speedo calibration

[fifty]

Anyone in the bay area have a speedo calibrator they would let me use? I bought my 02 used, it has stock sized tires/suspension on it now (but you could tell it used to have a lift). I have a feeling it had larger tires on it at some point because the speedo reads a bit slower than I am actually going.

I have yet to get a tuner (due to funds) which I believe could fix the speedo problem (I may be wrong there)...but I would like to have the speedo be somewhat correct...

Thanks in advance to anyone who can help me out
Btw I am in the eastbay/concord area...