A Trek TT bike comes with about a 73 degree seat post angle. What should someone do to convert it to about an 80 degree seat angle? I asume an angled seat post with the seat as forward as you can get it? Also are there any mods that should be done to the handlebar stem? Anything else to take into consideration…??
If you already have one of these and you’re set on riding it steep, then yes, a forward seatpost and probably a new stem to get the correct reach are in order.
This question always makes me laugh, though. Not to pick on you but I liken this question to “what do I need to do to be able to drive my car from the passenger’s seat?”. The bike was designed to be ridden in a certain position. Fork rake, weight distribution, etc, were all calculated for a rider in the intended position on the bike. For the same reason that trying to get too forward on a road bike is a bad idea, I think that trying to ride any bike in a position significantly different than it’s designers intended is a bad idea. If you really want to ride steep I’d sell the Trek TT and get something designed to be ridden at 80 degrees. Just my $0.02.
The bike was designed to be ridden in a certain position. Fork rake, weight distribution, etc, were all calculated for a rider in the intended position on the bike.
Yeah, but. . .Why is it that the Cervelos can be ridden either slack or steep, but no other bike can? Or is it that Cervelos are designed to be ridden steep, but can be converted to ride slack without detriment? Can other steep angle bikes do the same?
Trek TTs have a mast that runs right up to the seat. You can’t put a forward seatpost on, because of the length of the post from the bend to the clamp.
**Cervelo has tweaked the geometry of certain models to shift the window of acceptable seat tube angles forward by a degree or three. **
What’s the typical window of acceptable seat tube angles? If I get a 78 degree Quintana Roo, how steep and how slack can I make the effective seat tube angle before handling is adversely affected? How about for a 73 degree road bike?
I’ll preface this by saying that I have no science to back up any of what I’m saying- this is just my opinion. I believe, though, that shifting weight further rearward than was intended is less detrimental than shifting weight further forward than was intended so, yes, I believe that most bikes that are designed to be ridden steep could be ridden slack (assuming the top tube isn’t too long) with fewer drawbacks than trying to ride a slack-angled bike steeply. I’m sure there are ways to do the latter (fork with more rake, etc), but I’m not a bike designer so I don’t generally feel comfortable messing with a bike’s geometry. That’s why Gerard get’s paid the big bucks. Note that there are also drawbacks to riding stems at the outer limits (<90mm or >140m). For this reason I believe that while some Cervelo’s may be designed to be ridden steep or slack, I’m guessing that most of time the same rider can’t ride the same frame size both steep and slack (while maintaining optimal handling). In other words, if I’m riding a 55cm P3 steep, I would need a 52cm P3 if I wanted to ride slack.
I believe, though, that shifting weight further rearward than was intended is less detrimental than shifting weight further forward than was intended so, yes, I believe that most bikes that are designed to be ridden steep could be ridden slack
That seems to make sense to me. How come I never hear about anyone converting their tri bike to a slack position for a century ride, or whatever? How come noone ever recommends buying a tri bike as the only bike, and converting it to a road bike when one is desired? (Since so many people buy a road bike as their only bike, and then try to convert it to a steep angled tri bike.)
The bike was designed to be ridden in a certain position. Fork rake, weight distribution, etc, were all calculated for a rider in the intended position on the bike.
Yeah, but. . .Why is it that the Cervelos can be ridden either slack or steep, but no other bike can?
Other bikes certainly can, but Cervelo has tweaked the geometry of certain models to shift the window of acceptable seat tube angles forward by a degree or three.
Are you saying that some bikes do not have a 1-3 degree window to steepen the seat tube angle?
I work with an athlete who rides the trek TT. He has a seatpost with some setback reversed to get more forward on the bike. As long as you understand that doing so places more weight on the front end of the bike and thus makes the handling more twitchy than a bike designed to be ridden that way then it’s fine. It’s not too hard to adjust your riding to accommodate the different hadling characteristics.
There is a photo of his position on the bike here:
http://www.competitionzone.com/athletes/evans.htm
There is also another pic here:
http://www.competitionzone.com/athletes/tevans2.jpg
Joel
Guys, this “athlete” that czone is working with is non other than Tom Evans, second at IMC 2003, first off the bike at Wildflower 2004, First of the bike and second overall to Miles Stewart at Muskoka 2004. Tom’s the real deal. I think he’d be fast in that position regardless of whether is he is forward on a road bike (current set up) or seated on a tribike with the seat centred on the rails.
Myself, I’m on a Kestrel 200SC, with a straight up post with the saddle in the middle of the rails. Puts me at ~77 degrees with the saddle centre 70 cm from the middle of the BB. I am going to set up my Kestrel as a road bike in Aug and get a 52 cm 76 degree Guru Trilite set up at 77 degrees.
Grewalesque???
On the Trek TTT, the seat post diameter is a 25. There are two post available which can move the rider forward in that size (that I know of). The Selcof Bi-Position and the Corima Orbit. The Selcof, you must cut to fit but the Corima comes in three sizes and is carbon. With those posts and a seat with long rails, a more forward postion may be achieved. A Thompson seat post in size 25 without setback also can move the seat more forward, again dependent on the saddle rails. The differences in the stem would be a personal preference. The 2003-04 model does have bit of seat post adjustment (up and down) but the older models did not.