Hello all and thank you in advance for any contribution.
So as some of you may already know, I am a big guy. 6’9" and 225 lbs. I am currently running a TaG 09’ Leopard in a 2012 Tony Kart Racer. I have been struggling to find a good baseline for my size and package (fighting a hop in the hairpins). After adjusting setup and driving, I have been able to reduce the hop, but not eliminate it. Thanks to all for your suggestions thus far!!
On the advise of @tjkoyen I pulled the trigger on a “harder” axle ordering an H. I also pulled the trigger on the Sniper Alignment set. After successfully installing the new axle, I threw the Snipers on to check things out. Following all the centering steps, I was surprised to find the camber off from side to side. I neutralized all the pills on the king pins and checked again. Still off. Decided to run a Caster Sweep. Found what seemed to be a large discrepancy from one side to the other. With a ruler placed vertical on the lower steering support, I was getting a 2 cm difference from one side to the other on caster sweep and 1 mm (one dot negative, one dot positive on the grid) camber difference from side to side. I can reasonable assume something is bent and would explain my struggle in chasing a good baseline setup and inconsistent results.
My question is how bent is enough that it can not be fixed? Camber issue seems very small, but the big split on the caster sweep has me concerned. I played with the caster pills to see if I could lower the split, but it did not seem to make much of a difference without throwing camber readings out of wack.
I was involved in a fairly heavy crash witch ended up bending the LF corner about 15-20mm up. I had the chassis bent back and I am still competitive at a club level. I agree the frame probably wont be like new, but having your chassis straightened may be the way to go depending on your budget.
I was planning on having it straightened, but I wasn’t sure what the limit was in terms repair. With the caster sweep being the biggest hurdle. I would think the “C” is somehow twisted and if that could even be fixed. There is only a slight split in the camber, so I don’t think that is difficult fix. While at it, I wanted to see if they can take some of the sag out of the waist.
No need to be “mint” nor 2012. As I understand it, everything is transferable up until present specs. Looking at latest images, there have not been any fundamental changes to the base chassis. Only the the brake system has been upgraded at the caliper along with an optional larger brake rotor.
You mentioned in another topic about replacing just frames and it popped up in my interweb search for OTK 32 frame. I saw you mentioned checking with some of the bigger teams about unused frames for sale. I am still a club guy and do not come into contact with any of the bigger OTK teams. Do you have any suggestions for any contacts in my Region, Dallas, TX?
Thanks TJ. I tried to find a website or email contact for them. All I could come up with was a Facebook page, so I sent an inquiry on FB Messenger. Funny thing. Their KA100 Senior Driver, Austin Osbourne, is the one who sold me my kart or rather his father, Gene, did.
Greg, some other things to try to help narrow down your issue, look at your spindles and kingpins, they could be bent, make sure your height spacers are the same side to side, and double-check your readings by switching the snipers around (left to right and right to left) just to double-check your findings a small piece of debris on the magnet can easily change your readings.
I have spun both of the Kingpins and no wobble. Snipers are brand new and contact surface was clean. Ride Height is equal on both sides. Put new bearings in the spindles couple of months ago. A couple felt gritty so I just replaced them all, top and bottom on both sides. How can you test if the spindle itself is bent? Would need some kind of jig and references of measures. Even harder when their geometry is reversed side to side. I feel like getting it on a Frame Table would do a better job of identifying the variances.
I find the discrepancy you’re describing a bit odd. If its one box negative on one side and one box positive on the other then thats total 2mm difference in camber but then you say the caster sweep is 2cm or 20mm difference? I find that really hard to believe…if there’s that much difference in caster sweep it ought to be more than 2mm off in camber as well.
Make sure all the pills are facing forward both top and bottom on both sides.
I agree it is strange, but I checked everything multiple times. I suspect it is the right side that is out, but realistically it could just as easily be the left. My main suspicion for the right side is the paint is chipped away on the yoke. Like maybe it took a hit at some point.
With all four pill arrows pointing forward and zeroing the steering and toe, I get one dash above 0 and one dash below 0 on camber (each dash is 1 mm for total of 2 mm difference). If I place the ruler on the lower steering support with a magnet and turn the steering wheel both directions until the laser passes the ruler I get a 20 mm (2 cm) difference higher from the right side than the left. I cannot tell you what exactly those angles are as I have not broken down and done the geometry. What I can tell you is the split is nearly equivalent to rotating the top pill on the right side 180 degrees (arrow rear). As I understand it, each pill has a max throw of 3 degrees. Using both pills, top and bottom, give a max range of 6 degrees. Please correct me if I am wrong.
I had the ruler standing in front of the irregular shaped hole where the heel stop would usually be and my lowest caster number with pills all set neutral was 216 mm. The highest was 234 mm. When I swung the right upper pill to arrow rear, the number dropped to 217 mm. Now without any frame of reference other that comparing side to side, I know something is out. In the Sniper video put out by Power Republic he did a caster sweep with the same set up I used and both sides crossed at 186 mm. He did not specify which Tony Kart chassis he was doing this on, so cannot use that as proper benchmark. Distance from the laser will change the reading.
To really get to the bottom of this you need specialized equipment which a proper kart race shop/team would have…namely a frame table along with tools to measure caster angle of the C.
It is possible you can have a bent tie rod, rose joint, king pin bolt, spindle or steering shaft…they may all affect laser readings. Thats where the equipment above would isolate any discrepancy to the frame/chassis and frame/chassis alone.
What year OTK kart is this?
Does it have the OEM OTK pills? Ensure that the pills are all the same meaning not mixed and matched OEM/aftermarket which could explain what is happening here.
The OEM OTK pills on late model OTK karts each have 1.5 degrees of adjustment/throw…so 3 degrees per side if combined top and bottom. There are aftermarket pills available from 0 degrees (neutral) up to 2.5 degrees in 0.5 degree increments, hence my suggestion above to ensure you don’t have mismatched pills.
Have you centred the steering sweep? If not do this first then set the toe equal each side to something realistic (neutral to 1 box toe out) and then recheck everything.
Ensure your snipers are on in the correct orientation and that the bubbles are levelled.
I have reached out to a few local shops about straightening on a frame table, but no responses yet. Agree this will tell more detail than anything else. Do you know what the spec is for neutral caster in degrees should be?
It is possible, but I have either checked or replaced any suspected components except for the spindles. I will attempt to check them today as TJ suggested with a straight edge and follow up.
Good question. I was marketed to me as a 2014, but suspect it is actually a 2011 or 2013. It has the newer style pedal mounting (tapered shaft with square base) that extends from the front hoop. Floor tray says Racer EVK. Has M4 bodywork. Uses BS6 rear caliper and one-piece duel piston master cylinder. Chassis plate reads Racer 56/CH/14 BY66487. Not sure how to translate the serial number. B = 2012?
I believe it has the OEM pills. One pill was cracked at the locking screws and was replaced with another factory pill. The new one looked identical to the older ones aside from years of oxidation. No other markings to identify is from the others. I can swap the newer pill to the other side of the kart and re-sweep to see if there is a change. If so, that could be my culprit.
Yes. I did this with two methods and got similar results. Sniper instructions suggest laying a ruler centered over the bolts that connect the inner tie-rods to the steering shaft and measure the distance from the end of the ruler to the the tie-rod shaft. Equalize both measures, lock the steering wheel in place then zero toe for each side. Second, hold a piece of paper vertically away from steering shaft and spot where the two lasers overlap. This was the starting point for all of my other measurements. Constantly checking the bubble levels.
Confiirmed. Forward arrows on Snipers pointing to front of Kart. Confirmed. Bubbles all level.
Confirmed. Geometric center with a piece of paper as mentioned in #5.
Also confirmed clean contact surfaces between the Snipers and the front spindle axle making sure Sniper not sitting on weld seam. 1 mm clearance on both sides from welds.
I am glad to hear that the range is only 1.5 degrees per pill. It cuts my suspected damage in half. You would think with the slowdown in karting right now, more shops would be responding to business opportunities. I will keep trying.
1.) I am not 100% sure of this and have not been able to get confirmed literature anywhere. TJ used the current Homologation document where they have a schematic of the chassis (who knows if this is drawn to spec) but we measured off that with software and got around 13 degrees I believe.
2.) Yea that method Tj outlined isn’t always that straight forward. Sometimes its really hard to tell if a spindle is bent or not. The only sure way to rule this out is to get two known straight ones and redo the tests with them on.
3.) Afaik no one can give a definitive method to know what year exactly any OTK chassis is. Its all a guess. Your guess seems reasonable that it probably is somewhere around a 2012.
4.) For sure do this and get back to us, move that pill to the other side and see if you get the opposite on the lasers now.
5.) The absolute first thing you should do when you put the lasers on is loosen the tie rod jam nuts bothh sides without moving the actual tie rod setting. Next use a sheet of paper, put it in the middle of the kart. Turn the wheel and get the lasers vertically one over the other and then ensure the sniper bubbles are ok (if the chassis is 100% straight along with all components the lasers will overlay 100%). If you made an adjustment to the sniper position then redo the step above with the paper and check bubbles again. Once this is done, turn the wheel full lock over one side gently and hold the little ruler the sniper comes with perpendicular against the steering column in the middle area (you may need to shift your hand up/down to find where the laser is at). Measure the distance the laser is from the column and record. Turn the wheel hard over the other way and get the other measurement. Adjust the tie rods and keep splitting the difference until you get both measurements the same side to side. For instance if one was 20mm and the other 25mm. I’d either bring one up or one down to 22.5mm. Keep splitting the difference …you may have to go back/forth a few times. Once the measurement is equal put the sheet of paper back and find geometric centre. When you remove the paper the reading on both snipers should be equal in terms of toe if you did the entire process correctly. Next adjust each tie rod to get sensible toe, so anywhere from neutral to 1 box out. Once you’re at this point, recheck the camber/caster.
If after doing the above you still get the same results, one other thing I’d try to know if it has anything at all to do with the spindles is remove the hubs and place the snipers on the hub shaft…redo everything and see if the results are the same. If they are then most probably its the chassis.