i wanted to install a revspeed meter (rsm) from apexi but i heard that we couldnt. after i installed my wheels the speedometer is off about 5mph....i need some kind of aftermarket part which will tell me my EXACT speed. something similar to RSM. thanks!!

 

It has been discussed before. Mine was off about 2 mph high when I had the OEM tires on. Since you have a 2004 model, I'll bet you don't have the original tires on. The diameter of your replacement tires are most likely throwing off further.

 

My speedo is about 2 mph faster than I am really going. I have one of those radar "This is how fast you are going " speed limit signs by my house... I'll go by it at 45 and it will say 42 or 43. I think that'll be good for me for a while so I can retain that little safety speeding bubble, haha.

 

Why do you need to know your EXACT speed? this seems a little silly for any driving I have encountered. If you know it's off by 5 mph why not just adjust in your head?

 

It could also be the radar that is 2 mph slower...

 

This is America. We're too lazy to think for ourselves.

 

I get a blank stare most of the time I go by one of these signs (I'd say 80% of the time). But most US cars are off by a certain percentage. Just happens to be 2mph in the 80mph range.

 

according to my GPS, my speedometer is about 1mph faster than GPS's calculated moving speed.

 

Honda is actually getting sued over this ... turns out their Odometers for years have been reading pretty darn high (or over) on the US allowable limit (5% i think) .......Well Honda owners are in a class action lawsuit claiming that repairs just over warranty mileage should be covered because the odo. racked up way more than the actual mileage.
Funny thing is ... the guy who discovered this ... and "blew the whistle" on Honda did it by noticing that when he drove his Honda to work , and then his Mazda .. there was a considerable difference in mil;age.

Hmm no wonder Honda got a reputation as "reliable"

 

And no wonder they get good gas milage. They are driving slower.

 

^damn, man it all fits!

 

i agree,

with the stock tires and my new 245 / 40 18.

above 65mph it is off by 1.8 mph.. under 65mph it is about 1 mph.

this is wass enabled...

beers

 

We have a TL and got a notice that our warranty had been extended by a couple thousand miles due to the class action suit.

 

Well, I haven't noticed anything since changing my wheels..

 

Not uncommon for those unofficial speeds signs to be off as much as 10% (typically they read High- or say you are going faster than you really are).

A good GPS system is the only way to see really how close your speed is to the actual speed you are going.

My Tacoma is the only vehicle I have ever had that actually read the exact correct speed. Even my 07 328i coupe is off about 3 MPH and my old FC was off by about 10% (said I was doing 100 when I was doing 90-91).

My 06 RX-8 is only off by 1 mph.

 

My gps says im going 2.5 mph slower than my speedo says. I think i read on another thread that factory digital speedos have to read a higher speed than you are actually traveling to eliminate the chance of it saying you are going slower than you actually are. I understand that but still think its dumb, and why off by so much. I would just rather it be as accurate as possible.