Ways to check if a kart frame is bent?

Does anyone know how to check if a frame is bent? I really dont want to pay good money for someone just to say it isn’t bent. Any tips will help! Thanks

Set it on the ground, turn the wheel full lock each direction, lift the inside rear wheel with your hand, see if one side feels lighter or not. That’s a quick and dirty way to test it.

Throw a set of Snipers on the front and see how the alignment looks too.

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Measure each side from Kingpin to axle (or bearing carrier) and compare measurements. They should be the same for a sprint kart. I can’t speak about ovals.

You can do the same with diagonal checks too.
Check for a warped floortray and or mounting points that have been pushed back. This isn’t a very conclusive one of course because it’s not hard to swap a floortray.

If (and it’s a big if) the ground is level and the tires are equal circumference/inflation you can lift the front about 1" off the ground, slowly lower it down and see if the wheel on one side touches the ground noticeably sooner than the other.

I’m not super fond of checking lock to lock unless you’re really used to “feeling” it, but there’s certainly no harm in trying that along with the other checks.

Power Republic go through some of these checks in this video.

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You could also corner weight it, and see if the cornerweights are just super off.
Personally, I don’t have a problem putting a kart on a frame table, if you’re concerned about it. Piece of mind is always a good thing.

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Thank you James! I’ll give it a shot!

Does it matter if the engine is on or off? I did this earlier this year with it on and the rr stayed flat on the ground. Sadly I only have toe plates :frowning:

If I turn the wheel all the way to the left and press down on the right front the left rear pops up. If I turn it to the right and press down on the left front the right rear does nothing. Does this mean its bent?

It’s hard to tell honestly. It’s not super unusual for that to happen especially if an engine is on the chassis.

It depends on the Caster, ride height, toe, track width, tire pressure and Ackerman being the same on both sides on the front end. Rear hubs equal distance out from the bearing carriers both sides. Same pressures left/right. Flat and level ground too. It’s kind of a feel thing even at that I’ve found it to be inconclusive.

Was there an engine on the chassis? That will have an effect as it “weighs down” the “spring” of the chassis on that side.

If the engine was off and you are able to cancel out all the variables above then I’d say there’s a chance it’s tweaked at the waist. You could use the diagonal measurement to verify

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I took the engine off and did it, I measured the kingpins to the bearing cassettes and it was the same measurement, front and rear track widths are the same tire psi all the same, ackerman is the same. The toe is eyeballed at the moment. I bent the tie rod and kingpin last race when I smoked the barriers, which is why I’m concerned the frame may be bent lol. I put a new kingpin in and spindle bearings. Knocked the tie rod as straight as I can for now. Picking up a new tie rod friday

If you’re checking corner weights, you’ll want to check the front end geometry (camber, caster, toe, ride height) first to make sure everything is even. On the first kart we ever bought, I checked the corner weights and was initially thinking it was bent when the front end settings just weren’t the same on both sides.

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Thank you Chris! Corner weights meaning Lf, rf, rr, Lr when I put it on the scales?

I’ve done some looking and haven’t found much about using the snipers to help in checking the frame. While it would seems this could be used on the back half of the chassis it probably won’t tell you much about the front. The power republic video mentions a chassis jig, but I’ve never seen one or plans to make one. Does anyone have that information they are willing to share?

I think they mean a chassis table, pretty sure it’s just a flat table.they are probably expensive as all hell. I took my frame to comet and they put it on their table. It was bent 1/8th of an inch. $75 for labor, but atleast its straight now