how do you know, aside from getting a fit done is maybe a more slack angle is for you? is there any indication of riding style (less drop, moving back on the seat rather than forward, etc) that would sudgest this may be something to try?
thanks,
David
For me the deciding factor was comfort. I rode for five years steep on a QR Kilo and then Cervelo P2K. My neck and crotch always ached on long rides, even when set up in a perfect FIST position.
This year i swapped to a Kestrel Talon at about 76ish and have no discomfort issues. Surprisingly I’ve also been faster in this position, which maybe shouldn’t be such a surprise considering how being uncomfortable can sap your performance.
the reason i ask is my g/f and i have been trying to get her set up comfortably on a tri bike (we are about the same size), but she always ends up sliding back, and as she pushes harder she moves further back (whereas i move forward). the seat is already slightly further back for her. i thought it was just on my bike, but we tried about that is sligthly larger (she is about two inches taller, and same thing, started moving back), another rider that has done a decent about of fitting sudgested trying out a 73 degree seat angle on a dedicated TT bike, so i thought i was ask for some more opinions before we jumped into anything,
thanks!
One factor that may predispose a rider to aslacker seat tube angle is femur length. The longer the femur relative to the entire leg length, the slacker the seat tube angle.
Now, here’s the thing- it’s tought to predict how that may affect your running. In general a slacker seat tube angle will exert more asymmetrical fatigue on your legs, i.e., the larger muscle groups will be positioned for best leverage. The bike becomes somewhat of a leg-press machine. Now, this may make you faster on the bike, but there may be a cost on the run.
In general time trial bikes are set up slacker than triathlon bikes. Some of the reason for this is UCI rules, some is that a stage race time trialist doesn’t get off their bike and run.
When you talk about seat tube angles and actual seat tube angles it’s important to not be myopic about only including *bike *perfromance, but also remember that where you are relative to the bottom bracket may have a lot to say about your first few miles off the bike running…
In reference to this thread: http://forum.slowtwitch.com/gforum.cgi?post=1451080;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;;page=unread#unread and your question here, there isn’t a reference on comparing the two. It’s also hard to know if just sliding back means that she needs to ride slacker. It could also be that the bike you are trying to set her up on steep is too small for her. Or it could be that the saddle she is riding on has a nose that chafes; Dan saw this on one of the T-Mobile womens’ team riders - her saddle had a seam on the nose that was very uncomfortable during hard pedaling. A bike that is too small (too cramped in the cockpit) is a much more likely scenario than someone wanting to ride at 73deg.
thanks for the responce.
I also thought it might have been the saddle, but we have been through three diff saddles on two diff bikes, all three of which were very diff from the one before. same on all three. the two bikes (and the road bike with clip on’s ), were diff sizes, one is borderline too large, one looks good, but she is still moving back, and on the road bike she was decently set up but handling was very bad.
once we decide where she wants to go from here we will look into a fitting, just trying to work through some ideas right now.
thanks again
newbz - I agree with Rappstar in that the toptube/cockpit length is too short and that is why she is scooting back when gettin’ goin’. She might not want to ride 80 degrees, but 76 is probably good, not 73 (playing the odds here).
yep thats what we were talking about tonight, something in the 75 degree area like a cervelo with the seatpost back or something else in that realm .
I suggest you read Dans article on Cervelo P2sl. A Kuota K-Factor, or the like would be a much better fit than a Slack P2sl.
Could always get her a hot pink Planet X Stealth Carbon Pro - 76 degrees, light and priced perfect! They now have other colors …
You probably don’t want a cervelo with a setback post. The toptube will be very long, and that is usually a bad thing for women, who tend to have shorter torsos. I’d look at a European bike - perhaps the Orbea, which is meant to be ridden at about 74-75* and has a top-tube appropriate to that STA. Or the K-factor is another great option. You want a bike that is designed to be ridden at 74-75 if you are going to ride there, otherwise you’ll end up with way too much top-tube. The Soloist is another bike you’d want to look at.
What’s the price of the pink frame? Thanks, David
I think Dave (owner of Planet X) chimed in earlier on a different thread. But, the NA importer (Zedsport) out of CA should be able to help. Currently, framesets (without aerobars) are about $1,000.
Take a look at the Giant Trinity bikes. The carbon ones have a default angle of 75 degrees, but are adjustable roughly 3 degrees up or down. The Alliance bikes default at 78 and have the same adjustment parameters, roughly.
I have an Alliance and I can set it up quite slack or way over the BB. It’s a nice ride and it wasn’t too spendy.
sorry to bring this thread back up, but how do you determine what a long femur is. If i have a 87cm inside leg and a 48cm femur is that long, avergae or short? Have heard this term a lot but could not find an actual description of what ‘long’ is.