Track Tac

Early fire tire vs late firing tires

1fasttiller said:
So I'm incorrect in thinking that tires with too much grip (bite) would work better with higher air? Wouldn't the higher air cause the soft tire to have a higher and harder sidewall? Wouldn't it take some of the excess grip out? Higher air increases the spring rate of the tire so it takes away grip though?
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We talk about it all the time on here with rolling resistance and predators, its got to be the same with kids. The same reason you add air as the night goes on for outdoor racing as grip increases you add air, its just basically the way it is, I dont think what RP said makes any sense.
 
1fasttiller said:
So I'm incorrect in thinking that tires with too much grip (bite) would work better with higher air? Wouldn't the higher air cause the soft tire to have a higher and harder sidewall? Wouldn't it take some of the excess grip out? Higher air increases the spring rate of the tire so it takes away grip though?
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It's possible it could have helped a little, but higher air builds heat quicker so it's also possible the tire would have fell off quicker, I'm only pointing that out, it could of went either way, bottom line you were to soft and it would not of made enough difference in the end.
 
jaymancds said:
We talk about it all the time on here with rolling resistance and predators, its got to be the same with kids. The same reason you add air as the night goes on for outdoor racing as grip increases you add air, its just basically the way it is, I dont think what RP said makes any sense.
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There's a lot of things in racing that makes NO SENSE like cross, I'm only pointing out higher air builds heat quicker so it could of fell off quicker as well, it's not for sure you want a guarantee go buy a refrigerator !!
 
racing promotor said:
There's a lot of things in racing that makes NO SENSE like cross, I'm only pointing out higher air builds heat quicker so it could of fell off quicker as well, it's not for sure you want a guarantee go buy a refrigerator !!
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The physics of reducing friction, and ADDING heat, does not work. When friction is reduced, the heat energy associated with that friction is also reduced, which leaves you with a cooler surface. Adding air, and heat, does not make any sense.
 
jaymancds said:
The physics of reducing friction, and ADDING heat, does not work. When friction is reduced, the heat energy associated with that friction is also reduced, which leaves you with a cooler surface. Adding air, and heat, does not make any sense.
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AGAIN NEVER said it makes any sense, and didn't say it would have for sure, only pointing it out so the OP was aware as well, Per Todd Goodwin Higher air pressure builds heat quicker but will run cooler in the long run and will dissipate the heat quicker, BUT may slide on the track countering any of the benefits of the higher air pressure, particularly on long runs. Low air pressure will build heat slower but will run cooler in the long run, however a lower pressure may prevent the tire from ever coming in yielding an early deficit on the track.
In general what you state works out, However at times it can work just opposite.
 
No where near enough internal on a tire that was too old, and on the fresher set, still wasnt soft enough for Friday night. The adults were around a 42. You werent locked down, you just didnt have enough bite to make the kart work. Friday night track was a goat track.
The track groove was all prep, both days.
 
SoCo Tire Treatments said:
No where near enough internal on a tire that was too old, and on the fresher set, still wasnt soft enough for Friday night. The adults were around a 42. You werent locked down, you just didnt have enough bite to make the kart work. Friday night track was a goat track.
The track groove was all prep, both days.
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Interesting.
Why do you suppose he was seeing tire wear so badly then, Earl?
 
I can't believe he was sliding that badly though if he says he was locked down on day two and feathered the tires. I get the higher psi and not enough bite causing the sliding, but still doesn't explain the tire wear. A tire that's sitting/sliding on top of the track doesn't build as much heat as a tire that's locked into the track.
We're missing something here.

Earl and front runners were wiping tires with goat and considerably softer on duro, yet the OP was feathering on harder tires in a jr class without the aggressive outside wiping.
 
Wear wise- Sounds like its sitting on top of the track milling the surface of the tire off.

Bite wise- One of two conditions, too much bite locking down, or not enough and it runs out of bite at the end of the race.

We all know you don't make any speed in the kids classes by sliding or being excessively loose, but I always looked at it that the reason a lot of people say they're better on thinner, harder, less prep, more air on the kids even when off speed wise and thinking its right is that they're not sliding bad enough to actually slide, but are ever so slightly sitting on top and not aware of it. Same reason why on Saturday or Friday night races you can do this forever and be fast and win and not notice an issue or a need to change anything. When you get on a track as it sounds above you see that when others are right, its off, even if it is slight.

The other thing with kids I always look at is the split between adults and kids lap times, the closer they get on day shows the more bite the kids need since all of their gains compared to a normal night are coming from not slowing down or gaining speed through the turns.

A lot of this nuance also comes down to the kart itself, how soft and how much bite it is making, and ultimately how into the track it is.
 
CarlsonMotorsports said:
I can't believe he was sliding that badly though if he says he was locked down on day two and feathered the tires. I get the higher psi and not enough bite causing the sliding, but still doesn't explain the tire wear. A tire that's sitting/sliding on top of the track doesn't build as much heat as a tire that's locked into the track.
We're missing something here.

Earl and front runners were wiping tires with goat and considerably softer on duro, yet the OP was feathering on harder tires in a jr class without the aggressive outside wiping.
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Brian- just to be clear on day two features we didn't see the heavy tire wear at all. That was the set we used Friday night for the shoot out. The set we locked down on Saturday didn't feather at all, very light graining if anything. My tire guy just told me he did wipe a round of goat on them before he sent us out Saturday night too...
 
jaymancds said:
The physics of reducing friction, and ADDING heat, does not work. When friction is reduced, the heat energy associated with that friction is also reduced, which leaves you with a cooler surface. Adding air, and heat, does not make any sense.
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More air less contact patch . Less contact patch more slipping , via less square inches of contact . More slipping more friçtion . More friction more heat .
 
JRC_Performance said:
How were the tires prepared internally and how many weeks out were they? That’s be my first question if he was good at the beginning of the race then fell off on long runs.....
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I think the answer is in this thread some where .
Question is now , what the solution for coming in too soon .

A reroll with not enough internal comes in fast then fades .
More internally closer too race date ?
Or a fresh roll that comes in fast then fades .
Less internal ?
 
Once the outside prep wore off, the tire faded because lack of internal. Tire was so old that the wiping of the tire couldnt overcome the lack of internal. Even the re roll was older than what most guys had as single roll, that equated into too hard a tire.
Lots of the top guys were on 3 week tires, give or take a week.
Tires didnt come in too soon, they just werent the right tires in the first place, unfortunately.
 
Not that this was his specific problem because so many are explaining the reason it was a tire/prep problem, butt:

Do we all also rule out using low initial air pressure to get a tire to fire off quick and then rely on tire heat to bring pressure to what you want for the race?
 
I believe you’re spot on Earl. And thank you all for the input, we certainly know a little more now and will be a bit better prepared for the next one!!!
 
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