Speedometer Calibration Question

This might be another newbie question, I looked and didnt find anything on the search. Can the speedometer/odometer be recalibrated with bigger tires?

 

Yes, at least it worked for me.

My speedo was about 3 mph over my actual speed. Going from a 265/65R17 tire to a 265/70R17 put my speedo right on my actual speed.

 

no. only way to fix speedo and such is to regear. 4.10s w/ 33 should put you back to oem.(if you have 245s originally)

Rocketball - ?. you actually didnt recalibrate your speedo, just the original error in your speedo was corrected.

 

What do you mean by regear. Could you translate 4.10s, what does that mean? Sorry, i'm kinda new to the forum thing. Thanks

 

no worries. regear means to change the gears in your rear axle to a different ratio. you currently have a 3.73 ratio, meaning it takes 3.73 turns of the driveshaft to equal one full rotation of your rear axle. if you regear to a 3.91 ratio with 33" tires, you will get back to nearly the same speed reading as you did with your original setup.

now, regearing is expensive. your best bet would be to find a complete third member from a previous gen tacoma (95-04) and drop that in. if you dont want that, you will have to purchase a 3.91 gear set and have them installed. installation can run anywhere from $300 to $1000 for a single axle and im sure gears are over $200 (havent priced them, but this is my guess).

make sense?

 

which is not necessary for 33's on a v6 and it will most likely put ur speedo closer to actual than b4

 

^ your right actually (edited my original post), im thinking of my situation, where my truck came stock with 245s.

 

Thanks for the info. Sounds like a PITA. Is there a computer that can tell u ur actual speed with the biger tires?

 

So ur telling me that if I put on 33's, my speed will be more acurate than my stock tires? 33's is what I was planning on going with anyways. Hope this is true.

 

not really a pain. if you have the money or mechanic knowledge its not bad at all.

there are no computers that will correct this to my knowledge. is a calculator that you can play with different tire sizes and it will tell you all the dimensions and % difference.

EDIT: and after playing around with it, i take back what i posted earlier...33s and stock gears will have your speedo read slightly slow, but you should be ok.

 

In the 2nd Gen 4x4 up to +5% on the speedometer/odometer is normal, stock from the factory.

Going up from the stock 31" to 32" tires usually corrects the discrepency just about perfectly...

 

The end result is the same.

 

with my 285/70/17s (perfect 33" OD) my speedo is 3-4 MPH slow. Thats quite a bit off. The odometer is usually about 30 miles off at a fill up too.

 

brian thats what mine is off at 65, so iguess it just flips which way its off

 

hypertechs inline speedometer calibrator module will make the adjustment. All you do is program in the new tire size and connect it to the speedometer to fix any discrepencies created by the tire size or the rear gear ratios

 

I put 285/70 r17 on my 2014 4x4 and I was told regearing from my stck 4.10s to 4.56s would put the speeddo correct, but I went with 4.88s and it runs so much better than before. I have a 4 cylinder.

 

This. Love mine.

 

Hypertech makes a plug and play device to reprogram/recalibrate the speedo. Easy to use and inexpensive as well.

 

Just wondering how useful the Hypertech Speedometer Calibrating tool is. Was going to go from P265/65/R17 stock tires to Falken A/T P275/75/R17's and would like to have the speedometer and odometer be corrected WITHOUT having to regear... is it worth the tool cost?

 

It is literally impossible to get the speedometer, or odometer for that matter to be 100% accurate. About 5% error is as good as can be expected. That means you're off by about 3-4 mph at 75. This isn't anything new, all cars since they've been invented do this. We just didn't know until everyone got a GPS.

As tires wear down the diameter changes to roughly 1 size smaller tire. If it is calibrated 100% accurate when you're tires are new it will be off by about 5% as they are near the end of their useful life. If they are off when new, they will either be accurate when worn, or off even more.

Unless you change to a significantly larger tire I wouldn't worry about it. If your speedometer is within 5 mph at 75 mph you're chasing unicorns to get it calibrated. If you were to go from a factory 31" tire to 35" or 37" tires then it might matter. Not worth the trouble for 32" or 33" tires.

Do you mean 275/70/17. I don't think they make a 275/75/17. My truck with stock tires was 2 mph slower than my GPS. When I went up size larger the speedometer and odometer were right on the money. But as the tires wore the speedometer started showing me 2 mph slower than the GPS.