How to Fit Bigger Tires on 5th Gen 4Runner? (Cutting & Trimming Guide)

How to Fit 33″ and 34″ Tires on the 5th Gen 4Runner – Areas for Trimming and Cutting the Wheel Well

Areas to look at:

• Trimming the body
• Push back and relocate fender mount point
• Trimming front and rear fender liners
• Trimming plastic rocker panel caps (valance caps)
• Bending pinch welds
• Body Mount Chop (BMC)
• Optional: Bend pinch seam
• Optional: Remove splash guards

Recently, we wrote an overview of wheel size. In that post, we slightly explained what the largest tire size was that you can fit on a stock 4Runner along with a lift or leveling kit. We also talked about going beyond 33″ tires with lift kits and leveling kits. In that post, we covered tire size, tire specs, wheel sizes, and how they work with tire sizes, and much more.

Today, we are looking at what it takes to clear larger tires, and more specifically, 34″ tires.

If you are looking to upgrade your factory 31″ tires with 33″ or 34″ tires, this post is for you. We have the 285/75R17’s (33.8″) on our 2014 TEP and had to trim quite a few areas to prevent rubbing.

With this said, there is a big difference in running 33″ vs. 34″ tires.

Moving up from a 33″ tire to 34″ tire

34″ tires require much more trimming, bending, and cutting than a 33″ tire.

To run 34’s on your 4Runner, I would recommend an adjustable suspension or at minimum a 2.5″ lift or leveling kit. A Bilstein 5100, an Eibach stage 1 or a or something like the Falcon tow/haul kit would be good examples. For reference, we were able to run the 34″ tires with 2.5″ of lift in the front on one of our 4Runners.

Once you lift your truck prepare to trim/cut your body, fender liners, rocker panel caps, body mounts, pinch welds, pinch seams, and the splash guards. Keep testing the fitment until you are satisfied with the amount of clearance you have around the tires when turning your tires forward and reverse at full lock. Finally, make a run at stuffing your tires in an off-road scenario in order to prepare for the next trails ahead.

After going out a few times, we ended up doing little more trimming each time.

Let’s jump into exactly what area you need to trim in order to clear 34″ tires.

Recommended Tools and Materials

• Dremel
• #4 Hammer
• Vice Grips
• Lineman’s Pliers
• Razor Blade or Utility Knife
• 10mm socket wrench
• 10mm open-end wrench
• Masking Tape
• Optional: Floor jack
• Optional: Jack stands
• Optional: Rubberized Rust Encapsulator
• Optional: Plastic Edge Trim
• Optional: Powder Coating, Spray Paint or Bed Liner
• Optional: Grinder/plasma cutter for BMC
• Optional: Welder for BMC

Trim 4Runner Body & Fender Liner

This was one of the first real modifications to the 4Runner that had us rethinking larger tires.

“We have to trim the actual 4Runner body?” I said. Anyway, we did it and it wasn’t that big of a deal. It’s like ripping off a bandaid. You will be much happier with 34″ tires than that missing piece of your body. You need to trim your body in order for the 34″ tires to clear all the way around at full lock, especially when stuffed.

Not trimming your 4Runner’s body will eventually lead to rubbing when your wheels are at full flex and wheel lock (when your tires are fully turned, driver or passenger).

Do your best to pick a good line using some masking tape and then proceed to cut that line with your Dremel or cutting tool of choice.

Here is a post on cutting the body and fender liners for reference.

Push Back Fender Liners & Trim

Fender Liner Step #1 – Pushing the Fender Liners Back

The front fender liners will take some adjusting. To start, you need to locate the hole that your 10mm bolt is going through your body and into the fender liner. Loosen that bolt and push back your fender liner as much as possible. Literally, push the fender liner towards the front-end of your 4Runner.

Once you are not able to push any further (or, once you have gained desired clearance), mark the spot on your fender liner with a white sharpie at a new point where the body and liner meet. You’re just finding a new point on your body where you can attach the fender liners further inside the bumper.

After you have marked your spot, let the fender liner out again. Now drill a hole in your marked spot. Use a bit that is less than the width of your 10mm bolt for your bolt to feed through and catch on. After you have the hole punched, tighten everything up.

Note: There are two bolts that go through the body and into the fender liner, You may need to drill two holes for both bolts that secure the body to the fender liner, or just leave one bolt holding your liners in place.

Fender Liner Step #2 – Cutting unwanted section from front well Liner

After you have your new spots located, and mounted, turn your wheels and see where your tires are rubbing.

Steps for trimming your fender liners:

• Back out of your driveway and turn your wheels, passenger and driver, you will start to hear rubbing.
• If your driveway doesn’t work, find a spot where your front tires are higher than the rear tires, allowing them to “stuff” into the wheel well.
• As soon as you start to hear your tires rubbing, stop.
• Get out and mark the location on the fender liner.
• Pull back into your garage and cut off the desired amount of that section.
• Repeat these steps until you don’t hear rubbing anymore.

We had to cut off a good six inches of fender liner before we stopped hearing our tires rub.

Trim Plastic Valance Caps (Rocker Panel Caps)

Rocker Panel Caps After – And, they were still Rubbing at flex

You will need to trim your plastic valance caps.

Some people call them rocker panel caps, and some people call them valance caps. Either way, you will need to trim these pieces of plastic that interfere with your larger tires.

You don’t need to leave the inner bolt connected as the rocker caps are held in place by two small clips on the inside. You can actually take the entire inside of the rocker caps off, and just leave the face (the outside) showing so it looks factory.

How much you cut off depends on your goals and tire size but this area will need to be addressed as it does cause rubbing, even on 33″ tires.

Body Mount Chop (BMC)

Body Mounts: Before

Chopping The Body Mounts, Welding on New Plate: After 

This one goes without saying.

You will absolutely need to chop your body mounts.

Toyota extends the housing around the body mounts into the wheel well quite a bit. Most of this housing is just wasted space. You can take quite a bit of this housing off and give yourself plenty of extra space in the wheel well.

Companies like Metal Tech 4×4 have body mount chop kits, but any reputable 4×4 shop should be able to cut the ends of the mounts off and weld a new plate on.

If you don’t know how to weld, take this to a shop that can do it for you. The cost is pretty cheap ($100-$200), and any good shop should have a body mount chop done in a couple of hours.

Remove Splash Guards & Rear Fender Trimming

It might look gnarly at first, but trust me it’s not. It’s nothing that can’t be fixed.

If you make marks with a hammer or a cutting tool, you can cover this up after sanding down, then applying primer, flat black paint, then finally some 3m undercoating or rubberized flex seal.

The splash guards and rear fender liner are located in the rear housing of the 4Runner wheel well. Some 4Runner’s might have the actual mud splash guards. If you have these mud splash guards, you have the option of taking them off.

The inner fender liners on the rear wheel well are thick plastic pieces of plastic that prevent mud, dirt, and grime from hitting your firewall. But, the firewall is well covered by a thick layer of undercoating, so dirt and grime hitting this surface area can be washed away.

Removing and cutting these inner plastic pieces is not that big of a deal.

Pinch Welds – Hammer or Bends or Cut?

It really depends on how bad your tires rub with this area. We thought we solved all our rubbing problems, but then we added the wheel spacers. After the spacers, we started rubbing more on the fender liners and these pinch welds.

There are two points of the pinch weld that stick out a little further than the rest of the area (top image circled). In the top image, you can see the portion that we simply bent in. I just grabbed two pairs of vice grips/ clamps and peeled it back.

After Bending the Pinch Welds in

Pictured above is the lower area of the pinch weld. After rubbing at flex, I went back in and hammered both sides all the way back in towards the wheel well.

Be careful not to hammer this area too hard as you may risk setting your door jamb line off-center. Take your time and be precise about how you handle this area. Bending the metal is usually a safer option but sometimes you just need the force of a large hammer.

If you do decide to hammer these pinch welds back in or “fold them over” and end up with off-centered door jambs, you can always hammer the door jambs back into place from outside in.