Full Skinny on Hypertech In-Line Speedomoter Calibrator

I've run across a lot of threads that mention the Hypertech In-Line Speedomoter Calibrator on this site, but none that went in to full detail around the results with different settings or that really provided insights on the persistent discrepancy between the speedometer and odometer.

So, I thought I'd post what I worked through in my testing...

My 2009 Tacoma TRD Offroad came with 265/70R16's and, like most folks on this forum, I noticed the speedometer was corrected to near perfection when I went to 265/75R16's. At the same time, my odometer seemed off (short) with that change which led me to believe the speedometer and odometer were somehow governed differently. I then went to 255/85R16's and purchased a Hypertech 730107 to see how accurate I could get the speedometer and odometer to be.

The Hypertech application for programing the in-line speedometer calibrator allows you to use tire sizes or to program your own tire height/diameter in inches. You first reference the tire size you're going from and then the tire size you are going to in order to arrive at a ratio of adjustment. This ends up being the number the module uses to adjust what your speedometer and odometer receive. You cannot adjust the ratio directly, but can manipulate it by providing different measurements.

Here are the tests I ran with my Cooper Discover ST Max tires in 255/85R16...

First: Test from original factory size to new 33" Coopers

265/70R16 (30.6") to 255/85R16 (33.1") = 1.0803 Ratio
- Speedomoter and odomoter back to factory behavior
- Speed off (fast) by about 3-4mph at 65mph
- Odomoter off (long) by about 0.20 (two tenths) a mile over 15 miles
* The truck makes you think you're going faster than you are and getting better gas mileage than you are.

Second: Test from old plus size to new 33" Coopers

265/75R16 (31.6") to 255/85R16 (33.1") = 1.0447 Ratio
- Speedomoter and odomoter back to 265/75R16 behavior
- Speedomoter extremely close to perfect
- Odomoter off (short) by about 0.40 (four tenths) a mile over 15 miles
* The truck reflects your actual speed, but makes you think you're getting much worse gas mileage than you are.

Third: Test from original factory size to manipulated size

265/70R16 (30.6") to 285/75R16 (32.8") = 1.0726 Ratio
- Speedomoter only off (fast) by 2-3mph at 65mph
- Odomoter off (long) by slightly less than .10 (one tenth) a mile over 15 miles
* The truck makes you think you're going a little faster than you are and getting slightly better gas mileage than you are.

Fourth: Test from original factory size in inches to manipulated size in inches

(size not used) 30.6" to (size not used) 32.5" = 1.0620 Ratio
- Speedomoter only off (fast) by 1-2mph at 65mph
- Odomoter off (short) by slighly less than .10 (one tenth) a mile over 15 miles
* The truck makes you think you're going slighty faster than you are and getting slightly worse gas milage than you are.

I ended up going with that fourth test result with the 1.0620 ratio for a couple of reasons...

1: I decided the odometer being more accurate to me mattered most and this ratio gave me a great compromise between speedomoter accuracy and odometer accuracy.

2: The speedometer is quite close and I think it being slightly fast is okay partly because, if the speed of the vehicle is something that could impact transmission shift points, the speedo bein slightly fast would serve to help the motor and transmission a little with the loss of torque due to the oversized tires by causing earlier downshifts and later upshifts.

3: The odomoter is extremely close and I think it being slightly short is okay partly because, as the tires wear over time, it will only become more accurate and partly because, if anything, my estimated gas mileage will be slightly better than what I calculate for each tank.

To address a few things spotted randomly in other threads...

The speedometer and odometer are fed from the same source and cannot be manipulated separately, but are much closer in calibration than most seem to think including myself until I di this testing.

I don't understand why people are frustrated by the inability to manually adjust the ratio in the Hypertech application when you can make the same minor adjustments just by tweaking the tire measurements you provide.

I did not have manipulate the gear ratio data and left those at "stock", but am pretty sure that will work for anyone with a V6 gen2 Tacoma as they all appear to have 3.73 gears, but don't quote me on that.

Cheers!

 

Nice first post . Welcome to TW

 

I just got mine delivered yesterday. I will be going from DuraTrac 265/70-17s (31.7) to ST MAXX 285/70-17s (32.99) on my 09 Sport. I was going over your findings, the 1.0447 ratio put your speedometer was the closest and with the 1.062 your odometer was the closest, I decided to average the two and go with something in the 1.053 range. Ill do a follow up in a few weeks after testing.

 

Requires reasoning and experimentation, plus a bit of math skills. And it's not instant gratification like pushing a button. Too many can't even think outside of 'miles per tank', and forget they could apply the % delta of the tire sizes to a manual MPG calculation themselves.

In addition, it's not a cheap part, so the expectation would be it should be 'easier'.

I too would tinker to have the ODO be the most accurate, as all service items and MPG calcs come from that. A simple Garmin will display your MPH for you to keep you legal.

Nice first post!

Welcome!

 

Thank you for your thoughts on this. I have one in the garage waiting to be installed. Your notes here will probably shorten my install time!

Nice first post!

 

Thanks for all of the feedback folks. Even before joining, I got a lot of value out of some of the threads I dug up on the site. So, the goal was to give something back on a subject I hadn't seen covered as well as I would have liked. It's particularly awesome to hear someone else like @Scott B. might actually benefit from the post and save themselves some time or at least know what they are getting in to. @Clearwater Bill, you make a good point about the price of the Hypertech leading one to believe it would be easier to plug in your own ratios. I sort of lowered my expectations based on the feedback from others and ended up pleasantly surprised. I can easily understand having the opposite experience if you trust the reviews and use the cost as a rough indication of quality. I also didn't fully install it until AFTER I tested different configurations so that I could easily unplug, reprogram, and plug-back-in the module between tests. So, that reduced my frustration level quite a bit.

I've had it installed for a little over a week now and it's working great. The speedometer ended up showing around 2mph slow at 75mph and the odometer ended up being about .10 (one tenth) long at around 32 miles. So, for the Cooper Discover ST Max in 255/85R16 (actual measurement of 33.1") at least, the use of 32.5" from factory to arrive at the 1.0620 ratio ended up being about as close to perfect as I felt like I could get it.

 

In case these are helpful...
This is how I had the Hypertech "installed" for testing. You can see the actual control module in the top left. It was loose there and could be unplugged, removed, reprogrammed, and plugged back in for testing.

After all of the testing and programming was complete, I mounted the Hypertech PCB and controller module to the back of gauge cluster with double sided mounting tape.
It all went in without bunching or pinching and the clearance was good.

 

Took me a second to figure out how to connect it to my pc but once I got the right settings programmed works like a charm. Thanks OP for write up, got it installed in one try.

 

Here's my issue with the Hypertech:
When the weather drops below 50°F my speedometer and odometer don't work unless I turn off the truck and turn it back on.

Anyone else have the same problem? If so, have you found a way to solve the issue?

 

Nope. Haven’t seen weather above 35F in weeks. Was just -5 last week. No problems noted.

 

Hmmm... Interesting. Mine has done it every winter. I've had it on my truck a good 4 years or so.

 

Sub

 

I know most don't remember. Back in the day, when calibrating your speedo to different sized tires or gear change, you changed a little gear that plugged in from the outside of the trans., with a 7/16" wrench & a pair of pliers. 20 min. & a $7 dollar gear and all was well. Odometer worked off speedometer so when one was corrected, the other was also corrected. Sure is hard to accept the expense & aggravation of today. I'm old school, I can't imagine why something that worked great for 100 yrs. so cheap & simple has got to be changed to something so expensive & so complicated & hasn't improved anything. Sorry, I just needed to get that off my chest.

 

Because it's better. It's new, it's technology, so it has to be better.

In case anyone could not tell, the preceding was sarcasm. You see, I am still waiting for the paperless office that was promised 30+ years ago, back when computers were going to make our lives so much better.

I much prefer swapping gear also. My HyperLink still does not read correctly.

 

How do you adjust for bigger tires AND different gears?

 

Don't get the Hypertech. I was sent two units and they didn't work. Troubleshooted with Hypertech for a few days and could not get the truck to recognize the calibrator. You program it via your computer prior to installing. Look into the Dakota Digital unit. @EatSleepTacos wrote an install/how to a while back, not to mention its cheaper.

$114 Dakota Digital SGI-100BT Universal Speedometer and Tachometer Interface

https://www.amazon.com/Dakota-Digital-SGI-100BT-Speedometer-Tachometer/dp/B07YQ7P8SN

 

I AGREE.

I swapped the little gear in my 1994 pickup. Took me literally 10 mins and less than 10 dollars and worked great for 10 years before I sold the truck.

Now I've got a 2012 Tacoma that is about 3-5 mph off at 65. It annoys me, but I can't bring myself to one of these solutions.

I was not aware of the Dakota Digital solution. What is the ballpark install time on these and reliability? Now that I am thinking about it again and am in need of a project... I will probably convince myself I have to do this...

 

So how'd it go?

 

https://www.tacomaworld.com/threads...-an-easy-alternative-to-the-hypertech.622313/

 

I was able go play around with the numbers enough to got my speedometer zeroed in. I ended up @ 1.038.