maximum tire size for stock axle and gear ratios

[toyslug]

what is the maximum tire size recommended for the stock axles before one has to worry about excessive wear/tear vs. benefits of having larger tires; and max tire size limited by keeping the stock gear ratios? this is for a fj60 with 2" OME lift. TIA.


forgot to add the truck also has the 5-speed tranny upgrade and currently have 31x10.5 bfg a/t tires on 15" wheels 1" wider than stock wheels.

 

[Cruzerman]

Cruiser axle is tough, plenty strong for any tire you can fit on with a 2" lift. As for gearing, this is a matter of taste, so your going to get a lot of different opinions. IMHO, I would say 31". Above that, the truck seems geared too high for my liking. Especially with the 5 speed. I barely used 5th gear with 33's before I put in 4.10 gears.

That being said, if you want 33's, put them on with the knowledge that you may not like the gearing and it may have to be replaced. I did this, didn't like the gearing (loved the tire size though), and then bought a couple of fj62 third members. If you can't find these cheaper, cruiserparts has these for $200 delivered. Swap right in and have 4.10 gears. Also makes for a great time to do new brakes, 4runner caliper upgrade, and knuckle rebuild. Oh, and lets not forget a locker install.

 

[Ryan S.]

Many here have said that 33's are pushing it. Most say they are OK if you aren't pulling a load, and if you don't mind slipping the clutch a little more on the hill starts. But once moving, the rubber overdrive is nice. Next set of tires for me will be 33's, but I pull a small trailer sometimes, so I need to install 4:11's, which will bring it back close to stock.

 

[Micah]

i know that when you put bigger tires on you mpg goes down so... if you put 4:11's in and make it more like stock if running 33's will your mpg increase, get worse or stay the same? i really dont have much knowledge with gears and such, thanks for the info in advance.

 

[Stumpalama]

i know that when you put bigger tires on you mpg goes down so... if you put 4:11's in and make it more like stock if running 33's will your mpg increase, get worse or stay the same? i really dont have much knowledge with gears and such, thanks for the info in advance.

The idea that bigger tires= lower gas mileage is not necessarily true. Gotta be careful with absolutes on this board If you were running 31's with 3.70's then switched to 33's w/ 3.70's, your engine would be turning at lower RPM's at the same speeds, thus lowering gas consumption. I believe wind and rolling resistance factors are negligable (in the calculations) between these tires.
Try this page and put in your gear ratios and tire size: http://www.f-body.org/gears/
http://www.4lo.com/calc/geartable.htm

 

[pismo62]

I agree with cruizerman, I have a fj62 and put 33's on it, with 4.11. My feeling is I need to go up to the 4.56 gearing, of course with a locker (safety reasoning, I keep telling my wife). Good Luck. Guy

 

[Mark W]

Two differnet questions here.

1) what size tires can the axles handle.

I feel that with a 2F or mild V8 and leaf spriung suspension, up to 40 ich tires works fine. Larger tires, more powerful engine or a coil spring suspension set to make traction and you have more worries about axles.

2)Appropriate tires with stock gearing.

I'd consider 33s the limit. *Maybe* 35s with the 5 speed, but fifth gear would be pretty pointless. A set of 4.11s would work very well with 35s and your 5 speed.


Mark...

 

[cody c]

35's with 4.10's stock on the bj60. fith is a little pointless but i turbo-ed it and use fifth again. you might find 4.10 gears used from someone with a bj or be able to entice them to upgrade and get their old gears. ill be doing mine in the fall next year and will probally list them in the for sale section.

 

[Mike S]

31" for the 3.73 stock gears, unless everywhere you drive is downhill. Go to 33's with the 4.10 and the 5 speed - perfect.

 

[RredFJ40]

I love my 33x1050's and 3.73's on the road. I occasionaly pull a small trash trailer to the dump. I frequent hills and can pull a grade at 65 (speed limit is 55 around here) with no problems. But I also feel like my 2F has a bit more power than others have (just from hearing people complain). Off road is not so great, way too fast for slow technical work. I will be going to 4.11 or 4.56 soon.

 

[toyslug]

guys- thanks for your input