why does it.

 

Why would you even be going that slow in a Z car? LOL

Seriously though I don't know. I recall seeing other cars that started at something other than 10mph also.

 

i just found out they zero out at 20 mph so 40mph on the spedo would be 20mph and so on.

 

I'd have to say that this is incorrect. If your speedo says that your doing 60mph and you're really only going 40mph...no this would not have ever been allowed on the streets. The US laws and standards for cars sold here require your speedo to be accurate (at least when sold new). If your speedo is off then something else is going on, it was not made this way.

 

Texasz is right. Where at in texas are you located Texasz? Im in San Antonio.

 

No kiddin' your profile says you are in AR. I'm just up the road in Austin.

 

Been telling him to change that, but I think he's homesick for us in Arkansas. By the way Zack, Shane finally came by the other day and spent some time with me at the wash.

 

then y do they start at 20mph

 

nope. it starts at 0. then 10mph indicated. then 20.

 

The earliest of the 240s start at 20 (mine does). can't figure out why, but NO, it does not mean that 40 is 20 and so forth. From what I can gather, the tires' size has a lot to do with the actual speed of the car, not the speedometer.

There are lots of speedometers, both from parted-out 'newer' Zs as well as aftermarket ones that begin at zero, if having one will make you feel a bit calmer every time you pass a police car.