Picture dump of the new version of my mini t-bar.
Found someone who made me these brackets out of aluminium on his CNC mill for an extremely small amount of money. Looks a bit bulky (it’s still a prototype-ish thing, I could slim down the design, but in this case that would have made it a fair amount more expensive). One half bolts to the seat, and the other half acts as the clamp.
I welded up a new “T-bar” from a 22.2mm seatpost. It’s ridiculously heavy, as the steel tubing has a large wall thickness, but I had a hard time finding 22.2mm tubing in reasonable quantities anywhere. On the plus side, this way my amateur welding should be more than plenty. I might try to find someone to weld me a version out of aluminium, or a higher grade steel to get the weight down.
I like this “asymetrical-T-Bar” design a lot, but I might also want to try a few different ones at some point, with the clamp I have a really good starting point for that.
It required a very slight notch in the seatbase up front (2mm or so). If anyone has access to a cnc mill and wants to recreate it for themselves, I can send you the CAD files. It should fit all current seatbases that use allen bolts to the seat.
I have a few little things I would ideally like to change though, like building in a slight downward angle for the tube, a cutout on the bottom so it would fit on saddles like the stadium better. (The bolt pattern should fit, but if would sit “up” on the raised section. Which is probably functional, but not very neat.) Instead of a downward angle on the bracket, it may be easier to bend the tubing of the T-Bar by a few degrees.
I also suspect that while it is a tight squeeze, the 4 bolts for the “clamp” could be in front of the 4 bolts that go into the seat, which would be a bit neater. I was initially worried that for brakes with longer levers than my XT that might be an issue, but:
a) Looks like that isn’t an issue, at least with my T-bar design and handles (the clamp could be used for different ones too).
b) I pretty much threw the possibility to fit the brake “clamp” under the seat away by having the tube so close to the base anyway…