yotarover

anybody else encountered the issue with the speedo bouncing all over the place. bought the truck with 235/75/15's it'd say im going 60 or faster so i just took off them off put on my 33x12.5 and it's only 2mph off according to my gps. would this be a gearing issue? haven't checked to see what gears are in the front & rear. it rides and drives better with the 33's than it did 235's .

85gijunk4x4

when you put on larger tires, the speedometer isnt going to be accurate anymore. the larger tires make less revoulations at a given speed then smaller tires. it all has to do with the math that's involved with diamater and all that confusing stuff.

so you're speedometer is calibrated for 225's, but if you put 33's on there, the engine will still be running the same rpm, but the increased tire size will move the truck quicker down the road, thus confusing youre speedometer into thinking its going slower then it actually is.

so say @ 2500 rpm's you run 50mph with stock tires. put 35's on there and @ 2500rpm you will be doing 55mph.

you can accomadate for larger tires by changing your axle ratio's, but it will be costly, and most people if they arent going with a tire too much larger just learn to live with it.

if you change your gears, you will return to stock speedometer settings, gas miliage (the extra height my intefere with your airodynamics though) rpm's etc.

85gijunk4x4

and to answer another question, its not so much a problem with the gears, but just a matter of how many revolutions youre tires make.

and sorry to go on and explain gears to you, i can see now you have a good understanding of them LOL

yotarover

no i understand the gearing thing. it's just the speedo was bouncing like crazy with the stockers, but actually reads 40 when my gps says 38. before i threw on the 33's gps would read 40 speedo would say 60. it'll spin the 235's dry on the road even spins the 33 mts i have

85gijunk4x4

you've lost me

85gijunk4x4

wait, nooo, i think i've got it.

your saying its not the tire size in question, its wether the gears are stock or not, right?

yotarover

correct. lets say i have 5.29's wouldn't that set the speedo off if i stuck on the stock 235's ? sorry guys i shoulda been more specific i know how to find out what gears i have i just haven't checked yet.

85gijunk4x4

yeah, that'll do the trick. same as adding larger tires with stock gears, just backwards.

do the ole spin and count method and see what ya come up with.

and i guess your either a 22r or 22re, wich is pretty much un heardoff when it comes to spinning 33's

yotarover

i know nothing about the history of this thing, neither did the guy i bought it from . odo shows like 240k + miles but it doesn't have a tick or ting to it. 22re auto (transmisson was changed out for a auto at some time during it's life) i think it was a project truck that was never finished'


it's the same one i showed you a while back junker

yotarover

never mind lol