PDGA disc specs.

[Alexplz]

I figured out a while back that disc speed ratings are correlated with rim width, especially when it comes to drivers.

I at first assumed when I saw the pattern of disc speed rating compared to rim width, that pretty reliably 2.0 cm rim width meant 10 speed, 2.1 cm meant 11 speed, and so on.

However there are a few discs that buck this expectation; in fact it seems like there are a ton of them. I understand that disc flight ratings are subjective, but I like to look for patterns in something objective that I can reference and get an idea as to how a disc will fly compared with something else I've thrown.

It seems like some of the measurements on the PDGA disc specs doc are off - I can't put my finger on it for sure, but for example the underworld is listed with a rim width of 1.9cm, same as the saint. But the underworld rim seems more narrow than that of the saint when compared side by side eyeballing the two.

How are these measurements taken? Is there a more reliable source online I could reference for rim width and depth to give me a better idea of how to compare and contrast while shopping?

 

[MarkDSM]

Inbounds is what you seek as a base guide. http://www.inboundsdiscgolf.com/content/?page_id=431
There is an app too

(infinitediscs.com uses the inbounds guide with their retail listings)

 

[slowplastic]

This is all from personal experience, no inside info, etc.

Some of them can be off a bit if you try measuring with calipers, and 1mm still isn't that tiny of a measurement...some discs are halfway between 2.0-2.1 so depending on who measures or that particular disc it can seem off. If they measure one that is 2.04 and call it 2.0...you measure yours 2.07ish so you call it 2.1 and it seems "way off". I'm just simplifying based on measuring a few of my discs though.

As far as speed vs. rim width, some companies do it differently. Some discs I find that are more shallow will get bumped up in speed because they are more aerodynamic. For example the Trespass is 2.1, but shallower than Wraith/Destroyer, so they call it a 12 speed to match the Destroyer rather than Wraith class. Some blunt rimmed OS fairways get bumped down in speed a touch I believe, for example the FD3 is listed as 2.0 and speed 9. Although I can't remember when handling that disc if it felt Firebird width or wider.

 

[DiscJunkie]

I am not an expert, but I think some variation can be explained by plastic shrinkage.
After a disc comes out of a mold, it shrinks a bit while cooling. This shrinkage varies by mold, plastic, ambient temp and humidity.
Not sure if it would be noticeable, but it has been known to affect stability and flight characteristics.

 

[teemkey]

I figured out a while back that disc speed ratings are correlated with rim width, especially when it comes to drivers.

I at first assumed when I saw the pattern of disc speed rating compared to rim width, that pretty reliably 2.0 cm rim width meant 10 speed, 2.1 cm meant 11 speed, and so on.

...

Just look at Innova's mold3 series. Change the top, and the speed (and glide) changes in flight numbers.

 

[scarpfish]

Flight numbers are for marketing a mold, not science. Some molds have had their numbers changed. Teebirds and Eagles were speed 8 at one time.

That being said, an OS mold might be 1-2 numbers higher than a straight or US mold with the same rim width.

 

[curmudgeonDwindle]

Here is a fairly comprehensive source on disc measurements. I've not searched it recently and am ignorant of its 'up-to-date-ness': http://www.discgolfsweden.se/english/discar/discar.aspx
The site is a bit clunky but the stats are there...

Measuring the finished product is fruitless, for reasons other posters have noted - a disc's standard dimensions are taken from the mold.

It is also true that 'flight numbers' are a marketing 'ploy' to get a thrower 'into the ball-park' when meeting a new mold. The proof is in the throwing - especially when considering some companies' inconsistency with runs of the same mold...in this way all throwers are guinea pigs.

for what it's worth...

 

[DiscAnarchy]

Flight numbers are only a rough guide -- and sometimes not even that.

Until you throw a mold yourself, you'll never know how it flies for you.

For example: the flight numbers for me throwing an EMac Truth are going to be different from Eric McCabe throwing an EMac Truth.