Can Mumen rider resist a S Class hero punch? So Tank Top Master was about to hit Garou, Mumen Rider got in the middle and he received the punch for him, and he wasnt knocked out. I thought Mumen Rider was a weakling who didnt want to be promoted to B Class because he wasnt good enough (besides being his most powerful move throwing his bicycle to someone says a lot about how powerful he is) , but then, how could he resist a punch from Tank Top Master?
For me, the answer is yes.

He represents this hero of society that we often see in the Shonen. The kind of person born without particular talent, but to whom we are all related. It represents the normal human being, without power, but with determination. A kind of Saitama missed.

But he's got a strong resistance linked to his determination. We can see this in Episode 9 of Season 1 : He conceded Deep Sea King's blow and he remained conscious (he was still breathingafter that. Saitama caught him, but if Saitama was not here, after some break time, he would have stood up to fight Deep Sea King again. 
And Deep Sea King is seen as a S-Class Hero.




Another point is that it is indeed weird that Mumen Rider remained conscious after a whiplash from Tank Top Master. Even Garoh took more damages than him after such a punch. For me, the reason is that Tank Top Master had to hold back at the last minute, hearing the cry of Mumen Rider. ("Chotto Mattaaaaaaaaaaaaa")