But who knows why?
Go ahead and think about it, now take a guess...
Most of you will probably say it's because your tire will have a larger footprint, and therefore more surface for grip. This seems to be the logic I hear from people most of the time. But, anyone with a basic physics/statics class under their belt knows that that just means the force is just distributed over a larger surface (less force/unit area * more area = same normal force = same frictional force.)
Now, I assumed the lower pressure created a softer surface so the tire could better conform to the track surface...
Turns out everyone is kind of right.
The larger contact patch means that the rubber must flex more every revolution. This in turn creates more heat (hold a thick rubberband against your lip while you stretch it...heat), which in turn makes the rubber softer, increasing the coefficient of friction, and in turn, the frictional force.
Now, what I don't understand is why there is a limit to how low of a pressure you can run before it starts to slow you down. Is it due to it being more difficult to rotate at higher speeds?
Also, everyday all-season tires (stock) are made almost entirely out of synthetic rubber (oil and natural gas). Performance tires have a larger percentage of natural rubber (tree sap and carbon). The natural rubber has a CH3 molecule hanging off of each mer, where it is only an H in the synthetic. This makes it 'stickier', as the CH3 is harder to move over a surface. The downside of course being a faster rate of wear, as more of the material is left behind than with the synthetic.
If you ever have a chance to take an introductory materials engineering class, go for it, it's a hoot.
fortune cookie say:
better a delay than a disaster.
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Your tires actually start to cup in the middle once the pressure becomes too low, resulting in a smaller footprint. You also get too much rolling resistance at too low of a pressure.
this should also read at the strip!
sorry a drag strip is not a racetrack, even if pop culture has deemed it so.
You DON'T want low pressures at a recetrack or an autocross. You will most likely pop the tires off the rims if you do this. I've seen it before, not fun, and all together ruins your day.
-Chris
IamRascal wrote:this should also read at the strip!
sorry a drag strip is not a racetrack, even if pop culture has deemed it so.
You DON'T want low pressures at a recetrack or an autocross. You will most likely pop the tires off the rims if you do this. I've seen it before, not fun, and all together ruins your day.
yeah I'm getting pretty tired of people refering to drag strips as "racetracks"
I've seen the low pressure thing at a couple of auto-x events before...thankfully after the first run or so, someone usually notices and lets the person know that you need MORE pressure to turn right and left effectively
CACC BC Region - DSP
http:www.victoriamotorsports.ca
And I'm getting really tired of autoXers and roadracers with their little superiority complexes trying to belittle the form of racing that I participate in with their snotty little "its not a racetrack, its a dragstrip" comments. Get over yourselves.... It takes a lot more to be consistently fast in a straight line than you could ever know, and as competitive dragracing goes, its just as difficult, if not more so, to be successful at than autocrossing or roadracing. Let me see you guys cut a perfect light everytime, get out of the hole without breaking traction, and then make every single shift perfect.... Oh, and if you don't win the first round, there's not another lap to make up for it. So eat me with your snobbery.
Anyway, Notec, I run 15 psi at the track and thats good for 2.06 60' times on the stock RSA tires... so it must work to some extent
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
Scarab (Jersey Jay 1.8T) wrote:And I'm getting really tired of autoXers and roadracers with their little superiority complexes trying to belittle the form of racing that I participate in with their snotty little "its not a racetrack, its a dragstrip" comments. Get over yourselves.... It takes a lot more to be consistently fast in a straight line than you could ever know, and as competitive dragracing goes, its just as difficult, if not more so, to be successful at than autocrossing or roadracing. Let me see you guys cut a perfect light everytime, get out of the hole without breaking traction, and then make every single shift perfect.... Oh, and if you don't win the first round, there's not another lap to make up for it. So eat me with your snobbery.
Anyway, Notec, I run 15 psi at the track and thats good for 2.06 60' times on the stock RSA tires... so it must work to some extent
No one ever said it doesn't take a crap load of talent to be a top drag racer, it takes a lot of work to be able to cut a perfect light and acheive a good launch. Don't jump to the conclusion that because we prefer auto-x or roadracing that we don't appreciate whats involved in drag racing. The issue here is that in every other part of the world, the term "racetrack" refers to an oval or roadcourse, and some of us find it confusing or misleading when people talk about going to the track as opposed to the "strip"....you know symantics
CACC BC Region - DSP
http:www.victoriamotorsports.ca
actually i noticed this last time i was at the track, my first few runs i ran at 35 PSI, i cut 2.2 60 foots, then i lowered the tire pressure to 30 PSI or so, ran a 2.3 with tons more wheel spin. Put the pressure back up, and i got the 2.2's again.
2006 Black Cobalt SS Supercharged G85
13.91@102.77
Scarab (Jersey Jay 1.8T) wrote:And I'm getting really tired of autoXers and roadracers with their little superiority complexes trying to belittle the form of racing that I participate in with their snotty little "its not a racetrack, its a dragstrip" comments. Get over yourselves.... It takes a lot more to be consistently fast in a straight line than you could ever know, and as competitive dragracing goes, its just as difficult, if not more so, to be successful at than autocrossing or roadracing.
Hold your horses their man. I never said anything bad about drag racing. God knows I put it miles above oval track racing
.
But seriously it's misleading when I come in here looking for stuff about say running on a racetrack as opposed to a drag strip.
There 2 completely different sports, even the car setups are different.
Scarab (Jersey Jay 1.8T) wrote:Let me see you guys cut a perfect light everytime, get out of the hole without breaking traction, and then make every single shift perfect.... Oh, and if you don't win the first round, there's not another lap to make up for it. So eat me with your snobbery.
If you want to fight like that let me see you have to repeat acceleration brake, maintain balance, don't go in hot, gradually apply acceleration in relation to available traction , trail brake to offset car balance to induce oversteer.
Then all the crap going on inside your head
We could go on and on to the end of time but theres no point. I could argue that drag racing is every bit as hard as autox, but there's no point.. Do I enjoy going and watching cars at the strip HECK YES!!, do I have interest in running my own, not really.
I have one concise and true argument
A dragstrip is not a racetrack its a dragstrip. There 2 completly different animals.
Can't we all just get along.
-Chris
at a dragstrip you actually race against someone else. so yeah, a dragstrip can be called a racetrack
Im a Xbox 360 fanboy...and damn proud of it!!
Seriously people, drag racing is for fast cars and and autocrossing is for fast drivers
J/K
Each require a similar amount of different skills. Some prefer one or the other. At least neither races from stop light to stop light.
Drag racing a fast car consistently is very hard and so is driving a fast car on the proper race line.
Well, lets see what Webster has to say...
RACE: 4 a : a contest of speed b plural : a meeting in which several races (as for horses) are run c : a contest or rivalry involving progress toward a goal <pennant race>
TRACK: 3 a : the course along which something moves
take your semantics and shove it
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
What's with everyone being so dam nitpicky lately (or maybe it's just that I took a few weeks away from the JBO and got used to normal conversation)?
Zach wrote:Seriously people, drag racing is for fast cars and and autocrossing is for fast drivers J/K
Each require a similar amount of different skills. Some prefer one or the other. At least neither races from stop light to stop light.
Drag racing a fast car consistently is very hard and so is driving a fast car on the proper race line.
and I'm a slow driver, so...
Scarab (Jersey Jay 1.8T) wrote:Well, lets see what Webster has to say...
RACE: 4 a : a contest of speed b plural : a meeting in which several races (as for horses) are run c : a contest or rivalry involving progress toward a goal
TRACK: 3 a : the course along which something moves
take your semantics and shove it
You suck. I was going to post that argument!
Around these here parts of this here town, when you go to 'race', you head to the 'track'...and it's a 1/4 mile long straight section of pavement with a christmas tree looking thing at the front. Sorry if we're not as 'advanced' as the rest of you.
why'd you all have to go and ruin my post anyway?
fortune cookie say:
better a delay than a disaster.
Hey, I didn't ruin your post
There's your answer:
Zach wrote:Your tires actually start to cup in the middle once the pressure becomes too low, resulting in a smaller footprint. You also get too much rolling resistance at too low of a pressure.
From websters as well:
drag strip: the site of a drag race; specifically : a strip of pavement with a racing area at least 1/4 mile long
notice it says strip of pavement not 1/4 mile track, that's just silly, so you could call it race strip, but that just sounds silly.
race·track: a usually oval course for racing
dragracing: an acceleration contest between vehicles (as automobiles)
so if you wanna go down the dictionary route dragracing is only about the cars.....not the drivers by websters viewpoint
take your semantics and bite me
this argument is going nowhere
-Chris
IamRascal wrote:
Hold your horses their man. I never said anything bad about drag racing. God knows I put it miles above oval track racing
Okay, your saying oval track racing is not as difficult? When have you tried it, to say that. "Ohh, you just drive in circles, anybody could do that!" That seem to be the consensus, But what has Boris Said, Scott Sharp, Ron Fellows, etc...., said about oval track racing. They all agree that the speeds are allot faster than they realized, the cars are heavier, the tires are smaller and traction much more difficult to achieve and maintain!
Just thought I'd add my flame!
In my experience, every form of racing is just as difficult to be successful at. Each form of racing has it's own unique problems to deal with, Oval track(dirt or asphalt/open wheel or stock body), Drag(Heads-up or Bracket), Auto-X, Road Racing(Open wheel or full bodied) or Rally! Each one is just as fun and just as hard!
ok, now that we've done enough thread-jacking, lets get back on the tire footprint topic because that is actually interesting.
I have heard the same thing about a wider tire not affecting traction, but if that is so, then why does it always seem that it helps. Just like the lower pressure gives you a bigger footprint which seems to give better launches. There seems to be some relationship between footprint and traction that we are missing.
wider tires help traction because if you really think about it the actual contact your tire has with the road is only a couple square inches. any increase in that will have a drastic effect
going form a 205 to a 225 nets an aproximate increase of 10% more contact between you and the road.
Also it depends on your term for traction. traction is a limited asset. You have to distrubute it an "budget it" You've gotta distribute it between how much you want to use for acceleration, turning, and braking, over budget your traction and you'll lose it. Anything you can do to maximize traction will set the limits of the car further out.
A bigger footprint gives you better launches because there is more traction to use for accelaration, allowing for a harder launch.
-Chris
Sorry Notec, I didn't mean to get this as far as it went but it really pisses me off when people who participate in other forms of racing tell me that I don't race at a "track" as if calling a "drag strip" a "track" is somehow insulting to them. I put a lot of work into racing, and I consider myself pretty damn good at what I do considering how long I've been doing it (still not quite a year yet and I won the first bracket I ever entered against the fastest class of the day, and have gotten MUCHO respect at atco for regularly stomping mustangs and other supposedly faster cars). Beyond the fact that autocrossers race in a damn parking lot, and one of them is trying to tell me that I don't race at a "track".
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
Zach wrote:Hey, I didn't ruin your post There's your answer:
Zach wrote:Your tires actually start to cup in the middle once the pressure becomes too low, resulting in a smaller footprint. You also get too much rolling resistance at too low of a pressure.
Haha, sorry. My original intention was to reply to this, and then I accidently read the rest of the posts
That would make sense, as you'd now be heating up a part of the tire that is no longer in contact with the track. And yeah 'rolling resistance' was the term I was looking for earlier...but where exactly is the resistance? Does it come from having to flew the tire that extra bit? How would you find the point of peak gain (besides through trial and error)?
IamRascal wrote:From websters as well:
drag strip: the site of a drag race; specifically : a strip of pavement with a racing area at least 1/4 mile long
I feel sorry for all those 1/8 mi 'posers'...apparently they're not even racing
Websters is obviously very confused...
IamRascal wrote:wider tires help traction because if you really think about it the actual contact your tire has with the road is only a couple square inches. any increase in that will have a drastic effect
going form a 205 to a 225 nets an aproximate increase of 10% more contact between you and the road.
A bigger footprint gives you better launches because there is more traction to use for accelaration, allowing for a harder launch.
As I said in the beginning, a wider footprint would only distribute the load over a wider area (less force per area now), so it would not increase the frictional force by itself.
What I've heard about wider tires is that you can run them at lower pressures, and that's where the gain is.
However, I've thought about this one to many times, so a quick google search brought up this:
http://www.physlink.com/Education/AskExperts/ae200.cfm
explains it all, no more confusion, tell all your friends
fortune cookie say:
better a delay than a disaster.
Read me
Basically, the maximum static frictional force between a tire and any given road surface is roughly equal to the product of the coefficient of friction between the rubber and the surface, and the weight acting on the tire. That is simply the scientific equation for static friction..
Fs = Us * Fn
OR
Static friction = Coefficient of friction * Normal force (weight)
Notice that it has nothing to do with the area of the rubber/pavement.
Making tires wider has more to do with heat distribution and cooling than any semblance of "increased traction", except the traction that comes from keeping the tires at a more proper temperature.
I have to respond to this in regards to the racetrack. In my area people say racetrack and they mean the drag strip. Who really cares if someone post a RaceTrack and it is drag strip, or circle track. Why does it matter. If you read it and it is not what you want go out of the post. Dang. I get tired of this crap between autoX's and drag racers.
FU Tuning
John Higgins wrote:I have to respond to this in regards to the racetrack. In my area people say racetrack and they mean the drag strip. Who really cares if someone post a RaceTrack and it is drag strip, or circle track. Why does it matter. If you read it and it is not what you want go out of the post. Dang. I get tired of this crap between autoX's and drag racers.
The autocrossers are just PISSED that nascar owns most of speed channel and has done away with most of the real racing in favor of bullcrap shows that follow the drivers around. Somebody has to feel our anger.
