30's and speedometer

jstr180 · Mar 7, 2008

how far off will 30's throw off the speedometer. would you all suggest getting it recalibrated or would it not be that bad off? thanks yall!

reginald fairfield · Mar 7, 2008

If they are replacing 235's, it won't matter; they are the same size as 30's. What size tire are they replacing?

jstr180 · Mar 7, 2008

im not sure because im not the one doing it...its being done while im in iraq right now. whatever is stock on a 2000 xlt ranger

reginald fairfield · Mar 7, 2008

hmmm... if it is 2 wheel drive, they probably won't be 235's... Might make more of a difference. The way I do it is wait until I get pulled over and then tell the cop my speedometer's off. Judges are usually lenient with that...

Jorley · Mar 7, 2008

I don't know if this will help, but I put 31x10.50's on my '84 Bll and the speedometer is off by 5 mph.(55=60) that's all speeds. I checked it with a gps.

jstr180 · Mar 7, 2008

its a 4wd

reginald fairfield · Mar 7, 2008

Then it probably has 235's, they came stock. 30 inch tires are almost precisely the same size; the only advantage is that they are a bit bouncier, i.e. smoother ride... I did the 235 to 30 switch, good tire size to go to. I would not worry about the speedometer a smidgen. Be careful over there in Iraq bro.

jstr180 · Mar 7, 2008

thanks yall! i appreciate the help because all this off road stuff is a new thing to me but i like it...i did it before i left with some buddies and i was hooked...so now im setting up my truck for it...any ideas?

reginald fairfield · Mar 7, 2008

Too many... there are so many ways that you can go dude, it all depends on what you are into. If you like muddin and general offroading, a normal lift will suffice... Or you can go prerunner like Jim Oaks... Me Personally, I like conservative lifts with heavy duty components: tall pickups are over rated- they flip too easy. Money is another concern. Even if you do it all yourself, it still takes a fair sized wallet to buy all the parts. Sky's the limit until the bank shoots you out of it with bill collector bombs!

If I were you, I would just browse this site for a while, getting ideas. Then make a plan of action.

jstr180 · Mar 8, 2008

i appreciate all the advice...right now i just got a 3in body lift and i got the 30s put on. i am more just for general offroad...like trails...not really deep mud or rocks...to much to really mess up the truck because its also my daily driver...as far as suspension...what would be some good ideas? like does adding just new shocks do a whole lot or do you need a whole new suspension to get any effects from it? and as soon as i get some pictures of where its at right now i will post them in the thread for under costruction

kunar · Mar 8, 2008

on a 2000, crank the front torsion bars (check out the tech library) and some lift shackles or a taller block in the rear. add some decent shocks and some 31's or 32's and you should be set. on those trucks you cant do a whole lot more without breaking the bank. the other option is a body lift.

reginald fairfield · Mar 8, 2008

kunar said:
on a 2000, crank the front torsion bars (check out the tech library) and some lift shackles or a taller block in the rear. add some decent shocks and some 31's or 32's and you should be set. on those trucks you cant do a whole lot more without breaking the bank. the other option is a body lift.

Yeah, I reccomend the torsion crank as well. Maybe a small body lift too...

CanadianRanger · Mar 8, 2008

I tried a tire size converter and got these numbers...

Stock Tire - 235/75R15--------------Tire 1 - 30x9.50R15

Section Width: 9.25 in 235 mm----------Section Width: 9.48 in 241 mm

Rim Diameter: 15 in 381 mm ------------Rim Diameter: 15 in 381 mm

Rim Width Range: 6 - 8.5 in ------------Rim Width Range: 6.5 - 8.5 in

Overall Diameter: 28.87 in 733.29 mm --Overall Diameter: 29.99 in 761.74 mm

Sidewall Height: 6.93 in 176.02 mm ----Sidewall Height: 7.49 in 190.24 mm

Radius: 14.43 in 366.52 mm -----------Radius: 14.99 in 380.74 mm

Circumference: 90.69 in 2303.5 mm ----Circumference: 94.21 in 2392.9 mm

Revs per Mile: 720.4 ------------------Revs per Mile: 693.5

Actual Speed: 60 mph 100 km/h -------Speedometer1: 57.7 mph 96.2 km/h

Speedometer Diff: - ------------------Speedometer Diff: 3.878% too slow

Diameter Difference: - -----------------Diameter Difference: 3.74%

Size Converter: http://www.1010tires.com/tiresizecalculator.asp

reginald fairfield · Mar 10, 2008

CanadianRanger said:
Stock Tire - 235/75R15--------------Tire 1 - 30x9.50R15

Section Width: 9.25 in 235 mm----------Section Width: 9.48 in 241 mm

Rim Diameter: 15 in 381 mm ------------Rim Diameter: 15 in 381 mm

Rim Width Range: 6 - 8.5 in ------------Rim Width Range: 6.5 - 8.5 in

Overall Diameter: 28.87 in 733.29 mm --Overall Diameter: 29.99 in 761.74 mm

Sidewall Height: 6.93 in 176.02 mm ----Sidewall Height: 7.49 in 190.24 mm

Radius: 14.43 in 366.52 mm -----------Radius: 14.99 in 380.74 mm

Circumference: 90.69 in 2303.5 mm ----Circumference: 94.21 in 2392.9 mm

Revs per Mile: 720.4 ------------------Revs per Mile: 693.5

Actual Speed: 60 mph 100 km/h -------Speedometer1: 57.7 mph 96.2 km/h

Speedometer Diff: - ------------------Speedometer Diff: 3.878% too slow

Diameter Difference: - -----------------Diameter Difference: 3.74%

Size Converter: http://www.1010tires.com/tiresizecalculator.asp

See, it is only about 4 percent... That is nothing. You have to be going 100 mph before it is even off by 4, so no worries.

V8RangerBoy · Mar 11, 2008

Jorley said:
I don't know if this will help, but I put 31x10.50's on my '84 Bll and the speedometer is off by 5 mph.(55=60) that's all speeds. I checked it with a gps.

Something is lying to you. Basic proportional math will show you that your needle should be farther off the faster you go. That's interesting that your inaccuracy isn't speed-variable. :shok:

30's and speedometer

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