speedometer calibration

[xploder1208]

bump

 

[vela]

look what I found in there .... if someone serves http://www.explorer4x4.com/speedo.html

 

[cory32676]

33x 12.5x15 tires

Hello, greetings from Spain .... then if I put wheels 33 x12, 50 R15 teeth how many less would they be?

Thanks in advance......

I bought my truck with a crappy lift, generic shackel replacement. it sits about 2" taller than stock. and i am sitting on 33x12.5x15 ride is smooth with a little rub on inner plastic fender during sharp turn. my speedo is about 15mph off. what gear would I use? :exp:

 

[KPSquared]

I bought my truck with a crappy lift, generic shackel replacement. it sits about 2" taller than stock. and i am sitting on 33x12.5x15 ride is smooth with a little rub on inner plastic fender during sharp turn. my speedo is about 15mph off. what gear would I use? :exp:

That depends on how many teeth you have on your current gear. After that it's just grade school math.

 

[Maniak]

I bought my truck with a crappy lift, generic shackel replacement. it sits about 2" taller than stock. and i am sitting on 33x12.5x15 ride is smooth with a little rub on inner plastic fender during sharp turn. my speedo is about 15mph off. what gear would I use? :exp:

15mph off at what speed? Speedometers are off by a percentage, not by a speed.

Assuming it reads 15mph slow at 60mph (a total guess as to where you saw it 15mph slow) you need a speedomter gear that is 25% smaller than you have now (45mph is 25% lower than 60mph). Soo, pull the 1 bolt, pull the driven gear out, count the # of teeth (may also be written on it) and then get one that is the right percentage smaller.

~Mark

 

[jason's 94]

would changing from the stock 235 to 31's (goodyear authorities) cause any problems with it shifting and it would it be really worth to change the gear? don't really do any highway driving?

 

[little x]

Do these gears fit 91's? I ask because every online dealer I've ever seen lists the parts as 92+. Was there a difference in the 91 speedo gear or is everyone wrong about what years their parts will fit? I've gotten used to the speedo being 15% off, but for less then $10 I'd swap in a new driven gear, if it will fit.