# When you get boned by data

So I’m new, I get that. I make mistakes, I get that. What has me for ever frustrated is when I pull data and it contradicts all logic. I’m finding when someones tells me to “add a tooth or drop a tooth” the results often go in the opposite direction as the intension.

Scratching my head on this one. Today was a test day, where I was trying 3 different gears. And the data I pulled has me confused and I wondering if this happens to anyone else?

Example from today:

Gearing Ratio | Max RPM| Max Speed| Lap Time

1. 3.73 5,932 rpm 50 MPH 1:13.87
2. 3.47 5,400rpm 49.6 MPH 1:13.54
3. 3.58 5,679 rpm 49.8 MPH 1:13.51

At this point a part of me wants to say I’m new, so my driving is probably erratic and lacks consistency, which would account for the variables?

If you can’t carry the speed through the corner, dropping a tooth isn’t going to necessarily net you more top speed. Sometimes you drop enough gear that you start to be too slow off the corner and never recover the speed on the straight.

Just looking at this screenshot there are some drastic differences in apex speeds, so I think hunting the ideal gear is going to be tough until there’s a little more consistency between runs.

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Monitoring min RPM at each turn is probably going to help you more at this point.

I get boned by data too…. Lap times

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Sometimes I feel like I’m getting boned by coach when we look at data

Ask around for the gear that most are running and use that gear. Most of the time, gearing is not the problem, especially with new drivers. Have someone that weighs the same and is better than you but not too much better drive your kart. (Note: I’ve found that in shifters, a really good driver can saturate the data and there will nothing to look at.) Look at the worst corners and work on those and even ask someone about the driving line through those particular corners.

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Maybe I should explain what has gone into this, so you better understand why I am frustrated. I have two guys who are stupid quick, both around my weight (or within 20 lbs +/- as one if slightly heavier, and the other is slightly less). Both are on my chassis and running 206. Although they run different gearing (from each other), they are usually only one tooth off from each other. Both were nice enough to tell me what gears they run at various tracks (One thing I will say about TB Kart folks, they tend to help each other out). So I have a cheat sheet of sorts (gearing wise) that should always get me close (horseshoes and hand granades). I wish I could run with these guys locally, but neither are local and our paths rarely cross in real life. But both these guys competed at the level I’m at now, but both are now running in bigger series that I wouldn’t even attempt at my skill level currently.

So I am CONSTANTLY testing gears. I’ll try each of their gears, then I try my own. So usually anywhere I run, I’m testing at least 3 different gear sets on any given track day. But when I add a tooth, instead of getting more torque, I’m getting more in the straights oppose to the twisties. When I drop a tooth, I get the opposite affect again.

When I pull data, in most circumstances, I’m pretty consistent. Might be consistantly bad, but at least I’m consistent. Don’t get me wrong I’ve had times (like yesterday) where I was less consistent, but in either event; I’m getting frustrated when the typical logic yields (for me) the opposite result constantly. Which has me frustrated as a new guy.

Feels like I’m always trying to hit a moving target.

You say you’re running the LO206, but you list your max RPM lower than the rev limiter of the engine. Are you hitting the rev limiter on the straight?

Just doing some math, your top speed for each gear, at the rev limiter, should match the gear ratios. Gearing is pretty straight forward, lower ratios will always give you higher top speed so long as you’re hitting the same RPM.

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I think the gearing changes might be adding a variable. With that said I’m beginning to wonder if you’re down on power. Have you tried swapping karts with one of those faster drivers?

Possibly the engine is not performing 100% or the chassis is holding it back through binding brakes or a setup that’s making it run too “flat”

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I know it’s frustrating, but to quote the late Al Nunley:

“Tuning is hard”

You need more info. Was everything else exactly the same? Track temp? Tire pressures? Tire temp? Wind? Other karts on track (draft)? Tons of variables here. To James’ point, if you did these same 3 runs with the same gear, what would variation have been.

With 206, I have found gearing decisions easier to do based on “where” I hit the limiter on the track vs going back and looking at the data. Do I want to hit it sooner or later compared to my reference point.

On this particular track:

11psi (People normally run 10 psi on MG Yellows) I’m on reds.
No draft/ empty track
The straight away has a slight uphill portion, so I’m very close to hitting the rev limiter. But then I hit the incline and I just don’t quite get there.

Only alibi, is my new axle (this what its maiden voyage) and I removed a seat strut just to see if it loosened the kart up. I’ve been told it does. I just wanted to see for myself on this track day.

Do you hear other people getting on the rev limiter on the straight?

Are the karts your comparing against on Yellows or Reds? 11 seems low for Reds personally, especially on a 206.

Adding gear will band-aid poor corner speed and let you carry more speed onto the straight, if you’re not on the limiter.

Your RPM is responding correctly. When your ratio is lower you’re turning less RPM. That’s expected. The speed difference is coming from not getting off the corner as well with lower gear, and even though technically you have more top-end potential on that lower gear, you’re so far below the limiter your not making the ground up by the time you get to the end of the straight.

Gearing is worth a small amount of time, and yes, you will often be chasing a moving target because air conditions and temperatures and humidity are always changing, and your gearing will be affected by that. Honestly chasing the “perfect” gear is sort of a waste of time in your situation. Gearing is worth such a small amount of time that it isn’t worth getting this in the weeds over. Chassis changes and driving improvement will yield far more time. I would recommend on running whatever gear the fast guy says to run, and working on getting your driving and chassis sorted to make that gear work.

Everything I know about the 206 says you want to be hitting the limiter. If your fast guy gives you his gear and you’re not able to get to the limiter with it, you need to improve your chassis or minimum apex speed to make it work.

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My two penneth the for what it’s worth

Go up in teeth until you’re hitting the limiter. Bigger sprocket will encourage smooth throttle application, as you improve your driving and achieve higher corner exit speed you’ll notice you hit the limiter earlier. Then it’s time to remove teeth to maintain hitting the limiter at the optimum point on the track.

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ooooo…I like that idea!

That’s an interesting idea and makes a great deal of sense. What’s funny is that I used to do this backwards in kartkraft. Find the most aggressive gearing and learn to run fast laps with that then remove teeth to make it less knife edged once I have worked out timing/line.

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I agree with TJ above, it looks and sounds like you are not able to take advantage of the extra top end due to the RPM out of the corner being too low. Remember 206 racing is so much about momentum and carrying speed through the corners. If you or the kart is binding through the corner then going down on gearing will only hurt you more. Hard to tell from the picture, but what was the low RPM coming out of the corners?
I would be curious to see your laptimes if you had put in more time at the 3.73 ratio.

Good feedback. I know my exit speeds have been an issue in the past that I’m actively still working on; braking earlier and working on exit routes that maximize exit speed. Some corners I’m getting better on, but other kick my butt. I think gearing up makes sense so I’m all over the rev limiter (or as close to it as I can) as I experient with corning. As things get smoother, I can drop teeth as my racing improves.

So riddle me this thou. . . .

Imagine a left handed J- turn. I know I want to swing as wide as I can to the right, hit the apex, and keep the kart as straight as I can on exit to illinimate binding. I think I under stand the general concept. (Famous last words)

But what I find is if I swing too far to the right of the turn, prepping for entry, you encounter alot of track debris, which can kill traction (and speed) and cause the back end to slide which will kill momenteum and cause you to bind anyhow. In a case like that, what is the best action?

• Swing as wide as you can- while still avoiding the track debris?
• Do you undercut the inside with a generious amount of brake and just try to be a smooth as you can as to not bind? (Is braking better than binding in a situation like that?)

I wish I wasn’t on a primarily two stroke track. Because then I could see other peoples lines to determine what works the best. Both the two strokes (who are to fast and take a different line) and the heavily modified 4 strokes are just too fast for me to follow into turns. Plus their on yellows and I’m on reds.

Really what I’m talking about is that center hairpin turn on the right side of the track on the data shot. That turn really EATS MY LUNCH.

I’m having a hard time picturing what you’re describing, maybe a photo or track map would help? If you’re in the marbles, you’re not on the right line. That’s why there’s marbles there, because no one drives there.

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• Specifically referring to turns (9 going into 10) in the clockwise configuration
• But turn 1 also eats alot of peoples lunch. But that one I’ve gotten much better at.

Those are the two momentuem killers where I run where I cannot avoid binding up the kart.

Turn 6 is hoot going into 7! on a 206 (with enough practice) you can go wide open and its a blast to run.

Last weekend we had folks travel from 8 plus hours away. Both said this is the funnest track they ever run at. This track is North Florida’s best kept secret! The owner who designed it was a French F-3 driver. I’m lucky enough that its local to me.

I would treat it like a decreasing radius corner where t9 is a setup for t10.

Get too wide and you’re in the marbles.