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.
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
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.
Your speedo will read aproximatly 5.003% slower.