Tacoma Speedometer off?

Speedometer reads too fast, by about 2-3 mph @ 60 real mph... i.e. 4%
The odometer reads correctly.

Now, put on 1" taller tires and your speedometer will read correctly but your odometer will be slow or off about 4%.
We with 265/70-16 tires stock change to 265/75-16 know this quite well!

 

Not to beat a dead horse but on my 23 SR5 with the stock 245/75/16 tires it would read 1 to 2 mph faster than the GPS and road gps signs. Just swapped to 265/70/17 with the hypertech speedo calibrator and now it's 3 to 4 mph faster with the tire sizes entered. And my miles to empty has shot up to over 300.
Might take it off and return it

 

My 2015 tacoma reads 96 kph (gps) when doing 100 KPH.. Several of the cars I have driven are similar in overstating speed between 3 and 4 %
It does help those who dont know about it avoid speeding tickets since if you think you are doing 120 kph on the 401 up here in Ontario you really only doing 115.

 

Since Tacoma factory wheel sizes are 16”, 17” and 18”, I wonder if the speedometers are calibrated for 17” size and maybe Toyota figures the readout for 16” and 18” wheels is close enough.

https://www.iseecars.com/car/toyota-tacoma-wheel-rim-size

 

Speedometers, by desogn, can be off X percent. Tires wear and that changes speed. Going around corners changes speed. Approximate is good.

 

you mean to tell me my speedometer isn't as accurate as an atomic clock?
Man, these tacomas are garbage!!

 

Wow...2017 still shows 385 to 410

 

Designed that way to keep the Man from getting all up in your Jimmies. Your welcome!

 

The way it works is the speedometer is about 3% fast while the odometer is usually dead nuts on. For your hypertech to make the speedo accurate, the numbers you program into it need to be right. Hyper tech has always fixed it well for me. The reason I returned my hypertech is it had a weird interference with my turn signals when I’d unlock the truck. Made me concerned about that thing being plugged in.

If you simply upsized to 265/70R17, your speedometer should now read accurately while your odometer underreports by 3%. You go 100 miles on the dash, you actually went 103. Etc. I’d just return the HT and let the gauges be how they are with 265/70s.

 

This is probably why the state troopers won't ticket just 5 mph over the speed limit.

 

When I first drove my tacoma I noticed the odometer was reading fast...a mile was reading around .6 when I drove the truck through a measured mile on the highway. When I had my 1st toyotacare visit I complained about it. Whatever was done, did correct it when I drove off.

 

More than you ever wanted to know ...

https://www.roadandtrack.com/car-culture/car-accessories/a32026968/are-speedometers-accurate/

 

wheel size is irrelevant.

 

100% correct. Its the tire diameter. and you can have a 16 inch rim/tire that has same diameter of a lower profile 18 rim/tire

 

Eight you’re great.
Nine you’re mine.

 

Very good point. Here is a fun Tire Size and Comparison calculator.

https://www.blocklayer.com/tire-size-calculator

 

Legally, the speedometer only needs to be accurate to within 5% (In Canada anyway. I'm guessing the US is the same), so most vehicles are off a little bit.

You can use the mile markers that are on most highways to see if the odometer is accurate. Some highways here in Alberta even have designated odometer test markers.

 

What were the issues with your turn signals? I noticed lastt night that when I hit unlock the first time they dont activate, until i hit it the second time to unlock all doors. I thought there was something wrong with my Alpharex lights. I am one day out of the retun policy on the hypertech.

 

I found that mine DID unlock on the first click (the beep made its normal noise I believe but it’s been a while), but the turn signals didn’t illuminate. The second click I got the beep again and the turn signals did illuminate.

I noticed when I removed the hyper tech it was pretty warm, not sure if that had anything to do with it or not but I felt better about removing it.

I actually had a thread on this or I commented on an existing one (I don’t remember), but there were others who tested their hyper tech and they didn’t have that problem. I figured it was an automatic vs manual transmission thing, but if yours is automatic then I really don’t know.

mine did this behavior with both a rough country programmer from rough country and another one from scamazon. Both acted exactly the same.

 

I just went out to look at the lights and what you just described is what its doing . It unlocks / beeps but the lights dont flash until the second time around.
I guess im pulling it ouy and contacting Hypertech