Originally Posted by
Andrew R Stewart
1- I'm not sure i'd want such an extention of the ST above the TT. There is a reason that seat posts have a min insertion mark. It's to make sure the post extends below the junction of the TT and ST. Have your friend do a test build first with the extended ST and test to destruction, then decide if it's going to hold up for you. This is one of the answers to #3. The pro has done this trial and rejects or is good with designs before you ride the finished product.
2- Sloping TTs are common these days. Some lug sets exist for this design. Lugs can be tweaked a little bit for further angle changing. Have your friend help you here. he is the one building the bike and has the motivation to choose parts that both work as a final product as well work for his skill set. Another reason to trust the pro more, he has the experience in knowing which parts work for the design.
3- In theory if the design is the same, the torch control and brazing the same, the mitering the same, the paint the same (go on here with other building aspects) then the finished product is the same. but the finished bike is more the this to some customers. The name on the frame means a lot to some. The ability to fall back on a warranty has a value. Whether there's insurance (or not) could come into play if something goes wrong and some one gets hurt (and this might not be the rider or decided by the rider).
Last point i'll make is that I would be very hesitant to build a bike that the customer was providing the parts for and trying to control the design strongly. As the builder I have a stake in the finished bike meeting many needs, the customer might not be taking all of them into consideration. As a builder my reputation might be worth more then the profit. (Oh yes, you mentioned that there would be no profit). I have been is your friends position and ended up giving back my customer/friend's deposit to keep the friendship. Andy.
Andrew; +2 on it. I am of the opinion that the minimum insertion line on seat posts is just a "boiled down to idiot proof" level way for the manufacturers to suggest how the rank amateur can use their product without completely "&*%ing" it up. Probably also is an attempt to do a littel CYA for liability purposes. Eitherway, the extended seat tube shown breaks most assumptions... If I was asked to build that bike frame, I would swap out the normal seat tube for a fairly heavy straight gauge tube of the right diameter. Might even add an additional next size smaller tube inside it as a sleeve going down about 12 inches past the top tube intersection and just sweat it with silver after the main tubes are done... Worse case I might have to find or make him a seat-post to fit, but at least he wouldn't wreck the family jewels on a broken stub of CroMo...