From The Mall to the Trail: Fitting Upsized Tires on Our '04 Lexus GX470 Project

• September 14, 2021
• Story By
  Mike Garrett

For a long time, the 2003-2009 Lexus GX470 was one of America's most under-appreciated off-road platforms, combining stout body-on-frame Toyota truck underpinnings with a dash of Lexus refinement and V8 power. 

Today, it's fair to say that secret is out—and in the last couple of years both demand and prices for secondhand GX470s has soared. That means bargains are a lot harder to find these days, but the potential and capability of the first gen GX470 remains as strong ever.

Finding Craigslist Gold

That's also why I was surprised a couple months ago to come across a 2004 GX470 on sale locally for what seemed like a too-good-to-be-true price. The ad had just popped on Craigslist a few minutes earlier, so I called the seller and was pulling up to take a look 30 minutes later.

This example was 100% stock, had nearly 260,00 thousand miles the odometer and was being sold by the original owner. Along with the mileage the reason it was being sold so cheap was because it had a check-engine light illuminated on the instrument panel. He'd purchased a replacement vehicle and decided to sell the GX in "as is" condition.

After a test drive and a few minutes of thought I decided to purchase the GX at asking price. It would need a little bit of work, but even with that considered the deal was too good to pass up.

Getting on the Road

Fortunately, the check engine light was fixed $100 later after replacing both of the front 02 sensors with new OEM parts. The GX passed California smog with no problem, and with the mileage being so high I also decided to have a trusted local mechanic do a timing belt and water pump replacement to hopefully ensure the 2UZ-FE V8 would have plenty of life in it. Now it was time for the fun stuff.

For all of my car enthusiast life, my experiences were with road cars, usually low-slung, stiff riding and built for deserted highway on-ramps, twisty roads and weekend track days. 

The off-road adventuring thing had always been tempting for a variety of reasons, and I figured a 4x4 SUV like this used GX470 would be a great way to dip my toe in the water while also giving me a more practical family hauler and daily driver when compared to my 2016 Mustang GT. 

Sold as the Land Cruiser Prado overseas and sharing its underpinnings with the Toyota 4Runner, the upgrade potential for the GX470 is nearly unlimited. But first things first—I wanted to ditch the worn out stock tires and the crusty, chromed factory alloys that had been on the truck since new. 

Ridge Grappler Tires: an Easy Choice. Tire Size? Do Your Research.

Having heard so much about Nitto's legendary Ridge Grappler and it's great mix of off-road capability and on-road comfort, the hybrid terrain tire was the easy choice here. But what size to go with?

I could have simply gone with the same factory 265/65/17 (30.55") size, or gone with the slightly larger 265/70/17 (31.65") size that many Toyota truck and SUV owners go with.

But after doing a bit of research on online forums, and talking to some other owners, it seemed like a 285/70/17 (32.76") was doable with some minor modification. And since I'd be getting new wheels at the same time, I decided to go for it. Go big or go home, as they say.

While a suspension lift is part of my longer term plans, which will vastly open up room for bigger tires, for the time being I wanted to see what I could make work on an otherwise stock truck. 

Wheels? Keep it Old School

Now it was time to choose some wheels. The GX470 shares its 6x139.7 bolt pattern and basic fitment with most of other Toyota trucks and SUVs, meaning theres's endless wheel options to choose from. But there was one wheel I had my eye on even before I bought my GX: the KMC Roswell. This recent addition to KMC's lineup is styled after a vintage steel wheel, but in wider sizes and using much lighter aluminum construction.

The wheels are the same 17" diameter as the OEM wheels, but significantly wider at 8.5 inches. And they come in either a black or anthracite finish, the latter of which I thought would look great against my GX470's (slightly oxidized) gold paint.

But Will They Fit?

With the wheels and tires in hand, it was off to the tire shop to get them mounted and balanced. And then would come the big test of seeing how (or even if) they would fit.

Using a set of Gorilla lug nuts, we mounted the beefier Ridge Grapplers and KMC wheels without issue. Visually, it looked like they fit fine, but we wouldn't know much until I tried to drive the GX with the new setup.

And not surprisingly, the moment I tried to roll the truck out of the driveway, the rubbing was apparent. The rear was totally fine, but as my research had told me, there were a couple places where the tire made contact with the frame and body.

The Nip/Tuck

We rolled the GX around, turning the front wheels lock-to-lock to see where it was rubbing and then back in the driveway we went to do the necessary modifications. With the front wheels and tires off, we begin by removing the plastic lining from the fenders, opening up some much-needed room for the larger tires. We also busted out the hammer to bend in a small part of the frame that was lightly grazing the top outer part of the tire.

Next we pulled out the saw and trimmed a small part of the lower front fender where the tire was pushing the plastic outward, and did the same to some of the plastic running boards on the rear of the front fender. Fortunately, the cut to front fender was subtle enough to not notice without looking for it, and the running boards will likely be removed entirely in the near future.

Last, but not least, was to a notch a very small part of the outer frame where the tire was rubbing during U-turns at full lock. Had this been a brand new Lexus luxury SUV I would have been hesitant to do some of this stuff, but since this was a nearly 20 year old rig that was far from pristine I didn't feel too bad.

Mission Accomplished

All in all, it was pretty easy work, and the biggest issue may have been the decade and a half worth of leaves and dirt that fell out from the fenders when we pulled out the lining. 

We quickly put the wheels and tires back on and headed off for a drive, happy to see (and hear) that there was no more rubbing, even during U-turns and in tight parking lots.

So if you want to know if a 285/70/17 is possible on a stock GX470, the answer is yes*, with the asterisk being as long as you don't mind spending 45 minutes doing some light trimming and cutting. 

I'll be back again soon with some more impressions on how the new wheels and tires have changed (or haven't changed) how the GX drives, how it looks and how it performs off-road but I think it should be obvious from the photos just how much they've changed the personality of this formerly virgin GX470.