I have been working on a project to upgrade my Toyota FJ Cruiser with larger tires and better gearing.   Initially I was not planning doing this upgrade; however, this last summer there were a few situations that where the additional 1.5 ” of clearance would have helped.

To help me decide on the tire size and gearing to go with I created the following charts:

Gearing and tire size options:

	Current	Opt 1	Change w/ 33.81	Opt2	Change w/ 34.36
Tire	31.61	33.81	+2.2”	34.36	+2.75
Axle Ratio	3.91	4.58	.67	4.58	.67
Final Ratio @ hub	41.9	48.87	6.97	48.87	6.97
RPM @ 2 MPH (L)	891	976	85	960	69
RPM @ 60 (5th)	2494	2731	237	2687	193
RPM @ 75 (6th)	2494	2731	237	2687	193
Speedo  @ 3000RPM in 5th	72.18	66.20	-5.98	67.28	-4.9

Gear Ratios

Transmission:

Gear	Ratio
1st	4.17:1
2nd	2.19:1
3rd	1.49:1
4th	1.19:1
5th	1.00:1
6th	0.80:1

Transfer Case:

Gear	Ratio
Hi	1:1
Low	2.57:1

This site was lots of help in calculating all the information: http://www.ramblerman.com/blazer/gearcalc.htm

Parts Required:

Gears:  4.56 Ring Gears and carrier

Tires:  315/70/17 All terrain tires

Body Lift 1”:  Provided by Toytec

Speedo Adjuster:  There are a few companies that now offer this product.

Rims: 17 x 9 with 4.5” back spacing

Beadlock: This is an option and I would consider the internal beadlock from Staun

For the tires I am considering the following options:

Option 1 Goodyear Wrangler MT/R

Tire Size	Service Description	Sidewall	Rim Width	Section Width	Diameter	Max Load
LT305/70R17	119Q	OWL	8.0 – 9.5	12.2	34.1	3,000 @ 50

Option 2 BFG All-Terrain T/A KO

Tire Size	Service Description	Sidewall	Rim Width	Section Width	Diameter	Max Load
LT315/70R17/D	121S	BSW	8.5 – 10	11.8	34.5	3195@50

Steps:

First I will need to get the body mount cut to provide clearance for the front tires.

Second will be to lift the body of the FJ 1” to provide more tire clearance at full up travel. The bump stop will also need to be lengthened to prevent the tires from rubbing the top of the fenders.

While all this is going on I will be working on getting tires and wheels so one the re-gear is done all I need to do is swap the mounted tires out.

As I proceed with this upgrade I will be writing about each step.