I have some fold up dip bars and figured Id share some info on them since its pretty hard to find. The only review Ive seen was on Amazon and it was all positive but the length of the bars and I agree. When performing dips on them, your face is VERY, VERY close to the wall and it is kinda distracting and throws your movement off a bit. Other than that they are great. Very well made and heavy duty.
What I did to fix that problem was fasten them to 4x4s and bolt the 4x4s to the wall. Not only does it give you more room for your face but it makes them far more sturdy. For the money, its hard to beat these dip bars due to the quality and space it takes up.