Topic: 4.56 for 235/86-16 or 31.7inch tire

[deepsouth]

85 4x4 with 22r,5 speed trans ,comp cam,header,weber carb and 2.25 exhaust with a manga flow muffler. It has 4.10 gears in it right now.Recently purchased the 235/85s I like the tall skinny tires. I have 31s on it now they measure 29in from floor to top of tire,the 235s are 31.7. I don't rock crawl ,live in south Mississippi, just use the truck for normal truck stuff. Mainly pull the boat,haul four wheeler,firewood, pull small 10 ft trailer and drive 2hr  on the highway to where we hunt. I was thinking about regearing to 4.56s or 4.88s. Seems to me that 4.56s would be about right for what I want to do. I want to be able  to have enough power to pull the boat and trailer around,but also be able to cruise down the highway at  70 or 75 with revving the crap out of the motor. There is the smallest of possibility s that I may go to 255/85-16s  (33.3) but that may never happen. What do y'all think 4.56 be ok or 4.88s? I'm thinking 4.56 just not sure. I have searched just so many opinions. Looking for some first hand experience.

[OOPS]

The Toyotas that came with 31" tires had 4:88's in the diffs.

[deepsouth [OP]]

thanks oops, nuff said.

[H8PVMNT]

If you ever plan to tow choose 1 gearset lower than what you need as far as numbers go...

[Snowtoy]

The 235/85's measuring 31.7" unmounted they are about the same as a 32" tire, which is between the two available gear ratios.  Between the unladen weight of Toyota's, and what you use the truck for, you would want to go with the 4.88's which would be slightly over geared for the 235/85's, but not enough to have a negative effect on highway mileage.

These Drivetrain Calculators will let you see what the different gear/tire ratios combo's have on rpm and mph.

[deepsouth [OP]]

Thanks snowtoy

[helipilot77]

Here is the link to the tire and gear calculator I made. This seems to b one of the most common questions. You will need Microsoft Excel to run it.
http://board.marlincrawler.com/index.php?topic=93052.msg1044468#msg1044468