Bigger tires = bad speedometer readings - Please Help

[Rangerfreak]

Okay so I know there are plenty of threads out there on speedometers and such but I'm needing a little more information right now as I'm about to spend a huge sum of money. (sorry to be picky) So, I have a stock 2000 ranger 2WD (comes with 225/270-r15 or 27") and I'm going to get new BFG 30x9.5-r15's. I've looked everything up and figured out that my speedometer is going to be off by 11%. (at 65 reads 72.2) As of right now I'm pretty set on adjusting it for safety reasons (abs,speedo...etc) should i be? And to do this I'm going to need more information on how to. What tools specifically? Sorry I'm sorta slow but my friend has alot of tools. I want to make sure he has the right ones before I possibly go to the dealership to get the same thing done for 50 times the price.. sorry for the long rant and please help, much appreciated

 

[strvger]

honestly, i'm not sure it's worth all the trouble to go in there with new gears for the speedo. i've calculated my truck is going 67 mph when the speedo is reading 60 mph. i also know that an indicated 60 is right in my hp and torque range. that is close enough to the 70 mph speed limits on the freeways around here that i am satisfied cruising with my speedo at 60. actually i prefer to drive by the tach and keep it between 3,000 and 3,200 rpm when on the freeway. on the streets and side roads, i just keep up with traffic. again, i just pick the right gear to keep the revs above 2,000 rpm so i don't lug the motor. in unfamiliar places, i keep my speed 5 mph less than what is the posted limit just to be safe. as a side benefit, doing it all like this helps keeps me focused on the task at hand: driving. just my $.02.

 

[Toms01PSD]

You need to have it programmed with a scan-tool. Go to the dealership. They have the tool you need.

 

[JohnnyO]

Superlift makes a module to do that also. Dealer might be cheaper if they can reprogram it though.
Of course if you leave it the way it is you will put 11% less miles on your truck too.

 

[Rangerfreak]

Thanks all, I feel a lot more confident about what I'm doing. You all act like this is know big deal which is good news for me =) i guess ill start asking my friends what their scanners can do. anyways I'm about to get my truck back with the new tires. Wish me luck! Hopefully I won't be back with too many problems ha ha thanks again for your input