blog.futon.org

There are two major differences between the bi-fold and tri-fold frame types. The first difference is the number of times the futon mattress must fold when converting from the sitting to sleeping position. The tri-fold requires the futon mattress to be folded twice while the bi-fold requires that the mattress fold only once. The second major difference between the two frame designs is that the tri-fold utilizes the shorter “width” of the mattress for seating while the bi-fold utilizes the longer “length”. This gives the inherent advantage to the bi-fold because it looks much more like a conventional sofa-bed than does the tri-fold. It also provides a larger seating area for the consumer.