Building a Zuk

Page 5


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Zuk to Buggy - The Next Step

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Building an off-road machine is a vicious circle if you get the bug.  You will find every time you do an upgrade you make your favorite trails easier, causing you to seek out trails with a little more challenge.   Along the way you'll notice the rocks, ledges and obstacles growing bigger.  

It's been a while since I added anything to my building a Zuk page.  With another year to reflect on the recommendations I have made I still stand by all of them.  You will have a capable machine on 32-33" tires if you follow those suggestions.  But what if you get bitten by the bug and need to violate first goal in my buildup article: 1. Keep it light (so no Dana 60's or 35" tires)?  This is where I would start: 


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The stock axles will not stand up to any sort of hardcore four wheeling with tires bigger than 33's.  They are a time bomb waiting to go off.  Luckily there are two good options for a near bulletproof drive train (with the stock motor): Toyota mini-truck axles or Dana 44's of off a Wagoneer.  I won't go into the pros and cons of these two axles but I will give a few links here, here and here for some good spirited debate on the subject.  In my opinion I would buy whatever you can get cheaper and feel comfortable working with, for max width and sharpest turning use the Dana 44 axles.  With that said I took the plunge a year ago (Oct 2001) and started an axle swap using a pair of axles from a 1985 Toyota truck.  53+ trails later the axles are still holding.  During that time I went from a heavy 33 x 15.50 SX and a 94:1 crawl ratio, to a lighter 35 x 13.50 bias ply Baja Claw and a 117:1 crawl ratio. Based on that usage I feel the stock Toyota truck axles are a perfect upgrade if you plan on tires up to 35 inches tall and you are still running the stock motor. The axles continued to hold up even after moving to a 37 x 13.50 tire.  However, everything has it's limits, the last time I tore down the front end I found a cracked birfield.

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So the need to beef up the front end was at hand, I had actually already planned for this eventuality and had a pair of Longfields ready to go in.  Longfields (also referred to as super birfs) have proven to be stronger than the stock inner shafts.  If you desire, chromoly inner shafts are also available for the front as well as chromoly rear axles from All Pro Off Road. With these upgrades I feel tires up to 38 inches tall could be run with little worry of breaking.  I haven't upgraded the rear shafts yet, The stock rear axles hold up really well even under the heavier Toyota based buggies I wheel with so I am confident they will hold up under my lighter rig (but it's nice to have a cheap upgrade path just in case).

The bulk of the work in this swap was related to the front end.  a couple things to keep in mind:

  • The front springs need to be outboarded for a spring spacing of 29" to match the Toyota spring perches.   

  • To use an off the shelf hy-steer setup, you need to move the steering box forward.

  • The stock steering stops on the front axle need to be reinforced to keep them from crushing inward.  If they are not adjusted properly the birfield can bind.

  • Since the spring mounts and steering box need to be moved on the frame, now would be a good time to do a shackle reverse by extending the frame at least 7" forward.

You'll also need new 6 lug rims, I'd recommend 2" backspacing, combine that with wheel spacers later if you want to be wider.

For bigger motors you really need to go bigger running gear if your after bulletproof.


Another thing to consider before picking out those bigger tires is the gearing.  I am as low as I can go without adding a second transfer case or swapping in an automatic transmission.  With my 37's (which measure 36.25" tall), my 117:1 crawl ratio is adequate.  The stock motor does bog down easily.  I am hoping the extra 30 hp and torque of the 1.6 Sidekick motor will help.  With the Klune 4:1 boxes no longer being offered for the Samurai you will be faced with some pretty major custom fabrication to get a second transfer case in the Zuk.  I outlined some of the possible gearing options on page one of my  Project MP outline.  Bottom line, for anything bigger than a 37" tire, plan on dual t-case or converting to a V6 or diesel to bring the crawl speeds down.

Update - 4-17-03 I have had a chance to run my rig with the 1.6l 16 valve motor.  The extra horsepower is very noticeable both on and off-road.  I no longer have to keep the motor at wide open throttle to keep it in the powerband.  With the 1.6I can pull hills easily in 3rd gear vs 1st with the 1.3l. This really shouldn't come as a surprise since the 16v motor makes more horsepower and torque at 2500 rpm than the 1.3 makes at redline.  The extra power is also very helpful on the trail.  4 high is actually useable now, before the 1.3 would bog down so much I never used 4 high.  I would definitely recommend you not spend a cent on upgrading the stock 1.3l, save for a 1.6, you'll be much happier.

Lose that Sheet Metal

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The years of four wheeling had been a little hard on my Zuk's sheet metal.  The tailgate fell victim to the rocks on Asylum and the rear corners were used as pivot points more than once.  Removing the sheet metal affords some advantages; durability, increased storage can be designed in, and better visibility to name a few.   The biggest downside is you are now exposed to the elements.  I Invested in some warm, waterproof clothing for those few days it rains here in Arizona.

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There are hundreds of ways to tube a vehicle so I won't go into how to do it.  A couple things to keep in mind:

Storage - make enough room for tools, spares and an ice chest.  Large ammo boxes make great trunks.

Hi-lift - might as well make it easily accessible.  Mine is held on by one wing nut. 

Lose that Sheet Metal (and other things) - Part II

I tried to stick with leaf springs in back as long as possible but on the same trip I broke a birfield I bent both rear leaf springs.  This occurred when I tried to back into a wall while trying to do a multiple point turn.  While leaf springs are simple, they do inhibit potential flex, they are easily bent and they provide a stiff ride compared to some of the other options out there.   With two bent leafs and no spares I decided to go to the next level.  The rear suspension now consists of 4 links which locate the rear axle and a pair of coilover shocks w/ dual rate springs to support the vehicle.  The dual rate springs provide a very plush ride thanks to a lighter spring which is used to soak up most of the bumps.  As the suspension compresses, a second, stiffer spring starts to compress.  Thsi gives you teh ebst of both worlds, a soft ride that can stiffen up when you need it to.

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As you can see, this setup provides for a lot of articulation and allowed me to cut a lot more off of the back end.  I removed close to 100lbs of frame and tubing.

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I can now tackle larger obstacles without lifting a tire.  Another modification that really helped was the elimination of the rocker panels.  The rockers are replaced with a sheet of steel that runs diagonally down from the lowest part of my cage to the bottom of the frame.  This provides one large, smooth surface good for sliding over rocks.  It also provides for more clearance so in many cases you can totally avoid contact with the rocks as shown in the above picture.

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Here's a shot of the side and the new clearanced rocker panel.  Details of all these mods can be found in the project buildup pages starting here.