I’ve stumbled upon changing the seat post to get my road bike into a tribike position. Old articles from 2004 popped up about the M2 Racer power module and Thompson straight post and Corima Ellipse Carbon seat post. Are these still available or has any other posts emerged?
It sounds like 76* seems better than 78* and mine is 74* already. So I’m trying to get to 76*.
What should I do? It’s a loooot cheaper than getting a tri bike.
I understand the rear end will be lighter and squirrelier with the more forward position.
Any thoughts? Also should I be getting a shorter stem? I have 90mm on a Trek 1.2 54cm. I’m 5’9".
Here’s a real stupid question: why can’t you just turn the standard seat post around, it appears to be set back?
Is it too weak that way?
Thanks.
I put a Profile Design forward seatpost on an old road bike and loved it. I highly recommend trying it out. If it doesn’t work for you, then you keep it around to make any bike that’s too big a little smaller.
You can definitely use a Fast Forward or zero setback seatpost to steepen up your bike and help rotate you around the bottom bracket. The only real downside on a conventional road bike isn’t really lightening up the rear wheel, it’s the flip side of that coin, putting excessive weight on the front wheel and what that might do to handling. But realistically riding at 76 or even 78 degrees isn’t super steep and although handling might change a bit it probably will be manageable.
But don’t just make changes like seat angle or bar reach in isolation. It’s all part of a system which is well described here: http://www.slowtwitch.com/mainheadings/techctr/bikefit.html and with good illustrations here: http://bikedynamics.co.uk/FitGuideTT.htm
What stem length and what stem rise or how many if any spacers depends a lot on how far you rotate your position forward and up relative to what you’re riding now and how low you can comfortably and powerfully manage in terms of front end height and reach. So maybe you need a different stem, maybe what you have is good but could be flipped to a negative rise (i.e. dropped angle) position or perhaps you’ll swap some spacers out from below to above your stem. But if your fit is decent now, then moving your saddle forward and up (up enough to counter the effective lowering of the saddle that happens when you slide it forward) will allow a lower and more aero front end setup. If your current position is too low up front and leads to too tight a minimum hip angle at the top of the pedal stroke then perhaps all you’ll do is slide the saddle forward and raise it to open up the hip angle but it’s hard to say in a general sense what you’ll need to do as all of these things impact your final fit and we don’t even know how well or poorly you fit the bike right now.
But yes, a Fast Forward post is a pretty good idea if you’re trying to set up a road bike as a dedicated tri/TT bike. I don’t agree that 78 degrees is necessarily too steep and if you’re not limited by UCI road racing rules I’d suggest the forward post to get closer to 78 or even steeper unless you find your handling is too spooky when riding that steep on the converted road bike.
And some but not many seat posts can just be turned around into a forward instead of set back position. But many if not most seatpost clamp designs won’t let you get a good saddle tilt angle when they’re flipped around backwards. You can try it but don’t be surprised if your saddle tilt is way out of whack when you spin the post around.
Good luck,
-Dave
I used to use a Thomson (no ‘p’) setback post turned around “backwards” just like the Profile FFwd (although I don’t think the Thomson is bent quite as steep, but then I haven’t compared them side by side either). Might have to turn the top clamp piece back around though so it still meets the rails at close to the proper angle.
Dave,
I have the stem in negative set already and only 1 thick ring under the stem, so it is 1-2" below the seat now.
I’ll try and spin the seat stem around tonight. Thanks for the Fast Forward seat post recommendations.
I turned around the seat post. Leveled the seat. Did not change the height of the seat post or the forward or aft of the seat. Did 12 miles on the hilly route I usually go and had no right low back pain. The real test will be when I get out to 20-25mi and see if still feels good.
Question: should I have done anything to the seat post height or the for/aft of the seat?
Now my knees are hitting my areobars. Should I put another spacer under the stem to raise it up some? This will make me less aerodynamic.
If all you did is spin the seat around, set the same saddle fore/aft position, the same saddle tilt, and the same saddle height then you didn’t change your position at all and you’re riding the same position you were previously riding.
All a seat post, or long seat rails or steep seat tube angles do is position your saddle in space. The point of something like a Fast Forward seat post is to change the position of your saddle in space and to specifically move it forward so that the saddle tip is closer to (or in steep cases in front of ) the bottom bracket. If you do move your saddle forward in space you’ll also want to raise it as your seat height effectively drops as you slide the saddle forward whether you do that by sliding it on its rails, riding a bike with a steeper seat tube angle or use a forward angled seat post (or a reversed post that allows appropriate saddle tilt). And if you move a saddle forward and up then you’ve raised your hips relative to the ground which changes the drop to your elbow pads and your overall fit so this stuff is all intertwined but that’s mostly a good thing as moving the saddle forward and up but leaving the bars the same results in lower torso/back angles and generally a more aero position and can often allow even further drops of the front end.
But if you spun things around and set the same saddle setback you had before and the same saddle height you had before then you have not actually changed your position at all. If what you’re saying is the saddle rails seem to be in the same fore/aft position within the seat post clamp as they were before but now it’s in the forward position vs the normal setback position then you may have actually slid your seat forward but make any saddle set back measurements relative to the bottom bracket as that’s what matters. If you’ve moved forward relative to the bottom bracket then you’ll want to move your saddle up till the total length for the bottom bracket or pedal spindle at the bottom of the stroke is the same now as it was before which means the saddle is higher from the ground than it was before.
Good luck,
-Dave
-Dave
Dave,
Thanks for the input. I had taped the seat rails in front of the seat post clamp. The post clamp is definitely more forward . I put the seat back on with the tape in front of the clamp, so it is more forward without even sliding it yet.
I’ll rise the seat some.
Any thoughts on my knees hitting the aerobars? Maybe the seat raising will take care of it.
I just watched a Youtube video on aeroposition and I thought my elbows were supposed to be under my shoulders in a straight line, yet the video said the humerus is supposed to be inline with the forks! His elbows weren’t even close to the knees that way. I’m confused.
In terms of upper arms and reach, ideally your upper arms should be close to 90 degrees to your back/torso angle which for most folks is NOT dead vertical with respect to the ground. Only those with dead horizontal torso’s end up with upper arms close to vertical. If your torso angle is pretty high then you might want to tighten up that 90 degree upper arm angle a bit so you’re not stretched way forward but for skeletal support the goal should be keeping your upper arm relatively square to your back/torso which for most folks means a bit of forward slant from shoulders to elbows.
Thanks Dave. That maybe all I need. That would put the elbows forward just enough to clear the knees. I just slide the aerobars forward some.