Poliwrath on raids?

Stop wasting your time on this game, you will appreciate my advice when you leave it behind and talking to hot girls.

Don't bother unless you don't have enough Machamps. It could be worthwhile to have one in that case. Multiple if you have often troubles getting enough players for a raid and you actually need to make a difference.

Your two best pokemon against Tyranitar are going to be Machamp and Poliwrath with Rock Smash/Dynamic Punch or Hydro Pump. So unless you have 6 powered up Machamps, Poliwrath with the right moveset is worth powering up.

Poliwrath's only real niche is against Tyranitar as it resists all of it's moves, against fire types you're much better off using Vaporeon.

They're good Machamp substitutes but aren't as good as the real deal. Even if Tyranitar does have Iron Tail and Fire Blast, which is the best moveset against Machamp it shouldn't be too difficult if you bring enough Machamps.

Even if you don't have many Machamps, you can bring Vaporeon instead and save yourself some dust, I'm assuming most players these days have at least one good Vaporeon.