LX570 Build v37 for 37s

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TeCKis300

TeCKis300

10 Year 15 Year
Joined
Apr 27, 2011
Threads
185
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11,460
Location
San Diego
Stock on 31s, then 33s, 35s, and now what feels like build v37 of Flexus on 37s. Can't leave well enough alone and it's an itch that must be scratched.

Previous build on 35s - Builds - TeCKis300 LX570 "FLX" Build - https://forum.ih8mud.com/threads/teckis300-lx570-flx-build.1260158/#post-13989513

Previous build on 33s - LX570 Slammed on 33's - https://forum.ih8mud.com/threads/lx570-slammed-on-33s.975670/#post-10874074

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The goal of v37 continues an attempt to remain faithful to the Land Cruiser (LX?) spirit as mother Toyota (Lexus?) intended - a do everything robust vehicle. Meaning it's gotta do commuting duty, easy enough for the wife to drive, road trips, tow vehicle, date night, Costco runs... everything you'd expect a stock Cruiser to do well. Just turned up to 12 for added capability. Maximizing suspension travel without limiting up travel, while making sure there is enough clearance to really play in the dirt and rocks.

35s served such a good balance in the 3 years and 40k miles in that configuration. Hope I'm not screwing up a good thing as 35s might just be the sweet spot as an Overlanding rig build. I'm interested to see if I can still find that balance on 37s. While opening up Rocklanding capabilities. Granted one of the more significant trades is gas consumption, and I have an LRA aux tank to deal with that, but I'm hoping not to give up much else.

For those joining my builds, I'm big on using OEM parts where possible. As an engineer, I can appreciate how much more developed OE parts are than shiny aftermarket stuff. I look at these builds wholistically, just as I do in my day job, so things like suspension geometry, aero, and weight are major factors in my trade space. An OEM++ build is how I like to look at it.

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EDIT - Current build list updated 4/28/26​

Tires​

Suspension​

Body Lift​

Transmission​

Brakes​

Gearing​

Power​

Fuel​

Armor / Recovery​

Electronics​

Communications​

Lighting​

Roof Rack​

Interior​

Camping​

 
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37s TABLE OF CONTENTS​

Tires​

37x12.50R18 Yoko Geolander AT-X (Really liking this tire as an R/T tire in capability, with A/T sensibilities)
  • On Tundra 18x8 +60 wheels finished in satin black (104lbs total with tire)
  • Spidertrax 1.25" wheel spacers (Thanks @Artie!), effective offset +28mm
  • Apex RPV fast deflators
  • EZ Flate Locking Air Chucks (compatible with Apex RPVs)

​

Body Lift​

- NST Spec custom .75" Body Lift

Highly recommend 1" or 1.5" BL which is what NST currently offers. .75" is probably less than minimum and I was willing to do the additional massaging within the fender to make this work. To keep center of gravity as low as possible, even as BLs have minimum impact. Also to keep ergonomics of getting in/out and car camping good.

​

Front Wheel Well Clearancing​

See below

Rear Wheel Well Clearancing​

See Post #3

Additional supporting mods, previously done for 35s​

Suspension​

- AHC sensor lift 1.5" lift front / 1" lift rear
- AHC Long Travel
- Durobumps DBF17T Front and and DBR375 Rear

For IFS, lift doesn't necessarily apply as it doesn't change the suspension stroke limits. I want to make sure I have full clearance to stuff tires offroad when articulate. The Durobumps don't really limit travel either as they are more for g-outs in fast driving.

Brakes​

- OEM Tundra front Big Brake calipers, Tundra 354mm disks
- Goodridge G-Stop Tundra braided stainless steel lines
- Hawk LTS Pads

2016+ cruisers already have the larger 354mm disks, so this is for pre-2016. The LTS pads do wonders for increasing friction and bringing back much needed leverage. Enough that it brakes with no excusses.

Gearing​

- Tundra/Sequoia and 100-series OEM 4.3 gears

4.88s might be the better choice if regearing directly for 37s. I was pleasantly surprised that 4.3s feel great with 37s. 4.3s were practically stock gearing for previous 35x12.5s and IMO a better choice for that size. The impact going from 34.5" to 36.5" tall tires feel less than going from stock size to 33.2" tall tires in terms of gearing loss.

​

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Front Wheel Well Clearancing​

Disclaimer - While these instructions apply to 200-series in general, they are meant for the LX570. Land Cruiser are going to have a difficult decision whether to ditch KDSS to make this work as it's almost an impossible obstacle to work around for 37s. Or maybe your KDSS is clapped out and its time to get rid of it anyways? Jury is still out whether using Tundra arms / long travel is sufficient to create enough clearance, which then creates another issue at the fender. I won't address using the Tundra arms and perhaps some else can detail that strategy. My goal is to work within the stock fender as poking tires are not my thing for reasons such as aero drag and cutting fenders.

Before getting into the details, it's probably worth watching this primer to understand some of the dynamics at work


Wheel Offset​

I can't state this enough, wheel offset is critical in making this work. There are obstacles on all sides, including Body Mount, UCA, Fender, Sway bar. I would recommend an offset between +25 and +30mm. I'm using 28mm which is derived from using OEM 18x8 wheels +60 with Spidertrax 1.25" wheel spacers. Lower offset may seem like a solution, but they actually compound the issue of tire swing which puts the tire into the body mount. Zero offsets in my mind won't work unless you want to chop off and do major surgery to relocate the body mount.

Body Mount​

Even with optimal wheel offset and good alignment, the body mount is going to need an aggressive cut. It should look something like this where the rubber above just overhangs.

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I recommend doing a pie cut behind the original metal face, and bending the face back. Versus what many do in the aftermarket by fully cutting off the face to add some expensive piece of branded metal. Note I already had a BMC for 35s, so this cut might not look aggressive, but it is. Use the bushing bucket and holes as reference points to cut back to (credit to @MTKID ).

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The bushing underneath the chopped face is going to need trimming to avoid rubbing noises. It has an heavy integrated steel washer but it's quick work with an angle grinder.

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Control Arms​

I am using stock LCAs, and slightly modified stock UCA control arms. Note on UCAs, it's not advisable to use caster corrected aftermarket arms as these pull the tire closer to the body mount. It's best to use the LCA to correct for caster as this tends to push the tire away from the body mount. Yes, there's limited potential adjustment but it should be good enough unless the suspension is lifted 2.5"+. Large tires actually don't need as much caster as even with only 3 degree of caster, there's enough mechanical trail to maintain good straight ahead centering and stability.

The stock UCA can contact the tire at hard steering lock and full compression. For the moment I've clearanced the arm with an angle grinder as I'm trying to figure out exactly how much more space I need. It's still plenty beefy but I'll weld in some reinforcement later. There may be good aftermarket arms, but I prefer OEM and even with the relief cut, I'd wager it's stronger with longer term durability than most aftermarket arms.

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​

Fender​

Even with a 1" and possibly 1.5" body lift, the fender is going to need work as there's so much uptravel. My goal is to work within the fenders. Some may choose to cut the sheetmetal back about 1.5-2" which will work nicely too. My preference is to keep the stock bodylines so I pulled and rolled the fender out about .75" with an Eastwood style fender roller. Heatgun and patience. I used a wooden pole to measure from various points with a mark, so I could gauge how much I'm pulling. I also folded up the metal tabs that hold the liner. Lots of massaging and grinding. I also spaced out the lower edge of the fender with a 1/4"nut as a standoff.

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Body Pinch Weld​

Using a 3lb or larger hammer, fold over the pinch weld towards the outside of the car. It's a pretty stiff pinch weld of what looks like 3 plys, so it'll take some force and just keep working it to fold and stretch the metal. I've seen other truck guides to cut it into sections, but I prefer not to expose more metal and seems to potential rust. Have some seam sealant on hand to re-seal any gaps. This should open up the firewall side of the inner fender nicely for clearance.

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Fender Liner Plastics​

I wanted to get all the liner plastics back in and was successful at it. Lots of heat gun and massaging. The liners are more important than first blush as they serve to manage airflow but also to protect engine air intake from water, sand, and debris as it breathes from within the passenger side fender. As I was working the metal fenders and pinch welds, I made sure to keep the tabs so I can redrill attachment points in the plastic. Lots of new plastic clips and zip ties. The engine shields will need to be massaged back too. Heat gun to fold them in towards the engine instead of out.

The liner forward of the tire is completely intact. It makes an "L" underneath front bumper. Trick is to shorten up the horizontal part, and re-pin the whole liner approximately 2" forward from the stock position.

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Windshield Washer Reservoir​

With a 1.5" BL, the windshield washer reservoir under the driver side fender is probably okay. With 1" or less BL, there will need to be some massaging. I relocated a couple lines to the side and sanded flush the line clips for more vertical clearance. Also did some heat gun clearancing of the liner.

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Front Bumper Clearancing​

This is probably specific to my build as I assume most will be running aftermarket bumpers. It's very doable with the stock bumper! Again, I prefer the stock tuperwear for its aero and weight advantages. I don't have any pictures but the general strategy is to cut the lowest section of the wheel well lip off, then bond it back to the rest of the bumper with epoxy. Cut ~1.5" deep at the lowest part and taper up to the upper most plastic pin. See rear bumper clearancing for pictures on how it's done.
 
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Rear Wheel Well Clearancing​

The rear wheel wells will be easier than the fronts fortunately as big 37s don't need to pivot. All the clearancing to be done is upwards and aft of the tire. There's no clearance issues against the door part of the wheel well fortunately. For compression clearance consider the multiple modes of articulation that needs different types of clearance. When one rear tire dips and the other is in compression, there will be more travel up but also aft. When it's square compression on both sides, it will eat fender lip. Caution to those trying to run 0 offset, you'll eat major fender lip unless you severely limit travel. Also note for the running panhard correction kits or adjustable length panhard bars, the axle might displace to one side more on compression.

Fender Lip​

I don't have a picture and will grab one later. Rear fenders are thick and double walled and not easily rolled. The fender folds in about 5/8". Take an angle grinder with a thin kerf cutoff wheel and cut about 1/2" away, leaving an 1/8" of return. Need to cut the fender from bout 10 o'clock to 2 o'clock. Use seam sealer to recoat exposed metal.

Driver Wheel Well​

The tire on this side tends to travel rearward more. Will need to cut or hammer back the sheetmetal behind the mudflap about 1". There's also a spot where it comes closest to the frame rail where it protects the A/C condenser. More massaging required with less bodylift. You can see where the tire caught here and folded the metal up. This is where it needs to be massaged back more. Out comes the trusty hammer.

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Passenger Wheel Well​

Generally will need to push things back about 1" here too where all the AHC stuff is. My setup is different as it's cluttered with a lot of LRA Aux tank plumbing so it was a bit of work to get things pushed back. One difficult spot is the main gas fill pipe just above the frame rail where the coupling sleeve is. I don't remember if stock was exactly like this, but that'll be a close spot when the tire is compressed.

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Rear Bumper Cover​

This is going to require some art following the lines of the wheel well to cut the bumper back about 1.25" at the bottom. Strategy is to cut this pie section off. Then bond it back to the bumper skin with epoxy. I found Sikaflex not to work great, but HF Instant Set Epoxy to work wonders. Pictures describe the process better. It was possible to put the mudflap back with some new plastic clips and screws.

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Here's what the cut profiles look like after.

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Impressions​

These impressions are coming from 35s as that's been my daily setup for the past 4 years. Even from that size, the step up to 37s is significant between the 1" tire and .75" BL. It sits up high above general traffic. The LX could pass for a sleeper full size vehicle previously, but it sure sticks out with the amount of sunlight underneath and makes everything else on the road feel 3/4 sized. Several coworkers noticed right away and half of them I've never talked cars with previously.

Adding up height mods: 3" of tires + ~1.25" avg suspension lift + 0.75" BL = 5" taller. Invite AHC High to the party and that's a full 8" taller than stock. Yet the only thing here that lifts the rear axle particularly at the diff and lower shock mounts is the 37s themselves, which is why I'm a proponent of tires as real lift. What would be kissing the diff on a rock with 37s, would be a hard hit bringing the party to a stop on smaller tires regardless of suspension lift.

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They say larger tires make all holes and bumps smaller. Along with the added sidewall, on-road or off, it smooths over everything and the ride is fantastic with AHC on 37s.

Speaking of AHC, it's merits stand out even more. Being able to get into garages with an RTT or making car camping ergonomically reasonable. The AHC low kneel function subtracts ~2", so wife complains much less about 'only' 3" of total lift.

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Part of getting into 37s was to be able to rockcrawl and sidehill without resorting to AHC high for clearance. Traction works so much better with the suspension in its sweet spot, able to put down power more effectively for extreme grades and climbs like what's out in Moab. The track width is wider in AHC N height, which when combined with the overall lower center of gravity increases performance all around. The footprint on 37s is larger. The faces of the tire reach out further. Combined, makes significant improvements to approach, breakover, departure, and sidehill.

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Does this all stuff? Absolutely. I'm not building only a mall or rock crawler on 0 offset wheels. I want every inch of sweet suspension travel running high speed in the desert. I went wheeling 3 days in Big Bear to test it out. Between the malling, crawling, and fast driving, I was able to test out the setup. I did find a few spots that needed more massaging hence the recommendation for at least 1" BL. I spent another round inspecting all the wheel wells adding further massaging where there were witness marks. Some TLC with a hammer does wonders to buy more clearance. Comfortable to say its a success. Here's an impromptu RTI ramp, fully lifting two cross tires and stuffing two.

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I'll always be one step behind you...because you always make these mods work, and document them so well :P
 

What's Left​

EDIT: Putting this here as I've had success so far with clearance the sway bar. It's working well and I'll certainly come back if it stops working well.

forum.ih8mud.com

Clearancing Sway Bar for Large Tires

Looking to get this discussion going as to strategies to fit larger and full fat meats. I recently modded the LX570 sway bar to allow full steering lock on 37x12.5s. For context, I'm running +28 offset and on AHC high (about 4" total lift creating down-angle on the LCAs which pulls the tire...
forum.ih8mud.com forum.ih8mud.com

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PREVIOUS:
Minor rubbing on sway bar at full lock. Left rubbing mark is from 35s. Right is from 37s. Couple possible solutions include adding a bit more camber to push the tire out further. Or cut the curved faces of the sway bar and weld back some reinforcement.

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Mud flaps behind the front tire. Need to fabricate something as I don't like the idea of mud, dirt, and debris getting kick both under and over the rocker.

Towing 8k worth of trailer. Still need to modify a new drop bracket to account for the taller height. Will see how it tows.
 
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That just looks proper sir! But.....

FOR THE LOVE OF ALL THINGS HOLY, PUT CENTER CAPS ON THOSE WHEELS!!!! :p

Borderline getting to where carrying a spare CV is a good idea. Oddly, i know just the guy that will have an extra soon! :)
 
Appreciate these write-ups! I have the 1.5" BL on my shelf that needs to get installed, then a re-gear, and new wheels with 37s planned soon.
 
Those 37s look absolutely perfect on your LX! I've followed your build and suspension mods for a while now. Love what you've done and your thought process on keeping what you can as stock as possible.
 
I hope you will share your towing experiences on 37s.

My 35s on 4.88s with a nice anti-sway hitch tow my 7k trailer fine other than 6 - 8 mpg. Hoping to follow a similar path to 37s and what differences to expect, if any, while towing.
 
Got some more homework done with the write up above. Still some left to fill in.

Boston Mangler said:
That just looks proper sir! But.....

FOR THE LOVE OF ALL THINGS HOLY, PUT CENTER CAPS ON THOSE WHEELS!!!! :p

Borderline getting to where carrying a spare CV is a good idea. Oddly, i know just the guy that will have an extra soon! :)
Click to expand...

Hehe, I can't stand the center caps on these wheels. I've tried a couple times and frankly I like them without, for the moment. I might get bored enough to put something in the centers. Maybe 3D printed caps. Gotta leave something to so do for v38 right?

tbisaacs said:
You gonna go to 4.88s?
Click to expand...

Not out of the question. First impression is that 4.3s work much better than expected with 37s. I did a trip to 8k ft elevation, with family of 4 and full overlanding kit and the gearing felt solid. Including crawling on steep off-road grades. I think the only driving reason may be for towing, and really for the added safety of better engine braking.

I could probably justify building a set of front and rear 4.88 diffs on the side. And when ready, drop them in. I could probably sell the 4.3 set to offset the 4.88 diff build. Build v39?

2014 LEX 570 GA said:
WE HAVE THE MEATS
Click to expand...

Don't skip leg day! More tire, and less suspension lift IMO.

dubyahard said:
I hope you will share your towing experiences on 37s.

My 35s on 4.88s with a nice anti-sway hitch tow my 7k trailer fine other than 6 - 8 mpg. Hoping to follow a similar path to 37s and what differences to expect, if any, while towing.
Click to expand...

Now that the tires have scrubbed in and I've done some tire pressure tweaking, I'm feeling better towards trying to tow my 8k anchor. Even though RCTIP calls for only 35PSI, I find even unladen I need more like 43PSI for good stability. Probably need even closer to 48 PSI to tow but we'll see. I need to re-setup the weight distribution hitch on account of the added height. Just got the extended drop hitch shank in and hope to try not too much later.
 
TeCKis300 said:
I could probably justify building a set of front and rear 4.88 diffs on the side. And when ready, drop them in. I could probably sell the 4.3 set to offset the 4.88 diff build. Build v39?
Click to expand...

I will race you (after getting a ton of tips from you) on v39 :). Jokes aside I really appreciate the time you are putting into sharing the details here. Great stuff.
 
Looking forward to the rest of this, looks killer! Have always loved how the x-ats look too. Ran them when they first came out and definitely would again if I didn't need the snow performance.
 
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