# WWTP014: 45 Degree Cut Seat Tube



## Walt (Jan 23, 2004)

*Stress problem?*

What problem are you trying to solve? I don't think there is any harm in doing this, but it's not going to reduce any of the stresses on the post, if that's what you're after.

It'll look neat, regardless. I say go for it.

-Walt



jay_ntwr said:


> I'm planning to cut the top of my seat tube at 45 degrees to the axis such that the front of the seat tube is taller than the back of the tube ~1" and has a brazed on binder in the front to hold the post.
> 
> I'm sure it's been done before since everything has already been done. Is there a reason I've never seen this though? Am I failing to see why this is a bad idea?
> 
> ...


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## jay_ntwr (Feb 15, 2008)

I'm planning to cut the top of my seat tube at 45 degrees to the axis such that the front of the seat tube is taller than the back of the tube ~1" and has a brazed on binder in the front to hold the post. 

I'm sure it's been done before since everything has already been done. Is there a reason I've never seen this though? Am I failing to see why this is a bad idea?

I think it's a good idea because it mainly solves a stress problem that has ruined a couple of my posts. It also looks different and I think that is cool.

So what do you guys think?


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## restlessrider (Nov 29, 2007)

Sounds like you want to braze the binder near the top of the front?
The way I am imagining it, that would mean that when the binder is tightened it would be pulling the two 'tips' together. I think you want to make sure that the binder is brazed at the level where the tube completely wraps around the post. Any tubing or points above the binder are decorative - which I am not dissing - not necessarily structural.
Maybe I don't understand...
Rich


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> I'm planning to cut the top of my seat tube at 45 degrees to the axis such that the front of the seat tube is taller than the back of the tube ~1" and has a brazed on binder in the front to hold the post.
> 
> I'm sure it's been done before since everything has already been done. Is there a reason I've never seen this though? Am I failing to see why this is a bad idea?
> 
> ...


I did a half-miter and filed the curves on the top of this seat tube sleeve.








It is mainly for looks and a tiny weight loss. It will reinforce the back of the extended seat mast a bit but largely because it will be silver brazed together.

A cut like you want will look cool but will do little in preventing a bent seatpost.


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## D.F.L. (Jan 3, 2004)

If your binder is too high on the tall, front portion, it won't have much clamping power. The unsupported upper tabs will just pull toward each other, rather than wrapping the seat tube tighter around the post. It's a good idea to have material that runs from one side of the binder, around the post, and back to the other binder, in the straightest possible path.

If you build things properly and choose a good post, you shouldn't have any issues, even with a straight cut.


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## jay_ntwr (Feb 15, 2008)

Walt said:


> What problem are you trying to solve? I don't think there is any harm in doing this, but it's not going to reduce any of the stresses on the post, if that's what you're after.
> 
> It'll look neat, regardless. I say go for it.
> 
> -Walt


I've had a couple seatposts fail just above the top of the seat tube even when I've prepped the tube as best I can. I had a carbon one fail about 1/4" above the top and a Ti one (name rhymes with Hoots) crack in the same place.

What I figured out is that both of these posts were in frames where they were now about 1/4-1/2" higher in the frame they cracked/broke in. So I assumed it was from being scared in the old frame and I wanted to get rid of the scaring across the back of the post. So that was the assertion anyway.

From there, I thought that a 45 degree cut would create the most surface area and eliminate that scaring at the same time, at least spreading it out over a bigger area and I still believe that to be the case.

However, intuitively, I thought that the highest stress was right at the top of the seat tube. It turns out it's about 1/4-1/2" above the top of the seat tube after doing some analysis on it. Note how much cooler the first inch+ is with the 45 cut versus the straight cut. It also spreads stress more evenly over the back of the seat tube. And I think it'll look cool:


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## pvd (Jan 4, 2006)

Awesome! That's the kind of info I like to see.


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## Rody (Sep 10, 2005)

Jay,

I've been using this type of design since 94 and others well before that for the reasons you are now illustrating...never understood why people place the binder at the rear of the post where the highest stress is?

I'd suggest using a smaller miter angle to maintain a better surface clamping area. I personally use 12 degrees, but have played with greater.

I've attached two shots..one of a road bike with a greater angle, one of the standard design.

cheers,

rody


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## jay_ntwr (Feb 15, 2008)

D.F.L. said:


> If your binder is too high on the tall, front portion, it won't have much clamping power. The unsupported upper tabs will just pull toward each other, rather than wrapping the seat tube tighter around the post. It's a good idea to have material that runs from one side of the binder, around the post, and back to the other binder, in the straightest possible path.
> 
> If you build things properly and choose a good post, you shouldn't have any issues, even with a straight cut.


I think I have a solution for this as well. I've been toying with this for about a month now, this is just the first time I've said anything to anyone about it.

I'll get the shots up soon.


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## jay_ntwr (Feb 15, 2008)

Rody said:


> Jay,
> 
> I've been using this type of design since 94 and others well before that for the reasons you are now illustrating...never understood why people place the binder at the rear of the post where the highest stress is?
> 
> ...


Thanks for the feedback, Rody. Yep, it we're wanting to do basically the same thing for the same reasons it looks like. I'll toy with the angle. I'll put my 45 degree solution up here for you guys later in the week and see if y'all think it'll work.


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## Thylacine (Feb 29, 2004)

Isn't this a classic solution looking for a problem?


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## jay_ntwr (Feb 15, 2008)

Thylacine said:


> Isn't this a classic solution looking for a problem?


If I wasn't out one EC90 and one ~$300 post, I'd agree with you. Hey, the FEA is there and it looks like it should keep my posts working for years to come. Worst case, they break just like the other ones did but I tend to think this fixes it. Seeing that Groovy Rody is doing something similar and with good results reinforces all of it to me. Now if I was just jamming in a horribly machined $75 alloy post that everyone swoons over, I suppose it wouldn't be an issue.


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## Thylacine (Feb 29, 2004)

Did you angle the cut in the reverse direction too while you were at it, see what the ghost in the machine spits out?


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## dr.welby (Jan 6, 2004)

jay_ntwr said:


> However, intuitively, I thought that the highest stress was right at the top of the seat tube. It turns out it's about 1/4-1/2" above the top of the seat tube after doing some analysis on it. Note how much cooler the first inch+ is with the 45 cut versus the straight cut. It also spreads stress more evenly over the back of the seat tube. And I think it'll look cool:


Once you get a short distance away from the seat tube, shouldn't the seatpost stresses be for all intensive purposes identical? At that point, it's a cantilevered beam no matter how its clamped. I noticed the color ranges are different, but still something bugs me about the FEA results.


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> If I wasn't out one EC90 and one ~$300 post, I'd agree with you. Hey, the FEA is there and it looks like it should keep my posts working for years to come. Worst case, they break just like the other ones did but I tend to think this fixes it. Seeing that Groovy Rody is doing something similar and with good results reinforces all of it to me. Now if I was just jamming in a horribly machined $75 alloy post that everyone swoons over, I suppose it wouldn't be an issue.


$300 post?!? Dang, the $40 aluminum ones I use work just fine and I have never had a failure.


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## pvd (Jan 4, 2006)

I've found that the longer I build my own frames, the cheaper my parts get. My stems cost me $16 and posts $24. I'm just about to start fabbing my own stems, so that cost is going up by a factor of 4, so now parts are getting more expensive again. I don't even want to think about how much money or time I have into my new DH chainguide.


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## pvd (Jan 4, 2006)

I'd never use a brazed or welded on seat post binder. They are the worst. They will always turn into a problem or at least look like $hit in 10 years. Go with a separate part for the binder. They work better, they are stronger, they provide more support and they come in colors.


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## jay_ntwr (Feb 15, 2008)

shiggy said:


> $300 post?!? Dang, the $40 aluminum ones I use work just fine and I have never had a failure.


You need to ride a Ti post. They are worth every penny, especially if they don't break.

PVD, I've always agreed that a clamp is better than a binder but I've recently started to warm up to binders instead of clamps and this frame will probably end up with a binder. Initially, I'd thought about making my own clamp but that may be on #2 instead.


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## unterhausen (Sep 28, 2008)

If you are really worried about stresses, it seems like angling forward would be the way to go. I'm trying to understand the stress condition you have applied in the fea. Is it pure compression? Seems like the seatpost is in compression/bending, but the stresses look symmetrical. The wavy stress field on the angled configuration looks suspiciously like numerical instability.


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> You need to ride a Ti post. They are worth every penny, especially if they don't break.
> 
> PVD, I've always agreed that a clamp is better than a binder but I've recently started to warm up to binders instead of clamps and this frame will probably end up with a binder. Initially, I'd thought about making my own clamp but that may be on #2 instead.


_"...especially if they don't break."_ That is the deal killer. I have yet to see any ti post that did not have durability problems, usually bending. How they were clamped made no difference.

Most of my frames are built to use most of a 410-425mm post. Plenty of post to flex and they hold up.


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## Blaster1200 (Feb 20, 2004)

Rody said:


> Jay,
> 
> I've been using this type of design since 94 and others well before that for the reasons you are now illustrating...never understood why people place the binder at the rear of the post where the highest stress is?


I'm not an engineer, so I can't explain much here, but...I've seen quite a few number of frames break when the clamp slot is on the front. They all start the crack at the round part at the bottom of the slot, similar to what you have on your top photo.


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## shiggy (Dec 19, 1998)

Blaster1200 said:


> I'm not an engineer, so I can't explain much here, but...I've seen quite a few number of frames break when the clamp slot is on the front. They all start the crack at the round part at the bottom of the slot, similar to what you have on your top photo.


I have seen at least as many break with the slot in back. Not really a question of the slot location but whether the relief hole at the bottom of the slot properly stops the stress risers.


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## coconinocycles (Sep 23, 2006)

i like Al. seat clamps........one less thing to strip, can be switched to a QR unit, too......the braze-ons do look "cleaner" however. classy, too........most of the ST/TT/SS junction failures i've seen looked like they could be attributed to the reaming of material from inside the ST, resulting in thin spots where the material had to be removed due to heat distortion/excessive TIG penetration.........you need to address this in one of several ways in your design/fab process......if you do go with a pinch bolt don't over-ream your ST or you will F-up the binder when you over tighten it to keep your post from slipping.........so many little details....... :thumbsup: Steve.


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## RoyDean (Jul 2, 2007)

dr.welby said:


> Once you get a short distance away from the seat tube, shouldn't the seatpost stresses be for all intensive purposes identical? At that point, it's a cantilevered beam no matter how its clamped. I noticed the color ranges are different, but still something bugs me about the FEA results.


Yeah, and the wavy pattern at the seat end doesn't make sense if the boundary conditions are identical. Something is fishy with these runs.... could you zoom out and take screen captures of the boundary condtions of both runs?


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## Blaster1200 (Feb 20, 2004)

shiggy said:


> I have seen at least as many break with the slot in back. Not really a question of the slot location but whether the relief hole at the bottom of the slot properly stops the stress risers.


Agreed.

Most that I've seen with th slot in the back break at the weld in the front. Those that I've seen break with the slot in the front always break at the hole, not at the weld. I could only guess (I'm not an expert) that the hole in front seems weaker than the weld. But I can't really argue if it's stronger to have the slot in the front or back.


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## jay_ntwr (Feb 15, 2008)

Guys, I'm getting ready for the Ouachita Challenge today so I'll look at this next week and refine the mesh and see what happens.

I'm glad to see all this feedback on the idea though. It may turn out to be a bad one :madman:


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## RoyDean (Jul 2, 2007)

Meh, it's really not that important, don't worry about it. I suspect you'll find exactly what I expect... nothing (as in the boundary conditions are identical in both scenarios). Maybe just a meshing difference or some other little thing.


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## unterhausen (Sep 28, 2008)

the highest tensile stresses are on the front of the seatpost. The rear is usually in compression. Compressive stresses are generally safe for most materials. 

Frames that break are a different matter. Most of the broken frames I've seen have had the wrong sized seatpost installed at some point, or somebody just cranked the seat post binder bolt down too much.


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## unterhausen (Sep 28, 2008)

dr.welby said:


> Once you get a short distance away from the seat tube, shouldn't the seatpost stresses be for all intensive purposes identical? At that point, it's a cantilevered beam no matter how its clamped. I noticed the color ranges are different, but still something bugs me about the FEA results.


The wavy pattern certainly doesn't make sense to_ my_ intuition. I'm not going to say it's impossible, but it seems unlikely given a load in the linear elastic region -- maybe if the seatpost had buckled. It is a cantilevered beam, but it's under a compressive tip load, a bending load, as well as the clamping load. I would be very suspicious of these result had I done the analysis.


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## rocwandrer (Oct 19, 2008)

unterhausen said:


> The wavy pattern certainly doesn't make sense to_ my_ intuition. I'm not going to say it's impossible, but it seems unlikely given a load in the linear elastic region -- maybe if the seatpost had buckled. It is a cantilevered beam, but it's under a compressive tip load, a bending load, as well as the clamping load. I would be very suspicious of these result had I done the analysis.


agree completely.


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## jay_ntwr (Feb 15, 2008)

Ok, I tightened up the mesh (a lot) and checked the model a little more carefully just for good measure (and loaded it 50 lbs more). I'm still not seeing a reason NOT to do this though it does change the results of where the highest stress is a bit:


















As far as boundary conditions, I fixed the base of the seat tube (only 3" long on the straight cut, 3" on the back side of the 45 degree) and put 300lbs on an artificial saddle such that most of it is on the rear of the saddle. FYI, the highest stresses in the scale come from that artificial saddle/post interface. They weren't present in the last model 'cause I had a huge fillet to prevent them from coming into play. I took that out when I tightened up the mesh.

BTW, any of you guys make it out to Ouachita Challenge this weekend? What a ride. Make it next year if Arkansas is within an 8 hour drive of you.


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## Thylacine (Feb 29, 2004)

You still haven't run it the other direction to see what comes out.


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## unterhausen (Sep 28, 2008)

Thylacine said:


> You still haven't run it the other direction to see what comes out.


I always thought that looked goofy, but I also suggested it


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## rocwandrer (Oct 19, 2008)

it looks to me like now your failure stresses are lower down the post than is typical in real life, but ignoring that, the output looks pretty reasonable.

I suspect if you did a local buckling model, you'd find that there is some compression buckling that initiates compression failure just a bit below the theoretical compression failure load. Given that as a failure mode, using this stress field as a way of improving design is faulty. 

Oh, and I too feel that running the cut the other way will be more robust.

Edit: if I am right about failure initiation, the best thing you can do in the frame to help it is to apply less clamping force over more area to reduce the compression deformation of the seat post.


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## jay_ntwr (Feb 15, 2008)

*Shiggy, this is what you were wanting to see I think*


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## DWF (Jan 12, 2004)

rocwandrer said:


> it looks to me like now your failure stresses are lower down the post than is typical in real life, but ignoring that, the output looks pretty reasonable.
> 
> I suspect if you did a local buckling model, you'd find that there is some compression buckling that initiates compression failure just a bit below the theoretical compression failure load. Given that as a failure mode, using this stress field as a way of improving design is faulty.
> 
> ...


Agreed. Spoon at the back, not spoon at the front. Slot to the front if you wish. The post is a cantilevered beam, how you reduce loads on one is obvious. Also important to remember that the post is free floating within the seat tube, it is not bonded and stresses are not communicated as it would be on a solid model.


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## rocwandrer (Oct 19, 2008)

jay_ntwr said:


>


is that an illusion of perspective, or is that cut sideways?


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## jay_ntwr (Feb 15, 2008)

rocwandrer said:


> is that an illusion of perspective, or is that cut sideways?


It's cut at 45 degrees to the axis and the "tall" part of the seat tube is toward the rear of the frame.


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## rocwandrer (Oct 19, 2008)

jay_ntwr said:


> It's cut at 45 degrees to the axis and the "tall" part of the seat tube is toward the rear of the frame.


make the cut tapered (cut a round hole through the tube, off center, from the side), and the profile will look much better than the first iteration. you get some of that by just increasing the angle a lot, but it won't be any where near ideal. think of it a little like a gusset.


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> ...


I did not ask for it and i really do not understand what is being shown. In any case, the dimensions of the tubes (is the post even modeled as a tube?) seem off. I see no slot in the ST and no binder, either. These have to affect the stresses.

DWF's point about the ST/post not being a solid unit is good, too.


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## jay_ntwr (Feb 15, 2008)

rocwandrer said:


> make the cut tapered (cut a round hole through the tube, off center, from the side), and the profile will look much better than the first iteration. you get some of that by just increasing the angle a lot, but it won't be any where near ideal. think of it a little like a gusset.


Initially, this is what I toyed with. I couldn't get the cut the way I wanted it without a HUGE radius though and since I'm using hack saws and files, I abandoned that idea (for the time being). There still may be something in the future that will look like what you're describing here though.


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> Initially, this is what I toyed with. I couldn't get the cut the way I wanted it without a HUGE radius though and since I'm using hack saws and files, I abandoned that idea (for the time being). There still may be something in the future that will look like what you're describing here though.


It is not that hard to do with a half-round file. May take 10-15 minutes at most.


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## jay_ntwr (Feb 15, 2008)

shiggy said:


> I did not ask for it and i really do not understand what is being shown. In any case, the dimensions of the tubes (is the post even modeled as a tube?) seem off. I see no slot in the ST and no binder, either. These have to affect the stresses.
> 
> DWF's point about the ST/post not being a solid unit is good, too.


I thought I'd read you asking to see something like that somewhere--perhaps not. And yes, the post is modeled as a tube as is the seat tube. The OD of the ST is 1.25" (sleeved) and the OD of the post is 27.2mm. The model is "simplified" meaning that the binder and slot are not shown--that may prove to be a bad assumption and the point of failure because it's not like the stress that is missing in the seatpost is just gone--it should be distributed in the seat tube and may cause problems--dunno yet but I'd rather have that in a 27.2mm ID x 1.25" OD portion of steel tube since it's going to be on the frame anyway.

I'm not trying to determine exact stresses here either, that's not what I'm looking for at all. I'm looking for relative stress between the "traditional" 90 degree cut and something other than 90 degress, 45 degrees in this case. I believe that the binder and slot don't come into play as they both fall out of both equations--all things being equal. The seat tube/post may not be a solid unit, but them acting as a solid unit is a reasonable enough assumption--seirously, now much does your seatpost move around in the frame when it's clamped? I suppose we could talk this thing to death but the conclusion I'm making is that (while plenty strong enough) a seat tube cut 90 degrees to the axis of that tube is the least desirable solution of the three cases we've looked at in this thread so far.


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## Schmitty (Sep 7, 2008)

*I just modeled this in my head...*

I'd take a 90 degree, properly preped st cut (rounded edges on lip) of the appropriate length so as to not have too much post, and with a good quality post. If you do those things, all else is moot. An additional 2 cents, run an over size st, and turn an Al shim to get yourself back to 27.2 or whatever. If your breaking posts in an AL shim, time to give up biking.. or maybe switch to trials.

-Schmitty-


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## dr.welby (Jan 6, 2004)

jay_ntwr said:


> The model is "simplified" meaning that the binder and slot are not shown--that may prove to be a bad assumption


I used to work for a carbon seatpost manufacturer and based on what I saw come back for warranty, that is a bad assumption. The majority of broken seatposts we had showed localized damage from the seatpost slot.


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## jay_ntwr (Feb 15, 2008)

dr.welby said:


> I used to work for a carbon seatpost manufacturer and based on what I saw come back for warranty, that is a bad assumption. The majority of broken seatposts we had showed localized damage from the seatpost slot.


Yes, but of those, the overwhelming majority of the localized damage was from the slot being to the rear, not front of the post, correct?


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## dr.welby (Jan 6, 2004)

jay_ntwr said:


> Yes, but of those, the overwhelming majority of the localized damage was from the slot being to the rear, not front of the post, correct?


Nope, saw it happen on both, believe it or not. In fact, I saw a couple of weird failures that lead me to believe that the problem is more complicated than just a cantilevered beam loaded in one direction only.


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## jay_ntwr (Feb 15, 2008)

dr.welby said:


> Nope, saw it happen on both, believe it or not. In fact, I saw a couple of weird failures that lead me to believe that the problem is more complicated than just a cantilevered beam loaded in one direction only.


Absolutely it is more complicated than that! But it surprises me that the rear slot doesn't create more problems than a front slot (on post failure).

Of my post failures, all have been due to the rear facing slot (except for that one time I was doing stoppies on my road bike and broke the carbon post off of it coming down). I don't anticipate any more failures with this design though (as the seat tube isn't any shorter in the rear, just longer in the front). If they do fail the same, I suppose I'll have learned something but I still haven't seen a compelling reason not to do this so far AND it may actually fix the problem.


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## shiggy (Dec 19, 1998)

jay_ntwr said:


> Yes, but of those, the overwhelming majority of the localized damage was from the slot being to the rear, not front of the post, correct?


You are assuming again.


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## jay_ntwr (Feb 15, 2008)

shiggy said:


> You are assuming again.


I still find it hard to believe that this is a 50/50 proposition.


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## rocwandrer (Oct 19, 2008)

jay_ntwr said:


> I still find it hard to believe that this is a 50/50 proposition.


it can't be, because the proportion of clamp styles out there isn't 50/50.....


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## Gregg K (Jan 12, 2004)

If failure at the seat tube notch is due to hoop stress, then it shouldn't matter whether the cut is in front or in the rear. I think. I know there is a force component that the front of the seat tube doesn't see. But if the hoop stress exceeds the failure stress at the notch, then it would fail if in front or rear. Unless I'm full of it. Which is highly likely. 

I'm embarrassed to say that I am a mechanical engineer, as I've not even seen stress analysis for 20 years. I've only done analysis via calculator. And never had a fluid understanding of it all. I lost it at Moor's circle. Haha.


Oh dear, it's Mohr's circle. I've forgotten more than most people will ever know. Take that however you want it to mean.


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## vulture (Jan 13, 2004)

*dear god, just build the friggin thing*

Time to build. Since there are millions of examples of dang near every version of a seat tube solution in real world no matter what you do it should still keep the seat tube from slipping and if it looks cool you get extra points. This isn't rocket surgery or solving the world algebra problem. Building and riding bikes is more fun than playing with computers, Although an FEA paint job would be cool. One that changes as forces change as you ride...Hmmmm


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## shiggy (Dec 19, 1998)

vulture said:


> Time to build. Since there are millions of examples of dang near every version of a seat tube solution in real world no matter what you do it should still keep the seat tube from slipping and if it looks cool you get extra points. This isn't rocket surgery or solving the world algebra problem. Building and riding bikes is more fun than playing with computers...


Have to say I have been thinking the same thing. Part of the reason I wrote my _"Zen..."_ thread the way I did.


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## rocwandrer (Oct 19, 2008)

shiggy said:


> Have to say I have been thinking the same thing. Part of the reason I wrote my _"Zen..."_ thread the way I did.


build it in polycarbonate and wear polarized sunglasses.....


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## DWF (Jan 12, 2004)

jay_ntwr said:


> Absolutely it is more complicated than that! But it surprises me that the rear slot doesn't create more problems than a front slot (on post failure).
> 
> Of my post failures, all have been due to the rear facing slot (except for that one time I was doing stoppies on my road bike and broke the carbon post off of it coming down). I don't anticipate any more failures with this design though (as the seat tube isn't any shorter in the rear, just longer in the front). If they do fail the same, I suppose I'll have learned something but I still haven't seen a compelling reason not to do this so far AND it may actually fix the problem.


Seatpost clamps don't clamp with even pressure around the OD of the post/tube. They always pinch at the slot and the clamping pressure is always highly localized. If you want even clamping pressure, configure the seat tube as you would a collet. It'd be real easy to make a collet style insert that welded to the seat tube with a taper ring with a small skirt to cover the slots.


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## D.F.L. (Jan 3, 2004)

A collet would be easy (ask Klein), but a 45 degree collet would be something.

Jay, you'll be a little better off just staying traditional on this first one. There will be plenty of challenges to face just in the construction. There's plenty of time to think about making them better.


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## dr.welby (Jan 6, 2004)

jay_ntwr said:


> If they do fail the same, I suppose I'll have learned something but I still haven't seen a compelling reason not to do this so far AND it may actually fix the problem.


I say just try it. If you break a seatpost then you can feed that lesson back into analysis, and you can always cut the seat tube square and put on an external clamp/collar.


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## Thylacine (Feb 29, 2004)

jay_ntwr said:


> SomethingSomethingSomething.....


Actually it was me and Unterhausen that suggested angling it 'up' at the rear....umm....maybe because we _know_ angling it like that is lower stress....and that IT DOESN'T MATTER WHICH YOU CHOOSE BECAUSE IT'S A SOLUTION LOOKING FOR A PROBLEM.



Thanks for listening. :thumbsup:

Now go build.


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## jay_ntwr (Feb 15, 2008)

Guys, thanks for all the encouragement and discouragement, discussion, theory, recommendations, etc. This was a fun thread (for me) and I hope it was for you guys too.

BTW, my sleeve and extra practice tubing should be here today. I suppose what happens next is for me to know and you guys to find out.


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## timroz (Feb 25, 2007)

Man is this ever killing my buzz.

I thought a guy was gonna hack up some tubes, weld a frame, ride it 'til it broke, and 
document it.

I'd check back in 18 months or so, except you'll probably be discussing the finer points of bottom bracket thread grease viscosity.


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## Schmitty (Sep 7, 2008)

The fact that the 45 will need to have a brazed on binder totally negates any *possible* benefits of doing it that way. Seat clamps like Salsas that use a barrel nut are the only way to go for constant evenly distributed pressure. I run the slot of the clamp 180 from the seat tube slot to further decrease the chance of collapsing the st at the binder slot. Grease the inside of the clamp before sliding it over the tube, of course grease the threads, and the outside of the barrel nut to allow it to rotate freely.

This will work 100% of the time assuing the post isn't a total pos, that you don't have too much post sticking out, that there are no defects in the post, that the seat tube has been preped/assembled correctly, etc.

-Schmitty-


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## coconinocycles (Sep 23, 2006)

timroz said:


> Man is this ever killing my buzz.
> 
> I thought a guy was gonna hack up some tubes, weld a frame, ride it 'til it broke, and
> document it.
> ...


sweet! sh!t or get off the pot, right? Steve.


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## jay_ntwr (Feb 15, 2008)

coconinocycles said:


> sweet! sh!t or get off the pot, right? Steve.


I was once naive enough to think that all one had to do was file a few miters, weld it up, go ride it. The most frustrating thing I've already learned is that I'm constantly waiting on the FedEx truck to bring me the next thing I need to move forward since I can't just go out to my fully stocked shop and start building.


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## CheeseSoda (Jan 8, 2007)

+1 Schmitty.


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## coconinocycles (Sep 23, 2006)

jay_ntwr said:


> I was once naive enough to think that all one had to do was file a few miters, weld it up, go ride it. The most frustrating thing I've already learned is that I'm constantly waiting on the FedEx truck to bring me the next thing I need to move forward since I can't just go out to my fully stocked shop and start building.


sounds like you need to organise & get a comprehensive shopping list going........shipping kills......buy 2 of everything while you are at it. you'll be stoked you did. why don't you start a new thread of what you have & what you are building. i'll try to help steer you towards a shopping list. it does suck to not have what you need! i ran out of 29er CS's last year so this year i bought 30 sets...........Steve.


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