Tundra re-gearing

Fenrisulfr

Fenrisulfr

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Joined
Jan 27, 2013
Specs - 5.7 L V8 4x4 Tundra
Stock gear ratios - 4.1 (w/o tow package), 4.3 (w/)
Stock tyre diameter is 32"

I'd like to accommodate 39.5" ROK-10s, but that would imply a gear ratio of about 5.06*, whereas the largest one available is 4.88. Would I be able to get away with a 4.88 gear ratio and the IROKs without killing the transmission or another very expensive component? The worst this truck will see is gravel, ice, and snow, so the application would be for mild off-roading (if that).

I appreciate any input regarding the transmission. Thanks in advance

* (4.1) x (39.5)/(32)= 5.06
 
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should be fine with the 4:88s. That truck has a ton of torque and thats what gets you moving. Those 39.5 irocs will probably measure closer to a 38-38.5" anyway with my experience with irocs. tend to run smaller than claim. Allthough, you may begin to go through hub bearings in the front end with a big heavy tire and offset rims. Post pics when done! Sounds like a nice ride...
 
I think 4.88 would be the lesser of the worries jumping to 39's. I don't know yota's or tundra's but here's a reply from one of their forums about going to 38's. I run 4.88's on 33's in a Cherokee and it's over geared but 35-36 would be the sweet spot for me. Of course I have a manual which means I don't have the benefits of a torque converter like you will. Bottom line check the other factors like trimming and lift. Your braking, steering, towing will be effected even if it's a street rig.

if your looking for offroad and not a mall crawler, a SAS setup will be the best, it WILL cost a pretty penny, but probably not much more then the RCD kit, it will probably involve more fabrication but in general most off roaders I know of prefer a SAS for the articulation and ease of setup that comes with it.

That being said I dont know much aboru the RCD kit and it may or may not be good for offroad, plan on getting new rims with an offset so you can turn those big tires you want, the other thing I will not from personal preference is body lifts and heavy offroading seems to be a a bad idea. Think about moving the body up 3 inches and having these long bolts holding to the frame, now picture your truck swaying sideways and the tensile stress that will be placed on those bolts.

just some food for thought, oh and some more food for thought, I love my tundra, but it is an expensive rig to setup for 38's, there are other trucks out there that would be better suited for such a task, (although I am somewhat biased to 1985 and older toyota trucks that came stock with the solid axle)
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