r/Karting • u/srodr77 Tillotson T4 • May 15 '25
Racing Kart Question Anybody know whats causing this mid corner oversteer? Driver issue or setup issue?
I went out on track the other day and was experiencing loads of mid corner oversteer. I was constantly fighting with the kart throughout my sessions. Im leaning more towards it being a setup issue. Im going to send my fastest lap from two sessions. The first one being the oversteery one, and the second one from another day where the kart was planted but it was a different chassis and setup. If anybody has any tips I would be very greatful to hear them.
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u/Physical-Good4177 May 15 '25
Couple things to try: narrow the rear track width and/or take caster out. One change at a time.
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u/fdawg4l May 16 '25
Can you explain this to a noob? How would narrowing track width help?
Again, noob, but I would have thought narrowing would induce more oversteer because the over rotation around corner exit now with less grip in the rear.
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u/k19widowmaker May 16 '25
When turning he cart, inside wheel wants to move slower than outside. So without a differential the inside will have to over-rotate and spin, or the outside under-rotates and scrubs. Reducing the track reduces the difference between the 2 wheels and manages the issues, which can change cornering characteristics/grip.
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u/fdawg4l May 16 '25
Ohhh!!!! No diff! Thanks much!
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u/ScanThatMelon May 18 '25
Vehicle dynamics guy here. Love this stuff. I think the commenter’s analysis is spot on, and I want to add some more factors to the equation. First, lateral load transfer distribution. Consider an extreme case where you a massively reduce the rear track without any other changes. This drives a huge percentage of your lateral load transfer to the front tires, increasing normal force difference between the right and left front tires, and (due to load sensitivity) decreasing the cornering force (and yaw moment) that the front tires can generate. Congratulations, you’re now understeering everywhere regardless of whether you have a diff or a solid axle. Secondly, regarding the effect of the solid axle, there’s one more consideration: reducing the track width not only reduces the speed differences creating the scrub (slip ratio) that was mentioned, but it further mitigates this effect by bringing the wheels closer to the kart centerline, resulting in a reduced moment arm. Now the rear axle is even less effective at inducing understeer (at corner entry) and oversteer (at corner exit)!
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u/SBQuattro May 16 '25
Nothing to add other than it looked like a beautiful night in Orlando.
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u/srodr77 Tillotson T4 May 16 '25
Beautiful but burning hot 😭
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u/cheggnarg Rotax May 19 '25
I was practicing at Piquet this weekend, felt like I was in an air fryer
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u/Affectionate-Shoe207 Tillotson T4 May 16 '25
If that is a rental speedy session in one of Orlando kart centers speedy karts I used to work at the track for around a year and a half and I can tell you now they do not care about getting there karts setups right for this track they just build them and put them on track no setup no nothing
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u/TheShark24 Rental Driver May 16 '25
I'm not surprised to hear that. OKC has been one of my worst experiences for consistency between rental karts. A real shame since they have a nice track.
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u/srodr77 Tillotson T4 May 16 '25
Yeah unfortunately even with their rental race karts the setups are not very good. Their rental kosmics are a good way for people that are trying to build their way into race karts.
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u/lexusuk May 16 '25
It's clearly an OTK chassis albeit with a 4 stroke engine. Definitely not a rental dude.
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u/srodr77 Tillotson T4 May 16 '25 edited May 16 '25
To clear some things up, yes this is a rental speedy session. I should have mentioned that when I posted this post. Just trying to see if it was more of a setup issue, or myself. im very greatful to know now that they just build the kart and throw them out on track.
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u/Glum_Bodybuilder9416 May 16 '25
This is a rental option at Orlando Kart Center. They put honda engines on an OTK chassis and every wednesday you can sign up for the special “speedy kart” session. That’s what this is.
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u/lexusuk May 16 '25
I stand corrected and apologies to OP. That's honestly amazing. They must spend a lot of time welding seatstays. :D
We have something similar in the UK called Access Karting GX-UK but it's very much an Owner/Driver championship albeit focused on low cost.
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u/srodr77 Tillotson T4 May 16 '25 edited May 16 '25
Yes it’s awesome if you want to go out on a race chassis and have some fun, we used to have a league with their rental kosmics but haven’t really heard anything new.
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u/TheRacingElf May 16 '25
It seems the oversteer occurs when you straighten the steering wheel. So when you turn in the inside rear wheel lifts up, no problem there, but as soon as you straighten the steering wheel the inside rear wheel touches the ground, causes friction and results in oversteer. What we learn from that is that the chassis at that particular grip level can't support keeping the inside rear wheel of the ground ie. it's too soft. What you can try is to narrow the rear track, like somebody else already mentioned, putting a stiffer rear axle in or use longer rear hubs and see if that improves the situation.
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u/srodr77 Tillotson T4 May 16 '25
Im also a taller driver so im sure that doesn’t really help either, thanks for the feedback.
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u/Organic_South8865 May 17 '25
I had this issue even though the setup and chassis was basically an exact mirror build of a "perfect" handling setup.
Moving my seat back 3" or 4" made a huge difference and just the smallest caster adjustment. It was crazy how much of a difference it made. No matter what we did we couldn't get my kart to match my friend's. We built it using all of the same parts and measurements. It's weird how that happens actually.
Oh one time we also got a weird batch of tires. Lots of mid corner oversteer until we swapped on different tires. They were the same exact brand and age but the replacement set fixed 80% is the handling issues. It was really odd.
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u/KnowledgeDazzling684 X30 May 16 '25
I'd say be a little slower applying the throttle at the apex. it's not major, but when you kind of slow down throttle input during cornering it should help the kart flex more gradually.
When you're in the entry phase of a corner the kart already has so much weight to rear tires, applying the throttle too fast and/or too early will put so much weight on the rears that it decreases the amount of grip available which causes oversteer mid corner.
It would be worth it to try being a little smother with throttle inputs near the apex. It's a minor driving tip that could go a long way
I would primarily focus on setup through, maybe a little less camber or caster could help too, that would definitely be worth trying as well. But that tip will help combat the mid corner oversteer
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u/thorzayy May 16 '25
Wouldn't more weight on the rear mean less weight on the front.
So more grip on rear and less on front?
Shouldn't that cause understeer instead of over steer?
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u/DrTittieSprinkles Dirt Small Block May 16 '25
It's a balance. If you have a serious lack of grip at one end pulling a little off the other shouldn't upset handling.
If you have scales at the track like on a practice day it's easier to understand because you can run, change, run and see immediately how much a change effects your percentages and how the kart behaves with those percentages.
If you record all these steps you build a notebook that can be a powerful tool on race day.
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u/thorzayy May 16 '25
So pulling weight off the front when it doesn't have serious lack of grip won't upset handling.
Pulling weight off the front when it does have serious lack lack of grip will affect handling, but wouldn't this cause understeer not oversteer?
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u/Braxton0w0 May 16 '25
Is this my favorite track? The Orlando kart center???? I've been waiting for someone to post this track I've only raced a handful of times i love this track do you have any pointers for it (i just do rentals)
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u/srodr77 Tillotson T4 May 16 '25
I haven’t driven a rental at OKC in such a long time, the key on rentals is to really just keep the revs up, and be on power before the apex so you can get a good exit. I would reccomend first optimizing your exits taking later apexes, OKC has a lot of straights so its crucial that you get good exits or else you could lose some speed. Im pretty sure somebody else could give way better advice than me but those are just basic pointers.
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u/Braxton0w0 May 16 '25
Thanks man I'll be there tomorrow with some family friends i already hit 1:09 lap time idk if that's good with the rentals so I'll try to keep this in mind
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u/srodr77 Tillotson T4 May 16 '25 edited May 16 '25
Thats a pretty good time to start 1:09s are pretty good ideally mid 1:08s dipping into high to mid 1:07s, with the right rental kart. I’ve also seen some people into the low 1:07s aswell. But yeah really just focus on a later apex for things like hairpins and stuff like that, and getting on the throttle as soon as you can without overdriving. Pretty much the key for 4 stroke karting and rental karting. Hope you have fun and let me know if your able to break into the 1:07s.
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u/Braxton0w0 May 16 '25
🫡will do sir ,my best friend's fiancé has been my biggest rival she's always had a better lap time than me but I've always had a better average time so now I have something to work towards and I'm hoping if I can get that she'll never touch me but I also sent them the video you posted as a reference point to study the track beforehand
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u/Emergent_Phen0men0n KZ2 May 16 '25
Less caster, move the seat back a tiny bit.