Does anyone know of a good tool to correct the speedometer? I saw hondadata but I don't think they can correct the speedo variance plus they are expensive. My speedo is off by 2 or 3 mph depending on speed and over the life of the car it translates to about 2,500 extra miles that I dont have. Thanks..

 

As the speed sensor reads revolutions and sends it to the ECM, so I'll say the reading can't be altered, at least in the Honda lineup.
What make/size tires on the car? Get bigger tires.

 

I have the correct size now but in the past i think it is possible the size was incorrect. I will use gps this weekend to check mph. Separately i did see this post below and even though the sensor is is mechanical,, it does transition through the ecu and and tcu and some control circuit.. so who knows if the speedometer can be altered electronically.

VSS - Vehicle Speed Sensor Troubleshoot, Repair, Replace - How To.

 

If it's like a Honda V6 that has a little driveshaft, I would assume a different gear would do the trick, or with Jeeps they make a programmer that can be used to actually add the new tire size into the logic.
I have 245/45-17 tires and the speedo is dead on at 60, at least when they were new.

 

245 45 is not oem. Did you mistake that?

If you read that link.. its not a gear.. its magnetic

 

No mistake. Without looking up specifics, the OE Michelin 235/45-17 were 25.7" tall, same as the aftermarket 245/45-17. As the OE Michelin's were 25.7" I wanted the same height, so 245/45-17 it is.
Actually the OE Michelin's were sold out, no longer available maybe 3 years ago.
The aftermarket 235/45-17 is only 25.3" tall.

 

So, not all 235 45 17s are created equal? Haha

I wonder how they did math in 2005?

 

not all tire manufacturers use the same standard when making tires. I thought this was common knowledge. The only thing that has to be exact is the diameter so a 17" tire has to fit perfectly on a 17" wheel. But when it comes to width, its commonly known that some brands run slightly wider or slightly skinnier.

Its not just 2005, a lot of companies still do that today.

Also keep in mind a new tire will be marginally taller than a used one. 10/32" in tread is actually a noticeable difference

 

I always though 235mm was 235mm. And 45% of 235mm is 45% of 235mm. Yesterday or today. But whatever.

Anyway. Besides all that, Based on what you are saying, If the speedometer WAS correct in 2005 when the tires used to be smaller than today with "a bigger tire" then I should be going faster than what my Speedo says.. not slower. So you are exactly opposite as to what I am saying. I have hankook EVO tires. They are not that old. So I should be going faster than what the speedo reads if they truly did increase the size of 245 35 17.

 

?????????? How can you say the tires were smaller when the 235/45-17 OE Michelin was 25.7" and now the aftermarket then and now is 25.3"? Although only a .4" difference, the new tires are smaller, rotate faster at a given speed, so consequently the speedometer will show faster. OE tires are created by the car manufacturer, tread design, height, etc, and the construction is by the tire producer.

Way back when, there were 3 different Goodyear tires in 205/55-16 used in the new car market as, Mazda, Chrysler & I forget the third, each had a different tread design, but they were all the same model, Gatorbacks.
Here's one, width, the 245/45-17 I just installed on the TL has a tread width of 9.1" while Continental Sport Contact 3 255/40-17 is 8.5"

 

I didn't say the oe was smaller. You did.

 

Right here.. you said the physical size changed.

 

you didnt read my post correctly. I said some manufacturers make them with slight variations, could be bigger or smaller. I never said anything about 2005 standards vs 2014 standards. 235mm may really be anywhere from 225 to 245, again, it all depends on manufacturer.

I've heard the reason for this is when it comes to tracking or autocrossing, sometimes they limit the size, so manufacturers try to cheat by making them with slight variations. But I cannot verify the source of this.

regardless ...what are you using to calculate your real speed? GPS? have you used more than 1 source? Tests need to be done scientifically, Im sure I dont need to explain to you the procedures.

 

Quoteriginally Posted by Turbonut
No mistake. Without looking up specifics, the OE Michelin 235/45-17 were 25.7" tall, same as the aftermarket 245/45-17. As the OE Michelin's were 25.7" I wanted the same height, so 245/45-17 it is.
Actually the OE Michelin's were sold out, no longer available maybe 3 years ago. The aftermarket 235/45-17 is only 25.3" tall.

Maybe I should have used my abacus as I thought 25.7" was greater than 25.3".
Guess in your mind it's not!

 

Honda has always had the speedo read optimistically that is why there is a class action and the warranty milage was increased. Its not just the tires its the computer is erroneous

 

I personally use 245/40/18. I have compared my car speedometer to various gps speeds. It's pretty much within 1mph even at 80+mph

 

I just learned something about these Clusters! I just had my miles corrected on my new TypeS cluster and the guys I spoke to has done many mile updates. (he actually had to remove a chip from the circuit board to reprogram it)...


Anyway, regarding the speedometer variance: I still have a variance with my old cluster vs. the new typeS cluster. I was hoping for a change but the problem remained. I know what you are thinking, "Of course the problem remained Chad!" but hold on a sec. I found out that the problem is not the magnetic pickup sensor or anything related to that pickup system and deliverance to the Cluster. The Problem is inside the Cluster! I made a discovery on the way home this afternoon. When I was driving 70, my gps on my phone said 66/67. And also, I have passed many radars with my old cluster and it too said I was driving about 3 mph slower than the Needle arm on the speedometer. My new cluster is also about 3 or even 4 MPH difference.


This is why I know the problem is inside the cluster. I even called the guy back and he confirmed, the problem is inside the cluster.. And this is why: As I drove back, I held the speed constant and 70 and I reset the digital readout where it says "AVG MPG and AVG MPH". Take special notice the MPH the instant it appears! My needle said exactly 70.. and the instant the digital readout appeared, it said 67!! So there is a variance inside the Cluster! So, I called the guy and told him what it did, and he said YEP! The problem is the stepper motor. Denzo makes this same stepper motor for a tone of cars! And they have been using the same stepper motor for 10 yrs. And truth is, the stepper motor is analog and he said they have a margin of error of about 10% !! I was like Cow! He said you cannot fix that. And if you tried it would cost some bucks and its not easy! He said the best way to fix it, is to remove the needle with a TACH PULLER or TACH Remover (I cant remember the name) and then move the needle by 1 or 2 teeth! But this could cause the needle to sit a bit below the 0mph, but that is not really a problem. I think my needle is slightly above the 0 anyway. So, I think I am going to try it. He said he already removed the needles once, so they will be easier to remove now. So I may not need the Tach Puller. He said use a credit card and a kitchen fork (if you cant find a Tach puller) to pry up on the needle. The credit card is used to lay flat on the face to you don't damage the face cover with the fork.

 

Hold up a sec. I have better instructions. I just made the adjustment on the needle. And you dont need a fork or a credit card or a tach puller. All u need is a small screw driver and pry at the right spot. I have pictures. Will show later.

 

That guy told me to use a fork, but thats too big. Crazy.. Anyways, get a very small screw driver and do this:

 

so that changes the visual indication of your speed but won't alter your odometer reading at all, if the odometer was off then it'll still be off

the speed sensor for the speedometer in the car actually comes off the transmission as the output shaft speed sensor which wired directly into the ECU and the ECU provides cluster input over F-CAN in the car

the wheel speed sensors off the bearings are a part of VSA, not to be confused..

here's some proof of how it's doing it, if read in problems and fixes sometimes people snap an axle.. their indications..

1 - In drive depressing gas pedal the RPMs of the engine raise and the speedometer also raises
2 - Vehicle doesn't move anywhere
3 - Axles are snapped..
4 - replace axles and problem is resolved

So the wheel speed sensors are actually a part of VSA and not the speedo, no way to correct the speedo on these cars unless you changed the output shaft speed sensor or the way it picks up off whatever it picks up off of on the output shaft in the trans, probably just a magnetic pick-up off of something as an inductive proximity sensor

So if hondata can reprogram it that'd be the only way

 

regarding MPH, The digital readout on the info panel, inside the cluster, is correct. So, it leads me to think the odometer is correct. If the MPH NEEDLE is not the same as the readout, and IF it is because it runs from another source (which I have not verified) then my little needle adjustment as shown above will fix it just fine.

 

oic

 

I just noticed in the helm book the vsa sysyem has a speed sensor on each tire. So in my opinion those sensors are used to determine if 1 tire is skidding or lost traction in comparison to the other tires. Like is 1 tire skidding or are more than 1 tire skidding. That information could change how the system responds. I doubt those speed sensors are used to calculate MPH, but that information is not available to me. Only Acura would have the programming software which would show what it does with the information it receives from the sensors. But i know the primary function of the vsa is to control braking in a skid or if 1 tire looses traction.