35's vs. 37's

[Nay]

.I think if you were to install those brackets on a truck that didn't shift the axle you would create problems.

Why? Correcting wheelbase on a tall lift is a standard fare practice to maximize tire size and prevent excess bowing of coil springs on a tall lift.

This is exactly what the Jeep world does with adjustable lower control arms, because it is easier to open up the fore section of the front wheelbase than it is the rear, and keeping the axle more centered on a tall lift preserves static height geometry at the cost of pushing the axle forward slightly at full stuff. The more you build a suspension focused on down travel vs. up, the less impact this causes offroad. This is why my posts are at least partially focused on shock travel and suspension range of motion, as that will define how the tire fits (or doesn't).

In any case, take a look at pics of 80's on Slee's 6" lift. The shortening of wheelbase is visual, and adjustable arms, or adjusted brackets, can address this. Bottom line is you need to clear the lower rear point of the wheel well first, and vice versa on the rear. The easiest trim points are on the front of the front fender and rear of the rear fender - extra arm length can be a necessity if you really want more tire on a 6" lift than you can run on a 2.5" lift (that being the point of the extra lift).

Even in my pic here (again), you can see that with shifting suspension travel down that I am closer to the the front of the well than the rear. Same thing applies to the front - if I had adjustable arms you better believe that tire would be centered on stuff and my wheelbase would be right at stock. If I had 6" of lift and wanted to run 37's with a 2"+ bumpstop drop, I'd be looking hard at how my tire enters the wheel well and making the necessary adjustments. Except of course we have no adjustable arms on the 80 series market except for upper rears for pinion angle .

I would say the shortening of wheelbase on a tall lift is more likely to cause issues than correcting wheelbase at static ride height, because the former causes misalignment of mounts, and the latter can be addressed by how you design suspension motion (not all up travel like OME L shocks on a 6" lift) and if desired with a bit 'o cuttin'

 

[ats4x4dotcom]

Yes but that just puts the axle back in the stock location because you are compensating for the axle shift from how you corrected caster.

This drawing shows that near same shift in the axle's location. The gray drawing is the axle in the stock location. The green drawing is the axle after pressing in OME bushings. And the red drawing is after slotting the front hole by 14mm.

I think if you were to install those brackets on a truck that didn't shift the axle you would create problems.

Yor drawing has a flaw, for what you are trying to say.

The fact the bushes are the same distance from centre means the axle hasnt moved "back" 12mm, its moved up and back .45" as per your drawing.

The fact the front tyre now rubs on the bull bar since I moved it forward has proved that the 12mm is more than the amount the castor correction relocated it in a wheel base sense, probaly less than half of that, so maybe 1/4" or less with bushes is the real figure.

I dont think 1/4" is really going to cause anyone any problems.


Nay,

We are working on adjustable heim joint one end, rubber factory bush chassis end, and same for panhard rods at the moment, to improve free travel, and less bind, as well as compensating for larger tyres etc.

The rear lower arms we are going 250mm longer, and we are making front arms in a new design, going back to behind the gearbox x member, with a belly pan for front and rear mountings also.

 

[LC80Ducati996]

Well I have been hoping that Off road solutions would make a long arm 3+4 link coil over kit. They have solid axle swaps with 14" travel dual rate coilovers for Toy PUs.. Starting where we are on an 80 it would be much less work by comparison.

Getting back to just general fiting of larger tires one thing that can help no matter what lift is rolling the sheetmetal fender lip. I on a lift I would remove the flares, shocks, springs and not hace bump stop spacers on temporarily then I would roll the sheetmetal fender lip in and cycle the suspension using a jack on the axle (lifting axle assy only). Mark areas where it is danger close and those where it touches probably the front and rear of fender. Then trim and form the sheetmetal out of the way. Then i would cycle the suspension again to double check. prime, paint and stiffen as needed. After this put the flares back on and do it again. The front and rear of the fender where the flare is facing the tire tread will need to be trimmed. A custom rear bumper such as 4x4 labs allows for more room and you can mount a lower profile more flexable universal fit (longer lasting offroad) mud flap flap to the bumper.

I like the idea of longer arms. Also MAF has drop brackets for the rear control arm mounting locations. the have rear panhard, rear lower and rear upper.

IMHO droping the panhard frame mount is a good idea. Since there will be less lateral axle movement across the range of suspension travel. Longer rear arms will also reduce the amount of wheelbase change across the range of suspension travel as well. Lowering the frame side of the upper arms and lower arms (weld on DIY fab) may allow for them to also be moved forward a bit to further lengthen them.

 

[landtank]

Yor drawing has a flaw, for what you are trying to say.

The fact the bushes are the same distance from centre means the axle hasnt moved "back" 12mm, its moved up and back .45" as per your drawing.

It wasn't meant to provide exact measurements but to visually show you what I was talking about.

The missing element is the rear bushing mount. It's the change in distance between the axle's center and that bushing that actually shows the amount the axle shifts rearward from the factory position. And that bushing would be "up and back" in relation to the two bushings drawn in that pic.

I'd love to find a set of cheap used tires to bolt up on my truck just to see how they work. I have retained the axle's stock position and I would like to think Toyota engineered the axle to be centered in the opening.

 

[LC80Ducati996]

When you space the bumpstops down the axle centerline moves aft in the front and forward in the rear period. Toyota got it to what they thought was the right range from against the stock bumpstops out to full droop.

Want the same amount of travel with a centered axle. Make small changes to the length of the control arms.

Want a really long travel suspension without caster or drive shaft angle problems at bump or droop then relocate the frame side control arm mounts more towards the middle of the truck and make the arms much longer.

 

[LC80Ducati996]

After doing a 5k mile road trip plus trails from rock to desert in the stockish 80 last month and flogging a M1025 (Real Hummer) outside of cantonment for the last two days I have decided

1. yes I want 37" tires, gears and lockers.
2. Not all independant suspensions ride nice.
3. Lots of flex on a solid axle rig would be way better.
4. Even with the tq arm front and no payload on the rear the 80 rides and handles much better.
5. I get more airflow thru the 80s sunroof than the M1025's turret with the MA2 on it but less respect in traffic.
6. Some of the tricks I saw on rigs at MOAB will get used on it in addition to some I only saw on the handfull of solid axle 4wd desert trucks I saw in California.
7. A tire like the original goodyear MT works well in varied terrain. Hankooks are similar. I still want to borrow a rig with trxus MTs for a minute.

 

[619TOY]

Wow, now I see what happens when I go camping for a day; I get left in the dust on my own thread

Can we assume that changing the length of the rear lower control arms will produce no benefit in my rig? I am currently running a rear CV shaft and have the upper control arms set to put the rear shaft at exactly 90 degrees to the pinion flange. When I rub, I rub almost equally on the front and rear lower edges of the rear wheelwell (maybe slightly more on the rear now since I have moved the axle a little rearward during the adjustment). If anything, shorter rear lower arms would be an improvement (with stock mounting locations)

I can see the advantage of lowering the frame side panhard mount because with my axle dead center on level ground, the axle move enough to rub the outer wheel well lip on the left while it rubs the inner wheel well suface on the right. Something to consider when pushing the fitment limits.

Perhaps I am being a little naive in not worrying about the front because the front has never rubbed anywhere.

Perhaps Nay's picture doesn't accurately depict what he regularly experiences as far as uptravel but I regularly stuff my rears further into the rear well than that. I also know firsthand that trail conditions can put considerably different stresses on suspension travel from area to area. I ran CM07 and only rubbed a couple times the whole trip. However, I rub constantly in SoCal. In Moab I found myself dragging my rear bumper contantly (even with 6" of lift) and here, almost never.

While the trail pics are not closeups, here are a few pics of how a "normal" SoCal trail affects my rear tires as well as some rub spot shots. I am currently running 2 1/2" frame bumpstop spacers.

 

[landtank]

When you space the bumpstops down the axle centerline moves aft in the front and forward in the rear period.

On a stock 80 the rear frame mount bushing is actually below the center of the axle. So bump stopping the axle down actually put it further forward at full compression.

 

[619TOY]

Current rub spots; on right only the inner wheel well (harmless) and rear of flare and stock mounting points for mudflap.This usually knocks loose the lower flare mounting hardware which I reattach when I get home.

On left the upper wheel well lip as well as flare and rear of flare. If you look at the proximity of where the rubbing is taking place at the mudflap mounting points, it looks like a bigger tire would hit the bumper as well (although that's easily trimmed down).

With the 35's this all seems pretty harmless but I'm a little worried about how the 37's would escalte the problems.

Sorry about the picture quality the camera/photographer was struggling

 

[LC80Ducati996]

On a stock 80 the rear frame mount bushing is actually below the center of the axle. So bump stopping the axle down actually put it further forward at full compression.

That may be but say 4cm before bump at stock and 4 cm before bump with a lowered stop the axle will still be farther forward with the dropped stop.

Also if it does move the axle forward it must be compressing the bushings to do so since the four links are'nt too flexible. I also theorize that the bump stop actually flexes rearward.

 

[LC80Ducati996]

Current rub spots; on right only the inner wheel well (harmless) and rear of flare and stock mounting points for mudflap.This usually knocks loose the lower flare mounting hardware which I reattach when I get home.

On left the upper wheel well lip as well as flare and rear of flare. If you look at the proximity of where the rubbing is taking place at the mudflap mounting points, it looks like a bigger tire would hit the bumper as well (although that's easily trimmed down).

With the 35's this all seems pretty harmless but I'm a little worried about how the 37's would escalte the problems.

Sorry about the picture quality the camera/photographer was struggling

An adustable panhard will help the left and right side rub. Correcting the geometry by lowering the upper panhard mount will really help since not only will the axle be dead center at ride height but move up and down straighter.

Losing the stock rear flaps and bumper will help a ton too. I know I know $$$ which is why I dont have a 4x4 labs rear on yet but it will be soon. It will be soon but after my current 3 week training exercise and before I go to the sandbox.

 

[LC80Ducati996]

The pinch weld.. Well look at what they do on Tacoma inner fenders and jeep zj and xjs.. The jeep guys do much more little tweek like that because they run into problems at like 33" sometimes.

 

[ats4x4dotcom]

It wasn't meant to provide exact measurements

I would like to think Toyota engineered the axle to be centered in the opening.

And its been shown it isnt accurate, in design, or exacution, but feel free to update it, and post the new researched accurate version when you can.

And you didnt measure to see if Toyota centred the axle first?

If you did, at what ride height did you check it?

How much does it move fore and aft in its travel?

And how much more does it change when you space the bump stop and put a longer shock on?

These are all questions that need answers before you can assume 1/4" of movement is a bad thing....a good thing....or indifferent.

Going back to 40 series, we used to re drill the centre bolt holes 1" away to move the axles further aparty, and add a 1" tailshaft spacer, my last 40 we moved to 98" wheelbase, and we have been moving patrol axles with 1/2" spacers, because they are like a range rover bush on the chassis, for tyre clearance since the early 90's, none of which have had any downside, when taken into consideration by answering the above questions I listed as part of the build, along with the tyre size and clearance required.

You cant just "think" or "assume" thats what it is, your starting with, when it comes to suspension, while thinking your own part of the system is perfect to the milimetre, or your concentrating on an unknown.

 

[ats4x4dotcom]

The pinch weld.. Well look at what they do on Tacoma inner fenders and jeep zj and xjs.. The jeep guys do much more little tweek like that because they run into problems at like 33" sometimes.

If you have someone who is handy at bodywork, slotting the rear fender inner and pumping the fender, and welding in a filler is one way to fix the fender clearance in the rear, and doesnt have an effect on the outer section, so you can just stone gaurd the inner fender without any painting repairs on the outer panels.

 

[LC80Ducati996]

I think I could pull it off easy then have my bro bedliner it up after some POR15 primer

 

[bstain]

I remember running our 40's stock everywhere. I just moved to 35's on my 80 and I feel like I'm sellin' out. When will it end? Pretty soon we'll need buggy's to run all the old trails. Sorry for the hijack and rant it's just killin' me...

 

[LC80Ducati996]

Oh please when you see that the outside of the flare is unchanged and all tweaks are hidden...

 

[landtank]

Current rub spots; on right only the inner wheel well (harmless) and rear of flare and stock mounting points for mudflap.This usually knocks loose the lower flare mounting hardware which I reattach when I get home.

On left the upper wheel well lip as well as flare and rear of flare. If you look at the proximity of where the rubbing is taking place at the mudflap mounting points, it looks like a bigger tire would hit the bumper as well (although that's easily trimmed down).

With the 35's this all seems pretty harmless but I'm a little worried about how the 37's would escalte the problems.

Sorry about the picture quality the camera/photographer was struggling

I'm currently running Slee's 4" springs and have the same rub on the inner fender but not on the flare with 315s. But I am running stock rear links with a frame drop bracket for the panhard.

 

[ats4x4dotcom]

I remember running our 40's stock everywhere. I just moved to 35's on my 80 and I feel like I'm sellin' out. When will it end? Pretty soon we'll need buggy's to run all the old trails. Sorry for the hijack and rant it's just killin' me...

I think they call it "middle aged thinking"

I guess, since going to 35's 20 years ago, and running 36 and 38" tyres 10 years ago, and 40's recently, everyone has said for all that time, "where will it end" but there are still plenty getting around on 285's.

We have seen some trips run around here lately called "back to stock days" where you have to run std size tyres and wheels, no lockers to be turned on, to make a fun day without playing to hard, and brush up on recovery skills.

They have been popular.

 

[landtank]

The fact the front tyre now rubs on the bull bar since I moved it forward

These are all questions that need answers before you can assume 1/4" of movement is a bad thing....a good thing....or indifferent.

it would seem to be a bad thing.