My seat tip is 4cm in front of BB. This surprised me. I am curious where others have their seat tip in relation to BB.
on my P2C my saddle tip is 2 cm behind the BB.
3cm in front, back from a high of 7.
Dave Luscan
www.endorphinfitness.com
My seat tip is 4cm in front of BB. This surprised me. I am curious where others have their seat tip in relation to BB.
man you are relentless with the weird questions.
this largely depends on how long of a nose your seat has.
and where you sit on your seat.
my adamo isn’t front of the bb
but if I were on a normal seat im sure the tip would be
9.5cm behind bb with a Specialized Toupe Gel
.
Don’t really think it is a weird question. I am trying to better understand different parameters in fit.
There seems to be a big difference in where people sit in relationship with BB. Why? What are the trade offs?
I can find information about saddle height, reach, hip angle, drop, etc. But very little in terms of position of the saddle.
I thought you do a fit by setting everything and then buy the proper size stem. But why is my seat 4cm in front of BB? Why not 2cm instead and then instead of a 100mm stem a 80mm stem?
Is it power? Is it saving my legs for running? Is it aerodynamics? Is it a combination? I plan on playing with this after my last race next week. Mostly play with power in relationship with saddle position. I figure once I find the ideal position then I will know what stem length to buy to support. But are there any guidelines? I can’t seem to find anything on the forum. BTW, I sit on the very tip of my saddle so I sit in front of the BB.
Things don’t seem to add up. On my P2C if I use the front hole on the seat post then it would be almost impossible to get the seat back such that the tip is 5cm behind the BB. The saddle rails don’t look to be long enough. Do pros instead use the back hole? Do they use a smaller frame? I seem to be missing something in this.
So that is why I am asking so many questions about saddle position and BB. I want to understand.
5 cm in front of BB on a P2. I ride a PD TriStryke.
this is explained in some of the articles in this very site.
as you go lower and lower with your front end, your hip angle becomes more acute.
you can, to a degree, combat this by moving the seat forward relative to the bb. As you lower the bars and move the saddle forward, you rotate your body around the bottom bracket, preserving (or close) your normal hip angle that you would use on a road bike.
so the goal is to get as aero and powerful as possible. how far forward you saddle needs to go depends on how low you want to get up front, and what hip angle makes the most power for you.
but asking “how many cm in front of the bb are you guys saddles?” isn’t a useful question. one guy might have his farther back but ride on the tip. another guy might have it way forward but ride on the back end of the saddle. its going to vary all over the place.
Don’t really think it is a weird question. I am trying to better understand different parameters in fit.
There seems to be a big difference in where people sit in relationship with BB. Why? What are the trade offs?
I can find information about saddle height, reach, hip angle, drop, etc. But very little in terms of position of the saddle.
I thought you do a fit by setting everything and then buy the proper size stem. But why is my seat 4cm in front of BB? Why not 2cm instead and then instead of a 100mm stem a 80mm stem?
Is it power? Is it saving my legs for running? Is it aerodynamics? Is it a combination? I plan on playing with this after my last race next week. Mostly play with power in relationship with saddle position. I figure once I find the ideal position then I will know what stem length to buy to support. But are there any guidelines? I can’t seem to find anything on the forum.
Things don’t seem to add up. On my P2C if I use the front hole on the seat post then it would be almost impossible to get the seat back such that the tip is 5cm behind the BB. The saddle rails don’t look to be long enough. Do pros instead use the back hole? Do they use a smaller frame? I seem to be missing something in this.
So that is why I am asking so many questions about saddle position and BB. I want to understand.
The question is also irrelevant without knowing saddle height/frame size. A 5’ person won’t have the same setback as a 6’4 person.
This is a function of a lot of things - frame size, seat height, your height, your leg/body proportions, seat tube angle, saddle length.
I plan on playing with this after my last race next week. Mostly play with power in relationship with saddle position. I figure once I find the ideal position then I will know what stem length to buy to support.
Things don’t seem to add up. On my P2C if I use the front hole on the seat post then it would be almost impossible to get the seat back such that the tip is 5cm behind the BB. The saddle rails don’t look to be long enough. Do pros instead use the back hole? Do they use a smaller frame? I seem to be missing something in this.
Keep in mind that your body will not automatically adapt to positional changes. It takes time/miles. Just because you change some variable (like saddle setback) and you initially lose power does not mean that, once your body adapts, it wouldn’t end up being a more powerful position. It’s going to take a lot of time/effort to do this type of power/position testing right.
If you’re talking about triathlon pros, you are definitely missing something. They do not have to have their saddle tip 5cm behind the BB.
Regarding the rest of your post… You should check out the FIST articles on this very site. They discuss many of the questions you have, and even more of the questions you don’t even know you have yet.
Steve
Anyone know if Slowman’s seat height/BB offset/STA table is still available on this site? I was looking for it the other day and couldn’t find it.
Thom
I have a P2C w/ a Spec Tri-Tip (fairly long nose), tip is about 1/2cm in front of dead center. For most of my time in the aero position, I’d kinda like to scooch it forward maybe another cm or 2 (and add another cm longer stem) so I could get a little lower in front while still on the sweet spot of the saddle. As it is, i’ll scrunch forward onto the tip when I’m really hauling or facing a stiff headwind but find that a bit uncomfy for very long. The trade-off is I like to slide back and sit up on long climbs (or when sitting up in traffic or whatever) and so when I had it further forward I ran out of room in back. It also made it too hard to stand without having the tip of the saddle constantly jabbing me in the ass. I do like the long saddle for varying position on the fly as the terrain/wind changes rather than being rooted in just one spot. Might be different if I lived where it was flatter.
I think this is an interesting question unto itself because of two things. First, the UCI rule that the tip of the saddle must be at least 5cm behind the BB gives the impression that that is somehow “better.” Second, most of us started on road bikes or have road bikes and those saddles are always well behind the BB (or they are usually much more set back than the saddle on the tri bike for the same athlete, or at least mine is). So the question is valid to understand the range measurements that people have. But JackMott is right, you can’t just take that number without knowing all the others. Luckily, Slowman has convinced many pros to listed their tri bike dimension right here on this site. I bookmarked the thread because I like to go back and see, for example, how Rappstar has his bike configured. Here’s the thread:
http://forum.slowtwitch.com/gforum.cgi?do=post_view_flat;post=2288442
I have read the articles from Dan Empfield. Actually read them multiple times. I decided to re-read and realize the seat tip to BB distance is a by product of the seat angle. He states “The goal is to get you as close to 80 degrees of seat angle as possible”
So instead of seat tip in relationship to BB I really need to look at my seat angle and see how it relates to the 80 degree guideline.
I really suspect I am beyond the 80 degrees. Considering I sit majority of the time just behind the tip and the tip is 4cm in front of BB. But when I get home I will look at my position more closely.
Hearing where others position the tip was helpful in that it got me thinking I should look at my position and see if I might be a little too forward.
Thanks for the suggestion to re-read the articles.
BT, I think you should read again… yes, he’s talking about seat angle as a means of measuring how to set up your bike, but the REAL important number is HIP ANGLE. Similar to seat angle, it measures from the BB but takes each rider into account. You and I could have the same bike, same seat, same seat angle but different hip angles as we ride on the saddle differently.
You should be trying to figure out what hip angle you like (BB-hip bone-collar bone) and then get that hip angle on your bike adjusting seat angle and stem rise/reach to get it. As Jackmott says, you can keep the same hip angle by either being set back but high in front or rotate forward around the BB and be forward but low in front. Your call.