A quick thought to ponder:

paulkish

old fart
A quick thought to ponder:

Grip between the track and your tires can only eat hp, momentum and speed, if the grip is causing a conflict between tires for control of the direction.

Eliminate fighting between tires for control of direction and you can go faster.
Increase fighting between tires for control of direction and you WILL GO SLOWER.

That is beyond racing skills, what setup and driving is about.
 

OVALTECH1

Site Supporter
It doesn't matter what the grip is, the horsepower calculation is the same for a given rpm.
So your saying 7hp setup on kill with the tires right and free wheeling right at the ragged edge of loose will be the same as 7hp with a jacked up setup, alignment and the tires locked down…..
 

ABR #69

Member
I don't quite think that's how it was meant to be interpreted. But, technically the HP rating would still be the same. Not to be mistaken with how well the kart would perform.
 
So your saying 7hp setup on kill with the tires right and free wheeling right at the ragged edge of loose will be the same as 7hp with a jacked up setup, alignment and the tires locked down…..
Yes, 7 hp is 7 hp. How the kart will perform with the application of that 7 hp is another question entirely.
 

Bradley71

Member
Yall talking about this had me thinking about and open kart i had watched on a video the guy who won the race was on a 450 and he was on a rail.and by that i mean with the amount of hp he has and as fast as he was getting thru the corners and getting down the straights there was no sliping and sliding the rear end at all.he is obviously running a outside the box setup in his kart.
 
What I've been wondering the most about is air pressure. Like, if having the highest air pressure possible gives you the least rolling resistance, why not run higher amounts of inside prep for more grip so that you can have higher air pressure than everyone else? What's a good average air pressure to run other than the standard 5&6? Or what do the pros run in general for air pressure? Higher or lower? Idk
 
The Pros run what air pressure at the that specific time to get the best lap times possible. Air is track dependent with how much grip is available . Less grip in track less air, and vice versa.
As for internal, more internal plus higher air, isnt the same as the correct internal with the correct air. What i mean is you cant overcome too soft a sidewall by adding air. Now with the added air, you have changed the contact patch in relation to the track, you are going to build heat at a different rate, and you also change the "compression" of your spring/tire. Now if you already have tires with too much internal, you can use higher air and maybe get away with it for a lap or 2.
 

paulkish

old fart
you cant overcome too soft a sidewall by adding air.
Because how soft the sidewall is needs matched up to how hard or soft the >>track<< is

Why would you ever want to pick any tire other then the tire with the stiffest side wall?


I don't know the answer but think it's going to take a rare dirt track now a days to be or stay soft come feature time.
I don't know the answer but I don't recall very often seeing a kart track very soft and very high grip come feature time.
I don't know the answer but I think if racers weekly were given a >>soft<< high grip hp eating track where you had to throw the kitchen sink at it freeing it up come feature time to use a with a low hp engine, ... they'd go race elsewhere.
I don't know the answer but dirt racers brag about racing dirt and then ain't happy unless they get rock hard smoooooth dirtfault .
 

ABR #69

Member
An example is a track I frequent. The track is normally VERY good with Maxxis being the go to tire. So there was a large race the weekend this happened. Lots of UAS coming, Small blocks and such. Friday night was practice and sort of a drag race bracket style. Wed and Thursday we got an exceptional amount of rain and and the track was ran in for friday and it was very wet, tacky, also incredibly fast. The track record reportedly broken more than once unofficially. On prepped up Vega running low 11 second lap times. The official record stil stands at 11.66. Tales of 11.5, 11.4, even an 11.3 were spreading through the pits.

Come Sat morning it was quite cool, the track was ran in and prepped according to the Owners normal routine, calcium was put down, and everything went as normal. Well, with all the moisture from the previous night, the calcium on top sealed the track off. Everyone was struggling early thinking the track was going to carry over with the moisture and that the calcium would hold all that moisture in and it would be like friday night. Well, it did hold it in, but it sealed off and it was mid 60's and the track just got dry slick. No one could get a handle on it. I've seen this happen a few times, and everyone said, "oh you'll never get anything to hook up on this, we'll just have to wait it out till it starts to get good."

Just before qualifying I made the decision to abandon Vega and Maxxis and go with a Burris for a few reasons. One, prepping wasn't getting the tires in the track, just making them slide. So that told me no amount of prep or soft tire was going to get the job done. Two, the kart was driving off the corner decent if you backed up the entry. It wasn't getting in and then four wheel sliding through the center, but if you backed it up enough it would drive off as good as you could hope. Not fast, but better than sliding everywhere. Going to the harder natural rubber done two things. Still had good grip for drive off, decent roll speed, and could prep them and still actually get bite. But ultimately it solve ALOT, but not all of the issues of driving in and through the corner. Where everyone was suffering was the side walls were just too stiff and the tires couldn't grip through the corners. They needed side bite, and the softer sidewalls of the Burris was just that, it gave side bite. Dropping air can only accomplish this so much on a stiffer sidewall tire. You needed Burris at the end of practice into the first and second wave of Qualifying. By the end of qualifying into the first Consi's the track had started to come around enough the normal tire of choice for this track was starting to come back into play. Mainly due to the amount of karts getting on the track.

The track was harder, which normally would go to a lower 3-4psi Maxxis in the low 50's. But, turns out during that specific event of the track transitioning. It was dry slick and needed a softer sidewall to make enough side bite. Now we weren't setting any records, but it was enough to get the kart back on track for the day. We had decent qualifying positions for most of the races we ran that day and later that night we all went back to Maxxis as the track started to come around and get decently fast in the high 11's again. But, during the day it was way different than normal. But, it was all due to weather and chance. This is one example of many that could warrant a softer sidewall. It's not always about how hard or soft the track is. In this example the track turned out harder than everyone expected. But, it generally comes down to side bite, and I know not everyone can completely change brands.
 
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Eliminate fighting between tires for control of direction and you can go faster.
Increase fighting between tires for control of direction and you WILL GO SLOWER.
I agree! The same theory applies to various inputs that are attempting to steer (change direction) of the kart.

The rear axle and the front end are fighting over direction at which to move the kart for roughly 180° while changing direction from one straight to another.

As a starting baseline, this is exactly why I believe that Rear Stagger needs to match the geometry of the track. There is a mathematical perfect stagger that will allow a mounted axle to roll around a given turn radius.

I know you guys will crush me and say that there are many variables besides stagger. Yes, I know that. But, the perfect stagger in my opinion will reduce the amount of said variation.
 

paulkish

old fart
More stagger creates a situation where you can get more turning/rotation from your staggered solid axle.
If the added stagger does get you more rotation it's only because of your ability to load and control the grip of the rear tires.
Less stagger is the same.
The only difference is in how more or less stagger effects your ability to control on track forces needed to make your stagger function.

As a baseline your fine so long as you realize it's only a baseline.

If I were to calculate stagger choosing a particular place on the track, I'd choose 1/4 the way into the turn.
If the end of the track is normally two turns then pick the one of the two it would be most beneficial to have good stagger help you.
If each end of the track are taken as a single turn then calculate your stagger 1/4 of the way into the end of the track.

I picked 1/4 the way into a turn because 1/4 into a turn is where your most likely to maintain needed momentum.
 

ABR #69

Member
The only problem with "mathematical perfect stagger" is the fact that tires aren't solid objects. They're essentially like springs, they compress and decompress dynamically depending on load. Which changes stagger on the fly. So if mathematical perfect stagger includes calculating the dynamic load conditions throughout the entire track, maybe. I don't think there is a perfect stagger, but that's just me.
 
More stagger creates a situation where you can get more turning/rotation from your staggered solid axle.
If the added stagger does get you more rotation it's only because of your ability to load and control the grip of the rear tires.
Less stagger is the same.
The only difference is in how more or less stagger effects your ability to control on track forces needed to make your stagger function.

As a baseline your fine so long as you realize it's only a baseline.

If I were to calculate stagger choosing a particular place on the track, I'd choose 1/4 the way into the turn.
If the end of the track is normally two turns then pick the one of the two it would be most beneficial to have good stagger help you.
If each end of the track are taken as a single turn then calculate your stagger 1/4 of the way into the end of the track.

I picked 1/4 the way into a turn because 1/4 into a turn is where your most likely to maintain needed momentum.
My point is this another area where two points of adjust can fight with one another and absorb HP/speed.
 
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