Fragmentation Grenades have a damage code of 18P (+5 AP). With the wireless bonus you can easily blow them up in the same Initative pass that you throw them. (Although you should carry them in an wireless shielded bag until you throw them, to avoid hacking.) So no running away or throwing back. If the next wall is less then 9 meters away, the damage code will be even higher (chunky salsa effect). God forbid what happens when two walls are less then 9 meters away. If the grenade lies directly between your feet, or under a vehicle, the damage code is gonna be 36P because the chunky salsa effect will reflect it from the ground. (The chunky salsa rules actually mention the ground as a surface to reflect the explosion)
furthermore, if two grenades are taped together the damage code is 24P.

Those numbers seem insane. So dodging might be a good idea. If dodging is possible for an 18 meter radius explosion.

"Targeted by an Area-Effect Attack" Says you get a –2 modifier when trying to defend against weapons like spells, grenades, rockets, or missiles with a blast or area effect.

So it should be actually possible to dodge grenade explosions. I wondered what the threshold would be.

Is it simply the number of hits that the attacker produced when he tried to beat the treshhold of 3, for placing the grenade where he wants? So for the attacker it is actually a succes test and an opposed test at the same time? Or is it the number of net hits from the attacker that exceed the treshhold of 3?
What if the attacker didn't score any hits at all, but the grenate lands 1 meter away from you because of a low scatter roll? (Or because of a high scatter roll, if you where not his target.) Is the threshold then 0? Is the threshold then 1, because 0 is a stupid threshold?
Is it not possible to dodge grenades at all? That would be pretty hard if the grenade lands between your feet and you have to roll against 36P.
But the other way around, dodging a grenade that is thrown into the tiny room you are in (without even leaving the room) would be too easy if the guy that threw it in had only 1 hit.

Grenades are explicitly mentioned as something you can Dodge, therefore you can Dodge grenades. I imagine you need to equal or exceed the number of hits the attacker achieved...which means if the grenade scattered you are almost certainly going to Dodge the blast. This seems odd.

Guess what, Grenades suck in real life too. Hope you have cover. As far as the wirelessly detonating them, that might be something your decker should have on his hot list to watch out for. preemptively detonating grenades is a good thing.

Guess what grenades don't have that high of a casualty rate in real life. There are a variety of basic tactics that make grenades very survivable. Aparently they don't exist in Shadowrun though as they are instant balls of inescapable death. Which is both unrealisitc and not really fun.

I'm not sure why the chunky salsa rule keeps coming back. I'm no physicist, and I get that the shockwave will bounce back and do more damage, but doesn't the surface it hits absorb the shock as well? Even a metal box will buckle, pop, and shred to release the blast instead of purely microwaving the inner contents with 170P or whatever insane amount of damage.

The whole idea that we have to hit a threshold, roll for scatter, calculate blast radii and chunky salsa effects was such a lazy copy & paste from previous editions. I'm kind of upset that this very devastating/confusing/cheap option for combat wasn't overhauled for 5th edition.

(I will probably use a Roll your Saving Throw for Half Damage-style D&D mechanic, honestly. Calculate the DV based on distance from target, roll your defense test. If you win, you resist against half the DV. Bonus armor if you "hit the deck" as an interrupt).

Frag grenades will blow through up to 20 cm of brick, more than that and the blast reflects.
(I did the math once, with SR4 grenades)
((I don't know of any real frag grenades which have put meter wide holes in 20cm of brick...))

Please elaborate on said tactics. Last i checked real life grenades don't explode wirelessly. and if you want to talk about inefficient, the US military takes more than 1000 rounds to kill one man.

Dropping prone at more than a couple meters away vastly increases your chances/ There is a reason they instruct people not to drop on top of a grenade in the military. It is because grenades are very survivable without it, making the cover the grenade tactic just a pointless death. and while they are not wireless, you can time grenades to go off pretty damn close to when they land, the travel time should give people time to react.

your right, I can 100% see dropping prone be helpful against a grenade on the ground. If it explodes mid air, I would see that as less useful. Looking at the stats for SR5 yeah... they are pretty strong. I'd have to see how the higher armor ratings would effect them now. Everything seems to be geared to you need more armor or you die faster. I forget what show it was, but they set off several grenades next to dummies and pig corpses. They found that directly next to a grenade that you would experience 100 Gs of force. That is instant death no mater what you do.

As far as game balance goes, You probably shouldn't have the runners facing off against them that often. Cops won't use them. Period. Corp security teams might have access to them but the typical collateral damage would deter their use. In fact I would see pencil necks normally restricting their access anyways. Other runners, and gangers might use them.