I have changed from no front bar to a hard 30mm axle in the front and i didn’t really feel a change. I drive a 2022 birelart and I went out for a day of testing and wanted to get more comfortable with my kart but i jisted couldn’t feel any difference. This includes when i changed from a soft to a hard axle in my ka100. Is there anything i can do or change to make this change? I saw some people saying seat positioning is important for this but i don’t know the factory setting. I had decent tire on by the way.
BirelART has the factory seat position chart on their website I believe.
How long have you been driving?
5 years in karting, ive won some championships and i can keep up and race people like chase hand when he comes out but ive never got into small tuning increments. I want to learn to tune the kart off feel but im having trouble feeling it. I usually throw the kart into the corner with a flick but getting it consistent is hard to do. I know thats possibly the reason but i feel like if i calm it down and slowly turn in ill go slower.
Are you talking about the front bar to a hard,
The front stub axles to hards
or the rear axle to a hard?
The front bar change should be fairly major setup change, I feel like it is a pretty subtle change. It is introducing more flex through the entire chassis, depending on how the rest of the kart is setup it the flex may be a gradual change or sudden.
The front Stub axle change to a hard I have heard doesn’t do a lot
Rear axle change is also a major change which you should be able to feel, I changed from Medium to Hard and back to add and remove rear grip which was easily felt.
So I changed the front bar from nothing to standard to a 30mm hard axle front bar and didn’t fell the kart change at all. The other thing I tried was changing from a soft axle to a hard axle and everything felt the same. Times stayed the same, it felt like it rotated and dug into the ground the same. I understand its me who is the issue not the kart i’m just trying to figure out what I can do differently here in order to tune the kart.
Are you still talking about the front bar? An axle is the thing that connects the two rear wheels so I think you’re confusing folks. If you’re still referring to the front torsion bar (the optional bar that goes under your knees to stiffen the chassis) then better to just call it what it is - the front torsion bar, even if the bar you are using is a cut down axle.
On a Birel you can also change the stub axles on the front spindles, if this is the change being made that would be a small change. However, the Torsion bar, which is 30mm, is what I believe you and the OP are referring to. The front torsion bar should be a fairly noticeable change.
Colby…
As other threads have noted in the past, make sure your chassis is in good condition. Check welds for cracks, particularly the rear bearing carriers where they mount to the frame and all of the seat stays. Maybe verify nothing is bent on a table too. If there are issues, changes will have little effect. If everything checks out it may be your driving style.
For me, I don’t notice much change in rear axles either, but the front bar is a noticeable change.
I would check seat position to confirm it’s at the factory recommended settings, would confirm there are no cracks in the chassis, and check for straightness. Certainly an axle change and going from no front bar to a stiff front bar should provide some difference in feel, or at least a lap time difference so we want to rule out any fundamental chassis issues first.
Otherwise if you just don’t have a feel for the kart that’s not totally abnormal. Lots of drivers have a hard time tuning because the kart always feels the same to them, I often work with drivers who just lie to me when I ask what the kart is doing because they don’t actually know.
Always focus on breaking the corner down into three sections; entry, apex, and exit. When you’re out driving, try and focus on how the kart is reacting in each of these phases. If you have no natural feel of the kart’s handling, it will take some real active thinking and focusing on these things to notice them. Sometimes I tell drivers to focus on one corner phase at a time. So for a lap just focus on what is happening as soon as you turn the wheel at turn-in for each corner. Then the next lap, try and focus on what the kart is doing at apex at max load for each corner and so on. Doing this will eventually give you a full picture of the kart’s handling through a corner.
The good news is that if you’re able to somewhat hang with someone like Hand from time to time, you’ve got some level of driving skill, so if you can hone in on tuning the kart and becoming more synchronized with your handling you could probably be pretty quick on a regular basis.
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The only handling handling difference I’ve ever felt dramatically is with castor changes. I can count on one hand how many drivers I trust to accurately relay information about set up differences, otherwise I rely on careful analysis of data. In fact I knew a driver who won a very high profile global event who told me “I leave everything as standard and just add castor if I need it”.
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Front bar change on the BirelArt should be very noticeable. Even going from the standard 1.5mm bar to a 2.0mm bar makes a pretty big difference, so using the axle portion you mention should be a huge change.
The factory teams don’t usually stray too far from the factory setup (Base). Standard axle (F), Tillett T11t mounted per factory recommended position. If you’re chassis is already at or close to these settings and still non-responsive, then I would follow TJ’s advice and check closely for cracks/breaks in the frame.
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With all due respect, of course TJ and Evan can feel those changes. They are not “average karters”. I (the definition of an “average at best” karter) often cant feel a difference with front bar or no front bar. When that is the case, I just rely on the Mychron data and the stopwatch to tell me what I need to know.
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@fatboy1dh good point, I’m probably quick to assume.
@cr1003cr- don’t feel bad if you’re still developing a feel for these changes and how they affect the handling. The only way to learn is to try them. I would ensure that you’re driving is both smooth and consistent before going overboard with testing changes, as inconsistent inputs may skew your results. TJ has laid out a really great approach above for analyzing the corner and forming feedback. Personally, I use this exact method for every on track session to reflect on the kart’s handling and what changes might need to be made.
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One other note or thing to consider, depending on the track and conditions it may make changes hard to detect. In our region we have a very old track, very coarse and the track doesn’t take rubber well. Early in 2022 we went there and I was searching for grip (everyone was), I basically threw the book at it and the kart changed very little. Basically the tires just wouldn’t dig in to the track so the grip the kart would try to produce the tires would give me the middle finger. Was a very different experience for me as I can usually tune a kart decent.
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I appreciate that, but don’t be too hard on yourself Derek, it’s totally possible too that your chassis might not have as big of a reaction with a bar change as another would. Obviously chassis design will play a hand in how a kart reacts to individual changes. I have also driven karts that don’t have a lot of difference in feel with big changes or the difference is more subtle. From that perspective though, the BirelArt should provide a pretty big difference in feel with a bar change like that.
Evan also brings up a great point in the respect that maybe your driving style could have something to do with it as well. If you’re really flicking the kart around all the time, it’s probably not going to provide the same feedback it would if you were driving more smoothly and actually flexing the frame with the steering geometry. The issue with having a driving style like you’ve described is the lack of consistency, and the lack of feel from the kart because the inputs/reactions are so quick that you never actually feel what the kart is doing. Some of these chassis changes are going to be really subtle feeling, and if you are constantly flicking the kart over the limits, you don’t feel the subtle loading and unloading of the flex and weight transfer.
Ricky’s point about circuit surface is a valid one too. Some tracks are just going to feel pretty much the same no matter what. Concept Haulers comes to mind as one of these where the surface is so old and bumpy it doesn’t build rubber, and the corners are banked so the kart doesn’t really work as it normally would.
What track and do you have any on-board video to demonstrate?
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While my butt-o-meter isn’t super sensitive at least for my Compkart (similar enough to Briel 
) a front bar change was super subtle. No bar, plastic bar, metal bar, and a random carbon fiber bar a guy in the garage next to me had was very subtle. I gave up chasing front bars for a change. Just stuck with the factory bar and forgot about it. For a frame of reference, I can say quite the opposite for OTK. Simply rotate the flat bar from horizontal to vertical and it completely changes the reactivity of the front end to me. Just my two cents on the subject.
Thanks for all the great info! I checked my seat and its way off from the factory settings so i’ll adjust that and try again. On another note of tuning what would you recommend I do to the kart in this video to stop getting massive understeer. I felt like I couldn’t get down to the apex once the tires kicked in. I am the one in the pure white helmet in the 605 (forgot to put on my go pro so this 3rd person footage) Prairie City - Final Club Race - Main - YouTube
Could you clarify which chassis model you’re on? I assumed RY30 based on the mention of KA, but if you’re on an AM29 then the previously shared seat dimensions will not work.
Sorry, AM29. The KA100 chassis is a ItalCourse which responds slightly better to adjustments then the AM29 from my experience.
All good. Disregard the previous seat measurements then. I didn’t find any for the AM29, so you should ask your local dealer. In a pinch, the dimensions are probably going to be pretty similar to those for rhe CompKart 4R, listed below:
Thank you very much, I will!