New, larger Tires

[GregS96]

I currently am the proud owner of an '05 AEV-Wrangler Rubicon SWB with Goodyear MTR 285/75R16 tires. I am looking to purchase BFG KM2 315/75R16 tires. Will my AEV 3.75" Suspension lift comfortably accomodate the larger tires (33" to 34.8")?

[Mieser]

Most people are going to tell you no. I think they will if you spend the time to tune the bump stops and the axle position with adjustable control arms. Yes you will loose some up travel, but you gain a lower CoG and step in height. Other things to consider are front flare turning clearance when articulated, be sure to check the tire clearance with the rear upper spring mount ( if you have the 16" AEV wheels this can get a little light if your rear axle isn't centered ). You will also have to add a small spacer to the steering stop or install some bent lower front control arms to gain back full steering.

[AEV Dave]

They won't fit if you intend to wheel it. Thats the bad news. The good news is the only difference in most of the vehicles is the springs. So a new set of springs should get you what you need for a 315.

dh

[GregS96]

Dave, Thank you for the response....pardon my ignorance....Does AEV have such a set of springs which would work for my vehicle?

[AEV Jim]

I'll jump in here...
Yes we now have Nth-designed have springs that can adjust your ride height, but I will admit that I'm not super-familiar with the 'recipe' of the 'hybrid' suspension you have now (Dave will fill me in on this) - but rest assured that we can come up with a combination that could increase your ride height some, but to "do it right" for the roughly 6" of total suspension lift you need to clear those tires (assuming no body lift or Highline fenders), there's more than just taller springs that you'll need.

Also Mieser's comments are correct about the wheel offset/backspacing issues you'll have - our 16" Bridger wheels that you have do not position the tires far enough outboard to run the 315's without either doing as Mieser outlined or spacing the wheels out to simulate the offset of our 17" Pintler wheels.

-Jim

[Mieser]

Oh come on guys, you don't need 6" of lift for 315s! The green jeep is running an OME lift with a 1" body lift ( with bfg 315s), the silver jeep is running a 4.5" Nth degree lift ( with 35" krawlers ). Both these jeeps wheel hard. The green jeep has some slight rubbing on the front flares at hard lock with the tire stuffed....nothing that would destroy the flare.

[Jdemonto]

Before I went Highline I had a 5.5" lift with 37's..talk about rubbing!!

Jason

[AEV Jim]

Actually Mieser you're right...and wrong. The reason the green Jeep can run those tires with less lift is because the shocks are also correspondingly shorter. This means that the 'droop side' when articulating doesn't go as far down, which means that the stuffed side doesn't 'tilt' as far up into the wheelwell. This effect of having solid axles is significant because the front springs/shocks are only about 36" apart while the center of the tires is somewhere around 62" depending on wheel offsets, etc.

...so yes the green Jeep may 'mostly' clear the same big tires even when 'wheeled hard, but it's making do with less articulation than the fully-lifted rig (regardless of whether it happens to be an Nth TJLA or other brand).

Personally I like all the articulation I can get, so I prefer the recipe that makes tire clearance via suspension height so that it can also fit a truly longer-than-stock shock travel...but it does mean that the Jeeps c.g. gets higher, so there are reasons to prefer the short-lift-plus-Highline setup if you don't primarily run big rocks. You can see from my avatar that I've opted for running both long-travel/tall lift and high-clearance fenders (they don't happen to be AEV Highline which weren't out yet at the time)...and with 14" travel shocks in the front, those 37's need every millimeter of clearance even with the high fenders due to the extreme droop I have (I can get 48+" of air under one tire yet it still does the 700ft. slalom at nearly 60mph which is faster than a stock TJ can).

[Mieser]

I'd rather have the lower center of gravity than a few extra inches of articulation. Everyone has a different idea of what a jeep can be....and thats the fun part.

[Jdemonto]

I'd rather have the lower center of gravity than a few extra inches of articulation. Everyone has a different idea of what a jeep can be....and thats the fun part.

X2

Although Jim has a valid point, I would rather lose the droop for lower cog

Jason

[rubclt]

I have run both 6" with 35" and 3" with HL... If you are in the big rocks the higher lift raises the frame so you hit less on the bottom and flexes more, but on a SWB jeep the front end starts to unload more on steep rocks... I say SWB Jeeps should stay lower than 4.4"... IMO... a HL Jeep with LOG is stable, easier to enter/exit, but it rubs on the bottm a lot, better have nth skids on motor, trans, and TT, angain IMO..

Here is 6" nth LA and 1" BL (needs to be removed) with 35"

http://i44.photobucket.com/albums/f27/rubclt/DSC_0130-1.jpg

Here is 3" with highline and 35"

http://i44.photobucket.com/albums/f27/rubclt/DSCN1500.jpg

[AEV Jim]

All good comments everyone! It's true I like the big rocks,...but I also LOVE high speed desert and fire road trails too..and I do them in the same rig plus cross-country drive it to the trails most times. Ever since the Nth TJLA, I've ceased to subscribe to the lower CG-is-critical argument. The main reason that notion has been popular (and just to be clear it's not invalid) is because most suspensions have incorrect geometry (antisquat and antidive in this case) and way way wrong spring rates. when those are done right, stability both on-road at the limit of handling and off-road when pointed straight up a 6' ledge are both non-issues. My rig's tip-over angle is still about 50 degrees from horizontal...which is still way beyond my pucker factor! :)

-Jim

[rubclt]

The nth 6" LA on a Long wheel base TJ is the best combination I have tried to date... I am planning a 4.5 LA on my Highline LJ next... Just need the rear long arms...

[AEV Jim]

The nth 6" LA on a Long wheel base TJ is the best combination I have tried to date... I am planning a 4.5 LA on my Highline LJ next... Just need the rear long arms...

They're available and ready to ship!

[GregS96]

Jim,

I discussed the idea of replacing my 33" MTR tires with BFG KM2 315/75R16 tires to my '05 AEV-Wrangler Rubicon SWB in the TJ forum back in June. I recently bent my rear lower control arms on a Jamboree, and thought this would be an opportune time to considering ordering the parts you (AEV) have/recommend to properly add the necessary ground clearance.

[AEV Jim]

Hi again Greg (now I remember this thread!)

The short answer is: Not without some additional mods. As Mieser says, you can make your current setup work if you're willing to make some compromises - mainly limiting your uptravel to keep the 315 tires out of the front fenders and keeping the shorter (current) shocks to limit downtravel so that they don't tip into the rear spring seats...and limit the steering to keep the tires from hitting the front LCA's at full turn....not what you had in mind? If you intend to actually use your 315's in some full-flex scenarios (rockcrawling, etc.), then you need to make more room for the bigger tires. This can be done either by making the wheelwells bigger or lifting the Jeep higher or a combo of the two. With either way, you still should widen the track width to solve/improve the steering issue (tires hitting the LCAs) - ideally so you don't have to restrict the steering, and also the wider track will add more static flex by providing more leverage against the springs. I'd recommend a track of 62"...which means you need wheels with about -19mm offset, which is really close to our AEV Pintler 17's at -15mm.

How to choose more lift vs. body mods depends on how you want to use it. If you plan to wheel bigger rock trails, then you'll probably want the greater center (breakover) clearance of an all-lift solution, but if you only snow- or sand-wheel where off-camber is more common than high-centering, then a lower C.g. via the body/wheelwell solution is probably right for you. Here's a quick rundown of how I'd do either:

ALL SUSPENSION
to run 35" tires with standard fenders and no body lift - and assuming you disconnect the front stabilizer bar - you need 6.0" of suspension lift...and more specifically, you need the equivalent of 5.0" of bumpstop spacing in front to keep the tires out of the fenders. Normally I wouldn't recommend this much lift with a shortarm, but since you have (I assume?) the drop brackets that help the arms stay more level, you can do it. I'd recommend our Nth 4.5" springs with the rear relocator brackets and front spacers and 6.0" bumpstop spacer set to replace your current stuff if you want both to know you're high enough and upgrade your ride and handling at the same time (better spring tuning). If you're on a budget, just add the relocators and spacers and additional bumpstop spacing and keep the springs you have. Sorry I don't know exactly how high this will really put you because I don't know how high the 3.75" lift really is (lift heights are NOT all measured the same way unfortunately!).

ALL BODY
Of course we'd love to sell you a set of our AEV Highline fenders and flares, but they provide so much clearance that even the 35" tall 315's you're eyeing will look a little 'lost' in the wheelwells if you add Highline and keep your current lift height. It's not that it won't work, just an aesthetic thing really, and if your 3.75" lift is actually a little less, then I think it would look just fine and work great if you don't need the belly clearance.

HYBRID COMBO
The last option would be to add a little of both...this also happens to be the 'poor mans' option, and while not ideal, it will work fairly well: Add a 1" Body Lift (BL - which I normally abhor but they do serve a purpose in cases like yours), and add 0.75" coil spring spacers to your current springs. this should put you at about 5.5" of lift as far as the stock fenders-vs-tires are concerned. If you make sure you have the full 5.0" of front bumpstop spacing, then you should have similar tire/fender clearance to the full 6.0" suspension option, but with just 1/2" less uptravel (not too bad). Pretty cheap...and you could extend the cheapness by using wheel spacers to keep your Bridgers (and call your TJ the "Spacer Special" with all three types of spacers present :)
....of course you could also go mid-way and do our Nth 4.5" springs instead of the coil spacers.


Now...I never talked about shocks in the options above. Assuming you have OME TJ LongTravel shocks (N66L fronts and N67L rears), then you can keep the shocks in all scenarios, except that they'll be a bit too short for the all-suspension option. for that, we can set you up with bar-pin spacers to effectively lengthen the shocks and make them right for the 6.0" lift, but in the rear the better route would be to use our Nth Shock Shifter kit which now includes adjustment that will permit those shocks to work on a 6.0" lift.

Clear as mud? Hope not but understandable if it is...let me know...

-Jim

[GregS96]

Jim,

Thank you for the great information. I am leaning towards the "hybrid" model; keeping as much as what AEV originally installed in my jeep, just adding the extra inch (Body spacers?) to get the jeep with 35" tires to perform properly.

I took alook at the AEV quote (Keven Arnot was the Point of Contact), and the Suspension istalled is described as "3.75" AEV SWB Suspension. TJ ME long travel shocks, 3" extended urethane bumpstops were also installed (does AEV keep records of the vehicles they assembled?).

Would you be able to price out the neccessary modifications AEV could send me? I am also open to suggestions to replace the rear lower control arms I bent. Does AEV have any body shop recommendations within a few hour drive time of central Pa (Altoona)?

Greg Sheehan
GregS96@aol.com
814-932-3540 cell

[AEV Jim]

You're welcome Greg. Actually keeping what we installed on your rig originally makes it less "AEV" than it would otherwise be now that we have Nth suspensions in-house! I don't think we keep records that are detailed enough to know exactly what we installed on your rig, though some here might be able to get pretty close via memory and knowledge of what the 'standard setup' was back when we built your rig. I assume you missed a letter and you were confirming that you have OME longtravel shocks, so my assumption on shocks was correct?

We have some Nth fixed-length short-arms that you could use to replace your bent arms (stock ones??). Remember to do low-buck hybrid route correctly, you need ALL of the spacers: 1" BL, 0.75" spring spacers, additional bumpstop spacers, barpin spacers (to keep the OME shocks), and wheel spacers (if you keep your Bridgers)...and maybe longer brake hoses or space-down brackets (forgot that issue in my last post). Most of that is not normal stuff we sell separately, but we theoretically can. I suggest you call our sales staff to get help on ordering and to find the nearest AEV dealer to you...those topics are out of my realm...;)

-Jim