Begin Again: Support Your Local Kart Shop
Measuring the chassis on the table
The following is a continuing series ‘Begin Again’ written by R.K. Siler. The series began with Going Back to My Karting Roots in early 2020, followed by Strains, Rains and Pandemics in April. The following is his next edition to the series
Tiger Woods has a swing coach. Tom Brady has a throwing coach. Dirk Nowitzki had a shooting coach. If these greats have coaches, then don’t we also need a coach just as much – or more – than Tiger, Tom or Dirk? The obvious answer is, of course, a resounding yes. However, since karting is, for most of us, our hobby, we have to watch our dollars pretty carefully, so a coach for most of us is a “nice to have” at best and a nice dream at worst. That said, I’ve been reminded over the past couple of months that most of us have a built-in coach (read: free!) ready and available at our local kart shop. Here’s the back story to all of this:
I had felt that my kart just lacked overall grip despite many members at North Texas Kartways (NTK is my home track/club) telling me that the track itself has a ton of grip. As I mentioned in my previous article, I had found that my trusty tire gauge was not so trusty after all, and in fact it was off by at least 3-4 PSI for any given tire pressure reading. Forgive the commercial, but a quick call to Acceleration Karting had a new tire gauge and a new set of Evinco tires shipped to me (AKR must have a fortune tied up in their inventory-I’ve never had a back order from them yet!) and I figured that with new tires set at the right pressures, I for sure was going to be at or near the track record. After spending an afternoon pounding around NTK experimenting with different tire pressures, I was quicker but still a long way off the pace. The issue with my SodiKart continued to be a strong entry push followed by snap oversteer at the corner’s apex all the way out to the exit of the turn.
Get the chassis on the table to help see if it is straight or tweaked.
I went home scratching my head. It is one thing to be a few tenths off the pace but whole seconds is an entirely different thing. I’m OK with saying that my driving needs a lot of work but to be fair, I was never entirely sure what the chassis was going to do from one turn to another. Clearly, I had some sort of set up issue, so I ordered a set of Sniper Laser Alignment gauges (hello AKR), thinking that I might find something there-besides, I’ve always been wanting to try out the Sniper system since I first saw them, so this was as good an excuse as any.
The Sniper system revealed that I had toe-in on one side, toe-out on the other, and quite a bit of negative camber, which, if I held with my theory that NTK is a low grip track, then the negative camber probably was an issue and for sure, the front wheels being out of alignment was not helping. With that big change to my alignment, I headed back to NTK for some more testing. Thinking that I needed to practice running the track backwards (clockwise) since some club races were coming that would run the track in that configuration, I was brimming with confidence when I arrived but I quickly found that the chassis was now worse than it was before. It felt like I was trying to drive on ice, and other shifter pilots were blasting past me at will. Thoroughly defeated, I headed home, wondering what to do next. Clearly something was way off.
Fortunately for me, I have this habit of printing off articles that I find on the internet or, if it was really long ago, tearing articles out of magazines and putting them in a binder that I keep just for reference in case I might need it someday. Slowly going through my binder, I came across an article from eKartingNews that had been published in June 2001 (I told you I’ve been doing this for a while!) called “Understanding & Adjusting Front End Geometry” (here is one online from Comet Kart Sales. In this article, a couple of sentences jumped off the page at me. It said, “If the inside rear wheel does not lift enough, the front may tend to slide at turn-in, then suddenly gain front grip and flick the rear into a slide. This can be one of the most difficult handling problems to drive with and is often mistaken for a rear grip problem since the rear slide can be the dominant sensation.” WOW! That is exactly how I would have described how the chassis felt.
I made a quick call to Mike Jones at the Dallas Karting Complex, who just happens to be the importer of the SodiKart, told him what I was dealing with, shared what I had read from EKN, and before I knew it, I was headed to Mike’s facility east of Dallas for a complete re-do of my kart’s steering geometry.
The BFB under the guidance of Mike Jones at DKC.
The first thing that Mike did was put my kart on his chassis jig to check it for squareness, and sure enough, the chassis had about 5 millimeters of twist to it, most likely due to the fact that all my driving has been on tracks that go counter-clockwise, so the chassis turns to the left better than it does to the right. This is probably why the kart was so bad when I attempted to drive at NTK “backwards”…almost all the corners were now right handers, and with that twist, physics simply wouldn’t let the kart turn to the right like it should. With the kart on the chassis jig, Mike put a huge bar (the “BFB”) to the chassis to use as a lever and took the twist out of the frame, measuring the chassis at the spindle yokes with a dial indicator that is mounted on a fixture. Despite the “bigger hammer” aspects of using that huge bar to straighten the chassis, the process is very precise as Mike got the kart back to square in a matter of minutes. It helps to know what you’re doing.
With a chassis that we now knew was straight, it was time to add castor to the SodiKart’s front end geometry. Mike changed out the +1 caster pills with some +3 pills, and then gave me a set of +4 pills to throw in my spares box to try out. Having taken care of the caster, it was now time to finish the alignment process.
With the Snipers attached, Mike adjusted first the camber and then the toe…with the chassis straight, it wasn’t surprising to find that the camber and toe settings were all over the place, but they were brought back to where they needed to be very quickly, so that camber was set to zero as a baseline and toe was set to 2 millimeters out per side for a total of 4 millimeters of toe out.
With those changes in place, it was time to try the kart out again, and this time, the kart handled brilliantly, even on old tires. Turn in is precise with no sign of snap oversteer, and the kart now feels extremely planted and predictable. Now, it is up to me to drive up to the very considerable capabilities of a well-setup shifter kart, and that will come with lots and lots of seat time.
The Snipers go back on after adjustment to make sure front end is where you need it to be before getting back on track.
So, what happened, other than the obvious twist in the chassis needing to be addressed? I was lucky in that my son had taken some video of me driving at NTK, and so after reading the chassis article from EKN, I pulled out some of that video to take a closer look at it. By freezing the video and blowing up some of the frames, it became obvious that the inside rear tire never actually lifted off the track surface when I turned into a corner, so adding caster was a logical next step. The theory that Mike and I have is that at 6’3” and 180 pounds (so I’m relatively tall but fairly light for my height), my body mass was affecting the chassis in such a way that weight was not transferring as it should, so the inside lift of the inside rear tire was not happening. Whatever it was, the feedback that I am now getting as a driver from my kart is pretty amazing. I don’t have a problem at all working hard on my driving, but it is very tough when you know you are a very rusty driver attempting to “Begin Again” and you are also chasing a set up issue that you know is there but you just don’t know what it is that you are dealing with. It can be very confusing and frustrating, to say the least.
And that’s where a coach comes in. Sometimes, karters need a driving coach, and at other times we need somebody who can interpret information and suggest set-up approaches that may or may not work, but at least an approach can be designed to experiment with, and if it works, then great, but if it doesn’t work, that’s OK, too, because you’re learning and growing in the process. So, be sure to engage that coach at your local kart shop, you’ll be glad you did!
