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Cracked Quill Seatpost

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Cracked Quill Seatpost

Old 08-05-15, 08:16 PM
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Jgraham001
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Cracked Quill Seatpost

[ just bought a 564 Aluminum Schwinn bike on Craigslist. It is in really great condition and I am just looking to use it to commute to and from campus every day, not any hardcore cycling. I did notice a crack in the seatpost and the more I read about the quill seatpost, the more concerned I am that I made a major mistake. Is a crack like this a serious concern for simple daily commuting?
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Old 08-05-15, 08:20 PM
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not sure what a "quill" seatpost is. But unless you want to be Fuselli George in a Seinfeld Episode( "it was a million to one shot, doc") I 'd replace a cracked seatpost. I t won't be that expensive.
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Old 08-05-15, 08:37 PM
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It's basically a seatpost that clamps from the inside because the frame of this bike does not come with an outside clamp. They are supposedly super rare and expensive, not sure if there is a way I could jerry-rig a normal seat post to sit snug or not.
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Old 08-05-15, 08:38 PM
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Originally Posted by Jgraham001 View Post
[ just bought a 564 Aluminum Schwinn bike on Craigslist. It is in really great condition and I am just looking to use it to commute to and from campus every day, not any hardcore cycling. I did notice a crack in the seatpost and the more I read about the quill seatpost, the more concerned I am that I made a major mistake. Is a crack like this a serious concern for simple daily commuting?
Yeah, it's time to retire this antique. Use it for a paper weight or whatever.
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Old 08-05-15, 09:28 PM
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They do show up on E-Bay frequently.

Internal Expander Seatpost 27 2mm Moser Gara Leader AX Merckx Campagnolo | eBay
American Classic Quill Seatpost 27 2 Bike Bicycle Road Fit Schwinn Moser MTB GT | eBay
Internal Expander Seatpost 27 2mm for Leader AX Moser Merckx Campagnolo | eBay

I haven't messed around with seatposts much, but they appear to be pretty simple. You have the top, a tube, and the wedge.
You should be able to replace the tube portion with only moderate effort.

You might also be able to use yours until it breaks. Any chance the expander system would hold it all together? You might also be able to weld it, although I'd probably replace the tube rather than welding.
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Old 08-05-15, 09:51 PM
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Well, I learned something new today: Quill seatpost!!
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Old 08-06-15, 09:59 AM
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Glad that design didn't take hold. I guess someone thought it looked sleeker, or maybe they were worried about metal fatigue of an aluminum frame with a seat collar.
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Old 08-06-15, 10:01 AM
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Originally Posted by CliffordK View Post
You might also be able to use yours until it breaks. .
Seat post brakes at top of post. Seat slides off the back. OP's butt plants on jagged edge of post, which becomes a 27.2mm wide butt plug.

Not a risk I'd take personally.
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Old 08-06-15, 12:07 PM
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Originally Posted by merlinextraligh View Post
Glad that design didn't take hold.
Yeah. In either '90 or '91 I bought a Schwinn 754 that had one. It sucked (along with the rest of the bike). It kept sliding down.
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Old 08-06-15, 12:08 PM
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I wouldn't ride a bike with seatpost.
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Old 08-06-15, 12:19 PM
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Originally Posted by merlinextraligh View Post
not sure what a "quill" seatpost is. But unless you want to be Fuselli George in a Seinfeld Episode( "it was a million to one shot, doc") I 'd replace a cracked seatpost. I t won't be that expensive.
LOL! Maybe he could find a small "ASSMAN" bicycle license plate, too!
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Old 08-06-15, 12:23 PM
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I have a 564 and noticed that my seat post has a slight crack in it (nowhere near as nasty as your crack). I wrapped a band clamp around the post and tightened it as much as I could. The post hasn't moved in the seat tube since.

I have done some research specifically about these problems and resolutions to them that does not include trying to find a NOS part. One fix that I have seen and that seems fairly solid is the following:
1) Purchase new seat post 27.2mm
2) Purchase double seat post clamp (27.2 - 31.6) Gorilla Park Double Seatpost Clamp 27 2mm Bike White | eBay
3) Double seat post clamp will sit at the base of the post and clamp to top of seat tube.

I haven't pulled the trigger on this yet as the band clamp is doing its job. There is a Schwinn Aluminum Series Facebook page where someone has done this with success.
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Old 08-06-15, 12:35 PM
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There is a way to fix it. There used to be a person in a Facebook forum for the SAS bikes (Schwinn Aluminum Series... 564, 754, etc) that would put a collar above the screw that releases/tightens the quill. Unfortunately he was killed in a bike accident about a year ago. Unknown if anyone picked up doing those or not. There are also ways to make a homemade quill seat post. There is also an adapter that can be found people have used to make a standard seat post for on the old SAS bikes. I've had a few of those bikes over the years.

Edit: that's the double seat post adapter referenced above...
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Old 08-06-15, 12:36 PM
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^ I Was thinking of putting a seat collar on it. It would seem to make it work well you'd want to slot the back of the seat tube, and I'm not sure how much I'd want to mess with an old aluminum frame.

But a small slot an inch or so down with a dremel, and then a seat post collar would appear to do the trick.
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Old 08-06-15, 12:39 PM
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The problem with the idea of using use a standard seat post on one of those is that there isn't enough of the seat tube sticking up above the top tube. I had seriously thought about it
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Old 08-06-15, 12:45 PM
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A simple repair to the post that would be just as simple to monitor: put pipe clamps around the post above and below the crack. Get them tight. Mark the end of the crack. Now just check periodically to see if the crack is growing.

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Old 08-06-15, 04:28 PM
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Thanks for all of the replies! I'm not quite ready to dish out over $100 for a new seatpost, but I'm also not interested in having my anus obliterated. I'm going to try these two pipe clamps and watch it closely, what do you guys think? I'm thinking it will probably justdelay the inevitable, but I really don't want it breaking off in the middle of a ride.
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Old 08-06-15, 05:49 PM
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Seems Legit

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Old 08-06-15, 09:14 PM
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Originally Posted by Jgraham001 View Post
Thanks for all of the replies! I'm not quite ready to dish out over $100 for a new seatpost, but I'm also not interested in having my anus obliterated. I'm going to try these two pipe clamps and watch it closely, what do you guys think? I'm thinking it will probably justdelay the inevitable, but I really don't want it breaking off in the middle of a ride.
Seems like something I would do. I'll bet it'll be fine.
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Old 08-06-15, 09:27 PM
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Though possible, I doubt the seat post would wind up an anal probe or the equiv of something you'd see in the red room of 50 Shades of Gray... keep an eye on it and for other 'series' bikes if you really like the way it rides, might find a good seat post on one. All of the number series (and the Ontare) had that design except for the 354. The 354 had a standard seat clamp and will accept any standard seat post.
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Old 08-06-15, 11:15 PM
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The crack has already travelled through a hole of sorts. But, it may not hurt to drill a 1/8" hold at the end of the crack to help suppress propagation.

Is that a 27.2mm post?
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Old 08-06-15, 11:53 PM
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Originally Posted by CliffordK View Post
The crack has already travelled through a hole of sorts. But, it may not hurt to drill a 1/8" hold at the end of the crack to help suppress propagation.

Is that a 27.2mm post?
Good call!

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Old 12-02-15, 02:20 PM
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Originally Posted by Jgraham001 View Post
[ just bought a 564 Aluminum Schwinn bike on Craigslist. It is in really great condition and I am just looking to use it to commute to and from campus every day, not any hardcore cycling. I did notice a crack in the seatpost and the more I read about the quill seatpost, the more concerned I am that I made a major mistake. Is a crack like this a serious concern for simple daily commuting?
How's the seatpost holding up?

I recently found a used Suntour Quill very similar to yours, but without the crack.

Looking at the photo again, I think the top of the seatpost has been jammed downward by about 1/16", so the original crack may have happened fairly quickly on a big bump.

Anyway, if you are interested in a low cost trade-plus, perhaps we can work something out.

Post here and I'll send a PM.
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Old 12-02-15, 02:55 PM
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Originally Posted by CliffordK View Post

You might also be able to use yours until it breaks. Any chance the expander system would hold it all together? You might also be able to weld it, although I'd probably replace the tube rather than welding.
Worst advice ever given on BF...

Originally Posted by merlinextraligh View Post
Seat post brakes at top of post. Seat slides off the back. OP's butt plants on jagged edge of post, which becomes a 27.2mm wide butt plug.

Not a risk I'd take personally.
Exactly!
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Old 12-02-15, 03:33 PM
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Originally Posted by rmfnla View Post
Worst advice ever given on BF...
Based on what????

One would have to inspect the post carefully, but as far as I can tell, the bolt providing tension to the wedge also goes through the head of the post.

So for the post to sheer, you would have to have a crack that is travelling downward to change course, and travel in a circle around the post.
Then either the retention bolt sheers, or the head of the post would also have to sheer off.

Or, likely there is undue stress on the transverse bolt, and that bolt is at risk of sheering. The result would likely allow the head of the post to pivot, and the body of the post to fall into the frame.

Perhaps there is also some inconvenient twisting of the head of the post which would be noisy, and perhaps allow the post to slide, or interrupt the tension on the vertical tension bolt (causing it to sheer). Loosing that bolt would cause the post to fall in the seat tube, but generally not an emergency.

Or, maybe the lower half of the head would sheer off, allowing the post to twist, but not immediately fall off.

Hopefully the OP would be monitoring for change. And, it may not be comfortable to ride the bike with the post as-is.

A seat sliding or twisting would feel uncomfortable, but wouldn't necessarily be a huge danger.

Nonetheless, I have offered a deal on a replacement post.
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