Technical Notes provided by Joe Schaeffer

Rims/Bolt Circle size:
   Measured from stud to stud:
	3.23"=5.5" bolt circle.
	2.93"=5.0" 					
	2.79"=4.75"
	2.64'+ 4.5" bolt circle.

Flotation/Metric Conversion
             Diameter 
Floatation    (inch)   Metric Size
27x8.5R14      26.5     225/75R14
               27.5     215/75R15
29x9.50R15     28.5     235/75R15
30x9.50R15     29.5     245/75R15
31x10.50R15    30.5     265/75R16
32x11.50R15    31.5     295/75R15
33x12.50R15    32.5     315/70R15	
33x12.50R16    32.8     285/75-16

Section width: 
width of the tire between sidewalls NOT the tread width. 	
Usually measured in mm and the first number on a metric tire. 
Such as the "235" on a 235/75R-15 tire.

Aspect Ratio: 
Relationship between section height/width.
Aspect ratio is the "75" or "60" number in a metric rated tire. 
As in  235/75R-15

Tire diameter of a metric tire can be figured using:
	
	tire dia. = 2 x section width x aspect ratio + wheel size
					25.4			   100


Tires/Gears/MPH/RPM

	tire diameter = mph x gear ratio x 336
                        ------------------------
				  rpm

	gear ratio = rpm x tire diameter
                     ---------------------
		         mph x 336

	mph = rpm x tire diameter
              ---------------------
		 gear ratio x 336

	rpm = mph x gear ratio x 336
              -----------------------
		   tire diameter

NOTE: For rpm's other than hwy speeds you need to figure in 
trans gear ratio and x-case ratio. For mph at hwy speeds use 
5th gear OD ratio ie. 072:1 etc.

Actual speed: When changed to new tires and you need the actual 
speed withhout changing speedo drives. Bigger tires cause speedo 
to read slower than true speed. 

	actual speed = new tire dia. x indicated speed
                       --------------------------------
                            old tire dia.

Example: Old tires 28 inch, new tires 35 inch and speedo reading 60 mph
		
		35 x 60 mph = 75 mph true speed
		   28

To figure what indicated speed to run to achieve actual speed use:

	indicated speed = old tire dia. x actual speed
					new tire dia.

Actual new gear ratio with new tires:

		new gear ratio = old tire dia. x old gear ratio
						new tire dia.
 
Gears to install to restore original gear ratio after new tires:

	new ratio to install = new tire dia. x original gear ratio
						old tire dia.
		

---

Select pages from WAGONEERS.COM:  pull down to select  john's fotos --> http://wagoneers.com/FOTOS   FSJ - Full Size Jeeps 63-92 --> http://wagoneers.com/FSJ  WJ - Grand Cherokees 99+ --> http://wagoneers.com/WJ  XJ - Cherokees 84-01 --> http://wagoneers.com/XJ  The Bible --> http://wagoneers.com/BIBLE  Living By Faith   AMSOIL info --> http://wagoneers.com/AMSOIL  misc pages   UNIX info --> http://wagoneers.com/UNIX   john's vehicles   GUN CONTROL WORKS! read!  Snohomish Garden pictures  Help with Bible Study    A FREE GIFT!!! Buy this FSJ decal...   ...use PayPal to pay for it!

AMSOIL synthetic lubricants and filters (please use customer #283461) Shop AMAZON.com from wagoneers.com!  Search: All Products Books Magazines Popular Music Classical Music Video DVD Toys & Games Baby Computer & Video Games Electronics Software Tools & Hardware Outdoor Living Kitchen & Housewares Camera & Photo Wireless Phones Keywords:

---

these pages protected by US Copyright laws John Meister copyright © 1995-2001 all rights reserved contact john-at-wagoneers.com

Washington State has a $500 fine for "spam" (unsolicited commercial email)!

---

---

      read the Bible

---