Any rock crawler quickly learns that an axle with a locked differential looses some of its turning ability and both turning tires try to keep pushing the rig straight forward to some extent. But, if you want to crawl, locked axles are the way to go!
Still, we’d like to make those Clod gearboxes turn just as tight as possible so we can maneuver best we can in tight obstacles. Here we’ll take a look at the steering limitations of the stock and some aftermarket knuckles and the turning angle abilities of the stock Clod axles and aftermarket CVD assemblies.
To test the various knuckle setups, we built a simple test jig that uses a Clod axle tube. To that, we bolted each knuckle (without axle shafts) and checked its turning ability. A magnetic angle finder on a metal plate bolted to the outer knuckle face let us measure how tight each would turn. |
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| We measured with the knuckle arm pulled towards the gearbox (inside turn) and with it pushed away from the gearbox (outside turn). Here’s what we measured (tolerance ~+/-1 deg) on the knuckles we had available: |
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| Now, the actual ability of these to turn sharply is not all that important as each of them (or the axle tube) could be trimmed to gain more turning angle. The one exception is the stock knuckles. At a minimum, the steering limit pins on these should be removed as any axle shaft can take advantage of the increased angle this mod provides as we’ll see below. |
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| Next we’ll look at the steering limitation imposed by the axle shaft joints themselves. We wanted to test the angular limits of the axles so decided to find the point at which each axle started to feel as if it were binding. |
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| We added a small turnbuckle to our measurement jig so would could adjust and then lock the steering angle at any position. With an axle shaft set installed, we turned the stub axle while increasing the knuckle angle until we felt a clicking or binding and then backed off until it was eliminated. Here’s what we measured: |
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We found most current parts provide about 28 degrees of turn angle, while the Thundertech CVD axles offered the greatest at 32 degrees. While it may be possible to gain a bit more steering angle from the dog bone style shafts, it would come at the expense of grinding material off the shafts, weakening them. The CVD design uses a large cup that takes advantage of all the space within the backside of the knuckle.
Until now, we had never seen anyone quantify just how sharply these axle shafts could turn, but now we have definitive numbers. Despite locked differentials, having the ability to turn super sharp in the rocks is a plus along with a steering system setup to get the most from your knuckles.
Thanks for reading! |
