Seeking some opinions on the following issue I’ve had with a new chassis a couple weekends in a row, I have an Arrow X6.1 (Australian chassis), racing TAG Heavy (180kg kart+driver) I’m 6’ tall, I’ve been karting for a good while now and I haven’t come across this issue/s, I tried several things over the race weekend to help it with no positive results… long story short it currently has a Tillet T11T fitted, it seems to dart into the corner nicely but as soon as it does it feels as if the inside has already dropped and I’m being plowed on exit, causing to be slower tenths a lap from what times I’d normally be running, logically a tried a stiffer axle to see if the rear had too much push and not enough initial lift, had no affect other than adding slide, I then tried moving the seat forward 5mm to get some weight off the rear, this caused the kart to slide and plow, tight rear bar, added to the mid corner plow, I adjusted several driving aspects, allowing the kart to roll more mid corner, earlier apex later apex, slowing my hands down on the wheel. In the wet it was a bullet and on a very green track I was on the pace but when the track gripped up to normal conditions I found myself plowing from the middle of the corner with a slight slide on exit, now to me this indicates that I need to free up the kart, softer seat… softer front bar… perhaps negative front camber to give it some more front end in the mid corner? Any advise, opinions and live experiences are much appreciated, cheers!
Sounds like the inside rear is setting down too early indeed. It’s wet performance confirms that, as you have great turn-in and excellent traction on exit. You need more duration of lift in the dry. If you’re not feeling any snap oversteer, it probably isn’t lifting too hard and over working the tire, it’s probably just not lifting enough. To me I would guess the chassis is too stiff.
Few things I would try:
- negative camber can help lift duration
- help the chassis flex more with a softer seat or softer axle, or if you want to try something more interesting, removing seat stays. With taller drivers struggling with a stiff kart we’ve found removing seat stays to really change the feel of the kart for them.
- softer front bar might help the overall flex of the kart, in just wary of losing the already good turn-in you have, so I would hold off on that and work on the rear mostly for now
Sounds like your thought path is correct in my opinion, and sounds like you’re doing the right things in terms of figuring it out.
You mentioned tight rear bar, loosen it and use maximum width 140cm. 3rd bearing tight? Loosen it as well
More negative camber helps holding lift, softer front bar will also help holding the lift.
If that doesn’t help you can decrease caster slightly to get it to lift slightly sooner. Or try the other way around and use more and drive more smooth to help it to hold the lift for longer
Any seat struts? They help push the outside tire and lift the inside for longer I don’t think you should go for a softer seat with that weight, it will probably lift even quicker and set down quicker
It’s a 30/30 chassis and designed by the best. It should work pretty decently on the recommended setup. I would also compare notes with other drivers with the same kart. Also, wouldn’t a good wet performance indicate that the chassis is too soft. I would think that a soft chassis the IR could hike too early and too high. If you exhaust other options, I always fall back on checking the chassis for any cracks. Some cracks will alter the way the chassis flexes usually making it softer. Cracks can be hard to find, especially when new. A new crack might look like a paint crack at a weld joint. Try to move the suspect tube and see if the crack changes. Eventually the crack will get bigger but you’d have to drive if for a while. Weld crack are usually no big deal to fix. I would find a craftsman type guy that can TIG weld and remove all parts (seat, axle, bumper, side pods) so that the welder can easily weld around the tube and and turn the chassis over if need be.
If the kart is understeering from apex to exit, the inside rear is not lifting enough. A kart that is flexing too much will lift the inside rear hard and then snap to oversteer when the outside rear tire gives up. OP’s kart sounds like it isn’t lifting the inside rear enough or keeping it up long enough.
I disagree with Luka regarding seat stays. More seat stays will stiffen the rear of the kart. Yes they will drive the outside tire in harder, but they also limit flex, and personally I think it sounds like the kart needs to flex more. But seat stay tuning is lower on the priority list for me. I prefer to work with the other adjustments (the ones Luka and I agree on) first. I only mention seat stays because these past two seasons I’ve tried it with multiple tall drivers and they all like it with seat stays removed as they say the kart is much easier to drive as it isn’t as stiffly sprung and they can drive more relaxed than fighting a very stiff kart with lots of weight transfer. And it’s been faster.
I agree with this. I’m 6 foot, granted KA and not X30, but I haven’t run seat struts on a kart in 5 or 6 years. From OTK, CRG, Parolin, Kart Republic, all of them felt much better with no seat struts when I had the same issues you did, a push center off.
It is a pretty drastic change, so it depends on how bad the issue is, but I would second giving it a shot if you have the opportunity.
Yeah I didn’t see that he already had 1 stay at each side.
Since I’m pretty normal length myself (177cm) I have always benefited by running 1 stay at each side as I felt they don’t stiffen that much for me, they certainly help to lift the inside and hold it when I’m driving smooth😁
But yeah, it could probably be to much when you are a taller driver
Though the x6.1 is supposed to fix the issues from the X5, what you’re mentioning seems to be the same.
We chased an X5 every way we would but never found the set up that gave us enough entry and exit. In order to get one we had to give up far too much of the other. Balance was near impossible to get where we felt comfortable.
As you say; in cooler air, less rubber, lower track temp, the Arrow seemed capable.
Best things we found was a softer axle. Messed with Kartech, OTK, Righetti ranges of soft. OTK U worked for us. Going from the standard set up of +2 camber to neutral or -1 also helped.
I had some experience years ago with other models from Arrow. I’m not familiar with the X6.1, but if it behaves similarly to past Arrow chassis then here are some thoughts:
Directionally, I think TJ has some great suggestions here. Arrows of the past were pretty stiff, and very sensitive to front end changes (especially caster). Your feedback and your wet performance sounds very similar to what I experienced on an Arrow, and leads me to believe the inside rear is setting down too soon.
I would try the following changes in order:
- loosen side pods and rear bumper
- remove seat struts one set at a time
- softer front bar
- remove front bar
- reduce caster
- add negative camber
- loosen front hoop
It looks like you’re running Douglas wheels? Not sure if you’ve tried any others, but I would recommend a freer wheel such as the AMV 3F or OTK MXC. That will change the balance quite a bit compared to the Douglas.
Cheers mate! Gonna play around with the following changes this weekend and I’ll let ya know how she steers afterwards! Thanks!
The kart was set up using factory recommended settings, several others in my class with the same chassis had similar set ups from what I could tell and didn’t have the issues I had at the severity I experienced them at, will check for cracks! Thanks!
Seat will be my last resort, I had the front bar loose from the get go, side pods always loose, only thing i played with was the rear bar, I think neg camber will help a lot
Good to know! I was just running neutral all weekend, thought about neg camber but tried everything else first, still running arrow or did you ditch it due to it being hard to find a balance?
Yeah I’ve tried MXCs on my 2018 FA and my 2022 Kosmic when I had it, I found they slid too much and cooked the surface of the tire but might be a whole different story with the arrow, will defiantly look into it! Yeah gonna try most of the above mentioned changes! Thanks!
Hey Nik, where’s your seat at. In my Arrow I ran 150mm between axle and rear of seat. You can try loosening the front seat bolts to emulate a softer seat and see if that helps.
You mentioned reducing caster causing the kart to lift sooner. Are you able to elaborate on this. I get why this would keep the whelk up longer but would have thought it would also lift later. Not saying you’re wrong, just trying to understand.
Was at 150 when i moved it foward and it was worse to drive but not any slower or faster! Just slid on exit as the kart was pushing me
Hello, if you are not very tall you can try increasing the angle of the seat back.
The forces will do its thing to make the kart lift instead of the mechanical forces that does it quicker by forcing it with more caster. There for it will lift sooner, that is what I have experienced with less caster. With more caster it lifts faster but also sets down faster if you aren’t able to hold it and drive smooth.
This is just something that has worked for me