I have a question for you guys. Just had a Cannondale Ironman frame built up for my teen. The frame is the right size, but the reach is a bit long. Before I switch out the stem, how far forward can I safely go with the saddle? Thanks!
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Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
The short/easy answer is that "many" triathletes ride as steep as 80 degrees....which puts the front of the saddle inline with the bottom bracket. (drop a weighted line from the saddle and check)
The longer answer is that the frame might very well be the wrong size if the reach is too short for the rider's effective seat position. It's better for the bike to fit the rider than the rider to fit the bike.....
The longer answer is that the frame might very well be the wrong size if the reach is too short for the rider's effective seat position. It's better for the bike to fit the rider than the rider to fit the bike.....
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Since nobody else is biting, I'll give it an off-the-cuff-whirl. Assumptions: Normally proportioned rider, middle-sized frame, normal seat length, the reach really is too long.
If you drop a plumb line down from the nose of the saddle, you can get perhaps a bit further than this line being an inch in front of the bottom bracket center, as long as your rider doesn't start having handling problems from having too much weight forward. It's the handling issue that is important. BUT, if they are racing in USCF events, you must keep that plumb line 5 cm behind the center of the BB, unless there are problems related to structural issues that are addressed by their rules.
Whether or not this is a good position for the rider, well, that's another question...
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
If you drop a plumb line down from the nose of the saddle, you can get perhaps a bit further than this line being an inch in front of the bottom bracket center, as long as your rider doesn't start having handling problems from having too much weight forward. It's the handling issue that is important. BUT, if they are racing in USCF events, you must keep that plumb line 5 cm behind the center of the BB, unless there are problems related to structural issues that are addressed by their rules.
Whether or not this is a good position for the rider, well, that's another question...
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
Re: Fit ? Saddle, how far forward? [Titan]
[ In reply to ]
Ok, more info for you: normal proportions for a female, a little bit long in the leg (height 5' 3.75", inseam 29.75), 48cm Cannondale Ironman frame, San Marco Aspide Tri saddle, stem is 90mm, reach really is too long compared to her previous position, which was professionally fit by a FIST certified fitter.
She is doing sprint distance triathlons, no bike races. I moved the saddle to even with the bottom bracket and this has us almost there. I am concerned about the handling as this is her first real tri bike. We won't be able to get to the fitter for about six weeks as he is pretty far away. She really wants to get riding now, so we are trying to get her as close as we can. Thanks for your help.
She is doing sprint distance triathlons, no bike races. I moved the saddle to even with the bottom bracket and this has us almost there. I am concerned about the handling as this is her first real tri bike. We won't be able to get to the fitter for about six weeks as he is pretty far away. She really wants to get riding now, so we are trying to get her as close as we can. Thanks for your help.
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
on such a small frame, you should be able to get further than an inch in front of the center of the BB, the smaller the frame, the more forward you can move before handling begins to get squirrelly. IF she rides steep well, this stem may not be too long...just depends upon those other fit factors, and how well she rides steeply. Good luck!
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
Re: Fit ? Saddle, how far forward? [Titan]
[ In reply to ]
Hey Titan, thanks for your help. Just got back from a short ride and my daughter says the bike feels great with the saddle more forward. Her saddle is aligned with the bb and she feels the bike handles well. She still looks a tiny bit overextended to me, but she says she feels much more comfortable that way. She is very strong and muscular in the upper body, a competitive swimmer, flyer no less, so maybe that could be part of it. She felt like she couldn't breath as well when I moved it a little more forward to try. Thanks again for your help.
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Have a good read of Dan's article. Measure your seat height from the center of the BB to the top of the seat and drop a plumbline. Now measure to the center of the BB. Look on the chart and you'll see your approx seat angle.
http://www.slowtwitch.com/...ctr/anglevangle.html
http://www.slowtwitch.com/...ctr/anglevangle.html
Re: Fit ? Saddle, how far forward? [cerveloguy]
[ In reply to ]
Ok, I read the articles, both of them, and did the measurements. I came up with an "apparent seat angle" of 77.5. If she is comfortable and the bike handles well, is there anything else I should consider?
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Great! Check out Cerveloguy's link to Dan's article to find out her seat tube angle...I'm guessing it's going to be about 75-76 degrees without looking at the chart, nor knowing the distance from the BB center to the middle of her seat. On my bike, a 55 cm, I'm at about 77 degrees when I get almost to the BB, so she will be able to get to the BB and still be shallower than when mine is still behind the BB. BTW, the REAL important measurement of steepness actually has to do with where the center of her femoral head is located in relation to the BB...but, since we are often built differently, this relationship isn't talked about as much, and we default to the more easily measured points on the bike. This is another of the reasons a fitter can't just say, "Ride at 76.5 degrees for best performance", it's still somewhat of a guess as to what seat tube angle any particular person should ride, unless they test a lot.
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
You could take a digital photo with rider on a trainer and post here. Be sure to center the camera properly. This type of analysis may not be totally accurate for fine tuning, but is good for ball parking a position.
Re: Fit ? Saddle, how far forward? [cerveloguy]
[ In reply to ]
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Sorry the photo is so-o large, but I don't know how to fix it. Anybody have any suggestions. Thanks.
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Actually, she looks a little "scrunched" not stretched out. I can see the entire nose of the Aspide saddle and she is sitting on the back part of it. The frame seems about right. Is she having trouble breathing like this? Need to "rotate" her pelvis forward more. Perhaps raise the seat just a touch? Also, the Syntace bars with the more rearward placed arm rests would work better for her it seems.
____________________________________
Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD
____________________________________
Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD
Re: Fit ? Saddle, how far forward? [fishymom]
[ In reply to ]
Usually I print off the photo and measure various angles but I'm noticing your left crank isn't quite at 6 o'clock so I can't get an accurate knee angle.
At first glance without measuring, your position doesn't look too bad. Your toso/hip and torso arm angles appear both around 90 degrees and a plumbline from your ear dissects in just in front of your elbow where it should be.
At first glance without measuring, your position doesn't look too bad. Your toso/hip and torso arm angles appear both around 90 degrees and a plumbline from your ear dissects in just in front of your elbow where it should be.
Re: Fit ? Saddle, how far forward? [rroof]
[ In reply to ]
I'm with you. I hope SmAC sees this. It will be the first time in Slowtwitch history in which he recommends that someone raise their saddle.
Re: Fit ? Saddle, how far forward? [mr. mike]
[ In reply to ]
But I think the saddle height may be deceptive because the cranks are about 7 and 1 o'clock instead of 6 and 12. This will make her knee angle look a little less which you would see in a low seat. We need another photo with the cranks at 6/12.
Ok, here is another pic. I hope this one is better.