Speedometer Correction Alternative (With a bonus)

I noticed this has been a hot topic on the boards and I wanted to share the cheap and functional solution I discovered. I recently purchased a blue tooth OBD2 module off of Amazon. This is the exact one I bought made by Veepeak:

$32 Veepeak OBDCheck BLE Bluetooth OBD II Scanner Car Check Engine Light Code Reader, Auto Dual Mode Bluetooth Diagnostic Scan Tool for iOS & Android

https://www.amazon.com/dp/B073XKQQQW?ref=ppx_yo2ov_dt_b_product_details

It cost me a whopping 25 dollars. This module works with just about any application you can download for both android and Iphone. I went with OBD Fusion which cost me another 10 bucks. I went this route because of the good reviews and robust functionality of the app.

I can confirm that the module and app both work flawlessly on the Gen 3 platform. The application allows for various parameter's to be viewed real time(to include boost), and also allows you to alter the speed (in the app) to compensate for a larger tire. Tire size corrections are made in the settings menu, vehicle editor, and all the way at the bottom in the table titled "vehicle speed scale factor." I'm running a 285/75R18 (35" tire) and have the scale set to 1.16 and it's spot on with my GPS speed reading now. It alters the baseline speed using percentages rather than static number changes. This allows the change to reflect the correct speed no matter how fast you are going. You'll have to play with it in order to get it dialed in for your tire, but 1.15 is a good place to start for a 35. Note, this does not alter the vehicles speedometer. The corrected speed is only present in the application. I don't have an issue with this as the mileage is ticking on slower, so I'm getting the "extended warranty." The app is also fully customizable. I am using my phone as a digital gauge cluster and have my boost, corrected speed, coolant temp, oil temp, battery voltage, and torque output all up so I can monitor it. Very pleased with the outcome. I'm working on a phone mount as we speak that I can mount to the tray behind the display and combine a long arm mount with a magnetic docking wireless charger. I have a suction cup mount on the lower corner of the windshield right now. It works, but I don't like the blind spot it creates and I can't stand running a charging cord all the way across the dash. I want to move it next to the display, above the HVAC vent. (and not block the air)

Another alternative I looked at was the Banks IDash gauge. I think it's a neat product and I've spoken with Banks developers multiple times previously about the product. For me, it wasn't worth the 300+ bucks to purchase the IDash particularly because there is no future workings of a compatible Banks tuner for the Tundra. The real selling point for the IDash is It's integrability with other banks products like their version of the "pedal commander" and of course their ECU tuning products. Apparently Toyota is serious about keeping their computers locked down (and everything else) which leaves only piggyback tuners as an option for those that do not wish to void the factory warranty. I hope that the aftermarket industry doesn't take too big of a hit due to this. I was told by my dealer that just adding a 2" front leveling kit to my truck would void the suspension and drivetrain warranty. I know the law requires them to prove that the modification caused the claimed warranty issue, but who's really got the time and resources to fight that battle? I know I do not.

Anyhow, I hope my experimentation and result benefits a few of the forum members here. As much time as I spend on the road I like knowing my speed as well as having the ability to monitor key engine perimeters. You really can't beat 35 bucks, especially since you can move it from vehicle to vehicle, check trouble codes, and all kinds of other stuff. I'll definitely use this set up in my Jeep when I hit the rocks next trip.

 

Does the app change the calibration permanently? Or do you need to do this every time you drive the vehicle?

 

Title is a bit misleading imo, it's not really a speedometer correction but just displaying the correct speed on your phone. There's some other options too: there are free standalone speedometer apps, and usually a GPS speed option in the OBD apps I've used so you don't need to do a correction factor. Doesnt hurt to have more sensor data always being displayed though!

 

Any changes you make in the app stay put unless you go in and change them.

 

There are a bunch of free apps that work with the OBD2 module as well. The reason I went the module route vs. a stand alone GPS app is lag. There is zero lag with the module where as using an app/gps (in my case I tried my Navionics app), there was substantial lag depending on how the signal was. With that said, there may be an app that does nothing but track speed that could be much faster since it won't have as much data moving around as Navionics. I have not done any research on that as of yet. I haven't tried monitoring speed with my Garmin GLO 2 (satellite receiver) linked to my phone, but I imagine it would cut down lag time dramatically on a GPS based app as well.

If you have any application suggestions, please post them up. For overlanding, we use onX Offroad primarily, with the GLO 2 and offline maps, it's a kick ass tool for off grid navigation.

Having sensor access was actually the selling point for me. I cut my teeth rock crawling over 20 years ago. When you drop it in 4L and start creeping up the side of a mountain in 100 degree heat, you really need to have an eye on things. I have all my fluids and vitals on gauges in my JK so I can see problems before they happen. I won't be doing any rock crawling in the Tundra, but it may very well see some overlanding at some point. Installing gauges in the jeep sucked. It wasn't hard, just time consuming. Being married, kids, work, time is a premium for me. Being able to plug in a module and be up and running with live vitals on the truck was awesome and cheap compared to proper gauges. We spend a lot of time traveling when we can, so having accurate speed readings is very important to me. These old country towns over my way that have one stop light and the only place to get food is the gas station, the police will write you a ticket for going 2 mph over. (especially if you have out of state plates)

I do value your input however. I'm going to update the title of the post to be more specific.

 

Has anyone figured out an actual speedometer correction yet? I’m shocked Toyota can’t just let you type in your wheel size and fix the issue

 

You'd think that they'd facilitate this for the TRD lift. This is why I decided to stay with OEM wheel size for now, even though I'd like to go with 35's (33's just don't do the lift justice).

 

What is wrong with Waze? It's free on apple and Android car play, it gives gps speed and current speed limits. It functions natively to your infotainment screen. Sometimes my tundra reads speed signs and says I can go 100 in a 15 lol

 

The odometer will read less miles than actually traveled with larger tires. Some may consider that a perk, but I prefer accurate miles for recordkeeping and maintenance.

 

Huh someone says this doesn't adjust anything except the correct speed mph on the app/phone - not on your vehicle so I don't understand what your trying to explain. No app is needed if you just use Waze via android or apple car play to show correct mph/speedo that is not displayed on your speedo dash.

Also still waiting on a custom gen3 tundra torque layout, at least that app works with whatever Bluetooth OBD2 dongle. Been using custom layout for my ecodiesel ram showing dpf % and Regen cycles. And yes you can adjust for tire and speedo as well. Also you can run torque lite for free but has some limitations, it's the #1 paid app for auto/vehicle communications in Google play store for android, I think the 3x ram and ecodiesel forums vetted the obd fusion app and everyone went with torque due to sharing the custom layout, but maybe if you get ppl to use obd fusion here maybe it will catch on

 

Sorry was supposed to reply to the OP's statement about the odometer, but for some reason I quoted you instead.

 

To be fair the actual motion of all the parts is still "accurate". You drove 5000 miles, odometer says 4900, but the parts rotated as if they did 4900 miles. You could argue that the parts were stressed as if they went 5000 miles because the moment arm is a linear change with the diameter, but that doesn't compensate for inertia or other non linear variables as tire size increases so a moot point. Food for thought.

 

Agreed. Have you stayed with the stock Falken Wildpeaks?

 

Someone has to crack the programming of the ABS ECU. The factory tire size is stored in the memory. I have an ABS ecu from a 2011 Tundra on my workbench. Locating the data storage section and reprograming it are not an easy task. Something no one has accomplished yet.

Probably need an expert in imbedded system to read the microchip. Then you have to identify/locate the data that actually represent the tire size. Then a way to reprogram the data.

Need someone on the inside at Toyota to give us a little "help"...

 

Sorry for the really long delay. I got mine with the Nitto Ridge Grappler option; been pretty happy with them, but still want to switch to 285/65 R20s once (if) the speedometer/odometer issue gets worked out.

 

I have just been using the 5% difference with mine. I just add 3 mph to my speed if I am doing 60 mph on the speedo I am actually doing 63 mph.

5% is the difference between 265 and 295 in the tire sizing. 35" tires would probably be closer to 7% difference over stock.

This percentage of extra miles will not show up on the odometer so I will be missing those miles off the total. I can't see Toyota allowing access to changing this in the software. A programer might be able to crack it but that would be a costly endeavour.

There may also be a possibility of accessing the sending unit if it is a gear driven system and have a new gear made to change the ratio. If the signal comes from the ABS system, that might be more of a challenge. I am not too sure where the input signal is coming from but finding that out would be helpful to know if this can be done mechanically.