Fitting Full Fat 35x12.5 on an LX (2 Viewers)

Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Join along as I work through making the necessary clearance mods for 35x12.5R20s tires on my LX. These Toyo AT3s spec out to be 34.5" x 12.5". If you have any suggestions, I'm interested in hearing.

Note that this fitment is specific to the LX as it's easier to fit larger and wider tires without the constraints of the KDSS bar on the LC. Not that it couldn't be done (some have), but I'll let another thread address those specifics.

Basic requirements for fitting a tire such as this would be proper offset. I'm using 1" spacers with my stock wheels for an effective offset of approximately +35mm. Offset gets more critical with larger tires and I would recommend offsets between +30 to +35 to minimize mods necessary to make such a fitment work. This offset will put my mild Toyo tires into the fender lip at full stuff so +25 offsets are going to be more difficult. Narrow tires can be made to work more easily as others have proven.

1602011942057.png


1601247239179.png


Areas to address are primarily at the front axle
1) Forward of front wheel, liner
2) Aft of front wheel, remove splash guard
3) Aft of front wheel, sidestep and liner
4) Aft of front wheel, body mount
1601248048584.png

5) Spare tire

Rear axle
1) Roll fender lip


Additional potential rub areas if fitting more aggressive tires
- Sway bar
- UCA

Other recommend mods to support large diameter tires
- Re-gear for 6-speed
- Upgraded brakes (Tundra BBK)

35s in combination with AHC lift, and a mild .75" sensor lift puts things way up in the air at almost ~5.0" higher step in height, or total lift. With another .75" boost into extra high if AHC detects a stuck. Fenders measurements from ground are 38.25" front and 39.5" rear. Thank goodness AHC also lowers to keep daily functionality of loading people and gear reasonable.

1601322847787.png
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Forward of front wheel, liner

Here's the recipe for moving the fender liner forward. I used this same strategy for 33s, moving the liner forward about 1". 35s require it to be pulled forward more. There's no need for dramatic butchering of the fender liner. Most of the liner can be kept, and just pulled forward towards the front of the vehicle by ~1.75". Reuse the stock clips and drill holes to secure them at the new location. I added a 1/4" plastic clip for good measure. Then a couple small cuts (oscillating multi-tool) for the horizontal piece sticking into the well.

This is looking upwards under the bumper:
1601500616313.png


Clean and copasetic
1601500964857.png


EDIT: Rework the upper fender liner
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Aft of front wheel, sidestep and liner

The splash guard will need to come off. There's a chance it could be cut and shaped to be installed back, but I don't have info on that yet.

Under the splash guard, there are a few things to address.
1) Part of the sidestep return will need to be trimmed
2) The metal support bracket behind the trimmed part will need to be folded back with hole face at a right angle to secure mudflap. A wrench or a hammer works well on this.
3) Heat and reshape part of the liner where the rub marks show. Heat gun and a wet towel.
4) May need to fold or bend back where sheet metal joins
5) Body Mount - see next post


1603738547866.png


1601700353176.png


EDIT: Splash/mud guard re-fitted! Not without some effort:
1603739042237.png
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Body Mount

Clearance here is tight enough that it needs to be addressed. About a fingers width clearance at certain steering angles. There's a danger that if this isn't addressed, in situations such as heavy braking during accident avoidance, that the tire could contact, bind, and brake due to contact against the mount. Braking causing more tire pressure against mount potentially locking up the tire and loss of control.

Previously, many on these boards opt to use UCAs or alignment adjusters to move the wheels to create clearance. I don't believe in that strategy as my alignment priority is for correct suspension geometry and handling, and everything else is secondary. So chop goes the body mount.

Not quite a full chop. But strategic cuts to bend and reshape the mount with the original metal in place. 4.5" thin kerf on angle grinder and 3lb hammer does wonders here. Cut in multiple passes so as not to overheat the mount and potentially melt the rubber body mounts. Pictures will show the process better. I'm done cutting and shaping and will bust out the welder later this week.

1601262143407.png


1601262287299.png


1601262376325.png
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Spare tire

I won't go down the path of rear swingouts for several reasons. So I need to maintain a workable spare. I continue to be amazed at what the 200-series can fit.

My situation is a bit unique in that I have a 12.5 gallon LRA aux tank in the boot. This pushes down the spare by 1". I wasn't happy with how far my previous 33.2" x 12.3" tire hung down in combination with the subtank.

Ideally, I would have a matching spare as I did with 33s, but because of diameter and width concerns, led me to use a non-matching skinny - 275/65R20LT, specs 34.1"x11". Versus 34.5"x12.5" for the full fat 35x12.5 tires. The spare is still a full performance tire, so in the off chance I need it, I can still continue on whatever trip without concern. Those without a tank can get additional width accommodations by removing the bracket on the leading edge, and bending the tube bracket upwards, that comes off the rearmost frame member.

Diameter concerns to the 4x4 system shouldn't be an issue as they're close enough - 609 to 602 revs per mile, or about 1% diff. Whatever difference could easily be made up for in inflation pressure.

Fit in the boot is tight, but good enough. This pic is with the suspension in full droop, so there is the possibility of contact with the panhard bar on extreme compression. I'll check later but I think it'll fit with clearance.

1601311609535.png


Diameter comparison. Hard pressed to tell which tire is the shorter (hint: far right)
1601311741743.png


Spare in place
1601312322223.png
 
Last edited:
Joined
Oct 5, 2003
Messages
3,246
Location
Saratoga Lake, NY
So you decided on the Toyo AT3s... Looks great.
 

nwfl4runner

GOLD Star
Joined
Mar 11, 2018
Messages
658
Location
pensacola
Are you clearing the stock UCA at full lock on low? I needed a 1.25” spacer with the stock rims to clear a 11.6” wide tire, and I am running TC uppers...
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,816
Location
Houston
I'm sure you'll mention this, but I'm curious about your front sway bar.
My 12" wides give the slightest 1/32" kiss at full lock, and I'm on 1.25" spacers.
 
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Are you clearing the stock UCA at full lock on low? I needed a 1.25” spacer with the stock rims to clear a 11.6” wide tire, and I am running TC uppers...

Yes, just clearing. I would agree with the 1.25" spacers. What size tire are you on?

The AT3s seem less aggressive than some other AT tires which probably is letting me get away with this. I believe with M/T, R/T, or even an aggressive A/T like the Falken AT3Ws, there would be interference.

1601254792405.png
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
I'm sure you'll mention this, but I'm curious about your front sway bar.
My 12" wides give the slightest 1/32" kiss at full lock, and I'm on 1.25" spacers.

I did see really light witness marks. Full lock is low speed maneuvering so didn't seem enough to be concerned about. I think your tires are just a wee bit taller and mine just a wee bit wider so maybe a wash and about the same effect.
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,816
Location
Houston
I think your tires are just a wee bit taller and mine just a wee bit wider so maybe a wash and about the same effect.


Word. I'm not worried about it... it's the exact amount to wipe off any mud that might accumulate there.
Just for reference, my weighted width is exactly 34.5". Haven't checked my real life tread width.
 
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
295/60r20

Was that a shot in low?

I believe I'm in high mode there. Thanks for the heads up and I'll check it in low. I've only been on these one day so I haven't really pushed things, but didn't see any witness marks at first blush.

You have Cooper STT Pros right? 34.3" x 11.5". Almost same height but 1" narrower at least at its the widest part of the sidewall.

What's not mentioned is how wide things are at the tread. Your STT Pros seem to have much more prominent lugs that are squared off at the tread, where the critical clearance is.
 

grinchy

SILVER Star
Joined
Feb 17, 2018
Messages
6,685
Location
The Emerald City
Did you use an angle grinder or saw to make the relief cuts @TeCKis300 ? What’s the weighted diameter on those tires?
 
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Yup, trusty 4.5 angle grinder, thin kerf metal blade, without the guard to get at the odd angles. Sorry, no weighted diameter.
 
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
295/60r20

Was that a shot in low?

Thanks for the tip. I checked closer and there are indeed witness marks of rub. Seems to happen with larger compression and limits of steering input, so in low speed maneuvering. It's almost on the underside of the UCAs. I'll keep an eye on it and see how significant it is, and may go up to a 1.25" spacer if it's worthwhile to address. Sounds like you also went with aftermarket UCAs that may give more clearance?

This is also a good place to note that the Toyo AT3s are a middling aggressiveness, yet tidy tire. There are definitely more aggressive 35x12.5 tires out there with higher profile tread which may create more fitment issues.
1601310701247.png


1601310518147.png
 
Last edited:
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
Spare tire details posted above
 

nwfl4runner

GOLD Star
Joined
Mar 11, 2018
Messages
658
Location
pensacola
Thanks for the tip. I checked closer and there are indeed witness marks of rub. Seems to happen with larger compression and limits of steering input, so in low speed maneuvering. It's almost on the underside of the UCAs. I'll keep an eye on it and see how significant it is, and may go up to a 1.25" spacer if it's worthwhile to address. Sounds like you also went with aftermarket UCAs that may give more clearance?

Yup, the TC ones give a little more clearance. I went down this path and ended up pulling back. With the 20s and 1.25 spacers, I was looking at BMC/fender rolling at the top, and removing/relocating most of the fender liner mounts. 1 thought which might make this easier, is go ahead and discharge the suspension fluid up front. I think without fluid the truck should be resting on the bumps. Might be able to lock to lock without removing the strut?
 
Joined
Apr 27, 2011
Messages
7,507
Location
San Diego
I think it would be possible to bottom out the front suspension by putting it in AHC low, then running up on a mild ramp with a single corner?
 
Last edited:

Users who are viewing this thread

Top Bottom