Help me with steering issue, O mechanical geniuses of Pelican

[Deschodt]

I got my kid an electric go Kart which was supposed to be pretty cool. It's not bad but we're having issues with turns... Going right is fine, going left causes the chassis to raise the front left which therefore loses grip and it barely turns that way... Right good, left bad.. I measured a few things, adjusted pressures, took the wheels off and moved shims around, it's better and usable now but not perfect...

You might get what I mean in that crappy video... Full lock left, the front of the kart goes up and the left wheel almost is off the ground.

https://youtu.be/O7_bhud9JbA

On this picture the orange arrows show the direction of turn, the wheel movement, the blue one shows the part responsible... There were 3 shims above it, 2 below (not the same as the other side). I experimented a lot and it worls better with all the shims below it... If you disconnect the steering and simply move that front right wheel (on your left) the front of the kart moves up when it reaches close to full lock... 3/4 turns no problem, but full lock the think moves up 1/4 inch which makes the other wheel lose grip...



Go ahead, humble me, what else can I do to fix this... Thanks !!!

[Deschodt]

better pic of the angled wheel mount with shims, sorry for the nomenclature..

[asphaltgambler]

Is the right outer tie rod end hitting the bumper thingie when turning left? It looks bent inward only on that side

[wdfifteen]

The angled wheel mount is responsible for the caster angle, which helps the steering auto-center. Turning the wheels does lift the chassis up, and letting go of the steering wheel should allow gravity to lower the chassis and let the wheels return to center. I don't know why this effect isn't symmetrical on your cart, but that may be the problem. Caster does slow a car down, but it helps steering stability, which is probably a good thing on a kid's cart.
From the photo it looks like there is considerable toe-out of the front wheels, but that could just be the camera. I would check the tow and check the caster.

[Dansvan]

Are the inner tie rod ends by the steering stem in slotted holes? You may have to manipulate them in that location to make it steer correctly.

[dad911]

No warrantee?

My guess is either the spindles are welded onto the pivot at different angles, or the 'U' brackets are not welded on at the same angle.

If you remove front wheels and turn side to side, measuring from spindle to flat ground, you can probably see what is wrong.

Or measure camber angle/spindle with digital level (smartphone)

[LEAKYSEALS951]

^ agreed

I took the picture and tried to line it up as best as possible and it's probably the camera angle, but it looks like the entire u tab caster angles might be not right. I wouldnt read too much into my picture, but thats one of the things you need to rule out Look at how one bolt is visible, and the other just barely.



You could also use the tile lines on your floor as straight edges to see if the tires are acting out of whack, or if one tire is mounted further back than the other, especially as you go through the turning motions.

[Deschodt]

Warranty is a loose concept for something that came via lift gate truck in a welded metal cage on a a wood palette. In other words I ain't sending it back, ever ;-)

If you disconnect the tie rods altogether on both sides, and both wheels are rotating R/L freely inside the red U bracket, independently of one another, the left wheel movement lock to lock does not affect height, the right wheel moving to full inside lock raises the kart a little.. Moving the spacers helped a bit but not totally..

I suspected the angle of the bracket but this is not a weld for me to cut and redo at the perfect angle, I know my skills... I'll try to beat the bracket down a bit with a BFH and measure again tomorrow... [edit]: not a good place to put a level without dismantling everything again. Tomorrow... The U brackets are at the same height off the ground, so at least that's good. But the angle COULD be off a bit...

Thanks guys !

[dad911]

https://www.harborfreight.com/welding/mig-flux-welders/170-amp-dc-240-volt-migflux-cored-welder-61888.html

[Scott Douglas]

This kart obviously needs a good four wheel alignment and corner balancing.

[legion]

If this were a car doing this I'd suspect a problem at the back end. You'd expect the outside front wheel to possibly lift, not the inside front wheel.

Given that this is a go cart, I assume it doesn't have a movable suspension and the rear end is a spool. I'd suspect something is bent or welded in the wrong location. Start measuring and comparing the left and right sides--at the back end too.

[Scott Douglas]

I agree with leaky, the pivots of the king pins aren't located correctly. If you measure, I think you'll find they aren't the same distance from the center line of the rear axle.
Remember, three points determine a plane so if one of them is off it'll take the wheel out of the plane determined by the other three wheels when the wheel is turned.

[LEAKYSEALS951]

Bonus points if you can include home welded eccentric bolts into your solution to improve maximize caster/camber possibilities. - like this "random pics you have taken" pic:

[rick-l]

Originally Posted by Scott Douglas

I agree with leaky, the pivots of the king pins aren't located correctly.

Are those eccentric bolts on the kingpin bracket?

[Deschodt]

There are no eccentric bolts anywhere.. just a different # of washers on top and below the cylinder with the orange arrows, in the bracket, side to side...

[1990C4S]

I think a bit of sleuthing with a digital inclinometer, some string and tape measure will tell you where the differences lie.

Follow what dad911 suggested.

[David]

Karts will normally lift a wheel at full lock, but they would also normally be sideways at full lock so not as much of issue. How is it when not at full lock? Does it push at speed?

[matthewb0051]

My .02.

I know photos typically give the appearance of tires or wheels not in their correct alignment, especially toe in/out. I swear though that the tires look toe out AND looking at the tie rods, it appears that they are different lengths. The different lengths thing would not be a big deal if the column is not centered.

Anyway, just what I can see from the photos. Good luck.

[matthewb0051]

Just looked at the video. I see the lift when you turn left.

It looks like the entire left tie rod is moving in a higher plane as a result of the mount on the kingpin either being too high or moving higher as you turn the wheel. Maybe that tab on the kingpin is at an upward angle. Or maybe you are suppose to mount that tie rod underneath???

The right wheel and tie rod is staying in a consistent plane.

[Deschodt]

Originally Posted by David

Karts will normally lift a wheel at full lock, but they would also normally be sideways at full lock so not as much of issue. How is it when not at full lock? Does it push at speed?

yeah, not the same. It'll lift without moving.... It will hardly turn left, even at low speeds but it will turn right OK. Because when the RF wheel is on full left lock, the front of the chassis goes up 1cm and the LF wheel is now off the ground. So it turns with one wheel only. It's worse at speed, it understeers like mad.
It's better now that I played with shims and tire pressures but still noticeable.

Originally Posted by matthewb0051

Just looked at the video. I see the lift when you turn left.

It looks like the entire left tie rod is moving in a higher plane ... Maybe that tab on the kingpin is at an upward angle. Or maybe you are suppose to mount that tie rod underneath???

The right wheel and tie rod is staying in a consistent plane.

Sorry, crappy video, one handed, everything moves... The tie rod was thought #1, I disconnected them and simply turning the RF wheel by hand makes the chassis go up. Bending that tab was #2, I measured them to the ground, same distance now... I'm pretty sure the folks above are correct, the U shaped bracket is probably at a bad angle... It's hard to measure as is, I will remove both wheels and tie rods tonight so I can measure "clean". I have a welder but I don't see myself going that far, I'll hammer the bracket angle closer IF that's the issue. After that, the kid can manage, it's less noticeable off road, maybe I'm setting him up to be a dragster type rather than a road racer ;-x