could be this is a dumb newbie question, but here goes…
So cervelo has the flippable seatpost that lets the virtual seat tube angle vary from 74 to 79 degrees. This seems mainly like a good idea from a manufacturing point of view–you can offer both a steep and a less agressive geometry on the same frame. I always assumed you’d have to decide how you wanted to ride, then get the frame that fit based on the position you wanted to ride in.
But on their website, they imply that you could get the bike that fits and then go back and forth to figure out what suits you:
“But the bottom line is that one has to try both options to find out what works best. This is why both the P2K and the P3 come with a custom aero seatpost that can be adjusted to suit seat positions of 74-79 degrees with a simple flip of the head. Now riders have the flexibility to experiment with their position without risking that their bike will not be able to accommodate them.”
No offense to Gerard and the boys at Cervelo, but how can this be true? It seems to me that if I went to visit a good fitter and told him (or her) I wanted to ride at 79 degrees on a P2K, he could set me up just fine. Or if I told him 74 degrees, he could do that too. But how could we do both on the same bike? Doesn’t it seem likely that I’d need to go up or down a frame size to get the right top tube length, if I switched between 74 & 79 degrees? Not to mention raising and lowering the front end, and lengthening/shortening the stem? I’m just wondering because it seems like the decision about riding steep or not has to be made before buying the bike, and can’t really be postponed to a post-purchase trial period. And certainly can’t just be as simple as flipping the seat post, right? But I don’t know. I’m still one of the knuckleheads (sorry, slowman, but you ride what you got) trying to run a tri front end on a 73-degree road bike.
I’m set up at about 79 degrees on my P2K. When I flip the post to 74 degrees it feels way off because I’ve lenghtened the effective top tube. In order to make it work properly I should get a shorter stem and put a couple of spacers under the stem to elevate the front end to compensate.
My point is that a proper sized Cervelo frame can likely fit most riders in both positions, but you have to do more to achieve this than just flip the seat post around.
Your questions are basically Orang Utan’s asked nicely! Seeing you are a newbie here you missed the entire Orang Utan - Virtual TT argument.
I have a p2k which I have raced steep for IM and slack for TT (UCI rules etc.) Works fine both ways, slight modfication to the front end drop was all (plus change in seat post position) was really all it took.
I think you’re generally correct. If you are properly set up at 79 degrees you will need to raise the front end and shorten it to ride the same position at 74 degrees. Whether you can do this on the same bike depends… for example, if your 79 degree position uses a 130mm or 140mm stem with few spacers, you have quite a bit of room to go shorter and higher when going to 74 degrees. If, however, your 79 degree fit uses a 90mm stem and/or 4-5cm of spacers, you’re 74 degree position cannot be achieved on the same size frame. At least that’s how I see it.
If you look at the soloist, you can configure it steep or slack, but it is optimal as slack. In the slack position it is very solid handling bike. In the steep position it handles quite well for a road bike, due to the fact that the rear stay is only 39.9mm. If you ride it steep, you will likely need a longer stem and less spacers. If you ride it slack, shorter stem, more spacers.
The P2K is designed around a steeper angle. If you position it steep, it handles like a charm. You don’t need a super long stem and you’ll likely use minimal spacers. If you position it slack in the roadie position or ITU slam position, you’ll need an ultrashort stem and some spacers.
All of this assumes you have the correct size to start off.
thanks all, this is making sense. The trick seems to be to make sure that:
if I start out slack, make sure it fits with a shortish stem, and if I start out steep, make sure it fits ok with a longish stem. Otherwise I’ll have too much or not enough top tube to get to the other position.
if I start steep, also make sure and leave plenty of steerer tube so I can get higher if I slacken.
or, I suppose, go back to plan A and make up my mind before I buy. But it’s nice to hear you guys seem to make it work alright.
Hmmm… good question. I would expect that something else would have to change (frame size or stem length) when going from 74 to 79. I thing the “Flipping thing” makes more sense on the Soloist where you can go from 73deg road position w/o aerobars to 76 w aerobars by flipping the post and likely not changing anything else.