I have a road bike I use for long training miles (and a few races, but they’re just for practise really), and have a tri bike, which I ride in a very forward position.
I am considering putting in my old fast-forward seatpost on my training bike to replicate what my tri bike will feel like more closely.
Is this a good or bad idea?
I use my tri bike for fast or tempo rides, but anything over 1.5-2 hours I use my road bike. Up til now, it’s been in the usual standard position. This year, I am racing a general season: sprint/oly races etc.
If you ride steep (like forward of 80 degrees) then switching back to a slack angle feels really unnatural. Moving the seat forward can alleviate some of this, but it leaves you scrunched up unless you move your bars forward the same amount. I did this and it worked pretty well but was never really comfortable. When I finally bought a new road bike, I had it built at 76 degrees and that seems to work pretty well, though it still feels a lot like a Lazy Boy after riding the tri bike. Which is kind of what I wanted. Switching back and forth regularly helps as well.
If you intend it to be a permanent switch then you can go with a longer stem to match the new forward seat position and perhaps even a new fork with a little more rake.
Some of it depends on the handling of your current bike, though. If it is already quick handling, then moving the seat forward will accentuate that quality, perhaps more than you like.
Chad