Recalibrate odometer/speedo for larger tires?

Can this be done? I'm upgrading from 265/70/16 to 265/75/16. It's only an inch greater diameter and speedo errors are almost negligible, but the odometer errors will bug me much more.

Seems like you can update in the navigation system but it sounds like that does nothing for the odometer.

Really wanted to stick with the 265/70s but just couldn't find a tire I wanted in that size. Feel like I'm opening a can of worms here.

 

Sub'd

 

Check with these folks

http://www.hypertech.com/products-speedometer-calibrator.aspx

 

i'm running your set up. imo, it is not worth the price. if you were going 35+ then maybe. just my opinion man

 

Yeah was hoping the dealer or independent mechanic (preferably) can do this. I'll likely only need to do it once if there's no rubbing with these tires (fingers crossed).

 

It's not possible to reprogram it on the Tacoma, you would need to add a module to alter the signal going to the speedometer.

EDIT: See my below post, the speed signal on the 2016+ is actually sent from the Skid Control ECU to the Speedometer via the CAN bus, as such it might be more difficult to alter the signal than it was on 2015 and older trucks.

Jeff

 

you shouldn't have any rubbing. i know lots of people that went 265 and are fine.

 

OVtuning said he can compensate for larger tires built right into his ECU tune.

 

Interesting. I mean I guess it's possible if the Skid Control ECU pulls that calibration data from the Engine ECU, however the Engine ECU is not what sends the speed signal to the gauge cluster, and as far as I know OVtuning isn't tuning the Skid Control ECU.

(Note: The Skid Control ECU does pull some calibration information from the Engine ECU when performing a zero-point or other calibration, but I didn't think this was one of the parameters).

Jeff

 

I'm running 285/75/16 with a 3" lift. According to the flashing speed reminders they setup beside the roads, my speedometer is 2 mph off. I just ignore it. If a cop writes me up for speeding 2 mph then he or she is having a slow day or had a fight with the spouse or something.

 

Cool thanks for the assurance. The stock tires were shit! And I gained a half inch of clearance. Woohoo!

I'm really just concerned about incorrect mileage for service intervals and following detailed directions (e.g drive 4.1 miles and turn left).

I guess if I record my mileage at the tire change I can always calculate true odometer reading.

 

I found with the stock tires the speedo was reading high and then when I went to 265/75-16 it was almost dead accurate. Once I went up to 255/85-16 it started to be off noticeably over 30-35 and obviously got progressively worse until it was off by over 4-5mph at 70mph. Just gauging this from driving past the speed indicator signs on the side of the road.

Edit: I always forget to check if its a 2nd gen or 3rd gen thread . I have a 2nd gen.

 

same same, but different, but still same. you're good

 

check speed with a gps app on your phone. not a map app, but just a standard gps app that gives you velocity, altitude, etc. there are ton's of these for free. I like to use them when I'm on amtrack and trying to see how fast we are going. FYI, I've clocked the regular amtrack at up to 118 mph on straights out of NY pulling into CT and RI which surprised me. Anyway, They tend to refresh faster and be more accurate for speed since they just triangulte a few variables rather than calculating a few variables AND try to graph where you are on a map which causes a bit of a delay if your phone is a little older (like my iphone 5).

I feel like I remember when researching btwn 2nd gen, third gen, types of lift etc, that some 2nd gen guys wrote that speedo did not change on 33 when checking with an accurate gps. Something to the effect that they felt that the truck was designed to have a tolerance up to 33? or something about how maybe the truck was designed for 32/33's?

It was around march of last year that I looked this up so I may be wrong. I'm getting older and my memory is not as accurate. Anyway, check it with a gps app while you are driving.

 

It's even more fun to use your GPS app on an airplane! Can't always get a signal but when in a window seat you sometimes can. I got a GPS watch. Put it in cycling mode and watch it rack up like 8 miles a minute. It's pretty cool. I always try to figure out where I am and once I'm on the ground - and the map loads - it's fun to see how close I was.

 

Another thing you can try is to set both your trip odometer and a gps trip to 0 and then drive. I found that after 200 miles in CO and UT my truck was biased around 2% low. The gps indicated 200 miles while the truck's odometer was around 196 mi. It's good to have relatively straight roads or at least wide turns. Interstates highways are good for this test.

 

OP, Hypertech works. Also, see the link below for a guide as to how much your speedo may be off. Honestly, I have found that mine is always a little fast and a size bigger generally makes it dead on or so negligible until it doesn't matter.
https://www.tacomaworld.com/tirecalc

 

Dead reckoning is always an option. For odometer difference you could drive a controlled route with the current tires. Drive that same route with the new tires. Compare the difference and establish your control number. Lets say you drove 45 miles with the old tires and the distance was 40 miles with the new tires. 40/45= .888... So 40/.888= 45ish.....Magic!

 

Just in case anyone is wondering, the reason why Toyota does not let you easily recalibrate is it throws the Odometer off as well. If they let you recalibrate, you could just tell the vehicle it has 20” tires on it, while keeping stock tires, and when you sell your truck with 300k miles on it, the Odo would only read 200k miles etc. It is for legal reasons it’s locked out.

If you upsize your tires, without recalibration, you are actually reducing the accrued km on the odo, so it is a marginal win for resale.

 

Is this going to be a reality? I know there are big plans.