Speedometer adjustment

I went with 32 1/2" tires and it actually corrected my speedometer. (2015 Tacoma) Factory tires were too small and speedometer would read faster than I was actually traveling.
 
TacoKen said:
I went with 32 1/2" tires and it actually corrected my speedometer. (2015 Tacoma) Factory tires were too small and speedometer would read faster than I was actually traveling.
Click to expand...


If the tires were to small, the speedometer would read slower not faster...
 
No, that's not true. Speedometer essentially reads how fast the wheel is turning. Smaller tire covers less ground every revolution, so vehicle is actually going slower than indicated. A simplification, but that's the basic idea.
 
BillK said:
No, that's not true. Speedometer essentially reads how fast the wheel is turning. Smaller tire covers less ground every revolution, so vehicle is actually going slower than indicated. A simplification, but that's the basic idea.
Click to expand...

You saying to me or him
 
What I'm trying to say is that if your tires are too small, you'll actually be going slower that your speedometer indicates.
 
Larger tire = more speed on road than smaller tire at the same RPM. Speedometer measures transmission turns but does not account for size of tire unless re-calibrated for tire size.
 
TacoKen said:
Larger tire = more speed on road than smaller tire at the same RPM. Speedometer measures transmission turns but does not account for size of tire unless re-calibrated for tire size.
Click to expand...
And that's my question in a nutshell. How do you recalibrate so that it's right?
 
I've heard there's some box (suppose to be a real pain to install cause you have to take half the dashboard apart) just wondering if that's accurate. Back in the day I think all you had to do was change the gear size that bolted into the transmission. It's only off by about 5 mph that I tend to forget about and may cost me a ticket.
 
Unless you're making a really big change in tire size, the effect might not be too noticeable. In fact, Toyotas, for the most part, seem to be slightly off from the factory. Prior to my Tacoma (which seems to be off 1-2 mphs according to my Garmin GPS) I drove a Camry the always indicated about 2-3 mphs faster than I was actually going. My GPS may be off, but it's been spot-on in my Honda and about a half dozen rental cars over the past 5 years. I've read a number of postings here and on TW go guys who said their speedometers were more accurate after the tire change.
 
BillK said:
Unless you're making a really big change in tire size, the effect might not be too noticeable. In fact, Toyotas, for the most part, seem to be slightly off from the factory. Prior to my Tacoma (which seems to be off 1-2 mphs according to my Garmin GPS) I drove a Camry the always indicated about 2-3 mphs faster than I was actually going. My GPS may be off, but it's been spot-on in my Honda and about a half dozen rental cars over the past 5 years. I've read a number of postings here and on TW go guys who said their speedometers were more accurate after the tire change.
Click to expand...


That seems to also apply to the new Tacoma trucks. My 2015 would read 65 when I was going 62. When I upgraded wheels and tires to a larger size my speedometer now reads correctly. I've heard several others have had this happen to them also.
 
A cynic would say that speedo's read fast from the factory for the following reasons: You think you are going faster than you are, so you are all kinds of happy, you get more "miles" per gallon because your odometer is lying to you too, you use up your warranty faster.

Full disclosure: I am a cynic and every car I ever owned read fast.
 
With my stock factory on my 16 Tacoma am exactly 2 miles off says on speedo I'm going faster than actually clocked. On the 15 model I am 1 mile above what I am clocked with factory recommended size. I've yet to see one of the tacos I've owned to be exact. If you stay within a 5mph diff of what it reads on speedo would not warrant a ticket.. Life is like a box of tacos. You never know what your going to get ...,


2016 Tacoma Trd Off-road. (Silver Bullet)
2015 Tacoma Sr5. (Polar Bear)
 
Yeah, would just be nice to have it accurate. The faster you go the more it's off. 65 is actually close to 70. Lots of responses but has anyone actually had one adjusted that can tell me what it takes?
 
Robert Henkel said:
It's actually 1 mph off for every 15mph I go so 30 is 32, 60 is 64 etc.
Click to expand...
That's about exactly what my 2015 did until I went with the 32 1/2" tires. Now it's close to perfect. I have checked it with several of the radar signs on different streets/highways.
 
You must log in or register to reply here.
Back
Top