Granddaddy Steering

GCC

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I am close to finishing up my Spidercarts GrandDaddy gokart. I am not sure how to connect the steering wheel to the rack and pinion. The only thing I have so far is the rack and pinion with a 5/8" x 36 shaft. Can anyone tell me what I need to complete make the connection. Thanks.
 

J123

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Did you ever figure this out? I'm currently in the process of buying parts for a GrandDaddy build, but I'm a bit confused on what is needed since the Desert Kart supplier on the bill of materials is no longer in business. I found the link for the rack and pinion, other than that I'm a bit lost on what this should look like as well.
 

GCC

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Did you ever figure this out? I'm currently in the process of buying parts for a GrandDaddy build, but I'm a bit confused on what is needed since the Desert Kart supplier on the bill of materials is no longer in business. I found the link for the rack and pinion, other than that I'm a bit lost on what this should look like as well.
I bought a shaft with u joints from BMI carts. The ends have a spline connection that fit the rack and pinion and the steering shaft. I had to cut the shaft between the joints and weld in a extension to make it reach the steering shaft. I bought a short shaft to get the splined end to fit the other u joint. I made a coupler from a piece of 5/8 round tube steel to connect the steering shaft to the short spline. I also used a small pillow block instead of the steering block in the plans to attach the steering wheel to the dashboard. The steering block is soft rubber and broke before we even got to drive the cart. Let me know if you have other questions.
 

Snaker

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American Landmaster does/did carry that sort of parts also. But I couldn't get around on their website the last couple times?
 

madprofessor

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Congratulations, snowbird. That's as neat and clean-looking a build as anybody could hope for. Great seats too. There is one thing though that looks like it's not going to work right.
I wrote in a different post once about the use of pillow blocks in kart builds, and how great they are. A warning was mentioned about the "self-aligning" description given about those bearings. Wrote about how it's true that you don't have to line them up perfectly, but do try to get it close because they're not universal joints. Every bit of that was written concerning their use on axles and jackshafts, which means of course that there'd be at least two bearings involved on each application.
While your rack's input shaft is rigid and fixed, your steering shaft is not. You've only got a single bearing on it, and it's one of those sloppy stamped-out-frame ones at that, not the cast-iron ones in that previous post. Since that's not going to be a machined-fit race in the bearing, but rather a "self-aligning" semi-cushioned one, it's going to move around on you. You'd find that when trying to bounce along on any uneven surface, the forces arrayed against the steering would be strong enough to jerk the steering wheel all around in your hands, unpleasant and maybe even a little unsafe.
One more bearing anywhere between the steering wheel and the rack would get things to where you'd be happy about it. The best spot to rigid things up would be on the same shaft connected to the steering wheel as the one that's there now. However, a rigid mount somewhere along the intermediate shaft would also serve to improve rigidity, with only a little play in the wheel.
 

madprofessor

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I used the biggest ones the kart parts suppliers sell, 3/8", so 50 % bigger than yours. Snapped one just rolling it off the edge of the patio for its first test run. Yes your 1/4" rods are too flimsy.
Those 1/4" are best for low-slung track karts where the rods are and stay pretty much horizontal, with smaller tires to push. My current build has even more angle on the rods than yours. My solution for heavier ones was to build my own. 5/8" threaded rod inside of 1/2" EMT thinwall conduit, with a 5/8" threaded rod coupling in the middle for adjusting toe in or out. Kept the existing 3/8" rod ends, they're not a weak spot.
5/8" should work for you, but you'd likely have to change the rod ends too. Still, doesn't sound right that you're bending those 1/4". All I'm seeing in the picture is that you're tierods are hugely out of position compared to the A-arms, the bumpsteer would be horrible. The rods need to be parallel with the A-arms, and pivot inline with the A-arm pivots. They start out at the frame in the right spot, but then run uphill to the spindle arms at the wheels.
Looks like at the very least the rod ends at the spindles might be mounted on top of them instead of under them. That would correct some of it.
Or I'm just unable to see in that picture what's really going on.
 

Snaker

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Be sure to check that the heim joints allow full movement at any position of suspension travel.
If the ball joint hits its limit with more travel to go, it will bind up and bend/break something.
 

madprofessor

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Good call about the movement limits Snaker. BMI K___s sent me a set of 4 Full Range of Motion washers to get that extra range. Unfortunately they only had them in 5/16" to go on my 3/8" rod ends. They do really work though.
Found some 3/8" "cone washers" at an auto parts supplier online, ordered them in for my new replacement handmade 5/8"+ setup that's still using the 3/8" rod ends. Advising against that, made no difference at all. The 45 degree angle of the "cones" is not the same thing as the L-shaped step of the FRoM washers.
Always planned for using limiting straps to keep my A-arms from dropping too far when front leaves the ground, binding my unique plate hinge system at its limit of motion. Now going to set their length with exceeding the range of motion of my rod ends in mind. Have so much travel with my Monroe air shocks that a little won't be missed. The straps would be a great idea for a lot of people's builds.
Attaching a pic of my original setup, complete with standoffs on the spindle arms, before I snapped it like a twig.
 

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