|
|
|
![]() |
|
|||||||
|
||||||||
![]() |
|
|
Thread Tools | Rate Thread | Display Modes |
|
|
|
#1
|
||||
|
||||
|
Ball's Circumference
Hi everyone,
Does anybody know what is the exact circumference of the soccer balls used in the competition (HS300, DTI Sports)? |
|
#2
|
||||
|
||||
|
Re: Ball's Circumference
The regulation in the rules says the balls must have a circumference between 27 and 28 inches, when properly inflated... This makes the diameter a fraction below 9 inches. Hope this is the information you're looking for!
|
|
#3
|
||||
|
||||
|
Re: Ball's Circumference
We found during the build season that the balls can vary depending on air pressure and how they have been used and abused.
At the competitions (Chesapeake and Buckeye) it did not seem that the balls were inflated to 9psi because they were not nearly as hard as the ones we used at the shop. It never made sense to me why a ball rated for 6-8 psi was inflated to 9psi...safety issue? But to answer your question better - we saw 27.2" - 27.9" range |
|
#4
|
||||
|
||||
|
Re: Ball's Circumference
Quote:
It's funny, but after evaluating the speeds of the balls coming down the ramps from video of the tournament, that was the fastest ball ever at our tournament. Naturally it was just a hair too fast and missed our net. Our lesson learned, and the reason we have an additional bolt on net for Atlanta to remedy it, is that you can't count on repeatability. If there's even the slightest chance that something will malfunction or not perform correctly, it will undoubtably do it at the worst possible time. Murphy's Law, like the laws of physics, still remains undefiable. We're prepared for even the statistical outliers now and I suggest you be as well. |
|
#5
|
|||||
|
|||||
|
Re: Ball's Circumference
Has anyone measured any of the balls at competition to see what the actual variance is? They didn't seem to vary too much to me, but then again I can't really eyeball differences in circumference that well.
For design purposes though, I averaged out the Soccer balls to have a 8.75" diameter, which is about a 27.5" Circumference. This worked well for me, as competition soccer balls should vary less than 3/16" +/- from this 8.75" Dimension. |
|
#6
|
||||
|
||||
|
Re: Ball's Circumference
Quote:
I think part of the pressure issues comes from rough robot play. However, most of it is probably coming from the seams stretching and an over inflated ball. |
|
#7
|
||||
|
||||
|
Re: Ball's Circumference
I worked Field Crew at Dallas, we inflated the balls to a specific pressure and tested the other ones to be approximately the same (doing a bounce and "thumb push" test). There was no "standard" given pressure that was told to us, we used the indicated pressure on the ball and a gauge. But mostly we were looking for was consistency in the balls.
Balls were inflated so that when dropped from shoulder level, would bounce back to approximately waist level. We tried keeping ball pressures the same as the day went on, would check between matches. Your results may vary, it's up to the your field crew to keep balls consistently and properly inflated. Edit: Sorry if I'm not to informative, I'm about to leave for class. I'll elaborate later. Last edited by James Tonthat : 08-04-2010 at 10:16. |
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|