I had the following discussion this week with Paul Levine from Serrota in regards to seat height for a steep tri set up. [he also gave a lecture last year at IM LP ]
Paul,
I believe you talked about bike fit last year at IM Lake Placid If I remember correctly you mentioned that a TRI or TT position with a steeper seat angle generally calls for lowering the seat, relative to your road bike position. Can you explain the rational for this again. The general consensus seems to be the opposite. [as you move forward, you come closer to the BB and hence raise the seat]
Thanks for your time
AR
Re: Seat height -TT bike
Author: Paul Levine (---.nrp1.mon.ny.frontiernet.net)
Date: 05-28-03 13:39
Axel,
"The general consensus seems to be the opposite. [as you move forward, you come closer to the BB and hence raise the seat]"
This is true when you speak of fore and aft adjustments of the seat on the rails as it applies to maintaining the proper leg extension. But, with tri fitting the steeper seat angle and the seat height are determined differently than a road fitting. The steeper seat angle on a tri bike is suggested for some athletes to maintain the correct hip angle (Femur/ Torso) as the athlete rotates over and reduces his frontal surface area. This angle is determined by the athletes hip flexibilty off the bike.
The lower seat height, or the increased flexion in the triathlete's knee, is recommended because the hamstrings are being pulled up around the pelvis when the athlete rotates over. This movement causes an effective tightening of the hamstrings. By lowering the saddle it releases the tension on the hamstring. Additionally, it is important for the triathlete to be able to maintain his aero position. Being aero over a long time will cause the hamstring to want to shorten for the reasons mentioned above. The lower seat allows the hamstrings to have a more effective range of movement as they become fatigued.
Call me if you would like to discuss this in more detail
Paul,
Does this in essence mean, that my road bike seat height (approx. 79cm) will be higher than that of my Tri bike, [measured from ct of BB to the top of the saddle ct]? So far I have had my Tri bike at 79.5-80cm.
Author: Paul Levine (---.nrp1.mon.ny.frontiernet.net)Date: 05-29-03 12:57
Yes, your road bike should measure higher than your tri.
Paul,
I believe you talked about bike fit last year at IM Lake Placid If I remember correctly you mentioned that a TRI or TT position with a steeper seat angle generally calls for lowering the seat, relative to your road bike position. Can you explain the rational for this again. The general consensus seems to be the opposite. [as you move forward, you come closer to the BB and hence raise the seat]
Thanks for your time
AR
Re: Seat height -TT bike
Author: Paul Levine (---.nrp1.mon.ny.frontiernet.net)
Date: 05-28-03 13:39
Axel,
"The general consensus seems to be the opposite. [as you move forward, you come closer to the BB and hence raise the seat]"
This is true when you speak of fore and aft adjustments of the seat on the rails as it applies to maintaining the proper leg extension. But, with tri fitting the steeper seat angle and the seat height are determined differently than a road fitting. The steeper seat angle on a tri bike is suggested for some athletes to maintain the correct hip angle (Femur/ Torso) as the athlete rotates over and reduces his frontal surface area. This angle is determined by the athletes hip flexibilty off the bike.
The lower seat height, or the increased flexion in the triathlete's knee, is recommended because the hamstrings are being pulled up around the pelvis when the athlete rotates over. This movement causes an effective tightening of the hamstrings. By lowering the saddle it releases the tension on the hamstring. Additionally, it is important for the triathlete to be able to maintain his aero position. Being aero over a long time will cause the hamstring to want to shorten for the reasons mentioned above. The lower seat allows the hamstrings to have a more effective range of movement as they become fatigued.
Call me if you would like to discuss this in more detail
Paul,
Does this in essence mean, that my road bike seat height (approx. 79cm) will be higher than that of my Tri bike, [measured from ct of BB to the top of the saddle ct]? So far I have had my Tri bike at 79.5-80cm.
Author: Paul Levine (---.nrp1.mon.ny.frontiernet.net)Date: 05-29-03 12:57
Yes, your road bike should measure higher than your tri.