Current as of 11/20/18
^ proven partially true and untrue. it's a case of false advertising on WG's part and
bad poor wiki wording. SR only works on hull MOVEMENT ( W/S ) not HULL traverse (A/D),
There are three factors affecting overall dispersion. One due to moving traverse (affected by Smooth Ride), one due to hull traverse (Clutch), and one due to turret traverse (affected by Snap Shot),
ComputedDispersion = GunAccuracy * SQRT (1 + DispMovingTraverse^2 + DispHullTraverse^2 + DispTurretTraverse^2)
GunAccuracy = ReportedGunDispersion
DispMovingTraverse = DispersionMoving*HullSpeed (kmh)
DispHullTraverse = DispersionHull*HullTraverseSpeed (Deg/s independent of turret movement)
DispTurretTraverse = DispersionTurret*TurretTraverseSpeed (deg/s independent of hull movement)
Then Smooth Ride seems to be better than Snap Shot in many cases and the benefits of both are minor at best and misleading/useless at worst.
now with formatting for easy viewing!
disp = Gun accy*sqrt(1+forward moving^2 + hull turning^2 + turret turn^2)
^ ^ ^ ^
base value SR skill nada Snap skill <-- skills that help. BIA helps all.
and the files you can verify it in is:
it's unencrypted but you do need a tool reader to view it. Also the lang is python if its not obvious. Some people are reporting this as being encrypted. WG uses the Blowfish cipher, and its not too hard to break.
The Clutch skill can affect Hull turn dispersion by making it worse/faster for a shorter period of time. Nothing makes it better save equip/BIA. Clutch is still vital for tactical movement so it's validity isn't questioned but knowledge that it can make your dispersion worse while turning should be paid attention to.
.25 is pretty much the 'useful line'. I found that the actual line is a bit grey, but that it tends to stay between .25 and .27 on forward movement dispersion. Greater than .25 makes it useful, less than .25 or .27 is a case of diminishing usefulness and run something else. Exact dispersion on forward movement for your favorite tank can be found at tanks.gg in the stats or compare menus. Useful to have as a counter skill to clutch braking.
8_Hussars and my work on SR/Snap/Clutch:
.25 movement dispersion (which is fairly high) seems to be the 'useful' line for where SR is viable. save for sub tier 6 (and the scout/heavies of 6, not the meds generally) SR should be reserved for a 4th/5th skill. certain premium tanks (type 64, superP) benefit from having the skill but most won't see any kind of useful gain.
https://docs.google.com/spreadsheets/d/10VIumnYWrLsc2xpPFnZp-MaVdfBHg_xZOHb04ie1HU8/edit?usp=sharing Hull traverse google doc. interesting if you want the raw numbers and why people are all ORD > Clutch for non-casemates.
A note on dispersion: after turning for 1 second you have reached max dispersion and will carry that value until the turn rate is decreased or stopped.
It's interesting that Clutch can actually make turning dispersion worse.
moar talky and some maths. decent crew skill discussion if you are interested on FF and combat skills.