I just got a set of Snipers and was messing around to get to know the tool and learn how to do an alignment. It’s a Compkart Covert 3.0 R-22 chassis with only a few practice days on it. It’s never hit anything and has barely rolled over any curbing. I have watched the Power Republic video.
I did the swing test with the ruler against the steering column and got the low dead spots to match up (came out to 5.5mm each side). Centered the steering with the paper method, and set my toe to +1mm each side and rechecked the swing. When my swings match up with +1mm toe on each side, I was getting -3mm camber on one side and -2mm on the other.
I loosened the kingpin on the side with less negative camber and turned the pill one hole. Rechecked swing and toe, made some minor adjustments, and this gets it symmetrical, but I’m running different holes on the pills.
Maybe I’m just on the learning curve, but I’m pretty confident in my measurements…I took my time and was very careful with the spirit levels, etc. That said, I find holding the ruler against the steering column while trying to ensure you are at top dead center and turning the wheel is, well, less than perfectly precise.
Question: normal imperfect manufacturing, or problem with the chassis? Or maybe, “you’re doing it wrong, noob”?
Using Snipers, you measure in half blocks per millimeter (solid to hash = 1 mm). You stated +1 toe. Is that a half block in front of center or behind? Usually you toe out on a kart. -1 mm toe would be one half block in front of center (laser dot toward front of kark) on each side, for a total of 2 mm toe out (leading edge of tire pointing away from centerline of kart). Just trying to be clear about your +/- as it denotes direction. Camber is the same, (-) is top edge of tire leaning towards kart and (+) top edge of tire leaning away.
With those factors in mind, I am trying to visualize where you are taking your measurements from. Like in the video you mentioned, first center the steering with the paper method and with steering wheel straight turn the tie-rods until your dots line up vertically.
It’s best to start with your pills neutral first (camber/caster). To check straightness, zero the toe so each laser lines up with the vertical centerline n the apposing target. Don’t worry if camber is slightly off. +/- 0.5 mm is okay. Make sure your kingpins are loose. Sometimes the "C"s can be change your measures tight compared to loose. With the nuts loose on the kingpins, you can check for vertical play of the Spindle (part the kingpin passes through). If there is more movement on one side than the other, it could affect your measures. At this point you can rotate the kingpins while watching the lasers to see if there is any movement in the dot as you do so. If the dot moves around, you likely have a bent kingpin and any other measures will be affected. Assuming that checks out, you can then check caster sweep.
You first have to disconnect the front of the Nassau panel from the kart and raise it up so as not to interfere with laser/ruler. Mount the ruler using the magnet to the front of the kart frame. It does not mater so much as where, as long as its centered side to side and tall enough for the laser to cross it. Keep in mind the further forward of the lasers you mount it, the larger any differences between the lasers crossing it will be. If you mount the ruler where the lower steering column support block meets the front hoop of the frame, it is not uncommon to have 2 or 3 mm of difference from side to side. If you have 5 mm or more you likely have a frame slightly out of whack. Find someone with a frame table and have them check it. If you have less than 5 mm of difference, you can adjust that out with the pills. You may have to compromise a little camber or caster to reduce your splits from side to side. Just try to get the smallest difference of both.
We generally deal in tolerances not absolutes. If you have one side that seems more out of the norm than the other, ask yourself do I take curbs on that side more than the other? If so, you have probably tweaked that “C”, tie-rod or Spindle on that side. I have even seen a bent steering shaft throw off numbers. You can use the straight edge of the ruler to check tie-rods and steering shaft. Measure around several spots. Spindles and "C"s are harder to check and best to do on a frame table.
I didn’t understand why you would do a swing test against the steering column? As the spindle swings forward, the rise of the outside tire flattens out compared to the drop of the inside tire when the spindle moves backward. I don’t think you are going to get a good measure of caster variance as compared to mounting the ruler to the front of the kart. This has to do with the geometry engineered into the native caster angle of the kingpin and spindle to stub-axle inclination. During turning, if the outside front tire were to rise too much it could risk the frame coming into contact with the track surface.
I understand the markings on the Snipers, so 1mm=half a block, as marked by the dots between the grid lines. 1 block =2mm.
I’m measuring from the steering column because I’m copying the Power Republic procedure. It is shown at 3:55.
I’m using the positive and negative designations as marked for camber on the snipers, which is consistent with my understanding of how camber is measured on all cars. With respect to toe, I’m shooting for 1mm toe out on each side (not sure if I should call that positive or negative, but “in” and “out” are marked on the snipers).
I’m not checking for caster, so I have not mounted the ruler to the front loop of the kart yet, but I understand that process from the Power Republic video.
My issue is that I had to turn the pill one hole on the right side in order to get symmetrical camber. I’m running the original hole on the left (4th hole, as the kart was set up by Timmy Tech), and the 3rd hole on the right.
It is not uncommon for chassis to require a small adjustment from new. Some people like to put them on the chassis bench right of the box, some prefer to wait for few sessions to allow the chassis to relax the stresses. Nothing to be worried about, I’d find the closest team around you that offers chassis straightening services for a quick check and adjustment.
Second Andy’s comment. Totally normal for toe or alignment to be out a bit side-to-side on even a brand new kart. Just manufacturing tolerances. As Andy noted, drive it a few times and it might relax and even-out.
I’ve seen new karts measure worse than that out of the box. After all, it is a bunch of welded tubes; pretty easy for there to be some warping in the manufacturing process I’d imagine.
I wrecked and bent up my (very soft) ART GP frame in 2014, and we “fixed it” by setting the front end on a fuel jug and jumping on it to bend it back on the grid before the second heat. We “fixed it” too far just by stomping the front end a few times, and as my mechanic said once we realized it was now bent the other way, “just launch a few right-side curbs on the out-lap and it’ll even out”. And it kinda did.
We used to keep a wooden step, not for getting in the trailer, but for giving us something to set the kart on when we inevitably had to jump on it. Karts flex and bend, 1mm is totally cool. My current OTK kart is 1mm off side-to-side and has never been wrecked. Handles like a new kart still.
Agree with everyone here. I would run the camber pills in the same relative hole left to right side. It’s not off by enough to make a difference and I’d rather not try to remember I run one side offset by a hole versus the other. Sounds simple, but in the heat of the moment making changes it’s easy to forget.
One thing I notice is you don’t mention how you are placing the Sniper on the spindle. I tend to have the best accuracy in removing the wheels and putting the Sniper on the spindle shaft. While you can place it on the larger part of the spindle as shown in the Power Republic video there is a chance your magnet may not sit properly. Also, make sure your magnets are clean.
I’ve been taking off the wheels, mainly for ease of access and to avoid the tendency for the steering to fall into full lock under the weight of the wheels. But I’ve been putting the Snipers on the large part of the stub axle.
As others have mentioned, I always remove the hub and place the snipers where the hub rides. I even use the same spacers inside of the hub, but that’s just my OCD
Having owned a CompKart in the past, it’s perfectly normal for one side to be a couple of mm different that the other. I would have the chassis checked on a table if you have access to one, just to be sure. In the meantime, just use the adjustment in the eccentrics to get the two sides as close as possible.
In my experience, if you loosen the kingpin assemblies to make changes and retighten to then check the alignment, there will usually be some “slack” in the kingpin assembly. I snug the kingpin assembly, preload the spindle by pulling upwards on the outer portion of the stub (this simulates a load on the chassis), and then tighten the rest of the way. This will provide a more accurate alignment reading, otherwise you may find your reading to be a few mm more negative after running a session on track vs. the reading prior to that session. Hope this makes sense.
I went back into the archiives to find this image of how caster/kingpin inclination affect the jack of the front wheels and why I think it is better to check caster sweep in front of the stub axles rather than behind.
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Since the front end is offset 10-20mm to one side because of the motor. When your checking caster with a ruler will it not have different measurements because it will intersect at different times given the offset?
