SPEDOMETER RE-CAL

Okay, so before everyone jumps my shit about searching the forum-

I've searched and searched. Everyone says "buy bigger tires, your spedometer will be more accurate."


Well, I got 35's and let me tell you, the Texas Hwy Patrol disagrees- my bigger tires apparently say I go much MUCH faster.

Anyways- long story- does anyone know a way to re-progam my spedometer to be accurate? Im talking like something that lets me input my tire dimensions and then it knows how to re-cal my spedometer to reflect accurate speed.

I dont own a Garmin so I dont want to do this "compare to a GPS" unit BS.


Thanks for you help... oh and F#$( the texas highway patrol.

 

Might we just attack you for other items then?

1. Spelling "Speedometer" wrong
2. Using unnecessary profanity
3. Your misguided hatred for the police who serve and protect you daily
4. Your ignorance of the use of Tire Calculators which are all over the internet and help to calculate the effect on actual speed that each different tire size will have on your particular vehicle? (Google "Tire Calculator", they are a big help)
5. Generalizing that "EVERYONE says buy bigger tires, your speedometer will be more accurate". This should be re-written to "my idiot friends say..."

There's my help. Blunt but useful.

 

From clagary at that... Awsome... Im no help. But subbing for a real answer.

 

Answer:
Yes

Putting larger diameter tires on any vehicle will affect the speedometer and odometer readings. If you know the revolutions per mile for the original tires and the larger tires, you could calculate the speed difference. If they are already on the vehicle, you can also drive down the highway, set the speed at 60 MPH and measure the time it takes to drive between mile markers. One mile at 60 MPH takes 60 seconds. If it is not 60 seconds between mile markers, the difference is the speedometer error. Answer

For instance if your tires are 10% larger than the car thinks. Therefore, you travel 10% more than your car recognizes. This has two effects: Your actual speed is 10% MORE than what your speedometer is reflecting. (When your speedometer reads 60, you are actually traveling 66) 10=11, 40=44, 100=110 etc.

Your actual mileage is 10% MORE than what your odometer is reflecting. (When your odometer reads 100 miles, you have actually traveled 110)
So when you see a cop doing a speed trap, remember to slow down accordingly.
When you sell your car, don't forget to disclose that you have larger tires and that the odometer should read more miles than it does.

I don't know how they calibrate the speedometer these days. They used to swap the driven gear in the transmission. Contact Toyota or a good tire shop.

 

Theres a device you can plug in i believe its called hypertech. I dont remember how much they run though.

 

f the hwy Patrol because they gave you a ticket that you deserved?

 

Na he didn't deserve it. Someone on the internet said bigger tires would make his spedometer more accurate. Can't fault him.

 

http://www.amazon.com/Hypertech-730...r-2005-2010/dp/compatibility-chart/B001G9AMES

 

This. You have to pull out your instrument cluster to install it, but it's pretty straightforward, but make doubly sure you follow the directions carefully. It is possible to install the plugs wrong/backwards.

 

Speaking from experience there?

 

Of course a Garmin costs the same or less with no install, and does a hell of a lot more than display the correct mph.

But OP doesn't want that BS.

 

I used a "Speedohealer" on my motorcycles, most recently on my Ducati. Perhaps there is a plug from the speed sensor that can be used? I wonder if they do car/truck applications. Worth checking

 

So first off- I owe an apology. I can tell from some of the replies that I "offended" some of you. If that's the case I'm sorry, but I didn't use any profanity. I had a long day and posted the question after searching a long time on the Internet for answers with no success so I was frustrated and the Internet doesn't always communicate clearly- I.e. my sarcasm and frustration.

Yes, I'm not a fan of the Texas highway patrol because their organization is worthless. I've had to call their offices 11 times and they still can't tell me how many points will be assessed for this violation.

Comments regarding if they serve and protect me can be discussed in a different forum.

To those who addressed my question even after seeming so ornery- thank you, I appreciate it!!

And to the grammar nazis- thnk U 4 bein on top if dat! I shuld tipe wif spell check on

 

I would just get an ultraguage and calibrate it. Much cheaper and will tell you lots of other things like fuel economy, and pretty much all the other sensor readings from the engine. It's what I use.

http://www.ultra-gauge.com/ultragauge/index.htm