Need to regear 2006 Tundra DC

[RMCO]

Needed new tires and decided to have some fun with the truck now that it's about to turn over 100k miles and needs a list of PM items addressed anyways. Going with Toyo A/T II in 285/75R18 after picking up a set of 18x8 steelies and will need to regear. Unrelated, but absolutely loved the 255/85R16 Toyo M-55s that I finally wore through. Put 50k+ miles on them. Would recommend.

3.91 rear and ~31" stock tire size has the math at 4.40. Do you think 4.56 gears are enough or should I look to go lower with 4.88s? Wheels and tires are going to be a lot heavier than stock.

Truck is my daily driver in winter and sees a lot of highway miles. Summer it's my road trip/camping rig, but I've got a better mileage beater to put miles on.

 

[bkg]

Needed new tires and decided to have some fun with the truck now that it's about to turn over 100k miles and needs a list of PM items addressed anyways. Going with Toyo A/T II in 285/75R18 after picking up a set of 18x8 steelies and will need to regear. Unrelated, but absolutely loved the 255/85R16 Toyo M-55s that I finally wore through. Put 50k+ miles on them. Would recommend.

3.91 rear and ~31" stock tire size has the math at 4.40. Do you think 4.56 gears are enough or should I look to go lower with 4.88s? Wheels and tires are going to be a lot heavier than stock.

Truck is my daily driver in winter and sees a lot of highway miles. Summer it's my road trip/camping rig, but I've got a better mileage beater to put miles on.

Read the catch and release thread from addicted off-road in this section. He went 4.88's and had a great explanation why

 

[Samiman]

I have 4.30 gears in my 01 with 285/75/16 duratracs and it has plent of power. The other great thing is vehicles came with that gear from the factory. I have $350 into my gear swap. Front diff came out of a 4runner and the rear came from a t100. My speedometer is 2 mph faster with this setup.

 

[RMCO]

Just an update for anyone that might read this later.

I went with 4.88s with an Eaton (Detroit) Locker in the rear. Zero regrets. Feels spot on with the 35s. The locker is super quiet and I've had zero drive-ability issues. Hopefully it isn't too much fun once the snow flies.

 

[wrenchMonkey_]

Interesting. I am wanting to go to 315/70/16 some day and on my 06 DC I was wondering what I'd re-gear too. How is your fuel economy? How many miles per tank are you averaging now compared to before?

Thanks!

 

[RMCO]

Interesting. I am wanting to go to 315/70/16 some day and on my 06 DC I was wondering what I'd re-gear too. How is your fuel economy? How many miles per tank are you averaging now compared to before?

Thanks!

Haven't put a full tank through it yet. Still putting around breaking everything in. I'm running 285/75/18 on some steelies I picked up for pennies. I'll make sure to come back and post mileage numbers once I have some.

 

[wrenchMonkey_]

-------------------------------285/75-18 315/75-16 Difference
Diameter inches (mm) 34.83 (884.7) 34.6 (878.9) -0.23 (-5.8) -0.7%
Width inches (mm) 11.22 (285) 12.4 (315) 1.18 (30) 10.5%
Circum. inches (mm) 109.42 (2779.37) 108.71 (2761.15) -0.72 (-18.22) -0.7%
Sidewall Height inches (mm) 8.42 (213.75) 9.3 (236.25) 0.89 (22.5) 10.5%
Revolutions per mile (km) 579.03 (359.79) 582.85 (362.17) 3.82 (2.37) 0.7%


Youd be just a bit bigger than me, so I'll take the comparison.

 

[RMCO]

Last tank was good for 15.78 mpg combined. That's mostly dirt and rural highway, some city, and about 180 miles worth of freeway averaging around 80 mph without cruise control. Slow it down and set the cruise and I bet I can get more out of it. Not really all that bad for a 4.7l designed before 2000 mated to a 5 speed pushing 35s. I was mentally prepared for much lower.

 

[rickashay]

Interesting on the 4.88's. I have 4.56's and 35's and wouldnt have done it any different. I guess it depends how the truck gets used though.... mine is either parked or on the highway heading to the trails.

 

[Blender]

4.56 on 34" tires and I should have gone with 4.88. It's geared lower than stock, but still struggles up steep climbs at 65 mph. Way better control in the dirt though.

 

[seanpistol]

I have 4.56 with 35s and at times I wish I went with 4.88s, but my fuel economy is great. Practicality tells me 4.56 was the right choice since I daily drive my truck. When I'm towing toys or driving through the mountains, I wouldn't mind having the lower gears. It's all in how you use it.

 

[RMCO]

Better fuel mileage would have been great, but the truck just feels solid with the 4.88s. Total butt dyno effect. I forgot what the truck felt like stock after running 33s on stock gears for ~65k miles, but now it feels like it has many much more power, which is nice. I daily drive my truck but I don't have a commute to work so the loss in mileage wasn't a deal breaker. I'm either telecommuting or driving it to the airport. The rest is groceries or play.