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18x13/335 Square Under Stock Fenders

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boardkat

CAMtard
131
179
Exp. Type
W2W Racing
Exp. Level
10-20 Years
Lake Oswego, OR
.. and before anybody asks, no, there is not offset information contained within. Why? Well, ask yourself these questions - do you have:

Front
1.) Offset struts
2.) "Right-sized" piston or enlarged strut hole
3.) Camber plates
4.) More than -3.5 camber
5.) 700lbs+ 2.25ID 5" springs
6.) A BIG-ASS adapter (and not having an aversion to running one)
7.) Quik-Latch bumper attachment points
8.) Rolled/Pulled/Spaced fenders
9.) Fender liners removed
10.) Creative placement of various parts/lines
11.) Ability to stomach 2mm of inboard strut clearance and NO fender clearance with occasional rubbing/self-clearancing

Rear
1.) Rolled/Pulled fenders
2.) Springs in the stock location (or inverted coilovers)
3.) Inverted shocks
4.) Relocated e-brake bracket/line and other creative movement of parts/lines
5.) The "right" amount of -ve camber to meet your setup needs coupled with an offset that maximizes inboard/outboard clearance
6.) Fender liners removed
7.) Ability to stomach 2mm of inboard strut clearance and NO fender clearance with occasional rubbing/self-clearancing

.. because if your answer to any of those questions is no, then the offset won't matter anyway. There is a LOT of work and compromises required to make this setup fit square under the stock fenders - not gonna lie. And it's taken ALL of those things mentioned to make it work. I've spent many hours over the years measuring, test fitting, moving, thinking and just plain staring at things. It's not for the faint of heart, and you can really make it a lot easier on yourself just cutting and flaring your fenders. But I street drive my car, and didn't want to do a plastic flare/rivet job on it, nor spend the Texa$$$ amount on doing it right with a stock-like cut/weld/paint application (I don't do metal/fab/paint), and I'm trying to minimize my front/rear track and overall width. So here we are :)

OK, now that we've gotten THAT part taken care of, let's dive into the details! :D

I've been running an 18x12/335 setup quite successfully for the past few seasons, but I'm always looking to maximize my grip in the pursuit of those precious tenths on the clock. I was able to reclaim some inboard room this off-season by doing a lot of testing/math to determine what actual amount of travel I'm using up front for the various spring rates I've run over the years. The end result was the conclusion that a 5" spring "should" give me "just enough", which, in turn, allowed me to relocate my perch back above my tire for my desired ride height for additional inboard clearance. The natural conclusion was, "Hey, now I can fit an 18x13 up there!", and the end result was this showing up at my front door after (4) months of waiting:

40404162742_d71e3761fa_b.jpg

13" from bead-to-bead but almost 14" overall width
26619954418_e0e07d0c59_b.jpg

4yo for scale
40447954961_7d893dc6ee_b.jpg

I tried to weigh them, but couldn't fit the damn things on my scale because they're too wide! I did weigh holding a wheel though, and it comes in at just under 25lbs - surprising, because they're basically the same weight as my 18x12 - biggest difference being the face (F14 vs. CF5), since the barrel on the F14 rev2 is the same as the CF5.

So how much wider are we talking? Here's a comparison of my various setups:
40490746061_088cff5a22_b.jpg

19x11 | 305/30R19 Michelin Pilot Sport 4S
40490736581_e7e83b9dab_b.jpg

18x12 | 335/30R18 BFG Rival-S
40448402172_0edac1c1a2_b.jpg

18x13 | 335/30R18 BFG Rival-S
40448397192_403960722c_b.jpg

Ultimately, I've added an additional 0.75" of tire going from 12-13 on a 335, and the visual stretch of the sidewall (which was the desired outcome) should give me more sidewall support on a tire that tends to feel a little numb at the limit.

So how does it fit? Let's take a look!

Front, full droop:
40490749041_844325d5f8_b.jpg

40490751791_bab02065a6_b.jpg

Front, maximum compression (fender limited):
39595074615_d470af3456_b.jpg

39595072235_009eafef53_b.jpg

Here's how much shock travel is left right at the point of fender interference:
26619949438_b8da50199d_b.jpg

While it looks like a lot of travel left on the table, I've actually never experienced compression travel this far on a 700lbs+ setup - and now with a 5" spring, I'll reach block height before I ever reach this point. But block height is also past the point of maximum compression achieved, so the end result is - 18x13/335 works up front! :D

Apologies about the rear - I thought I took some pics, but apparently I didn't - suffice it to say that with some parts relocation, I moved almost all the additional width inboard, and used up what additional fender clearance I had left. Nothing on the table, it just barely fits, but with full compression travel without any fender or shock/frame interference! I'll remember to take some pics when I have the rear suspension apart in a few weeks putting in some final spring/alignment touches ahead of my California swing.

Of course, the proof will be in the pudding - I've got my first event of the season next weekend. But with 40deg temps (and most likely rain) in the forecast (par for the course this time of year in the PNW), I probably won't get to test the new setup until the Fontana Pro Solo in late March. Not ideal to be testing at a national event a thousand miles away, but I'll make it work - or not, lol. Stay tuned!
 
In for updates.
 

boardkat

CAMtard
131
179
Exp. Type
W2W Racing
Exp. Level
10-20 Years
Lake Oswego, OR
Bolted all (4) on for the first time tonight and took a drive with a few hard corners and bumps. No rub!
Sidenote: sticker BFG Rival S in cold (low-40s) and wet conditions don't grip so well. Tread carefully! o_O

Apologies on the potato quality pics; my garage is a lot wider than it is long (and it should be pretty obvious why I spend so much time on my back, inconveniently placed support beams FTL!!), so taking pics is difficult, especially in the dark!
38717920510_eabc3bf8d4_b.jpg

Front:
25657789267_6f63fe0cd0_b.jpg

40528188491_cfc55af117_b.jpg

Rear:
39817883644_efa5ef80dd_b.jpg

40485609862_fd5bdd4dc4_b.jpg
 
Last edited:

boardkat

CAMtard
131
179
Exp. Type
W2W Racing
Exp. Level
10-20 Years
Lake Oswego, OR
When do you get to test them out on-track/Autox?
not this weekend - i'll probably be hitting the course on the 1st run with temps in the low-30s. uggh.
one more chance to try it out in a few weeks on an airport course in a drier part of the state, fingers crossed. otherwise, i'll be hauling them down to fontana with me for the pro solo (3) weekends from now. they'll definitely be getting worked there :D
 

boardkat

CAMtard
131
179
Exp. Type
W2W Racing
Exp. Level
10-20 Years
Lake Oswego, OR
so i was wrong. i *did* get to test it out this weekend! weather was dry for once, albeit very chilly (sub-40deg). tires never really got to temp, but did put a good scrub on them, and validated that there is no rub/interference (on a very bumpy course, too).

39708094275_0aa7ddca9a_b.jpg
 
How difficult would it be to run a set of 11.5 squared with some of the modifications you have, I.E offset front strut, inverted shocks, and potentially the gt350 fenders. I dont like the way the 11.5 sticks out on the gt350r and id like to push it in slightly but im not sure if itl fit with coilovers in the rear, and as for the fronts id like to run a square setup with r888rs, however the tread width for the 305s is 11.5 inches. So id want to step up to an 11.5 as apposed to 11 square
 

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