What’s a fiddle block and why do you need one for your 4×4?

Mechanical Advantage is your friend, and the more the better, right? We explain what a fiddle block is and why you need one in your 4×4.

Most 4×4 owners are familiar with the concept of a snatch block, which is a form of pulley. Let’s say your 4×4 is stuck and it requires a force of 1000kg to free it (yes, yes, the correct term is newtons, but let’s run with kg) you’d use a snatch block to reduce the effort required by the winch. Let me explain.

A snatch block uses the principle of mechanical advantage to more or less halve the effort required to pull. So, in that example of a 1000kg pull, the winch need only produce 500kg of force, which we call a 2:1 mechanical advantage or MA. The tradeoff is speed; for a 2:1 MA, every metre of rope you pull in moves the vehicle only half a metre. It’s the same principle of leverage you use when jacking up a car or using a long-handled spanner on a tight nut; extra force but it takes longer due to extra distance covered.

Sure, it’s possible to rig two snatch blocks for a 4:1 MA, but now RED Winches has released its fiddle block for 4X4s which offers 5:1 MA. But what is a fiddle block? A fiddle block is a compact series of pulleys designed to give MA. They’re widely used in applications such as sailing and the aborist industry, but we’ve not really seen them for 4X4s. Part of the reason for that was because we used to use wire rope on our winches which required fairly large diameter sheaves (the wheel part of a pulley), and for many purposes, two snatch blocks was enough. Also, the more pulleys you involve, the more complex the rig, and the more line you use up in just rigging the winch setup before you’ve even moved the vehicle a centimetre.

Most 4x4s run a winch rated to 9500lb for a single-line pull without any MA (4500kg, for some reason we talk winch ratings in lb). The average 4×4 weighs under 4000kg, so two snatch blocks allow an MA of up to 4:1 which means that 4500kg winch could in theory pull 18,000kg.

But that 4500kg rating is only for a winch in perfect condition with one turn of rope on the drum. So if we take a more real-world view of assuming our “4500kg” winch will pull 2000kg, and quadruple it to 8000kg, and then take off say 30% for friction (more on that subject later) we’re still at around 5600kg, all pretty conservative estimates. That’s still plenty of pulling power for a 4X4.

So I think these blocks are a bit of a niche product, and I see the main market as the growing forward-control light-truck community, as people get fed up buying a 4×4 for $70k and then spending another $70k to try and make it carry loads it was never designed for. I’m talking here of Hinos, Isuzus, Canters, Unimogs and of course OKA which we recently featured. These vehicles weigh from 4500 to 10,000kg or more and don’t always have winches to match, plus they have the space and payload to take the relatively bulky fiddle blocks. And the fiddle blocks mean a normal sized 4×4 could get enough MA to winch a much larger vehicle.  

The 5:1 reduction also means you could use a vehicle to pull the rope instead of a winch; if you drove as fast as 5km/h, that’d be a nice and easy 1km/h pull speed. Imagine, say, a light truck bogged, and someone using a small 4×4 to recover it or even an ATV…that would, perhaps, be possible with fiddle blocks in a way a snatch strap couldn’t ever work. Also, much less dangerous as no kinetic energy involved.

The blocks weigh around 4kg each, are available in 12t and 24t capacities and take only synthetic rope up to 14mm which is about a 20t breaking strain (not working load limit). They are designed for use with soft shackles only, and they’re not snatch blocks so you need to thread the rope enough through which means no hooks. I would recommend using them with 50 to 70m of rope as the distance you can pull will be divided by 5, so 50m is about a 10m distance pull. It wouldn’t be a bad idea to perma-rig them with an extension rope, and then just attach your winch rope to the end. That’s kind of what I do with my own 4×4, I only run 20m of rope so I can do high fleet angle pulls (not straight on) and there’s relatively little rope on my drum at all times. I just attach a rope extension for more line, nice and easy.

The fiddle blocks are an interesting product, and I have a set coming on test, with an ATV and Canter from Getabout Training already lined up to see how we go with recovery. Watch this space for the results, and in the meantime, we’re interested in what you think. Let us know by leaving a comment below.

UPDATE: pricing looks to be about AUD$1000 for a pair.

Rigging a fiddle block is a bit complex, so we got Professor Pepper to produce a video explaining how it all works.

While you’re here subscribe to the MotoFomo Newsletter

Sign Up for the latest news, reviews, advice, buying guides and more delivered to your inbox every week.

Subscribe

* indicates required

LEAVE A REPLY

Please enter your comment!
Please enter your name here