OK I put 225/70R15 on my 83 2wd. Now I think my spedo is off. Its got a 5 spd out of 84, 4.10 gears. Other than having a cop gun me or follow someone I know how else can I find out how bad off it is. Anyway of recalibrating it? I live in a 45mph/35mph city and hit the freeway. I dont think it will go over 65 so if I can have a general idea of how fast I am going that probably work.

 

there is a calculator on www.4lo.com you input the stock size and gear and see how fast it goes.. then you put the new size... and it will show.... it may be such a small amount that there is no correction for it.... otehrwise you might be able to swap out the transmission speedo gear to get more close to the factory spec

 

Damn i dont know my original tire size. I bought the truck and it had 205's on it and it was already 5 mph off

 

it should say on the door sticker... were the gears changed? or are they stock? my 85 4x2 had 195/75/14 listed as the stock tire size

also, the stock speedometer is never 100% accurate.. most speedometers are factory set to about +/- 5 mph

 

10 mph off.

 

With the title of this thread I clicked on it with caution.