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Seat post stiffness: Compact frame geometry
This subject has probably already been discussed here, but I can't find
the specific info I'm looking for, so I thought I'd give it a try anyway. I've been using a Dura Ace aluminum seatpost (27.2 x 270 mm) on a custom-made steel frame with compact-geometry and I've always noticed a little bit of seatpost flex that can be a bit annoying at times. I have the Dura Ace post extended just shy of the "max' allowable line. Even though the seat post flex ends up providing a nice plush ride, I'm thinking of switching over to a graphite post that's been designed more towards a compact frame geometry, like a 350 mm Ritchey carbon post. Any opinions on graphite posts or opinions on relative seat post stiffness? Hate to change seatposts and find out the new one is no stiffer than the old one. Now I understand why 31.6 mm seatpost are becoming more common. Thanks, Steve T |
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#2
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Seat post stiffness: Compact frame geometry
On 23 Dec 2006 23:38:11 -0800, SteveT wrote:
Any opinions on graphite posts Wear disposable latex gloves when you handle them, or they'll smudge your hands. They're like giant 5B art pencils. -- Home page: http://members.westnet.com.au/mvw |
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Seat post stiffness: Compact frame geometry
SteveT wrote: This subject has probably already been discussed here, but I can't find the specific info I'm looking for, so I thought I'd give it a try anyway. I've been using a Dura Ace aluminum seatpost (27.2 x 270 mm) on a custom-made steel frame with compact-geometry and I've always noticed a little bit of seatpost flex that can be a bit annoying at times. I have the Dura Ace post extended just shy of the "max' allowable line. Even though the seat post flex ends up providing a nice plush ride, I'm thinking of switching over to a graphite post that's been designed more towards a compact frame geometry, like a 350 mm Ritchey carbon post. Any opinions on graphite posts or opinions on relative seat post stiffness? Hate to change seatposts and find out the new one is no stiffer than the old one. Now I understand why 31.6 mm seatpost are becoming more common. Thanks, Steve T I really doubt you are feeling that tube of aluminum flex. If it were, it would eventually break. Perhaps the saddle rails, but not that tube of 250mm of aluminum. |
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Seat post stiffness: Compact frame geometry
SteveT wrote: Any opinions on graphite posts or opinions on relative seat post stiffness? Hate to change seatposts and find out the new one is no stiffer than the old one. Now I understand why 31.6 mm seatpost are becoming more common. Larger diameter allows it to be *stronger* and still light. I did some calculations awhile back and concluded that a very long post (like 400mm) could flex enough that a sensitive person might notice it, but compared to flex in the saddle it is still very small. I doubt that you are perceiving flex in that post. Carbon posts tend to be more flexible than aluminum posts. If you want to try a stiffer post I'd look at heavy duty aluminum ones with a thick wall. |
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Seat post stiffness: Compact frame geometry
SteveT wrote:
I've been using a Dura Ace aluminum seatpost (27.2 x 270 mm) on a custom-made steel frame with compact-geometry and I've always noticed a little bit of seatpost flex that can be a bit annoying at times. I have the Dura Ace post extended just shy of the "max' allowable line. Even though the seat post flex ends up providing a nice plush ride, I'm thinking of switching over to a graphite post that's been designed more towards a compact frame geometry, like a 350 mm Ritchey carbon post. Any opinions on graphite posts or opinions on relative seat post stiffness? Hate to change seatposts and find out the new one is no stiffer than the old one. Now I understand why 31.6 mm seatpost are becoming more common. I switched from the Easton EC-70 carbon post on my Litespeed to their EA-70 Taperwall aluminum post, which is similar to your Dura Ace post. I find the bead-blasted aluminum post to be more rigid and durable than the carbon version, which would slip down in the frame under load. Nashbar has the 300mm EA-70 posts on blowout right now for $32.99, which is a fantastic bargain. |
#6
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Seat post stiffness: Compact frame geometry
In article .com,
"SteveT" wrote: This subject has probably already been discussed here, but I can't find the specific info I'm looking for, so I thought I'd give it a try anyway. I've been using a Dura Ace aluminum seatpost (27.2 x 270 mm) on a custom-made steel frame with compact-geometry and I've always noticed a little bit of seatpost flex that can be a bit annoying at times. I have the Dura Ace post extended just shy of the "max' allowable line. Even though the seat post flex ends up providing a nice plush ride, I'm thinking of switching over to a graphite post that's been designed more towards a compact frame geometry, like a 350 mm Ritchey carbon post. Any opinions on graphite posts or opinions on relative seat post stiffness? Hate to change seatposts and find out the new one is no stiffer than the old one. Now I understand why 31.6 mm seatpost are becoming more common. Are you certain that it is seat post flex you are feeling and not saddle flex? How have you determined it is the seatpost flexing? |
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