Silver 27.2 seatposts
#26
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I think this is the key... the grub screw that sets the tilt eventually displaces some aluminum in the plate that it bears against. This causes a lack of tension in the main bolt, which allows it to loosen.
I've got a few of these on my bikes, and have had this issue happen on one of them. After re-tightening it, the problem never occurred again.
The first generation seems a bit better in this respect. In the photo below, the first gen is on the left, and the 2nd gen (I believe) is on the right. The first gen has a rounded tip on the grub screw and hasn't produced any deformation in the plate that it contacts. The later generation design just has a bevel on the tip of the grub screw and this does produce some observable deformation in the aluminum plate.
The first gen is distinguished by the seat post having the head and the shaft machined out of a single piece.
The later gen bonds a separate head to the shaft.
As a bit of a disclaimer, I weigh about 155 pounds and tend to be fairly gentle on components. A more gravitationally enhanced person might reasonably have more trouble with this seatpost.
Steve in Peoria
I've got a few of these on my bikes, and have had this issue happen on one of them. After re-tightening it, the problem never occurred again.
The first generation seems a bit better in this respect. In the photo below, the first gen is on the left, and the 2nd gen (I believe) is on the right. The first gen has a rounded tip on the grub screw and hasn't produced any deformation in the plate that it contacts. The later generation design just has a bevel on the tip of the grub screw and this does produce some observable deformation in the aluminum plate.
The first gen is distinguished by the seat post having the head and the shaft machined out of a single piece.
The later gen bonds a separate head to the shaft.
As a bit of a disclaimer, I weigh about 155 pounds and tend to be fairly gentle on components. A more gravitationally enhanced person might reasonably have more trouble with this seatpost.
Steve in Peoria
#27
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Thanks for that detailed info as I didn't know there were two generations of this post. I weigh 165 lbs and usually think of myself as fairly light in the saddle, but have had AC post clamp bolts loosen up for no particular reason after hundreds of miles of being just fine. Last year, I was on a century ride, and almost exactly at mile 50, the bolt loosened. Unfortunately, the multitool I had with me wasn't quite long enough to reach the bolt head without me removing the grub screw first. That meant tightening up the bolt, but leaving the saddle at a bit of a nose up angle for the second 50 miles. I adjusted, and I've taken to putting a drop of red loctite on the bolt threads, and all has been fine since.
#28
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I think this is the key... the grub screw that sets the tilt eventually displaces some aluminum in the plate that it bears against. This causes a lack of tension in the main bolt, which allows it to loosen.
I've got a few of these on my bikes, and have had this issue happen on one of them. After re-tightening it, the problem never occurred again.
The first generation seems a bit better in this respect. In the photo below, the first gen is on the left, and the 2nd gen (I believe) is on the right. The first gen has a rounded tip on the grub screw and hasn't produced any deformation in the plate that it contacts. The later generation design just has a bevel on the tip of the grub screw and this does produce some observable deformation in the aluminum plate.
The first gen is distinguished by the seat post having the head and the shaft machined out of a single piece.
The later gen bonds a separate head to the shaft.
As a bit of a disclaimer, I weigh about 155 pounds and tend to be fairly gentle on components. A more gravitationally enhanced person might reasonably have more trouble with this seatpost.
Steve in Peoria
I've got a few of these on my bikes, and have had this issue happen on one of them. After re-tightening it, the problem never occurred again.
The first generation seems a bit better in this respect. In the photo below, the first gen is on the left, and the 2nd gen (I believe) is on the right. The first gen has a rounded tip on the grub screw and hasn't produced any deformation in the plate that it contacts. The later generation design just has a bevel on the tip of the grub screw and this does produce some observable deformation in the aluminum plate.
The first gen is distinguished by the seat post having the head and the shaft machined out of a single piece.
The later gen bonds a separate head to the shaft.
As a bit of a disclaimer, I weigh about 155 pounds and tend to be fairly gentle on components. A more gravitationally enhanced person might reasonably have more trouble with this seatpost.
Steve in Peoria
A friend was severely injured from a snapped AC post so have always been a bit skeptical of the standard road model.
#29
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#30
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Deda make a "classic" style silver seatpost that isn't too expensive, although it is quite long and you may want to cut it.
Also, some used Gipiemme seatposts can be found online that are pretty good. Mostly one bolt.
Does everyone really prefer the two-bolt stuff? I see a lot of talk about Campagnolo two bolt posts, but to be honest I always found single bolt easier to deal with.
I got a used bike (from a really skinny guy) with one of these posts. I didn't know anything about them and assumed it wasn't particularly special. But then I updated the bike with some other components and decided to weigh it out of curiosity. I couldn't believe that the AC post was the lightest of all my options. And now I know why...
Also, some used Gipiemme seatposts can be found online that are pretty good. Mostly one bolt.
Does everyone really prefer the two-bolt stuff? I see a lot of talk about Campagnolo two bolt posts, but to be honest I always found single bolt easier to deal with.
I got a used bike (from a really skinny guy) with one of these posts. I didn't know anything about them and assumed it wasn't particularly special. But then I updated the bike with some other components and decided to weigh it out of curiosity. I couldn't believe that the AC post was the lightest of all my options. And now I know why...
#31
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...IIRC, this is a Laprade, without any paint in the recessed facets. They also come in a sort of black anodized top version, and frequently appear in the 27.0 diameter.
#32
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If you like 2 bolt Campy with setback you will like the 2 bolt Nitto S83 with setback. About $100 but out of stock most places now.
#33
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Kalloy posts come in every size, length and configuration possible, for the lowest cost, from the world's largest producer of seatposts, bars, stems (plus Zoom suspension forks).
Seems the silver ones with zero offset are harder to find lately, so I grab every one I can find.
Strong as heck and usually a lot longer than needed.
25.6mm post shown here:
As for the lightweight or "weight-weenie" posts, it's the combination of rearward saddle offset and dynamic loading that does them in.
I'll probably never break one since my short torso has me positioning all of 145# well forward.
Seems the silver ones with zero offset are harder to find lately, so I grab every one I can find.
Strong as heck and usually a lot longer than needed.
25.6mm post shown here:
As for the lightweight or "weight-weenie" posts, it's the combination of rearward saddle offset and dynamic loading that does them in.
I'll probably never break one since my short torso has me positioning all of 145# well forward.
#34
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And FWIW, I never had a problem with AC posts, but haven’t used them in a while (and a pound or two) because they don’t have sufficient setback with my current frames.
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#36
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Easton/DA 7210:
DASPRight by Dave The Golden Boy, on Flickr
DASPLeft by Dave The Golden Boy, on Flickr
DASPRear by Dave The Golden Boy, on Flickr
Suntour Superbe Pro:
620 Build Seatpost by Dave The Golden Boy, on Flickr
Suntour XC Pro:
IMG_0222 by Dave The Golden Boy, on Flickr
M900-ish XTR:
M1000LT Seat n Cluster by Dave The Golden Boy, on Flickr
DASPRight by Dave The Golden Boy, on Flickr
DASPLeft by Dave The Golden Boy, on Flickr
DASPRear by Dave The Golden Boy, on Flickr
Suntour Superbe Pro:
620 Build Seatpost by Dave The Golden Boy, on Flickr
Suntour XC Pro:
IMG_0222 by Dave The Golden Boy, on Flickr
M900-ish XTR:
M1000LT Seat n Cluster by Dave The Golden Boy, on Flickr
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#37
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Don’t know about “everyone”, but I prefer two-bolt posts (1st gen VO Long Setback is a favorite) because the saddle angle can be easily and finely adjusted without disturbing anything else, quite valuable with leather saddles, at least for my “princess b**t”.
And FWIW, I never had a problem with AC posts, but haven’t used them in a while (and a pound or two) because they don’t have sufficient setback with my current frames.
And FWIW, I never had a problem with AC posts, but haven’t used them in a while (and a pound or two) because they don’t have sufficient setback with my current frames.
#38
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Am I doing something wrong? My experience is almost exclusively with modern Deda two-bolt posts, but I find that when I start to tighten them up the final turns on the rear bolt start to change the angle significantly. I take this into account, and adjust the front accordingly, but I don't find it to be a super precise method (as it seems the final angle will be determined by how tight I make the rear bolt). What am I doing wrong?
#39
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Am I doing something wrong? My experience is almost exclusively with modern Deda two-bolt posts, but I find that when I start to tighten them up the final turns on the rear bolt start to change the angle significantly. I take this into account, and adjust the front accordingly, but I don't find it to be a super precise method (as it seems the final angle will be determined by how tight I make the rear bolt). What am I doing wrong?
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#41
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I don't know if there's a trick or not but I've never had a problem. I do however know what you're speaking of. You just got to keep things into account. If you tighten up the back bolt and the angles changing then tighten up the front a little more. Anyways once you get them set they're set. I had a race face two bolt post like this and I could adjust the tilt by loosening one bolt a set amount of turns and tightening the other bolt the same amount of turns and you can watch the seat tilt as you did it. I will say with this velo orange long setback post though you don't seem to have that ability. It seems like I have to loosen both the front and the rear and then physically make my adjustment and then tighten them both up equally. I'm not sure what the difference is but the race face post is a joy to adjust
#42
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The Truvativ very long setback post, in the 26.8mm needed for the Miyata, was originally a black shaft, as in this photo.
It took less than hour with fine sandpaper followed by “Simichrome” polish for this. I was careful not to extend the sanding much below the seat lug area to preserve the original clamping diameter.
It took less than hour with fine sandpaper followed by “Simichrome” polish for this. I was careful not to extend the sanding much below the seat lug area to preserve the original clamping diameter.
#43
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+1. Kalloy Unos are light and have worked well for me. Cheap, too, at $25 or less.
#44
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interesting. It took me a while to see the difference because mine also has one forward and one aft bolt. Without being around my bike now I can't remember. Did they invert that top piece between the first and second generations? I can't remember if mine has a smile or a frown
Last edited by trail_monkey; 09-17-20 at 04:45 AM.
#45
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Nitto man, Nitto. I have no idea why they are called 'crystal fellows' but whatever, they are right up there with campy or better, and they make a 2 bolt too, for purists. The S65 is fine for most people. There's even a NJS approved JDM Jaguar super tough seatpost if you're hardcore.
Kalloy Uno rocks for a low cost seatpost. They are solid and hard to beat for the price. Take the logo off with acetone.
Kalloy Uno rocks for a low cost seatpost. They are solid and hard to beat for the price. Take the logo off with acetone.
#46
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interesting. It took me a while to see the difference because mine also has one forward and one aft bolt. Without being around my bike now I can't remember. Did they invert that top piece between the first and second generations? I can't remember if mine has a smile or a frown
Last edited by Dfrost; 09-17-20 at 06:47 PM.