Ah, the eternal question. Maybe it's even rhetorical? Now, and perhaps alas, that is no longer the case for me. I know with certainty the answer for my combination of wheels, suspension, tire style, and wheel arch trim. It turns out to be about 33" and slight change. But that's for zero touching for max stuff front and back and at full lock. Tested with a forklift truck.
First the data: BFG AT's 295/75-R16 with 152 procomp streetlocks at 3.75"BS and 1.25" spidertrax spacers. OME heavies front and rear.
In the quest for largest possible tires that have zero contact with the bodywork for any combination of tuck and wheel turn, I have had the plastic trim, body mounts, and wheel well interiors removed, chopped, and pounded. I don't think any of this could be taken any further without doing structural damage or rebuilding the wheel arches.
We tested the maximum stuff of the front and rear wheels using a forklift today. On the front, we used wheels straight-ahead and also maximum turn.
First off, the body mounts have been cut, the wheel wells beaten back, and the plastic fender trim removed. With the current wheels on the truck and with my prior fender trim etc. I was getting alot of contact near full stuff and with stuff plus turn. Here's an idea of the trim and well mods:
With the front wheel lifted, the clearance is not too bad. I estimated that there was still about 1" or so room at the closest point. The proximity also seemed kinda independent of tire width / outboard spacing. This results from the loss of the plastic fender trim. The limit is now wheel well:
When the rear tire was lifted and the body of the vehicle rolled over onto the front tire and with that tire at maximum turn, the clearance fell to essentially nothing. Again, this did not appear to be dependent on the tire width or outboard spacing as the limit was again the wheel well arch well inboard. Once again, this result only arises because I no longer have a plastic fender trim or a body mount bulge to catch on.
I retained the plastic fender trim on the back, and it just barely contacts the wheel at full stuff - so some plastic trimming will be needed. This contact is dependent on the tire width and/or outboardedness of the tire (so a thinner or non-spaced tire would clear without rub):
In summary: to use ALL of the articulation with ZERO contact, then the largest tire size that can be used is just a bit over 33" for an OME heavy lift. This is limited by the front accomodation. After the fender trim has been removed, the body mount aggressively chopped, and the wheel well "worked over", this accommodation becomes insensitive to tire width or outboarding. Obviously, if one is willing to accept some rubbing, progressively larger tires can be "accommodated". Indeed, for road use and moderate wheeling, tires upward to 37" are possible. My test-article 35.5" Pitbulls (labeled as 37") would fit for these uses. Lifts that move the vehicle front higher than the OME heavy will allow tires of larger size.
You are asking for trouble stuffing a 295s in there with standard offset wheels spaced out. While you may have some clearance when the vehicle is stationary, you will undoubtably make contact with the upper inner fenders when off-roading in any medium to aggressive terrain - this will cause deformation of the inner fender crush zones so many have experienced with smaller, properly spaced tire/wheel combinations, which can lead to structural damage of the front end sheet metal, and the fenders being pushed back into the doors. The larger, spaced combo you've installed will likey cause greater damage, or at least occur under less-stressful wheeling. In addition, from a strictly functional point of view, you've eliminated the wheel travel / articulation that makes the FJC such a fine off road vehicle - the tires have no where left to go... I hope it works out OK for you - Good Luck...
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You are asking for trouble stuffing a 295s in there with standard offset wheels spaced out. While you may have some clearance when the vehicle is stationary, you will undoubtably make contact with the upper inner fenders when off-roading in any medium to aggressive terrain - this will cause deformation of the inner fender crush zones so many have experienced with smaller, properly spaced tire/wheel combinations, which can lead to structural damage of the front end sheet metal, and the fenders being pushed back into the doors. The larger, spaced combo you've installed will likey cause greater damage, or at least occur under less-stressful wheeling. In addition, from a strictly functional point of view, you've eliminated the wheel travel / articulation that makes the FJC such a fine off road vehicle - the tires have no where left to go... I hope it works out OK for you - Good Luck...
Thanks for the feedback. The interesting (and kinda surprising) thing about the wheel accommodation test today is that the wheel out-spacing has been made irrelevant (Q.E.D.) The wheel well wall is the limiting factor now (because the plastic fender trim is gone and so are the body mount bumps), but the part of the well that is the issue is well inboard. It's sufficiently inboard that at this point, any equivalent backspacing would have the same limitation as my setup. The only way to make the tolerances better now would be to reduce the tire overall diameter - i.e. accommodation has now been reduced to a single-valued problem - purely to one of tire overall diameter. The most dangerous situation will be in a nose-down attitude with the weight on the tire at the inside of a turn. It is being pushed in that case such that a dynamic load could push it into the wheel well near the door frame. That dynamic load will obviously get worse as you go faster. (As a side note, I should mention that I've been wheeling this wheel setup with less body mount trim, wheel well trim, and plastic trim since Feb or March - no problems yet aside from noise as the plastic rubbed - the only thing I'd be worried about is landing jumps at full turn - but I don't really ever do Baja-style driving - but again, this is a problem that's independent of the wheel spacing).
But it's important to note that I have in no way damaged wheel travel with this setup except through a choice of tire OD that's greater than stock. Indeed, the OME setup, the wheel well/body mount/fender trim mods, and the sway bar removal have greatly increased articulation over stock.
Were the spacers used to widen the stance or so you can use the ProComps? Seem to vague remember you had fitment issues with the ProComps.
Yeah, they're only on there to make the procomps work. They'll come off for the stazworks/pitbulls. But it now means there's no way I can use the 35"s It'll have to be the 33"s.
So width doesn't matter, it's the diameter of the tire thats the limiting factor for you-for now. That's a bummer, I know you've wanted to go much bigger. Maybe it's time to change suspension.
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Sandoo Blue FJ
Walker Evans adj. F&R reservoir shocks. Pro Links. AP F&R bumpers. Demello skid. Mile Marker SE9500C. Viking Trail Line. Super Swamper LTB 34s on Tacoma wheels. 305 MTR on Wheelers wheels. Trail Gear Sliders, Aeroflow, Lightforce Blitz 240, Powertank 10lb, Hi-Lift, Jack Mate, Pull-Pal.
So width doesn't matter, it's the diameter of the tire thats the limiting factor for you-for now. That's a bummer, I know you've wanted to go much bigger. Maybe it's time to change suspension.
Looking at it, I'm probably getting close to the limit of IFS. If the front axle could be brought forward, then further downward displacement would help. But it's only going to have a limited impact with the current axle position since you bang into the rear of the wheel well near the door.
I annotated to show the main areas where the wheel gets closed to the well now (in this case, with all the vehicle weight baring down on the front and to the right - i.e. wanting to push the truck over the front right wheel). Points 1 and 2 limit above, and point 3 to the back. Since the curve near point 3 matches the swing of the wheel, and the limits at points 1 and 2 are near the centre of the tire, changing the effective tire width isn't going to help any:
Looking at this, one thinks "how can any 35" tire work?" - but it needs to be remembered that the truck has its left rear tire about 2 1/2 feet in the air at this point and all that weight and roll is the worst-case scenario for this wheel. Normal full lock and non-turned full stuff without all that weight on that side still has over 1" clearance for the tire all round. So 35" could fit all the way to full lock and full stuff. Just not at the same time and with all the vehicle weight on it. In other words, the 35" tires would be a limiting factor in this worst-case situation.
There is no way a 35 will FIT even with a 3" lift/suspension and the body mount chopped and plastic removed/cut off.
The photo above pictures my 305's (33.9") (Nitto T/G A/T 305/70R17) and it's not rubbing in daily driving but would/does under full compression. If I was a bit smarter, I would have gone to a 285 or a 295 if it was available because that's a far more practical approach.
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Mark, while I was working today I thought about this thread (yes, I multitask ). I was thinking if you tested your tires with street air pressure or trail air pressure. If a 35 is aired down to 10-15 psi, will it be at about the same size as 33 or not. 35s fully aired will be ok on the street since you won't be needing much articulation. Could you do this test again with trail pressure and see if you still get rubbing? Since your rig is still at MAF and all :P.
Thanks.
__________________
Click for the "Genie" build up
Sandoo Blue FJ
Walker Evans adj. F&R reservoir shocks. Pro Links. AP F&R bumpers. Demello skid. Mile Marker SE9500C. Viking Trail Line. Super Swamper LTB 34s on Tacoma wheels. 305 MTR on Wheelers wheels. Trail Gear Sliders, Aeroflow, Lightforce Blitz 240, Powertank 10lb, Hi-Lift, Jack Mate, Pull-Pal.
Mark, while I was working today I thought about this thread (yes, I multitask ). I was thinking if you tested your tires with street air pressure or trail air pressure. If a 35 is aired down to 10-15 psi, will it be at about the same size as 33 or not. 35s fully aired will be ok on the street since you won't be needing much articulation. Could you do this test again with trail pressure and see if you still get rubbing? Since your rig is still at MAF and all :P.
Thanks.
Ah, we have so similar minds! I experimented on the 33" that I have in my garage. I aired it down to about 8PSI - which I figured was gonna be what I trail / rock wheeled at. But I got the timescale wrong. The immediate effect of airing down (on these bias tires) was ... nothing. Still up there at 33". I checked like 18 hrs later, and they were down to 32.5". But since my air-down/air-up will be on much shorter timescales, even with the bias tires, I'm going to be stuck at the high-pressure radius
It'll have to be the 33"s.
