Speedo correction

Hey guys. What's everyone doing to correct their speedos after gear\tire change? Im running a older 3.0l r150f with a vss on 5.29s and 35" tires. Is there a stock VSS that would get me close enough or do I need to buy a signal converter? Haven't had a chance to test the truck yet to see how badly it's off. It's a 2000 taco is that matters

 

I'm having the same issue. I just went from 4.10's to 4.88's with 35's on my 3.4l. My speedometer is faster than what I'm actually going. So my speedo tells me if I'm traveling at 70mph, my GPS says I'm going 68mph. It was way off before I changed gears. If I was traveling 70, my GPS would read 77mph. Changing gears helped but I want a more accurate reading.

 

2mph seems pretty close to live with.
I just found this https://forum.ih8mud.com/threads/tire-sizes-and-gears.169817/
With 5.29s and 35s I think a vss from a vss for 4.3 gears would be pretty close. 20.78" per rotation vs 20.66" stock. Haven't done the math to see how accurate that would be at highway speeds though ‍♂️

 

This is a great topic, and one I wrestled with as well. Ended up writting up this fun post that outlines the issue and what's happening, and also talks about how to correct it with a new speedo gear.

Speedometers, Odometers, and Gas Mileage - All Lies!


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Part numbers for all speedo gears are in the post above, and here are photos of the change-out process - at least on a '00 3.4l V6.

Replacing the Speedo Gear


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Shout if you've got questions. There are other (electronic) ways to do to this as well, but I've got no experience with them so I'll let others chime in on how to do that.

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Dakota Digital!!!! Absolutely the way to go. Very easy to wire up (4 wires... power, ground, speed sensor in, speed sensor out) and you can fine tune it. If you decide to re gear later or go up tire size again, pull it out of the glove box and make the adjustments with the +/- buttons.

Dakota Digital SGI-5ELatest Design - Universal Speedometer Signal Interface Controller

Dakota Digital SGI-5ELatest Design - Universal Speedometer Signal Interface Controller

https://www.amazon.com/dp/B014N07F8W/ref=cm_sw_r_cp_api_i_TrqLDbVZA24FF

 

I ordered a combo Dakota digital tach\speedo converter. I have a VW turbo diesel swap. I currently have the tach adapter but the combo unit was only $10 more then the speedo converter so hopefully I can sell my old one and recover some of the cost.

Do you remember what wire or wires you use from the VSS for the input signal?

 

I can’t remember at the moment but I’ll be back in town and can get a picture for you then. There was a thread somewhere on here that talked about it too.

 

Would having your speedometer reading a faster speed also effect the true mileage?

 

yes, your odometer won’t read accurately either.

 

so would my odometer show more miles driven or less miles driven. Not sure what the equation would be to calculate it out.

 

thanks for posting this, wish I would've found this years ago!

 

A good way to know is to watch your GPS speed on an app or navigation unit. If your speedo shows slower than the GPS then you’ll rack up “less” miles on the odo. And “more” miles if your speedo shows a higher speed that the GPS (truck thinks you’re covering more ground).

 

If it's reading faster then you are going it'll rack up miles faster then you travel.

My Dakota digital speedo converter showed up on the weekend. Ive installed it but won't have a chance to configure it until my truck is on the road. My Ori shocks should arrive by Friday and then I'll be able to program it pretty soon. Install is fairly straight forward. The green\red (far right when looking at the plug) wire is the signal pulse from the sensor

 

Any recourse on my brand new 2019 SR5? Damn speedo reads 5mph fast at 70-75...

 

I just installed a ‘Hypertech Speedometer Calibrator’. It was a bit speedy at $220 but totally plug and play. You flash the control box via USB and software that you download onto a Windows OS, fill in the blanks (stock tire size, gearing, aftermarket tire size, gearing) and then plug the unit into the back of your speedo gauge.
It works very well.

 

The options discussed earlier were more for first gens, there may be better/different options for later models.

 

thats not too concerning IMO. I really needed it after regearing. It was wayyyy off after new gears.