Eagle Hop & Slide

Chassis Setup, Tires & Handling Forum
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I really could use some help and advice if anyone would kindly chime in.

Long story short (that’s a lie, it’s long), I have a 2018 Eagle and have been running Masters mostly at NCMP. I bought the kart used 3 years ago and it’s always been decent enough while I have been getting my chops back. Before the start of this season, I sent it to Bill Hamble for a check over and to cast out the demons, got it back and all is good. The first part of the season I was running up front(ish), the kart is working well, doing kart-like things and I am happy. Fast forward to now…

2 races ago, it was like a switch flipped. No matter what I do, it will not put the power down and exit the corner. It always either hops or slides and the steering feels numb and heavy and each corner a surprise as to whether it’s going to hop or slide. I tried to tune accordingly and all that seemed to happen was to change where in the corner it hopped or slid. I went from being consistently within a couple tenths of the pointy end of the pack to nearly 3 seconds off… I can’t drive this thing.

A few relevant bullet points to (attempt to) keep me from being too wordy:

•It scales out perfectly - right in the recommended windows
•No appreciable asymmetry on the front pills after setup
•Tires are new/good, no odd graining or wear
•No difference in feel on left or right corners - Each one is a surprise
•No broken welds or struts that I can find… though it feels a lot like a broken seat strut, but less consistent ironically
•My prep/shop work game is solid, so no stupid mechanical bugs (binding, dragging, etc)

I’m a ok wheel if my kart works like it should, but admittedly not one to shovel a pile of shi* to the front. You always hear these stories of guys taking taco shaped karts, flattening it out with a railroad tie and a come-along and then winning… that ain’t me lol.

I know this thing is old and it’s had a hard life, could it just be worn out? Seems odd it would just flip like a switch to me, but dunno. My last 2 races were embarrassing to be honest, even my wife got on me for spending so much money to suck like that haha. I’m beyond frustrated and frankly close to selling it all off and hanging it up. A fresh chassis isn’t in the cards right now, so I think I’m done for the year unless I can come up with something to try that I haven’t yet.

I am all ears to any suggestions or ideas before I set it all on fire. Thanks!

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It sure sounds like you have a crack somewhere to me. Light switch events in my Eagle experience have always been cracked seat struts. If its the stock black powder coat, it could be hiding a crack somewhere else too. Also check the welds of the bearing hangars to the tubes. It may be worth taking it back to Wild Bill and have him check it. He does a cool thing where he plugs the frame rails and then puts air pressure in them to find small cracks.

Another thing that could be done is to go ahead and have the powder stripped off. This will make it 10x easier to see any cracks. I have gotten to the point now where I strip mine at the welds as soon as I get it. Saves me the trouble later.

The last thing I will add is that the Eagle is not a mid-summer kart. It has way too much grip (especially at higher weights or with bigger guys). It was developed on old Bridgestone YHCs and it seems like as the tires get stickier, the karts get slower. Add in the fact that NCMP is one of the most temperamental tracks to “stuck down” conditions and you might just be so far out of the tuning window that it feels like its broken.

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I second what Derek said. Something broke, given that it was like a switch flipped. I’m not really a believer in a chassis “wearing out” aside from being bent or broken.

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3 seconds is huge, so if it flipped like that I would imagine something somewhere is broken or fundamentally wrong, as noted above.

If it’s unpredictable that is a good sign that there is something structural not quite right.

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I appreciate all the input!

It does make sense that it something structural given the switch moment. I’ll pull the thing down and give it a closer look. I should probably just send it to Bill for an exorcism regardless.

Derek, I also wonder about what you say of being out of the window too. I started to struggle more as the temps came up for sure. I’ve seen Eagles up front in the heat, so I know it can be done, but I am struggling to get it freed up and keep the inside rear from hitting me in the head. I have tried the usual stuff, but I am missing something. Provided I’m not broken (I kinda hope I am), are there any general tricks or ideas you’d be willing to share?

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Are you using the Beasley seat?

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For me, its about reducing transfer and reducing mechanical grip. I’ll let TJ double check my theories, but what I have found is that with the stickier tires (New MGs vs Old MGs, MGs at New Castle in July vs MGs at Whiteland in April), we have so much tire grip, that you almost cant compensate enough with reduced mechanical grip. Here are my go-to order of operations:

  1. Beasley seat to get CoG as LOW as possible. Weights on the floor pan, bottom of seat, etc.
  2. Lots of negative camber. As long as it is still pointing in on corner entry, take more out (like a lot - we have been off the snipers on negative camber… -12mm)
  3. Max caster out (top and bottom pills if necessary, 3 dots on top, standard offset on bottom)
  4. Narrow front and Widen the rear until it sits too flat and just sneak back a tiny bit. If it pushes on entry from the rear being so wide, you might widen the front just a tiny bit to compensate without hurting much. On rear width, I sometimes go much further than the standard Eagle window and still keep getting faster.

Kart is straight and not broken, but still slow?? Ok, time for Derek’s extreme’s. This works for me and i love it, but not conventional.

  1. Take a lot of cross out. If the track has 6 left hand corners and only 1 slow right hander, I would be down around 46-47% cross. If opposite (6R, 1L), I would cheat the other way and go 53-54% cross. This will release the LR easier and allow the kart to rotate better without much mechanical input (steering input).
  2. Caster split - Same thing here. If the track has big sweeping lefts and 1 tight right (think Old Whiteland Long Forward), I will run caster in the RF and out on the LF. This allows the kart to roll over on the RF instead of planting the RR.

If none of these work, I take a few races off to drink beer and come back in September/October when the temps are more reasonable and the track rubber is lower).

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Thanks so much for the detailed response! I have tried quite a bit, but havent been as far in any direction as you suggest. Sounds like I have some work to do!

As far as seats, I am running a T11t and I keep cracking them at the top right at my shoulder blades. 2 in a row. I cracked both sided of a brand new seat in 3 runs. I can just smash the sides in easily by hand now. Do you think that is caused by the extreme hopping? The kart changes a lot when both sides crack out.

I have access to a Beasley I could try, but at 5’10" I feel like it rubs my arm pits… Worth dealing with it to try?

Thanks again!

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T11T is the hard seat right? I would switch to a VG if you want to stick with Tillet. Softer is better on these things. Beasley is your go-to, tho.

All of what Derek said, extreme negative, max caster out, etc is the way to go.

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T11t is the “medium”, though I would suggest a closer look at how the seat is being mounted. Those seats shouldn’t be cracking in that short of a time period, and that problem is going to be much worse with a softer seat if it isn’t being mounted properly.

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This sounds like a seat strut / seat mount issue. You shouldn’t be seeing that, even with hopping. Given your other comments on chassis behavior, is this a new problem that corresponds to the performance loss?

My kid is just a touch over 6-4" and leans and puts a ton of load on the seat. In 2-1/2 years we have blown out lots of seat bottoms, but only 1 upper corner has cracked. Our first 2 years were in LO206 with the majority of our races on a very high grip surface where hopping could be bad enough to hurt ribs. Now we run KA100. The only time we blew out a side was from someone’s kart crawling up in his lap and caving the seat in on him.

  • Use adequate sized washers to spread the load
  • Make sure all strut tabs a bent parallel to the seat at point of attachment
  • Tighten the upper and lower seat bolts thoroughly
    -You can loosen them to see how a more flexible seat behaves, but I don’t recommend leaving them loose.
  • Check seat struts for cracks that could be putting all the load on one side
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The seat thing is admittedly weird, and I can’t help but think it might be pointing to a bigger issue.

As far as how it’s mounted, I’m really not sure what could be wrong with it. It’s right where it belongs according to the “Ole Eagle Baseline” and the scales. All the tabs are parallel to the seat, mounted with all the proper hardware and washers. When bolted up, the seat isn’t spread, tweaked, wedged or otherwise loaded up in anyway; it fits nicely. I’m pretty anal about how my chairs mount and spend a lot of time making sure it’s all proper as I can. Unless I am missing something (always possible) I think mounting issues could be ruled out, but again, I don’t really know and am here to learn.

A bit more backstory on the seat breakage… I started the season with a new seat. A few races ago, probaly the 5th race on this seat, I show up at NCMP and the kart is a pile. I go to work on it and it gets marginally better, but still much like I explained above, just felt sorta like the usual broken strut, but also not quite. I get it home after the race no broken strut, but I notice my seat is cracked on both sides at my shoulder blades, not just white and spider webby, but whole top flange/return is split. I thought to myself, well there’s your problem dummy, then go buy a new chair. Next race out, kart is still a pile and in 3 short practice sessions, the back of my brand new seat looks just like the one I took out.

I am not sure what would cause this, but to me to break that upper flange, it seems like the seat would have to be sqeezed from the sides, not leaned into per se. Just going by what seems logical in my head, not that karts ever follow that…

Thanks again for your time helping me figure this out

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I would just laminate more material to the seat sides - repair the old seats and douple/triple the thickness of the laminate around the mounting points. Make the whole side stiffer

Or if you buy a new seat, laminate it thicker before use. No sense putting it on if the previous ones have failed. It just isnt strong enough.

Or if you are uncertain what to do - make a comparison test : reinforced old vs new bone stock

I think you will like the reinforced more. For me the stiffer the sides - faster I go

I have a nek seat at the moment. I have laminated more carbon to the mounting points and it is still not stiff enough. The seat gives at these attachment points. I need to redo the seat during the winter or make a new seat. Any time I have broken the laminate I cant transmit weight to the outside wheel. Flexible sides also hurt my ribs

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Some cracks are really hard to find, in the photo below, I thought the paint was lifting but I was able to slide a piece of paper in the crack. Kart would buck and hop in certain corners. The crack was much larger when the paint was removed. When it was welded up, the kart handled as it should.

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I’m afraid that with where I’m at, if I stiffen the seat its gonna lock me down even more.

I’ve also never had an issue with the mounting points; not so much as an egged out hole even. I am pretty confindent it’s not a mounting issue, but at this point, I am lost as an easter egg so maybe I am missing something in that respect.

I have attached some pictures of the first seat that broke. I know it doesn look like much, but its split all the way through the flangle on both sides. When it’s out of the kart, I can push in on the seat sides and it squeezes together easily and the splits open right up. When I switched to the new one, I could feel a difference, but that lasted 3 runs as I touched on above.

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Does this seem odd to anyone else? I feel like somehow it’s both a cause and effect of handling issues, but can’t muster how exaclty. Am I crazy? (Wait, don’t answer that).

Please keep the thoughts coming!

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I am of the opinion, crack in a seat strut.

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The seat cracks are puzzling. I would guestimate that it is from excessive flex from the chassis. Again, in the form of a crack somewhere that we are missing. I dont see how the seat could be cracking there (consistently) without something else causing it.

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I agree with Derek. Very strange to see a seat consistently crack on that edge after such a short amount of use.

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Ok, you all have me convinced something is cracked and I haven’t found it yet. Might be time to break out the wire wheel and jewler’s loop…

I do think it’s flexing a ton too. I can feel the seat squeeze me a little when the inside rear tries to hit me in the head.

I think something broken coupled with being off on setup for heat and grip has gotten me where I am. I’m going rip it apart and see what I can find. Thanks again for all the suggestions.

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So I am starting to learn how to understand bad performing chassis by virtue of getting to drive broken karts. You can feel a bit what’s going on and then go “Aha, the kart behavior is telling me X”.

So I had a kart that could turn right, but with angle in, past a certain amount of throttle in a right turn, the kart would stop turning and basically push but not slide. This made me think that the front end wasn’t connecting properly with the pavement once a certain amount of load went through it and that it must be due to a front end chassis issue. Perhaps the chassis was flexing wrong and that was changing the grip of the kart once you asked past a certain point… I was correct!

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Now to figure out why kart 8 is exhibiting similar behavior.

I’d like to intentionally bend up stuff to see what does what. Ie bend the spindle on one side, etc. I need a good whacking hammer for this project.

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