Maximum tire size without a lift?
 

What is the maximum tire size for a 94 4runner that is at stock ride height? I remember reading somewhere that the max size without any rubbing is around 32-33 inches, is this true? I am currently running 31X10.50's and would like to get some bigger tires, but I don't have the funds to lift my truck so......

33x10.50's with some hammering of the pinch weld

# 2 from the VERY VERY VERY FREQUENTLY ASKED QUESTIONS https://www.yotatech.com/~corey/4runner_faq.htm

2. What is the largest tire I can fit under my stock 4Runner?
For 1st and 2nd gen 4Runners and trucks you can safely fit 32x11.5s with little or no rubbing. For 3rd gens you can fit 265/75 R16.

However, tire size varies by manufacturer so some may rub a little more than others. Mud tires tend to vary more than street or A/T tires so they may rub even more. Also, 2 hidden concerns with going bigger are the speedometer offset and the possible loss in power. The loss in power is the result of the change in the effective gearing by going to a bigger tire. The severity of the power loss is dependant on your present gearing and how large a tire you moved up to. To remedy the loss of power you should change your gears in your differential(s).

Having said that, usually if the tires are only enlarged 1 inch most people just live with the loss of power and speedometer error. Most 3rd gens don't feel the loss of power because the engine is more powerful.

IMHO, 33x10.50 fits better than 32x11.50 ...

A guy on here ran 35x10.50 with no lift, and he claimed no rubbing, but the pictures sure looked like he rubbed A LOT.

I have fit 34x9.50 TSL's (same diameter as most 35's) with no lift, but they definitely rubbed, even after pinchweld beating and some minor trimming. Different offset rims might have cleared it, a 1" body lift would have definitely cleared it.

I'm sorry for asking another noob question, but what do you mean by "hammering the pinch weld"? And how much of a loss of power are we talking about?

For lift vs. tire size information as well as fender/pinch weld mods, see:
- http://www.4crawler.com/4x4/ForSale/...it.shtml#FAQ10

http://www.4crawler.com/4x4/ForSale/...BodyLift49.jpg

No loss of power with taller tires, what you lose is torque to the road, assuming gearing not changed. Loss = new-tire-diameter/original-tire-diameter, so with say a 31" tire, you lose about 10% torque and the engine revs drop about 10% over stock.

So in other words, it would just take a little longer to get rolling/pass on the highway since not as much torque would be transferred to the road?

Yep, more shifting or shifting sooner, slower acceleration and probably lower MPG since the engine is working harder. Your speedometer and odometer will also read slower than normal. Would be about like the difference between 4th and 5th gear on a manual tranny.

How would I find out what gears my axles have short of looking on the vehicle specifications plate?

you can jack the vehicle up and rotate the rear tires to discover the ratio.
look here
http://www.4crawler.com/4x4/4R_TechInfo.shtml
and here
http://www.4crawler.com/4x4/ToyVIN.shtml

If you dont have money for a lift and regearing are you really wanting to spend more money at the pump? You will feel a difference, in take off and in your wallet, if you go to a 33 without regearing. Just some food for though...

Yeah I tried it and went back to my 31's until I get the cash to re gear. it was horrible.

Torque and power (you must mean HP) are 100% directly related.
Decrease torque and you decrease HP.
Decrease HP and you decrease torque.
Increase torque and you increase HP.
Etc.
Etc.
.
.
.
.

As an interest point and an aside, engine dyno's don't measure HP.
They measure torque and then the HP is computed from the torque.




:)
Fred

* look at the axle code on the door jam. but according to you dont want to go this route.

* try to balance your truck on jacks to count the number of rotations of the drive line vs wheel rotations, but good luck telling the difference between 4.1, 4.3, 4.5 or 4.8 rotations

* pull you diff apart and count the teeth on the ring and pinion gears




usually cross referencing you axle code on the door jam is the easiest.

I think 4crawler means no loss of power from the engine/technical point of view, FredTJ is referring to "at the wheels" or butt dyno.

TECHNICALLY, the engine is still putting out the same power/torque, but with the higher effective gear ratio, you see less torque at the ground, which is technically less power (since power basically is torque * RPM)

Less "power" at the ground IS less torque at the ground, no technically about it ;)




:)
Fred

You have less torque to the ground but more speed, as bigger tires will make you go faster for the same RPM, given everything else is the same.

Speed really has nothing to do, directly, with torque or HP ;)

However I could argue that, given your statement above, that you will not have more speed, as you won't have enough torque (HP, whatever) at the ground to get your up to redline in top gear :)
This is actually a pretty common "complaint" from those who go up to bigger tires and don't re-gear.
"Geee, I can no longer even use 5th gear" ;)



:)
Fred

Power equals energy, and energy is conserved, so power is conserved - less torque has to equal greater speed.

Power is a function of force and speed, or work per unit time. So if you have 10% less force (torque) but 10% more speed you get the same power as before. Assuming there is enough torque margin in the engine to handle the larger tires, at a given engine RPM the ground speed will be faster with a taller tire than with a shorter tire given the same gearing. And I do know that aerodynamic drag and frictional forces do increase with speed.

Agreed, if you are at the max torque output of the engine and you try to add 10% load, it will slow down (or at least not speed up). And if you are right at the bottom of flat part of the torque curve, slowing down the engine speed will cause a loss in torque that it can put out. It is usually torque that folks "feel" as (horse)power as it is torque that causes the vehicle to accelerate. And as Carrol Shelby used to say "horsepower sells cars but torque wins races".

But if you have an engine that puts out 100 HP and you change the size of the tires, the engine will still put out 100 HP, that power does not vanish. And if you chage the gearing to match the change in tire size, you should get the same speed and acceleration as before, neglecting the increased rotational inertia of the heavier tires.

If this were not the case, if I put say 14" tires on my 4Runner instead of 28" stockers, I would now have twice the engine power or 232 HP instead of 116, and if I went to 7" wheels (yes ridiculous size) and I would double my power again up to 464 HP.