The Truspeed Unit Is Easily Installed In Less Than An Hour And Even Easier To Calibrate. Our math skills have improved over the years as aftermarket tire size offerings have increased. The 35s look like 33s these days, while they used to look monstrous next to the little 31s we ran on our '71 Bronco years back. Nonetheless, we still had to do the math to figure out what the actual speedometer reading was, considering the larger-than-stock tires.
The basic formula for the job goes like this: New tire size divided by old tire size multiplied by speedometer reading equals actual mph. Not that difficult, but it only works for your head. Your vehicle speedometer will still read incorrectly. Now, what if we told you there was a way to calibrate your speedo to the new tire size or gear ratio and, furthermore, be able to recalibrate whenever you go back to the original tire size, all at the flip of a switch? Crazy, huh? That's what we thought. But it's the truth. It's the Superlift TruSpeed Speed Sensor Calibrator, and it takes the fuzzy math out of determining your actual mph.
The TruSpeed unit is available for GM, Ford, Chrysler/Dodge, and Jeep vehicles and can calibrate the speedometer using three different methods depending on the situation and vehicle application. The methods include calibrating by tire size change, gear ratio change, tire size and gear ratio change, and percentage change. Once installed on the vehicle, you can use the supplied charts to determine how to adjust the TruSpeed to gain actual mph. The unit is calibrated by using a special key (included) to turn adjustment screws, which can be turned at any time, with the ignition on or off, and even while the vehicle is moving (though we don't suggest attempting this if you're sitting in the driver seat).
Another plus of the TruSpeed is that it gives you the option of running two different size tire sets while maintaining the proper calibration. This is achieved by the flip of a switch from Setting 1 to Setting 2. This is a great feature because it offers the ease of not having to recalibrate when you swap from summer to winter tires or run larger meats on the trail than you do for daily driving. Superlift recommends verifying and fine-tuning the calibration after adjusting the screws. This can done by testdriving the vehicle using highway mile markers for reference, even though the most accurate method is to compare the speedo reading with that of a Global Positioning System (GPS).
The TruSpeed Speed Sensor Calibrator from Superlift Suspension Systems is the new wave in speedometer correction. It alters the speed signal at its source, so speedo reading, ABS function, and transmission shift points can be corrected.
Although we'll probably still use the old math skills from time to time to figure gear ratios and whatnot, counting our toes to get the mph is a thing of the past. The TruSpeed unit is easily installed in less than an hour and even easier to calibrate. The only downside we know of is that we can't feel like we're going 90 in the slow lane anymore, while we're actually going 55. We'll get used to it, though. You will, too.