The Bolsheviks were able to win the civil war because the White Army, were made up of many independent groups and generals (there was poor communication between them), and the Bolsheviks had stronger armies, more advantages from the land and civilians, and the Bolsheviks had 3 amazing leaders to lead the way to victory. The Russian Civil War lasted from October 1917 to October 1922. At the very beginning, the Bolsheviks claimed the land of Petrograd, Moscow, and the area between the two cities. This was a great start for the Bolsheviks, knowing they captured the capital first. However, the Mensheviks, did not have a common leader throughout all of its armies, instead they had a variety of generals with varying amounts of experience. the Bolsheviks were able to easily win the civil war, because they had many advantages, versus the White Army, who was disorganized, disadvantaged, and had many enemies; rather than allies.
The White Army had many disadvantages for their side. For one, they had many different groups with different ideas on how Russia should be ruled. The White Army, or the Mensheviks, had many anti-bolshevik individuals within their wide spread groups. The colonies of the Mensheviks disagreed with each other's political goals and each group of the army had it's own independent general, with their own agenda and placement. Their militia was formed in 1918, during the uprising of the Czech Legion. The new army was too unprepared to fight. The Menshevik colonies were unorganized, by using soldiers that survived WW1 and new volunteers to supply the army. For Generals they used former tsarist generals, that had varying levels of expertise and skill. Generals of the White Army used the same kind of methods and forcage in war, just like the Red Army and Cheka used during this time period. This caused many locals to dislike the White Army, the same way they did to the Red Army.