FJ40 Suspension/Tire/Rim Advice

[Azrocks]

Sorry you all are hearing so much from me today. I'm feeling like I have the flu and have been kicking it in bed today (well as long as I can stand it).

I'm getting ready to redo the suspension and tires/rims on my FJ40 and would like the suggestions and advice from the collective group. I posted in the general section because I'd like to hear from the other short wheelbase crowds as well. Here's the variables to consider.

- I'm not going to be doing any "hardcore" rockcrawling in this rig. I do push the capabilities when offroading but can usually finese my way through stuff because of experience behind the wheel. I have no desire to trash this vehicles sheet metal.
- I will be putting an ARB in the rear axle at some point.
- I have a SBC, 4.10's and stock driveline
- I have already done the Saginaw power steering conversion.
- I am looking for a taller tire but not too wide.
- I have the tools to do whatever work I need to as far as fab and install.
- I will be pretty heavy when loaded up. Eventually I will tow a trailer. Will probably skip having a rack. The RTT will wait for the trailer.
- I will be getting a winch and aftermarket or homebuilt bumper.
- I love to drive this thing as much as possible, even around town when I get the chance.
- I plan on doing trips into Mexico including Baja.
- I want to be able to maintain highway speeds. I have 31's right now and can travel at 75 comfortably.
- I'm looking for a tire that is reasonably quiet.
- I want to do at minimum a 4" lift for clearance

It wasn't too long ago I wouldn't have considered anything other than an SOA and 37's. I still wouldn't mind doing a SOA if it made sense but 37's are probably not warranted. I would like to hear what you all would suggest as the direction to go with this. I'd like to set this up right the first time.

Thanks tons in advance for any advice you might have.

 

[Grease Cruiser]

I would go with the 2.5" Old Man Emu (Dakar) springs. They offer a nice ride and handle great. With a shackle reversal up front and extended shackles in the rear, you will get your 4" lift. With this setup, I would run a 33X10.50 BFG AT or MT. Or, I prefer a 16" rim as the load range goes up on the tires, I'd go with a 255/85R16 (33X10 +/-)

If, you are leaning towards the + side of the 4" lift, you might as well go with the SOA. If you go with a SOA setup, 35's would look much better than 33's.

SOA 40's ride great, they are nice and soft. The SOA setup with 35's may be a little more than what you want, especially in a 40. It all depends on what you are going for.

 

[ntsqd]

If comfort off road is the goal then I would consider using high quality mono-tube dampers. To me this means a brand name like Bilstein, Fox, King, & possibly Radflo. Know that the off the shelf valving may or may not be exactly right, but if you get them from someone like Lee @ Raceshock.com I would expect the valving to be pretty close.

 

[Rezarf <><]

As a 40 owner, I would suggest the OME suspension too. Just as mentioned about to get 4" of lift.

I would suggest getting the matching steering stabilzer and OME shocks. I would not suggest mono tube due to the fact that if I rock dents the housing you will loose a lot of performance. They are amazing shocks but for offroad I prefer the nitro/oil shocks with a rock shield. OME has shocks perfected for the 40's.

Tires are like salad dressing, everybody likes dressing, but everyone likes something different. Personally, I love the Goodyear MTr's. Great on road, and great off road, except for mud... surprising!

Wheels, aluminum would lighten the rotating mass... which is good. However, grey factory steelies look AMAZING! Getting them to fit a 12.5" tire is a pain though, you have to have them split and widened... not cheap.

Dakar, is the new name of the OME springs and they are the best out there IMHO.

Have fun sounds like a great build, make sure to post up pics of your progress.

Rezarf <><

 

[ntsqd]

snippage....
I would not suggest mono tube due to the fact that if I rock dents the housing you will loose a lot of performance. They are amazing shocks but for offroad I prefer the nitro/oil shocks with a rock shield.

I see your point, but counter it with my ~7 years of chasing desert racers. While I'm sure that it can happen and that it probably has happened, I've never seen it happen. Some of those years were with multi-car teams or pit crew clubs. Never seen or heard of it happening by a rock.

What I have seen is oil lost due to excessively rock pitted shafts, but that's everyone's problem, not a problem unique to the mono-tube design.

 

[Azrocks]

Thanks for the replies. I'm not a big fan of shackle reversals so I'll skip that. It looks like a SOA is probably the best option at this point. I'll probably do the FJ55 springs up front.

I don't want to go too big on the tires. I get bad enough gas mileage as it is. I need all the help I can get. I know 35's are going to be hard to find on the road but I'm going to have a full size spare on the carrier and another on the future trailer.

I need to figure out a wrap bar that will work with a 79. Any suggestions?

I'll have to check out the MT's. Sounds like they have the characteristics I'm looking for.

 

[ntsqd]

I would build something like the "Wrap Trap":

If you plot the pinion angle vs. travel in a leaf spring system you'll find that the pinion angle doesn't change very much - if at all - thru the whole range of travel.

A MS-ME friend of mine did this development prior to deciding what sort of system to either buy or make for his EB. The Wrap Trap essentially turns the front halves of the springs into lower links of a 3-link system.

The anti-wrap arms with two mounts on the axle put huge loads into those mounts. These 'A' type arms force a rotation which puts an S-curve in the spring that wouldn't be there otherwise. To be honest, I've not had much success convincing those indoctrinated by POoR to use the Sam's/Kopycinski design that it isn't all that great of a design. Then they wonder why they have to use a 3/4" G8 bolt at both axle mounts to keep them from shearing off.....

 

[Rezarf <><]

I see your point, but counter it with my ~7 years of chasing desert racers. While I'm sure that it can happen and that it probably has happened, I've never seen it happen. Some of those years were with multi-car teams or pit crew clubs. Never seen or heard of it happening by a rock.

What I have seen is oil lost due to excessively rock pitted shafts, but that's everyone's problem, not a problem unique to the mono-tube design.

Good point, some make it sound more common than perhaps it actually is...

counter accepted

 

[ntsqd]

FWIW I have seen it happen. But by other metal parts that didn't used to be in that spot.......

 

[Azrocks]

I would build something like the "Wrap Trap":

If you plot the pinion angle vs. travel in a leaf spring system you'll find that the pinion angle doesn't change very much - if at all - thru the whole range of travel.

A MS-ME friend of mine did this development prior to deciding what sort of system to either buy or make for his EB. The Wrap Trap essentially turns the front halves of the springs into lower links of a 3-link system.

The anti-wrap arms with two mounts on the axle put huge loads into those mounts. These 'A' type arms force a rotation which puts an S-curve in the spring that wouldn't be there otherwise. To be honest, I've not had much success convincing those indoctrinated by POoR to use the Sam's/Kopycinski design that it isn't all that great of a design. Then they wonder why they have to use a 3/4" G8 bolt at both axle mounts to keep them from shearing off.....

I'm very interested in this. I agree with your statements on the two axle mount systems. It seems like over and over again I hear about failure and the need to use heavier hardware. I also like this design because with my 79 I have a gas tank mounted underneath there and am limited in space. I'll read more about it. Thanks!

 

[Hltoppr]

I'm gonna put in my vote for an OME/Dakar 2.5" lift....just get the "ultimate" kit from Kurt (CruiserOutfit here on ExPo) and be done. You might want to stay away from custom set ups if you're gonna do Mexico....you can easily get a set of springs repaired in the middle of nowhere...not custom 4 links, etc.

Tires. I like BFGs...thousands of miles and no problems in Mexico or anywhere else. 33s will be fine for expedition work, and you could still find one if you needed to...

I like 15" rims....but 16s are common enough to go that route too.

-H-