Ultimate distance; Weight.

So, people will swear that, in theory, light discs should go farther than a heavy disc that is thrown the exact same way.

But, is that necessarily true?

The way I learned about velocity and that stuff, was that velocity = force x weight, or something along those lines. So therefor, heavier discs should fly further than a light disc.

[MIDiscGolfer]

Velocity = distance/time Force = mass * acceleration
The second equation is what you're looking for so in general given the same amount of force the lighter object will undergo greater acceleration reach greater speed and go farther. This is assuming everything else equal, drag, angle, ...
The problem is your arm can only move so fast. This is why you can throw a baseball farther than you can throw a pebble. Given the same amount of acceleration a heavier object will be less suseptable to outside forces like wind and drag. So the definative answer to your questin is it's different for everyone. You need to find what weight works best for you. Most people I've seen throw discs that are too heavy so I would experiment with lighter discs and see if it helps. I have found that I really lke the 165-170 range.

[Bill Burns]

It also depends on the moment of inertia of the disc. The greater the percentage of the disc's weight is in the rim, the greater moment of inertia it will have, and if two similar discs were spun with the same RPM and thrown with the same velocity, the one with more weight % in the rim would spin longer, and would therefore, go farther, I believe.

I keep the option to be wrong, though.

[Hootie]

I think lighter discs of the same model and plastic go further than heavier ones for my throws. It seems a lot of people buy super-heavy discs straight up, but I think starting lighter (160-165g if you can) is better (and an extra benefit is the lighter discs have less fade in my experience). The only downside is that the lighter the disc, the more wind-affected it will be.

[Noah Brooks]

I love throwing heavier discs... but my furthest driver is a 169 Star Destroyer. I bombed that baby ~470 today. When I throw my heavier destroyer in the same exact way and same condition it just doesnt have as much glide.

[Matt]

I've experimented with light (150g) discs. For me they looked like they were going to go really far, but then would just drop out of the sky like they hit a wall. It was because they lost their spin. Heavier discs will spin longer which will help them go farther.

The one thing the hasn't been mentioned yet is lift. The lift generated as the disc moves through the air will have a greater effect on the lighter disc, helping to keep it aloft longer.

So the answer is that you have to find what works best for you. I tend to carry max weight stuff for my shorter discs because I feel like I am getting better consistency and accuracy. But for distance and tailwinds I go lighter like mid to upper 160s because I seem to get better glide that way. Much lighter and I lose distance due to the lower inertia.

[nitegolfer]

I think it used to be, "throw max weight for max distance", but with some of the newer molds this saying may need some rethinking. For me I get better distance outta a 180g Roc compared to a 175g Roc. But, I get better distance outta a 170g Star Destroyer compared to my 175g Destroyer. It is probably that I do not have the power required to snap a 175g Destroyer to get max distance. But if I go down too low in weight, say a 150 class, then the power that I am putting on the disc makes it act too understable. I don't have a definitive answer but like others are saying, it depends on your own capability to throw a disc along with what you like to find the happy median.

A lighter disc may get you a faster release (arm speed) but may lose that increase fighting through the air with less momentum. For me the name of the game is to get the disc to perform a high speed turn where the disc "turns up" some, but not completely over, in order to get good distance. And, with a lighter disc this high speed turn can be easier to accomplish which results in more D compared to a heavier more overstable disc in which I lack the power to throw the same way.

Always heard to throw heavier when throwing downhill due to 'Momentum" which is mass x velocity. And, I tend to throw lighter when throwing uphill.

[Donny Olow]

Well ....................as I get older , I don't throw much Max weight discs. My Drivers went from 175 to 171 . Midrange went from 180 to 176.

[Ryne]

I'd agree with nitegolfer, the key to big D is getting a big turn and s-curve out of the flight. Personally, I love smashing 150's, but I also live at 7,000 ft elevation and the thin air makes everything more stable - that's probably the only reason i can crank on a 150 and not have it dive into the ground.

[CBass]

There may not be any cut and dried method of determining what disc should go farther for you. You'll know what works for you by trying different weights of the same disc. I've found that heavier and also more stable discs are better for windy days.