This doesn't really surprise me. The seatpost attempts to put a tri bike seat angle on a road bike. So it moves all you weight more forward than normal and places a higher percentage of your weight on the front wheel. This makes your steering more 'twitchy' and less controllable. Tri bikes handle this by 'slowing down' the steering to counter for this higher percentage of weight on the front wheel.

i.e. if your bike is a race bike w/ quick steering this seatpost in the forward position will make the steering crazy quick. If you have more of a touring road bike with calmer manners it will still quicken the steering but maybe not to scary levels.

 
How long is your stem?

You can reduce a lot of twitchiness with a longer stem, yes it may move more weight further out, but it will slow down the steering response as well.

Have you adjusted the front after installing the new seat post?

That thread title is kinda misleading--what you're saying is that the fit you've dialed in and the the geometry of your particular bike, using the Redshift seatpost, is scary twitchy. The Redshift seatpost is a design compromise that meaningfully moves the saddle forward and up as though the seat tube were steeper, but not as drastically as a tri bike for the precise reason of reducing the issues you're having. Personally, on an SL2 Specialized Roubaix, it accomplishes that design objective exceptionally well. But I can certainly imagine that on a different bike geometry it might not work out so well.

I'm curious--you say you previously had a tri fit set up on your road bike with aero bars (and it sounds like regular aero bars, not shortie ones). If that fit was remotely functional with a regular seatpost, then I'm not surprised the forward position of the Redshift seatpost was dysfunctional. The point of the Redshift seatpost is to be able to set up functional road and tri positions, not to be able to set up a rear functional tri position and a forward tri position that's equally functional.

Oops yes I meant I have managed to make my bike scary twitchy...

The aerobars are regular ones (and to answer another point - the stem is 100mm).

> The point of the Redshift seatpost is to be able to set up functional road and tri positions, not to be able to set up a rear functional tri position and a forward tri position that's equally functional.

When I changed the seatpost, I set it at the rear position based on the fit numbers for road (75), kind of expecting that when I moved the saddle to areo position I would be good. ho-hum maybe back to the fitter....

My thoughts from a previous redshift thread:

I had the redshift setup on my Neuvation road bike.

Nice setup, except I found out my wheelbase is a bit short for me in the aero position.

I'm between sizes on bikes and when I bought my Neuvation I could've gone 54 (w/ long stem) or 56 (short stem). I opted for the 54.

Well, it's always been good to me, except in the aero position, the shorter wheelbase revealed itself through a twitchy ride.

I decided to return the sytem. . . but not before I crashed, HARD. It looked like the Hulk bent the aero bars straight back.

I contacted Redshift, they accepted the return for a full refund! :-o

The seatpost does work very well though.

I feel that if I had a longer wheelbase road bike, this would've worked well for me as my eyes looking down at the ground would not have been in front of the front axle.

Mike

It's interesting, I'm wondering whether the Redshift seatpost works so well for me because my Roubaix has a somewhat long reach for me, so that I have a very short stem. As a result, my weight is farther back relative to others in this thread.

The Roubaix is quite short in the front but more importantly it is very high.
You will find that your aero position is very modest indeed due to the front end height and consequently places less weight forward than the OP is experiencing.

You may also be a taller rider and if moving from 10cm behind the BB to 5cm it will not be the same as a short person going from 4cm behind the BB to somewhere in front of it.

So your results may vary the impression you get.

After being one of the early adopters of forward positions, I can tell you that 5cm in front of the BB on a road bike is unhealthily dangerous.

Yep, I'm impressively inflexible, so my aero position is not as aero as many.

I'm of average height. But the Redshift seatpost doesn't move the seat that far forward, it seems to me one would need to have an almost-vertical seat tube to end up in front of the BB.

EDIT: Thinking about this more, when you describe a seat position that's well in front of the bottom bracket, you're describing an effective seat tube that's actually more than vertical, i.e. angled forward? That sounds bizarre to me, even tri bikes don't have vertical, much less forward-leaning, seat tubes. Maybe you just meant that the very front of the saddle was in front of the BB?

I have a Redshift seatpost on my 2015 Argon 18 Gallium Pro. It works perfectly in both positions. I have an all Enve front end - stem, aero base bar and clips ons. I raced that bike in USAT Du Nats this summer just as a test with no issues. I have two tri bikes both with aggressive positions so my first I thought is maybe you have an acclimation problem. I spent a few rides practicing going in and out of aero with the Redshift seat forward, then staying in aero holding one aero bar while grabbing a drink or something. Then I was in full control. But if your front end is twitching even with you firmly holding the aerobars, then you must be out in front a little too far.

But my Argon was set up for road, then I put on the Redshift. You indicate your position was already set for tri before you got it. Maybe that is overly aggressive??