 30 Posts
Top