Chassis straightness without a straightening table

I have 2nd hand kart that got into an accident. (bent tie rods & axle)

Last weekend I got up on the scales and they were way off IMO.

FL = 66.3
FR = 75.5
RL = 112.8
RR = 102.4

When doing front end alighment with the sniper tool, the two dots don’t come together at the center (steering shaft). One is higher / lower than the other.

Is this a sign of a bent chassis?

We don’t have a chassis straightening table in the vicinity. What do you guys suggest I do?

Appears the left front is bent up some. The old school dirty method is put a block under the right front kingpin have someone sit on the right rear and jump on the left front. Scale and repeat until close. It’s not the best or most accurate way to do it, but it does get the job done.

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Thanks for the feedback. I saw the process in a youtube video once.

As for the sniper alighnment… the two dots should meet in the middle when centering the steering shaft right? This is now not the case…

Theoretically, with everything perfectly straight, they should. Are your pills in exactly the same spots top and bottom? Can you get your camber correct using pills?

This is going to be an unpopular truth, but I have seen new chasses where the lasers aren’t perfect and you had to use the pills to even them back out, so its not a 100% guarantee that your chassis is tweaked.

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If it’s perfect yes they should, without going on a frame table it’ll be tough to get them back to perfect like that. Doing the brute method I suggested will work for fixing the weights, and “may” bring the lasers back closer together but it’s not a guarantee.

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I guess it should be asked, were your scale numbers perfect before the accident?

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Even new chassis aren’t always perfect for sure, often they need a little tweaking to get just right.

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I don’t have the numbers before the accident.

Thank you all for your input.

Is your chassis bent…maybe, but the snipers aren’t the only thing to go by. You mention axle in the accident is that your front or rear? Your front axle(s) could be bent which could cause both issues you are describing (scales and lasers not lining up).

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Have you set the sweep to make sure that steering is truly centered?

Looking at the numbers it’s not that bad. Things to look at once you make sure your steering is in fact centered.

Washers/ride height same both sides
Caster same both sides
Is the axle in straight and the bolts in cassettes not high or low in hanger holes

You can find 3-5lbs just in having bolts sitting at bottom or top with the play in the hanger holes

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The rear axle is bent.

I checked and corrected the sweep before centering. During the centering I noticed the two laser dots don’t lign up. So I rechecked the sweep.

CAVEAT: I’m certainly not an expert but this is my collective experience and thoughts but it all depends on your expectations from the kart.

In general, the axle has to be straight and the scales have to be level to each other. Looking at the corner weights, the kart chassis definitely is twisted may be somewhere in the 6mm to 8mm range, that’s a lot.

image

Squaring the chassis by scales and jumping the frame is ok, if you’re not looking for perfection but having it straightened on a table keeps the entire chassis straight and they can also take out the sag in the frame rails. Also, if the C-brackets are bent, they should be able to realign those also. If you decide to take it to a straightener ask them if they can straighten the C-brackets and check for sag. Some of the older chassis are known to sag. If it’s really bad you can see it when the kart is on the ground.

I’ve never tried this but what if the kart were blocked up on the frame rails and C-brackets with equal spacers on scales w/o the tires. In this situation, I wouldn’t worry about the front to rear levelness because it’s the twist that needs to be looked at. This might yield some better results for checking straightness and it could be done without the driver. Also, twisting the frame with a long bar between the left and right C-brackets and is better than jumping the chassis but much more difficult.

Front end check: When centered with the pills set for zero camber and toe set, how much camber is there and what is the camber difference between the left and right front? I’d more concerned about the differences in camber, which would indicate that the C-brackets are bent. 1 mm difference is good and 2-3 mm difference is probably ok but it depends on what you’re expecting from the kart.

All these are crazy suggestions but eyeballing it might be good enough, there is a youtube vid on this. HOW TO: 3 Ways To Check If Your Go Kart Chassis Is Bent - POWER REPUBLIC - YouTube

I don’t know if anybody mentioned this yet, but did you check the tire pressure before you scaled?

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I’ve got this setup for measuring the chassis.

So far I’ve only used it to align the front but planning to check my TaG chassis when I rebuild the kart in a few months. For the price (I paid $750) it seems like a great way to be able to check your chassis easily.

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I got on the scales after a session, so the tires were hot, and not have equal pressure.
I know it’s not perfect, but I started this thread seeing the big difference in weights and seeing that the lasers don’t meet at the center.

For reference, I’ve used my cross adjsuter to purposely race with higher cross than that on a track that has mostly right hand turns… Its not that far out.

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