SFO - PEK - BOM with 1 hour 45 minute transfer time at Beijing Capital Airport

Hello,
I am arriving on Air China from San Francisco (SFO) to PEK terminal 3 at 17:55. My connecting flight in from PEK to Mumbai (BOM) at 19:40. Is 1 hour 45 minutes sufficient transfer time? Is there a lot of walking involved or should I request the motorized cart to assist with moving from one gate to another? If I miss my connecting flight, will I be able to get a later flight at no additional charge? I am an Indian citizen and do not have a visa for China