Jim Jeffries reputation proceeded him to this modern day. There are very few video documents on Jim Jeffries so we have to rely mostly on oral testimonies of those who have actually fought or seen him. I won't doubt the words of Jack Johnson, Sam Langford and even Jack Dempsey after them all of whom attested to Jeffries physical qualities and capabilities. Speed is relative but Louis was never known for that quality as he was known for his famous line, " You can run but you cannot hide" as he was almost upset by the quick stepping and fast punching Billy Conn..So Louis's perceived edge in speed and mobility should not be in the discussion here especially in the light of what Johnson said about Jeffries being quick and light on his feet for his size. Let's talk more about punching and taking power and stamina and fighting style offensively and defensively. Louis was largely unbeaten in his prime but he was also hounded by inconsistencies on account of poor preparations and even poor conditioning. He struggled against foes he was expected to bowl over easily like Tony Galento, who was no more than a glorified slob, Arturo Godoy and an already aging Buddy Baer.

On the other hand, Jeffries was considered as among the always well fit and conditioned heavyweight fighters of all time and among the physically gifted. He virtually retired undefeated as heavyweight champion his lone loss coming in a comeback after more than six years away from boxing where he had to shed about 80 pounds to get back to his fighting weight of 220 lbs.versus Jack Johnson. Of course, already aging and bereft of his prime time muscle mass, Jeffries did not stand a chance against a well conditioned Johnson.

Taklng all things equal prime for prime, I won't discount a Jeffries win over Louis by decision or even KO.

Jeffries had less than 25 pro fights. how he became champion is beyond me. he defeated an aging Corbett who he had great trouble with the first fight. he defeated fitzsimmons who was really a middleweight. he wasn't as great as everyone proclaimed him to be. Louis had five times the amount of fights he had. if you watch the Johnson vs Jeffries fight you will see an aged Jeffries lose terribly. his fighting style left much to be desired. a prime Jeffries would be cut to ribbons by a prime Louis where Louis fast combos would bash in Jeffries face cause Jeffries couldn't block and led with his head

Joe Louis will win by KO easily, I don't think James J Jeffries is the toughest heavyweight boxer ever nor the one with the most stamina as there were fighters such as Joe Frazier and Rocky Marciano who had much better stamina, Joe Louis was all around better and had devastating quick explosive combos which would send Jeffries to sleep early

jeffries was slow and could be outpointed over 15 rounds. if the first corbett fight was a 15 rounder, gentleman jim would have won it by a landslide.

while louis isn't a slick boxer like corbett, he'd still take jeffries to school.

Louis all day. Superior skills. Speed. Quickness. Power. Ring savvy. The guy had it all in a compact body no heavier than 210.

I don't see him beating Louis. I'd give Louis a 15 round decision or a knockout in the later rounds of the bout. And I hardly see him beating Dempsey! I'd give Dempsey a knockout in the 8th.

How good would "The Boilermaker" do against "The Brown Bomber"? Jack Johnson once said that a prime Jeffries would've beaten Joe Louis and Jack Dempsey in one night, without any troubles. Jeffries is the toughest heavyweight boxer ever and the one with most stamina and probably with the hardest chin(he could take Bob Fitzsimmons best shots with loaded gloves on and was still standing). Plus he's the fastest moving 220 lbs boxer I've ever seen. On the other hand Louis is the best puncher ever, has faster hands and is a better boxer overall. There are only a few Jeffries videos on YouTube, mostly Jeffries at training. 15 rounds, you decide.