Tri-Bike Fit - one size fits all?

Tri-Bike Fit - one size fits all?

Post by AL » Thu, 31 Aug 2000 11:37:28


I am in the process of converting my road bike (TREK 2100 Carbon Fiber) to a tri bike.  I've got
the aero bars, I've even got the forward slant seat post thing.  I read all of the info I can
find including the detailed stuff on the extreme tri website.  Boy did that confuse me.  

My torso is long for my body. (Actually my legs are short for my body but that is a sore spot.)  
The new set up FEELS funny.    

What are some rules of thumb for FEEL as far a tri-geometry goes?  Does it just take time to get
used to something new?  I come from a road biking background and have always raced a standard
road bike set up.  Now that I am planning on longer distance races I wanna try a standard aero
set up.  If anyone has encountered a similar problem please share you $.02 with me.

Al "the distance from my navel to my solar plexis is measured in light years" in Houston.

 
 
 

Tri-Bike Fit - one size fits all?

Post by KevinM » Thu, 31 Aug 2000 12:26:12

Al,

First, the link below provides perhaps the definitive word on the subject.

http://www.slowtwitch.com/mainheadings/techctr/bikefit.html

Now, my uneducated babble...
Using a forward post may be effectively shortening the top tube too much for
your long torso.

The compromise that I've used is converting from a typical setback road
seatpost to a mountain post and sliding the saddle all the way forward on the
rails.  Results have been good and comfortable for me--a good compromise
between "road" and "tri" positions.

Good luck.

-Kevin Munday

 
 
 

Tri-Bike Fit - one size fits all?

Post by shars.. » Thu, 31 Aug 2000 04:00:00

I've heard that if your forward seat post shortens the top tube too
much, you can switch out for a stem that extends the reach...

Quote:
> Now, my uneducated babble...
> Using a forward post may be effectively shortening the top tube too
much for
> your long torso.

> The compromise that I've used is converting from a typical setback
road
> seatpost to a mountain post and sliding the saddle all the way
forward on the
> rails.  Results have been good and comfortable for me--a good
compromise
> between "road" and "tri" positions.

> Good luck.

> -Kevin Munday

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Before you buy.

 
 
 

Tri-Bike Fit - one size fits all?

Post by rjweis » Thu, 31 Aug 2000 04:00:00

Been there done that, I moved my seat fwd and lay out pretty far on my
Syntace C2 bars...I'm pretty comfortable but the bike handles like crap.
Going for my water bottle on the seat tube is an adventure.

I'm in the process now of getting a true 78* tri bike, Cervelo P2K.

Putting to much weight up front is dangerous.

Ron

 
 
 

Tri-Bike Fit - one size fits all?

Post by Matt » Thu, 31 Aug 2000 04:00:00

Does the typical tri-bike handle as poorly as I've heard most road
bikes do when tri-fitted?

I've head that even with the Cervelo's, you have to turn the seatpost
around to get the true 78 degree angle...Is that true? If so, it's
something to think about.



Quote:
> Been there done that, I moved my seat fwd and lay out pretty far on my
> Syntace C2 bars...I'm pretty comfortable but the bike handles like
crap.
> Going for my water bottle on the seat tube is an adventure.

> I'm in the process now of getting a true 78* tri bike, Cervelo P2K.

> Putting to much weight up front is dangerous.

> Ron

Sent via Deja.com http://www.deja.com/
Before you buy.
 
 
 

Tri-Bike Fit - one size fits all?

Post by cog.. » Thu, 31 Aug 2000 04:00:00

I think it would help if you could expand on exactly what you think
feels "funny" about your new position. If it is how the bike handles,
that is likely related to having more weight than normal on the front
wheel. You might eventually get used to such a feeling, but a bike
designed with the aero position in mind is generally a better solution
to handling problems. OTOH, if it is the act of pedaling itself that
seems odd, then perhaps you need to rethink/revisit the relationship
between seat and bottom bracket. The principle as I see it is that you
bring the seat forward only to the extent needed to maintain a constant
thigh-torso angle, but not one centimeter more. IOW, the handlebar
position ends up dictating the seat position, instead of vice-versa as
is classically the case. However, if you are not any lower on your aero
bars than when on your drops (as is true for many people when simply
slapping aerobars on a road bike), then there's no reason to bring the
seat forward at all.

Even if you maintain a constant thigh-torso angle, the motion of
pedaling will still change slightly, but most people find that they can
switch back and forth from a classical road position and the aero
position fairly easily.


Quote:
> I am in the process of converting my road bike (TREK 2100 Carbon

Fiber) to a tri bike.  I've got
Quote:
> the aero bars, I've even got the forward slant seat post thing.  I

read all of the info I can
Quote:
> find including the detailed stuff on the extreme tri website.  Boy did
that confuse me.

> My torso is long for my body. (Actually my legs are short for my body

but that is a sore spot.)
Quote:
> The new set up FEELS funny.

> What are some rules of thumb for FEEL as far a tri-geometry goes?

Does it just take time to get
Quote:
> used to something new?  I come from a road biking background and have

always raced a standard
Quote:
> road bike set up.  Now that I am planning on longer distance races I

wanna try a standard aero

Quote:
> set up.  If anyone has encountered a similar problem please share you
$.02 with me.

> Al "the distance from my navel to my solar plexis is measured in light
years" in Houston.

--
Andrew Coggan

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

Tri-Bike Fit - one size fits all?

Post by Dan Empfiel » Fri, 01 Sep 2000 11:28:15



Quote:
> The principle as I see it is that you
> bring the seat forward only to the extent needed to maintain a constant
> thigh-torso angle, but not one centimeter more. IOW, the handlebar
> position ends up dictating the seat position, instead of vice-versa as
> is classically the case. However, if you are not any lower on your aero
> bars than when on your drops (as is true for many people when simply
> slapping aerobars on a road bike), then there's no reason to bring the
> seat forward at all.

well put.

slowman

--
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Tri-Bike Fit - one size fits all?

Post by Kaelon » Fri, 01 Sep 2000 14:39:53

<< Does the typical tri-bike handle as poorly as I've heard most road
bikes do when tri-fitted? >>

Usually, if you put aero bars and a forward seat post on a standard road frame,
you wind up putting more weight on the front wheel, which can affect the
handling. Most people won't have much trouble adapting, though. Most tri-bikes
are designed to eliminate this problem by using shorter chainstays and a more
relaxed head tube angle, effectively moving both wheels "forward" under the
rider, and keeping the weight distributed evenly. The relaxed head tube also
makes the handling a little slower, which makes the bike more stable when on
the aero bars. My Specialized Transition wouldn't make a very good crit bike,
due to the slower handling, but it's a much better handling and more
comfortable bike with aero bars than my Trek or Mondonico...

 
 
 

Tri-Bike Fit - one size fits all?

Post by fabiose » Tue, 12 Sep 2000 08:55:25

Find a bike shop with a TRIATHLETE on staff.. Most tri bikes-REAL tri
bikes-are designed around the rider weight being over the front wheel. The
distance between the BB axle and front wheel axle is longer to accomodate
the more aero' position. A road bike with a fudged "tri" set up will handle
poorly every single time. Though your body MIGHT be able to be placed in
that aero' position, the BIKE can't accept it and isn't designed to. If you
are a full on tri guy, get a full on tri bike. My $.02 -Fabio


Quote:

> << Does the typical tri-bike handle as poorly as I've heard most road
> bikes do when tri-fitted? >>

> Usually, if you put aero bars and a forward seat post on a standard road
frame,
> you wind up putting more weight on the front wheel, which can affect the
> handling. Most people won't have much trouble adapting, though. Most
tri-bikes
> are designed to eliminate this problem by using shorter chainstays and a
more
> relaxed head tube angle, effectively moving both wheels "forward" under
the
> rider, and keeping the weight distributed evenly. The relaxed head tube
also
> makes the handling a little slower, which makes the bike more stable when
on
> the aero bars. My Specialized Transition wouldn't make a very good crit
bike,
> due to the slower handling, but it's a much better handling and more
> comfortable bike with aero bars than my Trek or Mondonico...