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Discussion Starter · #1 · (Edited)
Everyone knows the FJ comes from Toyota with oversized body mounts in the front wheelwell that severely affect the installation of larger tires. The FJ owner only has 3 choices, dont put on bigger tires, install one of the new & way too tall 6" lifts, or cut the mounts to enable larger tires with smaller lifts, keeping the vehicle lower & more stable. A search on this site will produce many photos and descriptions of how body mounts have been done, this is just a post of how I do them.
I have done several sets of body mounts for myself and board members, but yesterday while doing them for Jeshua to clear his 285's with no lift, I had a thought of how to get a bit more clearance than the way I was doing them previously. After finishing them, and considering how tight they wrap the factory bushing, I dont know that you could get any more clearance for bigger tires than this. This setup has less than 1/4" gap between the bushing and mount face. In addition, I use 3/16" thick x 2" wide steel to reinforce the mount - I know you can get away with 1/8" but for the difference in cost why skimp. It is a harder job to work & bend the 3/16" around the radius of the bushing, but not having to ever worry about it failing is worth the extra effort.
When he pulled into the driveway, it was evident the tires were rubbing the mounts and here's what I saw


And when the wheel was turned it was easy to see the contact


Fter pulling the tire it was easier to see where the tire was contacting the mount. Surgery will be necessary.


Here's a shot from below of how huge the body mount is from the factory, you can see how much area the tire was rubbing along the bottom of the mount


and from the top... these are obvoiusly the "before" shots


Now we cut... I always wonder whats going through the head of the person watching me cut on their truck. I look at where the most forward edge of the bushing is and mark the mount about 1/4" in closer to the frame (this is more than you would need to fit a 33x12.5 or "305" tire, but this allows adding a 35" tire later if desired.) Then remove the bushing and cut up, over & down the back, following the radius of the bushing cup. DONT CUT INTO THE BUSHING CUP, CUT AROUND IT! The bushing cup is the dipped part that the top bushing sits in. If you run a 35" tire (I do) then the bottom lip of the mount will rub the tire, so I trim the bottom lip further and knock off the edge with a 45" slice, and round all corners with the grinder. This is the reason I use thicker material than needed. The red line is where I will put a 2" slice in to bend the face in a bit farther - this is the different step I thought about mid job & Jeshua volunteered his truck as guinea pig.


Here's the cut mount with edges ground & cleaned and slice in the top radius


After installing the bushing over the stud, I hammered the flat face under the slice to about 1/4" from the bushing and ground the area to be welded. Make sure and get plenty of penetration, you dont want cracks!


From this point, you can do 2 things, make a cardboard or paper template of the plate to cover the cut, or what I do is weld the plate to the face of the mount on the vertical section, and about 1/2" along the top. Then hammer and stitch it around the radius of the mount until it meets the back of the mount, and finish weld it along the back. I prefer the smooth factory look, so I add material where needed and smooth with a sanding disc - I like the new 3M purple 36 grit ones, they last about 5x longer than the old green discs. It will look like this


From the top you can see how close it follows the raduis of the body bushing


From the bottom, you can see the upper bushing cup. The crucial clearance areas for the tire are the front to end (9 to 12 o'clock position). Once it wraps past the edge of the bushing farthest from the frame the clearance is inconsequential because if it would hit there, it would be hiting on your firewall too and thats another tech article


Making sure the bushing clears the new mount face


Heres the finished mount with the bushing installed. If there's a way to get more clearance I'd love to see it. After doing the mounts this way I plan on redoing mine with the slice cut and getting the 1/4" extra clearance, as that will eliminate the slight remaining rub I experience on my FJ with the 35" tires and 17x8.5 rims with 3.75" backspacing


And here's Jeshua's finish painted mount with the 285's installed back on, and no lift


and with the wheel turned - this is the closest the tire will ever get to the mount


With the extra step of the slice cut the total job took 4 hours. But now the FJ has plenty of clearance at the body mount to run bigger tires even with no lift. Its not that difficult and keeps those expensive tires form getting torn up every time they rub
 

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wow awesome writeup. Thank you.
 

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Thanks for the write up with the pics.
 

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Discussion Starter · #5 ·
You guys asked for a 4 light setup - we are fulfilling your requests. The airdam and light bar are back in the fabrication shop, all light bars will have 4 mounts, and you have the option on the airdam of smooth, 2 hole, or 4 hole designs to choose from.
 

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You guys asked for a 4 light setup - we are fulfilling your requests. The airdam and light bar are back in the fabrication shop, all light bars will have 4 mounts, and you have the option on the airdam of smooth, 2 hole, or 4 hole designs to choose from.
sweet, i cant wait
 

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RockKrawler, nicely written post. However I would have to disagree with you on your statement that FJ owner's olnly have three choices.

Now I'm no vender, nor am I a mechanic or a wheel/tire or suspension whiz. But I am an FJ owner/operator......and I have in fact had larger tires installed, 285/70/17 Bridgestone Revos, on the stock 17" alloys, stock suspension (no lift) and no cutting or grinding on the mounts. The tires never rubbed anything, fully turned, even when climbing a curb and turned. (Admittedly, hard core rock climbing might be different).

I then decided on changing wheels to 17" black steelies (OEM). And still no rubbing or clearance problems.

I recently had a 3" lift kit installed (for looks mostly), I now have twice the clearance at the rear part of the front wheel well than I had before. And still no bubbing at the mounts.

I sincerely believe the clearance and rubbing problems encountered are mostly brought on by one's eagerness to make something fit where it is not intended. (Mostly wheels that have the wrong offset and/or sopacing while also installing tires that are just too large for the application) And that your well written and documented post is a good solution for those situations.

It just seems like a lot of chopping, grinding and cuttin' that isn't necessarily unavoidable.
 

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RK: Man, that was a cool compendium of information. Now you got me concerned. I am thinking about upgrading my tires and wheels to the following specifications:

AR Chamber Black Teflons on 16x8 (part. 3985-6838)
with
Toyo Open Country AT's (305/70/R16)..

Do you think I will have a body mount issue? If there is a way to figure this out, i am all ears!

Thanks,
 

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RocKrawler AWESOME WRITE UP MAN!!!

I would never run 35"s on mine but I would love to throw some skinny 34"s on mine with my 3" lift and am afraid I will have to do some trimming. I will never do this myself but I love the write up and will gladly print off yoru directions as a guide for my local fab shop.
 

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Discussion Starter · #14 ·
RockKrawler, nicely written post. However I would have to disagree with you on your statement that FJ owner's olnly have three choices.

Now I'm no vender, nor am I a mechanic or a wheel/tire or suspension whiz. But I am an FJ owner/operator......and I have in fact had larger tires installed, 285/70/17 Bridgestone Revos, on the stock 17" alloys, stock suspension (no lift) and no cutting or grinding on the mounts. The tires never rubbed anything, fully turned, even when climbing a curb and turned. (Admittedly, hard core rock climbing might be different).

I then decided on changing wheels to 17" black steelies (OEM). And still no rubbing or clearance problems.

I recently had a 3" lift kit installed (for looks mostly), I now have twice the clearance at the rear part of the front wheel well than I had before. And still no bubbing at the mounts.

I sincerely believe the clearance and rubbing problems encountered are mostly brought on by one's eagerness to make something fit where it is not intended. (Mostly wheels that have the wrong offset and/or sopacing while also installing tires that are just too large for the application) And that your well written and documented post is a good solution for those situations.

It just seems like a lot of chopping, grinding and cuttin' that isn't necessarily unavoidable.
I appreciate your opinion, but you have to understand that when a customer wants to run a non-stock rim they often have non-stock backspacing that pushes the tire out, that causes the tire to swing in an arc instead of pivoting on center, which typically causes the rubbing issues. Also understand that just because 2 tires have the same size numbers, they arent necessarily built the same, and may vary quite a bit especially at the shoulder, or corner, of the tread. The corner is usually where it rubs.
You are 100% correct that clearance and rubbing problems encountered are mostly brought on by one's eagerness to make something fit where it is not intended, but not everyone has the ability or resources to fund and install a lift. On the last 2 vehicles I have done, both 305's and 285's were fit with no rubbing and no lift on the mounts, and clearancing the mount is definitely cheaper than adding a lift. Many people are very preferential to certain tire brands, or they just got a smokin deal on a particular set and couldnt pass it up. They want a way to make it work until they can afford to make it fit. Thats where this job comes in. If you want a 35" tire you have to do it regardless of backspacing, and that goes for most 12.5" wide tires, even 33's. Me, I got a smokin deal on my 35" BFG's, so I took them to hold me over until I can get Goodyears or Toyo's. Personally I HATE BFG MT's but I made the concession for price. While the Revos worked for you on stock rims, not everyone wants that setup, but you made some valid points.
 

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Discussion Starter · #15 ·
RK: Man, that was a cool compendium of information. Now you got me concerned. I am thinking about upgrading my tires and wheels to the following specifications:

AR Chamber Black Teflons on 16x8 (part. 3985-6838)
with
Toyo Open Country AT's (305/70/R16)..

Do you think I will have a body mount issue? If there is a way to figure this out, i am all ears!

Thanks,
I think the width of the tire is going to be an issue at the body mount, but the offset of the rim should help. If you dont have a lift, I'd bank on modding the mounts.
 

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Discussion Starter · #17 ·
RK: Man, that was a cool compendium of information. Now you got me concerned. I am thinking about upgrading my tires and wheels to the following specifications:

AR Chamber Black Teflons on 16x8 (part. 3985-6838)
with
Toyo Open Country AT's (305/70/R16)..

Do you think I will have a body mount issue? If there is a way to figure this out, i am all ears!

Thanks,
already responded above
 

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I think the width of the tire is going to be an issue at the body mount, but the offset of the rim should help. If you dont have a lift, I'd bank on modding the mounts.
RockKrawler:

Thank you for your opinion. I will have to take that into consideration if I
don't get the lift and consider a narrower tire that wouldn't cause issues.
Another concern that I have right now is concerning lifting and warranty
but that's another thread. :slant:
 

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Great write up RK!

I finally got around to chopping mine this past weekend and I did have one comment. I noticed that allot of the posted "chop" pictures (from everyone) have removed what I think may be more material than needed. Cutting more off the body mount than the effective radius arc of the wheel-well does not gain you anything.

However having said that, as long as it's all welded back up I don't see how it could hurt anything.
 
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