crxracer7

any mechanic? really? i work at les shwab now.. haha maybe i can do it.

jung4g

dumbass, if you change the wheels, it's likely that the actual tire size will be a little different. Even a 3% change is an extra 2mph off at 70mph (if you think it's safe to go 7 over, you're actually going 9 over, which will probably be rounded up to 10 over, now you're at 80 with a ticket ). Plus all speedos are going to be off by a little bit, so you need to take that into account.

The best way to figure out (and yes, this is your responsibilty) your speedo error is to get a descent GPS unit, while they are not totally accurate for location (usually 5-10m circle), they are very accurate for velocity. Just cruise at what your speedo says is 10/20....50/60/70/80 and record the speed on the GPS, then you'll know what's really happening.

Cops know that speedos are off, cop cars have to have theirs tested and it is usually recorded in the driver door sill. I saw one car that almost 6% off at 70. (said 70, was going 74).

Best idea is to go the speed limit when you're alone, the speedo error shouldn't be enough to get you pulled over unless you're on dubs or something stupid. If you're in traffic, just go with the flow, and never lead a pack.

88crxSi

careful carl

do the math.

185/60R14, 195/50R15, 205/40R16 all have the same rolling diameter (within 1%)

whiterice

I went to San Diego the past weekend and they had speedometer checks on the road. Basically 1, 2, 3 mile signs. Just time youself at a certain speed and do the math.
You must have a steady foot or cruise control to get it right.
My cruise control was set to 70mph and after the calculations it came out to 69.9XX mph

bumblezc

What a good time to hit the dyno!! It will tell you the truth

B00M3R

Or buy a GPS system.
they can tell you your speed.

jinxy

just have your friend go 35mph in a car infront of you. then follow him and keep the same speed. its not real hard to do.

Cray91

I have known two people that got their tickets continued for 1yr because of a speedo error.

It was just a matter of a lenient judge and it being their only speeding offense. They didn't really get off though, they essentially got 1yr probo and had to have the speedo fixed. If they fucked up, they got both of the tickets.

edit- A cop is a -----tard if he gives you a ticket for 10 over on a freeway. So long as you were decently with the flow of traffic, and not tailing anyone or anything.