Transitioning from slack to steep

Triathlon Forum
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My current bike is a bp stealth copy with 73 degree seat tube angle and 56cm virtual TT. The reach on this bike, as best I can measure, is 400mm. I have a forward post (although not that forward) and my adamo race all the way forward. With this set up I am 5 cm behind the bottom bracket. From the bottom of the head tube to the bottom of my stem (which is 100mm by -6) it measures 165mm (actual HT is 120mm, yes lots of spacers), with 11cm of pad drop. I am about 6’1" tall.

With a lot of the bikes I’m looking at the reach is much longer than 400mm when the head tubes get to where I need them to be. Now, if I buy a bike with a reach of about 450mm and ride with the nose of the saddle even with the bottom bracket, have the same stack and stem length, I should have the same fit coordinates, correct?

My question is, if I do switch to a steeper angle, is there going to be an adjustment period going from 5cm behind the bottom bracket to even with bottom bracket? I understand I should be able to drop the front also. Is there a rule of thumb for however many cm you move the saddle forward you can drop the front x amount of mm. Am I completely off here? I just do time trials, so no running afterward. My position feels good but I haven’t ridden steep so nothing to compare to. I’m not opposed to riding steep. Right now the closet thing I’ve seen is the Slice in 60cm size.

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I go from slack on my road bike at 73 degrees to steep on my P2K at 80 degrees without any issues. Dan has a good article in the fit section for setting front end height, but basically drop it down a bit at a time until you feel uncomfortably compressed then back it off a couple of cm. You can then just experiment with some fine tuning over time, spacers are easy to change around.
Basically your hip angle should be very similar to when you were riding slack, you just rotated forward and down around the bottom bracket.
edit: The main issues people run into in riding steep are more weight being supported by the upper extremities, more pressure on the taint and more strain on the neck. For most these dont seem to be an issue, but for some they can be insummountable.
The Slice is a very nice bike, but it does have relatively more stack than say a P3 or DA. That may or may not be an issue for you depending on how low you want to take the front end.

Kevin