Hello,
I have an '04 4Runner Limited V6 4wd and TPMS (with 78k miles on her.)

I am about to change my rotors and brake pads (all 4 wheels) in the coming weekends.
I went to order some Centric rotors from tire rack, but the site (after entering my vehicle information) "offers":

1) Note: (Front) Plain vented rotor. For models with 319mm diameter front rotors.
or
2) Note: (Front) Plain vented rotor. For models with 338mm diameter front rotors.

Does my 4Runner require 319mm or 338mm front rotors?

Thanks again!

I believe that only the Sport models had the 338mm rotors. The 319mm rotors should have a 13WG or 13WL marking on the calipers while the 338mm rotors have a 13WH marking on the calipers. Here's the rotor diameter as indicated by the markings on the calipers:

13WH- 13.3"/338mm rotor diameter
13WL- 12.6"/319mm rotor diameter
13WG- 12.6"/319mm rotor diameter

This thread may also help:
How To: Upgrading to Sport Brakes (319 to 338mm)

I called the local parts department at the dealership. The parts guy gave me two part numbers for the 2004 V6 4Runner Limited:

43512-60150 (For 17" wheels)
and
43512-35320 (For 116" wheels)

Does it make sense the the 17" wheels would require the 338mm rotors and the 16" wheels would require the 319mm rotors?

Nope. Don't go by the 16" 17" thing. Because you have a LTD, the only way to know for sure is check the P/N's that was given to you on the calipers above or actually measure the rotor. Chances are that yours are the 319mm, but some LTD's came with the bigger brakes.

Yeah your limited could have either size. The dealer should be able to use your VIN and look up what it had when it came from the factory. Other than that you have to take the wheel off and look.

I will take the wheel off and check it tonight for sure.

Thank you very much for helping a complete novice!!!

Even easier that putting your faith in a parts monkey, you can look it up yourself at Toyota Auto Parts at Toyota Parts East | Genuine OEM Toyota Parts Enter your vin and you will see what size rotors you have.

Did not work for me.

Lots of references to parts for 17" wheel for my VIN
and we know that is not enough info for rotors and calipers

I was happy to see on my '05 V8 4x4 LTD had the 338mm rotors.

Seems odd to me they would put larger rotors on but, from what I understand, the pads are the same size as other models. So, my pea brain tends to think I'm getting the same amount of friction when the brakes are on. It's still a two piston caliper from what I've read.

Other than perhaps better heat dissipation due to more mass and larger surface area, I don't really see the point. I'm not a mechanical engineer though so maybe I'm missing something.

4 piston, but yea. I agree.

This point seems to come up every time there is a discussion on rotor size. I can see your rationale in the thought, but it's because braking is a function of torque arm, or "moment" if you will, not just a straight force and friction calculation.

So the further you get away from the hub (bigger rotor), the more force you are able to apply. Good analogies would be: the arm on your breaker bar, trying to push a door shut with 1 finger close to the hinge vs close the handle, or trying to stop a spinning fan blade at the hub vs at the blade tip.

If it were just a linear force calculation, all rotor surfaces could essentially be sized just big enough to accommodate your pad size (barring the whole heat dissipation thing).

Hope that makes sense.

So I have the front wheel off, and see a clear 13WG.

I unfortunately see no marking on the rear wheel.

Is it safe to assume rear is the same as the front? If not, where is the marking on the rear? What am I missing??

Thanks!

319mm for 16" , 338mm for 17"

If you put the smaller on the 17" set up it'll go on just fine....BUT..the rotor will rub the dust shield and make a Horrible noise. BTDT, wasn't paying attention when ordering.

So in my humble opinion, if your truck came with 17" then get the 338mm. If you or previous owner has changed wheels.... start consulting part #'s.

I have 17" original wheels (I am the original/only owner).
The earlier post in this thread said that you can't necessarily base the rotor size on the tire size.
Do you disagree?

I'll take a stab at just measuring the rotor tomorrow.