Early Rus settlement of northern Russia was via Viking style boats exploring the river banks for encampment sometime around the 8th century. These people settled down to become farmers and it wasn't until the 16th century before the Russians crossed the Urals, again using boats to explore rivers like the Ob.
What if the Rus, or a branch of them kept moving and started settlements east of the Urals earlier on, perhaps going around it via the arctic coastline, so that by the time of the Mongol conquests the Ob and Yenisei are dotted with Russian towns? Assuming the Mongols are not butterflied away what impact would this have on Eurasian history?