Unexpected high odometer

[chimoman]

Just checked against the highway markers. Mine was speeding up the further I went. Pretty much right off the first 2 km. I had gone 20km according to the Trans Canada markers but 23 km by my odometer. Hmmmmmmmm. I'm going to test again this afternoon. If it turns out to be that way again then I will make a video and post it up. I went from 20's to 17's for the winter. I have also put 43 000 km on in 11 mos. Seems a little much to me for the amount of driving I have been doing.

 

[peterk9]

Just checked against the highway markers. Mine was speeding up the further I went. Pretty much right off the first 2 km. I had gone 20km according to the Trans Canada markers but 23 km by my odometer. Hmmmmmmmm. I'm going to test again this afternoon. If it turns out to be that way again then I will make a video and post it up. I went from 20's to 17's for the winter. I have also put 43 000 km on in 11 mos. Seems a little much to me for the amount of driving I have been doing.

43,000 km in 11 months! I'm just below 7,700 km in that time frame! That includes 2600 km driving back and forth due to my part time job. That contract ended early June and I'm now fully retired. I doubt I'll have more than 20-25,000 km on it when the 4 year lease is up! The 17's will add a little to the actual distance driven but not 3 km in a 20 km drive. With the 17's on, I believe mine adds just a little over 0.1 km in a 14 km drive. That is the distance from the service station I usually fill up at to my home.

Peter

 

[stripesace]

I'm I am not the only one who thinks there odom is racking up miles faster than the ones actually driven. I haven't done any GPS, known approximate distance checking. I drive a lot but I've never put more than 16k a year on a car... Definitely going to happen this year.

 

[CulturalInfidel]

smaller wheels/tires will definitely cause the odometer to rack up miles slightly faster... but it depends on the overall size of the tire... If you know the actual tire size (compared to the OE tire size) then some very simple math will allow you to figure out how much error is due to the different tires.

 

[peterk9]

smaller wheels/tires will definitely cause the odometer to rack up miles slightly faster... but it depends on the overall size of the tire... If you know the actual tire size (compared to the OE tire size) then some very simple math will allow you to figure out how much error is due to the different tires.

For chimoman and myself the Speedometer Difference is 1.689% too fast. Revs per Mile: 692.6 (20" OEM) vs Revs per Mile: 704.3 (17" Winter rims).
This does not account for the extra mileage chimoman is accumulating. As I indicated in my post, with the 17" wheels my usual 14 km trip (OEM) turns out to be just over 14.1 km while chimoman, using the highway markers for a 20 km distance seems to be putting on 23.0 km.

I use the tire size calculator on www.1010tires.com to get all my numbers. You can enter your OEM or current tire size and up to 4 additional sizes and get all the figures you need. It will also show you which tires are available in those sizes.

Peter

 

[colintrax]

I can't believe this went 2 pages before you said you put on smaller tires. Smaller tires make the speedo read faster. Just the same as bigger tires make it read slower. Stick to the stock size
BTW, no speedo is completely accurate. Nor are tires actually the same size as it says on the sidewall.

 

[peterk9]

I can't believe this went 2 pages before you said you put on smaller tires. Smaller tires make the speedo read faster. Just the same as bigger tires make it read slower. Stick to the stock size
BTW, no speedo is completely accurate. Nor are tires actually the same size as it says on the sidewall.

not sure who are referring to with your post. The original poster did not mention 17" tires at all. If you are referring to chimoman, he did mention it in today's post which is the first one he posted noting the mileage difference.
Both he and I switched to the smaller 17' base model steel wheels for Winter tires. Our 17" Winter tires were around $169 ea. A 20" would be around $400 ea, with a very limited selection, never mind trying to find a 20" steel wheel. We are both aware that the 17" will produce different readings compared to the 20". This was all researched months ago before we bought them. Having said that, the difference in speed is minimal. 60 mph will read 61 mph.
None of this accounts for his jump in mileage. I do not have the same problem and yet we are both running the same Winter wheel (Ford base model) and tire package.

Peter

 

[JDraper]

What size are the 17" tires that were put on for the winter? (width and ratio)

 

[peterk9]

what size are the 17" tires that were put on for the winter? (width and ratio)

245/65r17

 

[JDraper]

Hmm..I get a little different change than you got. Using BF Goodrich's tire calculator, the 20" OEM's come in at 684 Revs/mile and the winter tires come in at 704 revs/mile for a 2.84% difference.

Still not enough to account for the difference in km's shown.

 

[chimoman]

I tested again this afternoon, 3 times using highway markers. The first test from my post I said I was adding an extra 3km. The second test wasn't as bad. Over 30 km markers my odometers ready way 32.6 an additonal 2.6km. Same as the second one on the way back. Both tests I reset my trip odometer to 0 and lined the nose of the vehicle even with the marker. What has me worried is it seems to increase the further you go. the first km was dead on then it gradually got worse. The further I drove the further off the odometer went. I only went 30km. Over a 400 to 500km trip I feel this could compound. Strange for sure. I will talk with the service dept tomorrow as I have an appointment. Tire sizes shouldn't create this much of a difference. Especially when the said they calibrated for the different tire size. At this rate, I'm adding approx 7-9km/100km. (based on the 30km tests.) However, I feel that it may be upward of 10 as the distances increase more sharply toward the end of the 30km. At this rate I'm adding around a 100km/1000. Not being a math wiz this is an additional 4000km on my odometer and that may be worse if it is speeding up the longer you travel.

 

[peterk9]

Hmm..I get a little different change than you got. Using BF Goodrich's tire calculator, the 20" OEM's come in at 684 Revs/mile and the winter tires come in at 704 revs/mile for a 2.84% difference.

Still not enough to account for the difference in km's shown.

In the 255/50 size on the BFGoodrich.com site I couldn't find anything larger than a 16 size.
The tirerack.com shows the revs/mile for the 255/50R20 OEM tire to be 691 which is very close to what I got on the 1010tires.com site (692).
But as you said, non of this accounts for what chimoman and a few other members are seeing when the odometer seems to randomly add distance.

Peter

 

[yow04xplr]

I think there is definitely an error in how the speedo is calibrated on these vehicles. Maybe we could get the members here who have a GPS to check if there is a difference between the reading on the speedometer and the reading on the GPS. If enough of us do this, it will give us an idea whether there is a trend here or not. As previously posted, my speedo reads 2-3 kph fast at 120kph with the stock 20's, and 4-5 kph fast with the stock 17's.

Martin V

 

[peterk9]

I think there is definitely an error in how the speedo is calibrated on these vehicles. Maybe we could get the members here who have a GPS to check if there is a difference between the reading on the speedometer and the reading on the GPS. If enough of us do this, it will give us an idea whether there is a trend here or not. As previously posted, my speedo reads 2-3 kph fast at 120kph with the stock 20's, and 4-5 kph fast with the stock 17's.

Martin V

Hi Martin. If you are running the 245/65R17 in place of the 20's like I am, then your 4-5 kph faster reading at 120kph is acturate if the speedo is off 2-3 kph with the OEM wheels. When going down to the 17's, the speedo will read 1.689% faster which is what yours does based on the reading you get with the 20" wheels. So the only problem here is the reading with the OEM wheels. I don't really know how acturate speedometers usually are but I would assume it is not abnormal for them to be off slightly.

Peter

 

[dutchman71]

8000 miles since August on my stock Limited with 20" wheels, way more than ususal, but I don't have any scientific evidence. Next longer trip I will compare to my GPS...

Hope this really isn't an issue..

 

[yow04xplr]

I don't really know how acturate speedometers usually are but I would assume it is not abnormal for them to be off slightly.

Peter

Peter,

Both my 04 Explorer and my wife's Highlander are spot on!

Martin V

 

[harlenm]

I have a handheld GPS, running stock 20" wheels. Will test tonight and see what speedometer reads vs GPS.

 

[JDraper]

Just FYI, my truck seems to be right on the money with mileage, so I don't think it's a systemic problem.

 

[peterk9]

Just FYI, my truck seems to be right on the money with mileage, so I don't think it's a systemic problem.

I believe mine is also correct only because it seems to indicate distances very close to my previous '09 Highlander which had 19" wheels.

Peter

 

[cnsheets]

On my way to work this morning, I set the trip odometer to zero, then set my destination for work on the NAV(EX Built in NAV).

NAV said I was 24 miles from my destination. When I got to work, I looked at the trip odometer, it read 23.9

I then used google maps on a PC to route the same route with the same start and end points. It said destination was 23.9


This was only one test, but everything seemed to match up well.