It was a screwy setup for sure. Trying to induce all that jacking and then going stiffer on the axle is somewhat counterintuitive, but we were really trying to hike the inside rear and absolutely pile-drive the outside rear tire, and we thought maybe the A would allow that while still keeping it free in the rear. I’m not sure the A really made much difference.
The other theory was to get the rear soft so that it flexed easily but didn’t overload the outside tire too badly, so the binding wasn’t there, but we could still have a nice squat off the corner for traction to keep it from sliding.
I saw OTK karts with two seat struts per side and a Q axle in, I saw OTK karts with no seat struts and low ride height, I saw OTK karts with the H axle in…
and of course for the final Sunday, there was a threat of rain and it started sprinkling on the grid and I was completely ready to go out on a dry track on rain tires and pray for a down pour within 5 min (85% chance of thunderstorms within 10 min said the radar as we walked up to grid) but it was never declared driver’s choice on tires because it wasn’t actually raining yet. Fortunately I didn’t get to make that call, as it never did rain. Need to download a new weather app.
@tjkoyen Randy runs the OTK for world formula on Tuesday and Saturdays. Lap times are very similar and sometimes faster than the Yamaha Pipe. A little different set up from KA but the common theme we have is .
We’ve been narrow, wide, full-min caster, neg-pos camber, air 17-28, seat struts on and off, bar flat and vertical. Only ran the N there. Debated putting on the H or HD for Tuesday since rubber will be higher than it will be all year.
Never have found that set up that made him say, that’s it! It’s confusing for sure.
Though the track has gotten better, I think the very tightly grouped and packed aggregate in the asphalt just doesn’t let much rubber truly get into the surface. The tires don’t have as much fine grit sandpaper look to them as they did previously but still seem off from what you’d expect a tire to look like.
Exactly how I felt about it. Clearly some people can figure it out, the usual suspects were mostly still up front, but our tent wasn’t quite finding what we all needed. I didn’t really have any good data to go off of as our other guys are still pretty fresh and were on different karts too. Only reference I had was Kopp but he was on the Yellow and the X30 Master weight is a different ball game too. Plus he’ll admit he wasn’t at his peak this weekend either.
I found this to be the case when I was there in 2019 running Pro Shifter in the SKUSA Great Lakes series. I had heard it would be very low grip, so I showed up with a stiff ass setup to try and drive the tire into the pavement…needless to say, it did NOT work, and I ended the weekend on a super soft setup that got me the win.
Fast forward back to this weekend on an already soft kart (KR), and I felt like I was struggling for grip most of the time. Very tough to find that balance of rotation and side bite.
We struggled to get the inside rear up at all. So I think what was happening is that early in the weekend, we had no lift but the kart was sort of flat-sliding a bit to keep it free. When the rubber built, we attempted to get side-bite and try to get the kart to work ‘properly’, but we still weren’t getting lift, so what we were doing now is both rear wheel were still on the ground, but now we are grinding that outside tire into the track so hard, that we are scrubbing speed and binding the tire as it tries to twist mid-corner and rotate the kart. All we did by adding jacking and attempting to add lift was to induce scrub and bind. We went the same times, so maybe there was some give-and-take and we made up time somewhere in the corner and lost it in another part of the corner.
Yup. I had this problem both years but far worse last year. Possibly an outcome of short man’s disease. In Masters, the tall guys seems to do well at RA.
Last year, on Sunday, the kart was flat as a pancake - it was as if I was dragging another kart around behind me. For me, the last series of turns are really tough to get the IR to lift. This is deadly as the last turn leads to the long uphill straight.
This year, per tuner par excellence @Muskabeatz, we cranked in full caster and +4 positive camber. It was much better. I was also switching between 3F, Lynx, and Tiger. 3F did not work for me.They worked better @Muskabeatz who is ca. 6” taller than me.
Although I suck at RA, I still like driving the track. The chicane, turn 3, the off camber left, the diving right hander, the double left are all a ton of fun. The track has a lot of character and it is a nice part of the country. We won’t even mention Siebkens, New Glarus beer or the cheese curds. I have been to RA probably 10x (2x for karting) and I always find something new I like about the area.
Didn’t move it forward but we had to toss weight on and tried to move weight forward. Balance didn’t feel awful.
Agree Paul, the 3F wasn’t working for me either. It was too much forward balance and the rear was too free. It might’ve been tunable from there but we went back to the MXC because it was one variable to eliminate for us. I think that wheel would be great in normal situations with real grip. I was amazed that Lemke just uses the 9F basically always, but he’s an alien.
I have only recently started using the OTK wheel line. And i often get told my setup choices are weird. I love the 9F. I wish i could drive it more to solidify more data with it. Instead i end up taking the known of the MXC.
Id be curious based on what im reading.
Our local track is like this occasionally and i will go a stiffer axle but run almost minimum width rear, 10mm front, half caster and a chrome bar. Kinda odd, but works.
My kart felt better on Lynx and rear width at 1380mm. 3F at 1398 was NG. Day 2 final I tried our highest grip wheel, Tiger at 1390. It felt great on the warm up lap but I did not make it pass the first turn. I think I had a top 5 kart . That is my story and I am sticking with it.
It looks like as if it’s all in the side bite of the OR. No side bite = no IR lift. Then you’re stuck with sliding the kart around, like a indoor kart.
Did anyone get their karts behaving conventionally?
It’s easier being a back seat tuner. In the midst of a race weekend I can’t think analytically, so I start trashing or asking.
I found that the track changed pretty drastically for the final each day, and during those sessions I was dealing with a kart that was actually over-stuck, especially on Saturday. Made a ride height change (frame all the way up) Saturday night and that really seemed to help keep the kart free throughout the final on Sunday, though it still didn’t give me the pace to contend with the faster guys.
Another change that really helped on Saturday in terms of managing rotation and side bite was going to a shorter axle. Started on a 1040 Medium, cut it down to 1010, and that woke it up dramatically. Freed the kart on initial entry, and made it more nimble/predictable throughout the entire corner. By the time we got the final on Saturday though the M was too soft, and the kart was over stuck.
I did everything possible to get side-bite, but all it did was induce bind on the outside tire. I had 5-dot pills maxed out on top and 3-dot pills maxed out on bottom, front bar at 45°, jacked up rear ride height and raised seat, stiffened seat, narrowed rear… And like I said, I tried to make small moves toward side-bite on Thursday and all it did was make the kart bind, while still being flat.
I tried MXJ wheels and they already were overheating Thursday. I can’t imagine an aluminum wheel would fare very good. Track temp was warm. Another difficult part about RA is the surface requires you to run pretty high pressures to get the tire to function at all. Pretty much everyone I know of was 5-7 psi higher than normal. I did want to try MXJs on about 13 psi just to see if I could get the tire to work in a lower range with more sidewall deflection to help the kart dig in better, but didn’t have a chance to try that.
If the track was behaving conventionally, it’s a pretty easy problem to solve when you lack side-bite. RA does not behave conventionally.
Widening the rear doesn’t change the grip level. It changes the rate and amount of IR lift. Wider is slower lift because you’re not letting the kart tip as easily.
That’s the tough part. The track felt like we were stuck, but if you walked out there, I’m sure the track wouldn’t have felt sticky at all. That’s why I wanted to try the A axle, because I felt like while there wasn’t enough grip out there to make the kart work, the rear still felt like it needed to be freed up.
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