i havent changed the settings in the tuner for 33's. its set for 31's.

but i was driving alongside my friend the other day on the highway, and called him and asked how fast we were going. he said 70. thats what my speedo read.

he was in a stock rav 4.

so what gives? im confused.

 

dude, same thing with my truck.. i was driving into base and the radar thinger said i was going the exact speed my speedo said.. except i dont have a tuner at all and i have 35's..

i was thinking the exact same thing..

 

I think they're set fast from the factory. That's the only explanation. Well actually no, that radar could've been mis-calibrated or the RAV4 could've had a fast speedometer.

Via GPS, I've checked my speedometer. I had stock 235/75R15 (29") to 31x10.5R15 (31") and I noticed a difference. My speedometer is slow at anything above 35 mph.

 

Yeah mine is off too from 29" to 32"

 

It's common for stock speedometers to be off by a few mph. They arent calibrated for complete accuracy.
If you ever sit in a cop car, well a crown vic anyways, it will say on the speedo that it's been accurately calibrated.

Get a gps and check it. it may be right at 40mph and 2 off at 60mph...

Who knows...

 

Yeah its hard to say.. i went from stock to 31s to 33s and now i have a tuner with the correct speed. But one thing for sure i've noticed is that the faster you are travelling the more off your speedometer is going to be

 

In mine, I got slight bigger tires, and now 0-35 is accurate, and anything above is 5 below.

 

My speedo reads 80 when I'm doing 78, so you bumping up to 33's probably just closed that gap.

 

actually mine did the same with my gps. i always thought the gps was off, but now that i think of it, that wouldnt make sense would it?

 

Arn't speedo's allowed to be +/- 5% ?. So who knows, your speedo might have been -5% and now with the 33's it will be correct.

Mine is off from going to 29's to 32's as well.

The reason it is going to be less accurate at higher speeds, is because it changes by percentage. Hard to explain lol.

Ex: Your speedo reads 100 mph with 29's. Going to 32's it will be about 9% difference. so when it reads 100 mph on your speedo, with the 32's you will be going 109 mph. But when you are going only 50 mph, you will really be going 55-56 mph. Not a huge difference, but something to keep in mind when there are police around.


http://www.1010tires.com/TireSizeCal...?action=submit

Your speedo will read aproximatly 5.003% slower.

 

yea when im going 70 according to radar and gps my speedo says 75
hopefully when i step up to 33s it will fix that prob
but yea ive heard that our speedos are calibrated perfect for 32-33s

 

with my truck, even when i had 4.56s it would read the correct speed at low speeds. up until about 32mph. i was using my GPS for my speed readings

 

I had a gps in my white non fx4 ranger and with 245's i was at 100 with my 265's i was around 109

 

ive used the mile markers on the side of the road to figure out my calibration. When it says ive gone 1 mile on the road, my odometer reads that i only went 9/10th of a mile. So im 1/10th of a mile off. So when my speedo reads 50 mph, i do the math and know that im really doing 55 mph. speedo says 70 mph, im really doing 77mph... and so on.

Simple break down for all the math wizzes out there:

1/10th of 50 = 5
50mph + 5 (for correct calibration) = 55mph ( new calibrated speed)

1/10th of 70 = 7
70 + 7 = 77

 

from 27 to 30 mine is only noticeably off after 50mph