Axle Winching

 

   
 
 

Axle Winching (more uses for your winch)

This is another idea that filtered down from the rock crawling competitions to the recreational wheelers.  The basic theory involves attaching your front mounted winch to the front axle so you can compress the front suspension when desired. I planned for this usage when I built my buggy so my winch rope drops right down from the winch and I hook the clevis on the end to a tab on the front axle. On a leaf sprung rig you will need to route the winch rope to pull directly over the top of the axle which may require a pulley or a cross member you can route the winch rope around.  (I suggest using winch rope since it can bend around tighter radii than wire cable can)

Compressing the front suspension comes in handy for steep climbs since it lowers your CG a bit, cuts down on axle hop and can help provide more traction by shifting the weight of the rig around (imagine the vehicle pivoting on the rear tires towards the rock face it is trying to climb).  One other benefit is it makes the obstacle feel less steep than it really is since the front end is brought down and the front suspension is no longer unloaded, this can provide a much needed boost of confidence to the driver.

I have also found it useful to compress the front suspension is some off camber situations.  In the picture above I compressed the front end to level the cab when my passenger side front tire dropped into a hole.  What I like about this is it allows me to run with more up-travel on the suspension for smoother pre-running and allows for taller belly clearance for crawling around in the rocks; when the time comes that I need a lower cg or tighter suspension I can simply winch the front (and soon rear) end down and reap the benefits of a lower and stiffer suspension.

  

As silly as it may sound I found the most important detail when setting up the front winch was the placement of the controller.  The easier the controller is to reach the more likely your are to use it.  I tucked mine between the passenger seat and switch box so I can comfortably reach the controller even when strapped in to the seat. 

The next logical step is to have the ability to compress the rear suspension, this should further aid stability in some off camber situations and also help when driving down very steep inclines by keeping the rear suspension from unloading. Unlike the front winch, the rear mounted winch has a few additional challenges that must be overcome.  First you'll want a smaller winch out back to save weight and money.  Most people use a 1500-2500lb winch for the rear.  These small winches are typically light duty and should not be used as a limit strap so you will need to route the cable around your limit strap and have a way allow for slack in the winch line to keep the rope from unwinding on the drum.  More on this in a moment.

I did some searching and found a fairly inexpensive 2000lb ATV winch on E-bay that looked like it would work.  The specs on this winch are posted in the picture above, the most important feature was a load holding brake.  Many of the small winches do not have a brake so look carefully at the specs.  I also liked how the internal gears were metal (some are made with plastic gears).  The whole package included wiring, an easy to mount switch to control the winch, a small mounting plate and even a roller fairlead.  After bidding I ended up paying $60+ shipping for the winch.

I mounted the rear winch under the passenger seat by installing a new cross member so the supplied mounting plate could be welded between the existing and new cross member. I also eliminated the fairlead mount from the mounting plate. I initially centered the winch on the frame  and then realized the motor stuck out far enough that it would interfere with the upper link so keep in mind it will have to be offset slightly to compensate for the motor. The winch original came with 50' of 5/32 wire rope.  I replaced this with 15' of 5/16 fiber winch rope I picked up from www.mcmastercarr.com.  The part number is #2302T11 and includes a hook for $13.21.  The line is rated for 1700lbs.  McMaster-Carr also offers a 1/2" winch rope assembly for $17 which is rated for 3700lbs (#2302T12).

I routed the winch line over the rear cross member by making a small roller using a pair of tabs and one of the rollers from the supplied roller fairlead.  I made the tabs high enough to keep the rope captured and smoothed out their edges really well on a buffing wheel.

Once the winch rope clears the roller it attaches to the axle.  If I need to I can go back and add a snatch block to the axle, then route the winch rope back up to the chassis which would half the load the winch line is seeing. To keep the winch rope taught but still allow some play so the winch line does not act as a limit strap I attached a pair of small bungee cords to the rear of the chassis and then looped them around the winch line (seen in the second picture above). The only thing left to do is test it.

Update 10-24-05 - I have been able to use the rear winch a few times, this picture is from Collateral Damage, driving down the biggest ledge.  Sucking down the back end definitely helped, I think I would have gone over forward without it because the rains had washed out a 3 foot deep hole at the bottom of the ledge that I wasn't expecting.  I do need to install some sort of pulley to the rear axle to half the load on the winch rope, after the obstacle above I noticed the winch rope was breaking.