Rear Steer Idea

OK, you’ll probably think this is a mad idea, but here goes… the whole idea of this “Lil’Bugga”buggy build idea was to build a small, cheap US crawler inspired buggy, tube frame, single seater built with as many standard / cheap / replaceable (Suzuki Jimn) parts that I’m fairly used to fiddling with, but on a budget and using home engineering… With all that in mind, read on… LOL

I’ve already narrowed two Jimny front axles by 13” and trussed them for strength, so that I can use the shorter sideshafts on both sides of the diff, this gives me several benefits – the smaller track width, and as a consequence of the front axle mounting radius arms (being shorter than the rears), a shorter length too, stronger bearings in theory, disk brakes all round, and of course the possibility of four wheel steering! That combined with an open diff with 26 spline HD TrailGear shafts and CVs with rear fiddle brakes should give a very manoeuvrable fun to drive offroad buggy…

“We” (on the BigJimny discussion forum) had quite a debate about using a front axle rotated 180 degrees and used as a rear axle, as to whether it would turn in the right direction… but I was vindicated after lots of thinking and finger twirling that it would. So I’ve recently – still being incarcerated in hospital – been giving the rear steering some thought, and an initial sketch –

So, I drew a (very!) rough sketch of a front axle at the top of the sheet and then turned the sheet round and drew another the same to try and work out the direction of steering needed… I want a gated lever (more coming on that) so that if I push the lever left the rear steer would go ”left”, etc… So that took some thought as you can see by my scrawls and corrections… I initially thought in my mind that I’d need to reverse the direction, so the idea was to strip a spare Jimny transfer box I have to both reverse the direction of the lever turning the steering box at the back whilst also increasing the rotation speed of the steering shaft, otherwise the steering lever would need far too much movement to affect the rear steering enough, hence the big cog driving the little cog…

BUT, the direction of the steering lever is infact correct, so I’d need some other way of increasing the rotational speed of the steering shaft in relation to the steering lever… enter good old eBay again…

And I found a ”used” reduction gear coupler advertised at £65 but the ”make an offer” button secured it for £50, a reasonable price for both parties I felt. So, using it the other way round will give me a 9:1 increase in rotational speed between the steering lever and the shaft… and it’s a big chunky engineering unit with 14mm shaft inputs and outputs, with four threaded mounts on each side of it

And a lot easier than stripping a transfer box, and trying to make something up…

So, in the end…

A “gated” lever will normally sit Centered, to steer the rear wheels “left” as indicated by the dashed tyre outline, I’d just have to push the lever knob forwards out of the gate and to the left aided by the 9:1 increase box (reduction gears used backwards) and with the power steering box helping too, move the lever across and back into the Left position in the gate… and vice-versa for Right of course…

I’ll need to experiment with the amount of movement in the lever before making and positioning the gate with the steering stick..

Just to confirm – the rear steering is proposed to be the same as the front… a standard Jimny power steering box with shortened and sleeved steering shafts… so ”just” a front axle rotated 180 degrees to go as a back axle… The power steering pump will be plumbed to run both power steering units in parallel, as the rear won’t be used that much?

I’m hoping this will all work to give me a home engineered / on the cheap basic rear steering system! We’ll see how things go as the build progresses!

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