Originally Posted by
Nyah
By "pusher" do you mean pedal? The position of the front wheel can be accommodated by adding-to/subtracting-from, the toptube, on each side of the hinge in equal amounts. For instance, if 3" were subtracted from the toptube on each side of the hinge, the front wheel would still contact the chainstay in the same location, even though the TT is now 6" shorter. Perfectly do-able, you just have to subtract equal amounts.
Pusher is a simple derailleur employed on Brompton and located underneath the chainstay, that ends up pointing upwards upon folding. Basically the fold of Brompton and its locking are such that any increase in wheel diameter, including the maximal tire width, must add to the wheelbase. This is exactly what is encountered here as the wheelbase increases by about 5". Can you get around that? Yes, if you change details of the locking of the fold. However, then you throw in some potentially flaky elements that can come back to haunt you in the future. It depends what your priorities are, how much effort, time and money, the design and its execution will take. Everybody is free to design and make their own bike. I was commenting on the bike as it was made.