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Learn & Test: How to Calibrate Speedometer for Bigger Tires

Noticed that your speedometer is off after installing new tires? Well, you need to learn how to calibrate speedometer for bigger tires. Hold up. It’s not as hard as you might think. You just need a speedometer calibrator and an app on your phone.

At most, you might spend 30 minutes setting everything up. Still, it’s pretty easy, and you don’t need to leave it up to a certified professional.

That being said, below, we’ll cover every step you need to adjust your speedometer.

What is a Speedometer?

A speedometer is just a gauge that picks up your speed when your car is in motion. This device uses a needle that either goes up or down.

As this needle goes up or down, it indicates your current speed.

This is a must for all vehicles. Otherwise, you wouldn’t know the speed of your car.

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Why You Should Recalibrate Your Speedometer

Understanding how to calibrate a speedometer for bigger tires is simple, but if you don’t want to, here are some reasons why it is worth your time and money:

Reckless Driving

The first reason you need to recalibrate your speedometer is simple: if the speedometer is off, it’s pretty hard to tell your current speed.

And while some drivers might be able to get away with it, there’s a high chance you could get in trouble if your speedometer is no longer working.

For example, you might lose control over your vehicle

Furthermore, it’s seriously annoying to look at the speedometer and not tell the actual speed.

It is Illegal

Check your local laws to find out whether it is legal to drive with a broken speedometer. However, in many places, it is against the law to drive with a damaged speedometer.

There’s not much to it other than not being able to tell what speed you’re driving at. This is dangerous and unethical.

Sure, you might never get caught, but the moment a police officers finds out, you might not be off the hook anymore.

It is Hard To Sell

Want to get a new vehicle but need to sell your old car? Well, you might want to think twice. You see, it is hard to sell a vehicle with a damaged speedometer.

There’s no way to tell how many mileages you’ve got on your car, which drivers need to know before they spend any money on your vehicle.

This is useful for things like warranties and other parts of your car.

Also, it’s a little bit scummy to sell your car with a broken speedometer. There’s a reason why it’s illegal to drive a vehicle with a broken speedometer.

It’s a Must After Getting Bigger Or Smaller Tires

As you might have noticed, it is necessary to learn how to adjust speedometer after getting bigger tires.

But many drivers don’t know that it’s also a must to change the speedometer after installing smaller tires.

It throws off your speedometer just like bigger tires do. This also holds true if you lift your truck.

5 Signs Your Speedometer Cable Is No Longer Working

Like we said, if your speedometer is acting up, it is mainly due to bigger or smaller tires.

But if you suspect that there’s something fishy going on, then there’s a high chance your speedometer cable is not working.

Speedometer Does Not Pick Up Any Speed

An easy and common way to tell there’s something wrong with the speedometer is when it doesn’t move at all.

The needle inside the gauge should either move up and down as you’re going down the road.

If it’s not moving at all, perhaps the speedometer cable is no longer working and needs to be replaced as soon as possible.

Weird Noises

If your speedometer cable is acting up, it will make weird noises when the vehicle is in motion. This noise could also come from the needle going up and down.

So, take some time out of your day and do some digging until you find the culprit.

As a rule of thumb, the speedometer itself never stops working. Instead, the wires are responsible for these problems.

Speedometer Randomly Goes Up And Down

Your speedometer should go up and down smoothly. It should never go from 30 to 70 mph instantly.

Instead, it should slowly go from 30, 31, and 32. So, if you noticed that the needle randomly jumps as you’re driving, it means the speedometer cable is the culprit.

Check Engine Light Is On

Noticed that your check engine light comes on? Then there’s a problem with the speedometer sensor.

You see, your speedometer sensor is inside the transmission and attaches to the driveshaft.

If this sensor is not working anymore, the check engine light will come on. Even if that’s not your problem, the check engine light always means trouble.

Car Loses Power

This might sound silly, but if the speedometer sensor quits working, your car will lose power.

But why is that? Your fuel injection, or EFI for short, delivers fuel to the engine, and one of the sensors responsible for this job is the speedometer sensor.

So, you can probably see why it’d be a problem to have a faulty speedometer sensor.

Unfortunately, this is a severe problem that needs to be addressed as soon as possible. Otherwise, it could damage other parts of your vehicle.

How to Calibrate Your Speedometer After Getting Bigger Tires

Now that you know why you should adjust your speedometer, here’s how to calibrate speedometer for bigger tires like a professional:

1. What You Will Need

There are two tools you will need to recalibrate your speedometer. First, get a speedometer calibrator.

This is the most essential tool you need to get. Otherwise, you’re not going to able to readjust your speedometer.

Second, grab your phone and download any speedometer app. That way, you’ll know whether this procedure worked or not.

As to which app you should download, we would recommend Waze. But feel free to download any app you find.

2. Set Up Your Speedometer Calibrator

Your speedometer calibrator should come with an ODB2 port and a USB cable.

That said, you have to download the latest software update from your manufacturer’s website.

To do this, go to your manufacturer’s website and download the latest update.

After that, connect your USB to the speedometer and the other end of the cable to your computer.

Now run the program you just downloaded. The app will run and install the latest firmware update.

Do not disconnect the speedometer calibrator as it is installing all the necessary packages for the app to run.

When it’s done, you should get a pop-up saying that it’s safe to disconnect the device from your computer.

3. Plug Your Speedometer Into the OBD2 Port

Here’s how to adjust speedometer for larger tires: First, grab your OBD2 cable and plug it into the OBD2 port.

If you don’t know where this port is, it’s usually located underneath the dash. Now plug the other end of the cable into your speedometer calibrator.

The device should now begin to boot up, and then it should display a screen with the following text: “Turn the key to the on position, but do not start the vehicle.” Do as it says, and then move onto the next steps.

4. Press Y to Move On

The screen will display information about your vehicle after it has started. At some point, the device will tell you to press “Y” to continue.

When that happens, the device will notice that the tire height has been changed from the original and let the driver know. When that screen pops up, press “Y” to move on.

5. Input Your New Tire Height

You now have to press the up and down arrows to input the new height. That said, press the up or down arrow several times until you get your new height.

For example, if the tires are 30 inches, insert 30 inches. After that, press “Y” to save the current data.

6. Input Your New Axle Ratio

Once again, if the axle ratio has been changed from the original, insert the new axle ratio input using the up or down arrows. Finally, if you have an automatic transmission, press “Y.”

7. Begin Programming

After inputting both the new tire height and axle ratio, press “Y” to begin the programming process, when your device is setting everything up, please do not disconnect the connector.

This might take some time. So, hang in there as the computer is taking care of everything. At some point, the device should tell you to turn the key off for 30 seconds.

After that, press “Y” and unplug the cable.

8. Start The Car

Technically, everything should now be working, but we like to play it safe. Remember the app we talked about earlier? Well, open it up and then start up your vehicle.

That said, here’s how to calibrate speedometer for larger tires: make sure that the speedometer in the dash matches the speedometer in the GPS on your phone.

However, keep in mind that it might be slightly off. It isn’t perfect, but it’s more than enough to point you in the right direction.

Got stuck somewhere? Then here’s a simple video for this job:

How Much Does it Cost to Adjust a Speedometer?

Upon looking up some places and averaging out the cost for this job, we’ve concluded that the average price goes from $70 to $80.

This is a quick and easy job and doesn’t take much time.

We’d say you’re better off getting a speedometer calibrator and doing this job yourself.

It’s a little bit more expensive to get one of these devices, but it’s worth the money if you plan on adding bigger tires in the future.

Frequently Asked Questions (FAQs)

Feeling confused after going through our how to calibrate speedometer with bigger tires guide? If that’s the case, check this section for more info:

Can I calibrate my speedometer for larger tires?

Yes, you can adjust your speedometer for larger tires. You just need to get a speedometer calibrator.

Plug it into your OBD2 port, follow every single step the device shows, and you’re good to go.

Does increasing tire size affect the odometer?

Yes, getting bigger tires will throw off your speedometer. Instead, it will read at a slower speed than you’re driving at.

Also, smaller tires can cause your odometer to read at a faster speed. So, you have to adjust the odometer to get rid of this problem.

Can you reset your speedometer?

No, you cannot reset your speedometer. It is illegal and unethical. It’s not like you can fool everybody and expect drivers to believe you’ve never reset your speedometer.

They can tell. Even if you’re installing a new engine, you still can’t reset your speedometer.

How to know if my speedometer is broken?

A simple way to tell if the speedometer is broken is when it doesn’t register any speed. Even if you added bigger tires, it should still register some speed.

Also, if you hear weird noises coming from the dashboard, there’s a high chance the speedometer is no longer working.

Conclusion

See? It doesn’t take much time to learn how to calibrate speedometer for bigger tires.

To recap, you need a speedometer calibrator and a speedometer app. This app will use your GPS to measure your speed and display it on your phone.

We need this app to find out if the adjustment worked out. But other than that extra step, we still think it is easy.

We know some drivers just don’t mind, but it can be dangerous to drive with a broken speedometer, as we explained at the beginning.

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