| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | If you install larger tires, you will not know any difference on the speedometer unless you change speedo gears, so find some mileposts 10 miles apart to determine your true speed. Then remember which percentage your speedo is off, keep it in your memory. Other speedo gears may not be available.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| 
