Quote. I'm 6 feet and ride BMX and mountain bikes. You are not too tall for BMX, you are just not used to it. Eventually you'll feel comfortable. As already said, a bike with a 21 inch toptube and bars with 8 inches of rise would likely feel the most comfortable for you.My dad who's 6 foot 8 races BMX in the cruiser class (24 inch wheels) and he has no problems.ou are not too tall for BMX, you are just not used to it. Eventually you'll feel comfortable. As already said, a bike with a 21 inch toptube and bars with 8 inches of rise would likely feel the most comfortable for you. My dad who's 6 foot 8 races BMX in the cruiser class (24 inch wheels) and he has no problems.