My speedometer is way off

[91White-T]

Drove by one of them speed things the other day, my speedo says I'm doing 40, but the speedbox says 31... So I drive by it a couple more times, consistently off by about 10mph at low speeds, I didnt try it at more than 40 since it was in a neighborhood. Now it makes more sense why I have to go 80 to keep up with slow traffic, when the thing shows 95 it feels more like 80! What could possibly make it off by this much?

PS BTW, I have stock size tires so thats not it.

[Project_Legacy]

wow thats a big difference. so your tires AND wheels are stock size? i dont know what else could cause that.

[Manarius]

Drove by one of them speed things the other day, my speedo says I'm doing 40, but the speedbox says 31... So I drive by it a couple more times, consistently off by about 10mph at low speeds, I didnt try it at more than 40 since it was in a neighborhood. Now it makes more sense why I have to go 80 to keep up with slow traffic, when the thing shows 95 it feels more like 80! What could possibly make it off by this much?

PS BTW, I have stock size tires so thats not it.

If I'm not mistaken..the thing that reads speed is in the tranny or someplace close. Maybe that thing is broken

From what I understood, our speedos are off 10% not 10 mph.

[douglas vincent]

I have proven on two vehicles that the speedo is off 10%, just about right on the nut. Thats the most I have seen them off.

[legacy92ej22t]

Hmm, everytime I pass one of those radar signs it's almost dead on....with my +sized wrx wheels and tires.

[Legacy777]

The WRX sized tires 205/55 r16 is just about right for the speedos on the turbo legacy to be dead on.

[BAC5.2]

Just like on lots of motorcycles, lots of cars speedo's are optimistic. Probably to help reduce speeding.

[Manarius]

Just like on lots of motorcycles, lots of cars speedo's are optimistic. Probably to help reduce speeding.

I don't know about that. My dad can lay down the speedo on his '80 Honda CB750 in 3rd gear (80 MPH). I can tell you, it feels like you're going 80 MPH.

[tris91ricer]

Just like on lots of motorcycles, lots of cars speedo's are optimistic. Probably to help reduce speeding.

I don't know about that. My dad can lay down the speedo on his '80 Honda CB750 in 3rd gear (80 MPH). I can tell you, it feels like you're going 80 MPH.

... on a vehicle that's meant for speed. I think what Phil is getting at is that if people thought they were going faster than what they're really traveling, it'd be safer. It's a psychological battle, that's all.

[BAC5.2]

Just like on lots of motorcycles, lots of cars speedo's are optimistic. Probably to help reduce speeding.

I don't know about that. My dad can lay down the speedo on his '80 Honda CB750 in 3rd gear (80 MPH). I can tell you, it feels like you're going 80 MPH.

When I'm going 50 on my CBR, it feels like I'm going 50, but I assure you I'm probably only going 40. It's a lot different on a bike than in a car. Most vehicles, bikes and cars, have optimistic speedometers. Get a GPS and find out for yourself.

When there's only 400 pounds of metal UNDER you, and not 3000 pounds of metal AROUND you, you feel like your going a lot faster than you are. All about perception.

I think it was Albert Einstein who said, put your hands on a hot plate and a minute feels like an hour. Put your hands on a hot woman, and an hour feels like 3.5 minutes . It's all perception.

[mhrallyteam]

mine is 20km/h off, even when i'm stopped!!