Cracked Syncros seatpost fixable?- Mtbr.com
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  1. #1
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    Cracked Syncros seatpost fixable?

    I have a Syncros post with a crack in it. According to the 1994 Syncros catalog on mtb-kataloge it's made of 7075-T78 aluminum. Now IANAMBIPOOTV (I Am Not A Metallurgist But I Play One On TV) but I seem to remember that the 7000 series doesn't require heat treating. As you can see, the crack is just below where the post head joins the tubular shaft.

    Can this post be welded without heat treating and be done so safely? As a shop owner mentioned to me, catastrophic seatpost failures can be quite dangerous. It's a cool post but I'm not willing to risk injury. So, think this is a goner or a fixer-upper?

    Pinguwin



  2. #2
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    Goner. I wouldn't even think of trying it unless the bike is hanging in a museum for show. Replace it.
    Needed: 26.8mm XTR seatpost, blue GT/Grundig Jersey.

  3. #3
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    Quote Originally Posted by gm1230126
    Goner. I wouldn't even think of trying it unless the bike is hanging in a museum for show. Replace it.
    Agreed.

    Cool post with the old vertical lettering...but there are enough of them out there to where you could get a replacement relatively cheap.

    Really not worth the time, effort, and risk of repair.
    -eric-

    http://www.rumpfy.com
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  4. #4
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    As far as i know 7075 can not be welded, not property at least...

    I'm pretty sure the seat post head is criogenically press into the seat tube and also bonded, so maybe you can Heat the post up, take the head off, cut the amount of damage post and then re-insert the head (heating the post/Cooling the head), yes is not perfect (the logo will be cut short) but still better than trashing such a piece of history.

    I also know of a guy here in san Francisco that makes "Metal String rap" that is used by the military for external guzzets like you may need, but even then the structure of the tube is already compromise.

    Will be a shame to discart it, let me know if that is the case and I may try it to fix it for you or at least buy it from you and fix it for my self.

    I'm not a metallurgic expert, but I do play one 8 hours a day 6 days a week.making fancy and very strong motorcycle parts.

  5. #5
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    I didn't think it would be fixable but figured I would ask. I've got a few NOS bikes that will probably remain garage queens. And Rumpfy, before you start ragging about Garage Queen Kleins (GQK's), not all are Kleins. One is a NOS American M16. Might put it on one of them. The crack is actually very hard to see and I had to take a number of pictures for it to show up as it did.

    Patineto, tell you what, if I don't put it on of the NOS bikes, I'll contact you, ok? Actually I don't think (I don't have the post handy to check) but it appears to be three pieces, the post, the head, and the cracked part appears to be separate from the other two, so cutting off the damaged part won't work.

    Thanks for the replies, guys.

    Pinguwin

  6. #6
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    There was an article about lightweight gear in Bike, or was it Dirt Rag, maybe 10 years ago?? It featured a guy telling about his seatpost breaking on a ride. The line sticks in my head to this day, I do paraphrase a bit, but here's the gist of it. "I'm riding down the trail, and hit a bump, not even a really big one. Next thing I know, I'm on the ground, assesing the damage, and things are feeling a bit strange. I soon found myself in a position no man should ever be forced to be in, face to face, with my own pink glistening nut" If that won't stop you, I don't know if anything will
    This is a Pugs not some carbon wannabee pretzel wagon!!

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  7. #7
    Doesntplaywellwithmorons!
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    Most 7000 series alloys used to make WELDED aluminium frames don't need to be heat-treated a second time after the frame is welded together to have good strength but they should be artificially (or naturally if you don't mind waiting a month to ride it) aged afterwards to relieve grain stress. But we're talking stuff like 7005 and 7020 which are around 45ksi in ultimate tensile strength. 7075-T6 which is what many companies used for seatpost shafts is about 83ksi, and its not readily weldable either. The difference between 7075 in its annealed state and heat-treated and artificially aged T6 temper state is about 50ksi. In other words, it more than doubles in strength so if you were to "heat it up" like you're proposing to try and fix it, you'd be cutting its strength in half.
    I don't post to generate business for myself or make like I'm better than sliced bread

  8. #8
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    Ditch the seatpost...the potential consequences far outweigh the cool factor that only 1 or 2 people might appreciate in any given year...

    Think of it this way...would you rather hear "hey, nice seatpost man!" and "I'm sorry sir, we had to put 117 stitches in your scrotum and reconstuct your anal sphincter completely. You may need to eat soft food for a few years." in the same day?

    NO style is worth that, as far as I'm concerned.

    But maybe I've said too much.

    -Richard

  9. #9
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    The post is only for display only and the last two posts have only made it even more that way.

    I was in a tree once and jumped the last six feet down. There was a jagged, metal pole 30" long in the ground I didn't see and put a serious gash in my thigh, about 1" away from where the leg joins the torso, it was the most painful thing I've ever experienced and I still have the scar. Yes I nearly lost my male stuff but also very close to killing myself by getting impaled. It was 25 years ago but I still cringe whenever I think of that experience and even the emergency room staff reacted when they saw it. Dee & Richie have brought back those memories. Yikes.

    I was unlikely to use it even before I asked but it's good to have fellow-vrc'ers to emphasize how bad an idea it could be. As always, thanks.

    Pinguwin

  10. #10
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    Quote Originally Posted by pinguwin
    I didn't think it would be fixable but figured I would ask. I've got a few NOS bikes that will probably remain garage queens. And Rumpfy, before you start ragging about Garage Queen Kleins (GQK's), not all are Kleins. One is a NOS American M16. Might put it on one of them. The crack is actually very hard to see and I had to take a number of pictures for it to show up as it did.
    Man I better check your posting, When I was living in Colombia I have seven klein's (It helps to be the dealer) from Rascal's to adroid's and I got lucky to also have one of this American's too, among many nice steel bike's including a few Yo-eddy's.

    Patineto, tell you what, if I don't put it on of the NOS bikes, I'll contact you, ok? Actually I don't think (I don't have the post handy to check) but it appears to be three pieces, the post, the head, and the cracked part appears to be separate from the other two, so cutting off the damaged part won't work.

    Thanks for the replies, guys.

    Pinguwin
    You see mister PinguWin..

    That is the difference in between the ones that "Play's on TV" and the ones that do it for a Living..

    You need to analyze how something works and why it was made that way from the start (many times to improve manufacturing efficiency and ensamble) and finally figure out if you can fix it or not..

    Personally I'm being using Syncros seatpost since 1991 when they use to have the top flat plate that damage the bolt treads if the bolts were not perpendicular, So I made (Yes with a dremel, a hacksaw and a bunch of files) my own top plate using "wobble" Nuts (Pivoting) that self align with the bolts in a similar fashion to they later design.

    Anyway before Syncros I have many seat post and they always bend or fail (Fat ass, to extended, long legs, to aggressive jumping, whatever) my 3er Klein attitude came with a IRD post but even that one bend a little, but then one day I got my first Syncros post and end up being a similar experience to the time I got my first chris king headset, a.k.a. one less thing to worry about and my bicycle life was never the same after..

    Today I have about 14 Syncros posts, a few stems, bottom brackets, jackets, hats and a bunch of never being used T-shirts from my interbike days because I find them Venerable as well as 23 king headsets because they are the very best..

    Anyway will be a shame to see such a piece of History go to "seat post Valhalla" with out dyeing in battle like it deserves.

    I never took one of them apart, but I'm sure even Syncros products are bound by the laws of fisics, so most be a way to fix it and do it right, for me will be a Honor just to try..

    Ps: I have two seat post clamp failures over my years of MTB racing and hard riding (from 1983 to about 1995) and nothing really bad happen, but for sure it can get ugly in a hurry.

  11. #11
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    Quote Originally Posted by pinguwin
    And Rumpfy, before you start ragging about Garage Queen Kleins (GQK's), not all are Kleins. One is a NOS American M16. Might put it on one of them. The crack is actually very hard to see and I had to take a number of pictures for it to show up as it did.
    Nothing wrong with having some garage queens. I do.
    Plus I know you ride the hell out of one of your Kleins.


    Its just a general observation that theres a high ratio of street ridden or wall hung Kleins out there. Thats all.



    Lets see some pics of that M16!
    -eric-

    http://www.rumpfy.com
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  12. #12
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    You can find syncros seatposts on ebay regularly anyways so unless yours is an oddball diameter, just buy another used one that's crack-free.
    I don't post to generate business for myself or make like I'm better than sliced bread

  13. #13
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    Ah Rumpfy, the garage queen comment, I know that you're chomping at the proverbial bit to dig at Klein owners, so I just thought I would pre-empt the comment you so badly wanted to make. Actually, there are three of my Kleins that I ride regularily.

    I have to say that I am surprised at the number of pristine Kleins out there, so yeah, lots of Queens. The M16 is frame only and won't be completed for some time but I'll post some pictures of it. I want to wait until a bike is complete or nearly so before I'll post, but not in this case. Even the Team Moosepoop bike is slated for some changes with painting the rims (awaiting an airbrush), so nothing except your Tomac bike is really ever done.

    Pinguwin

  14. #14
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    Interesting thread. I bought a Syncros Seatpost via Ebay the other day. On second sight after getting the parcel I recognized black tape around the post just under the post head. After removing the same crack as pictured above appeared.

    Needless to say, the seller didn't answer questions and was unsubscribed from ebay a few days later...

    So my question concerning repair or not is answered...

  15. #15
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    i have second thoughts about riding non craked syncros post.
    get a thomson. or a ringle if you must have uber coolness.
    WTB: Bomber Z2 1 1/8 steerer, in good to excellent shape OR bomber rebuild kit.

  16. #16
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    Quote Originally Posted by MendonCycleSmith
    There was an article about lightweight gear in Bike, or was it Dirt Rag, maybe 10 years ago?? It featured a guy telling about his seatpost breaking on a ride. The line sticks in my head to this day, I do paraphrase a bit, but here's the gist of it. "I'm riding down the trail, and hit a bump, not even a really big one. Next thing I know, I'm on the ground, assesing the damage, and things are feeling a bit strange. I soon found myself in a position no man should ever be forced to be in, face to face, with my own pink glistening nut" If that won't stop you, I don't know if anything will
    i
    know of one short lightweight roadie who broke a syncors post while riding. it wasn't a warranty and the guy has no need to BS. he was riding and the post head broke. one of those "ears" on the head broke clear.
    i had a syncros and it was safe. i also had a thomson. when it was time to depart a frame w/one seatpost guess which one left the house?
    i don't f%^&& around w/ stems, forks and posts.
    WTB: Bomber Z2 1 1/8 steerer, in good to excellent shape OR bomber rebuild kit.

  17. #17
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    Quote Originally Posted by drullse
    the seller didn't answer questions
    Ah the travails of ebay, been there before. FWIW, the post came on a pricey bike which had some other problems. The seller had 100% positive feedback and probably wanted to keep it that way. It took a while but I eventually got $200 back, which was a reasonable cost to replace broken parts.

    In adherence to the "Bike money remains bike money" rule, the $200 is going to buy more goodies.

    Pinguwin

  18. #18

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    change in name...

    Quote Originally Posted by pinguwin
    Ah the travails of ebay, been there before. FWIW, the post came on a pricey bike which had some other problems. The seller had 100% positive feedback and probably wanted to keep it that way. It took a while but I eventually got $200 back, which was a reasonable cost to replace broken parts.

    In adherence to the "Bike money remains bike money" rule, the $200 is going to buy more goodies.

    Pinguwin
    Even if it's for display only...you may forget and hop on for a ride..if it then breaks we would have to change your name from "pinguwin" to "paingoinin"

  19. #19
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    Lol

  20. #20
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    They must have had a run of bad tubing and machining, I have seen at least a dozen that broke in a similar fashion. The majority of the ones I saw usually "peeled" away from the bonded head at the rear or front. i bet if you check closely, you'll find other cracks near the bolts.

    Worst injury I've seen from a failed seatpost (not syncros) is a broken rib. It broke in 2 places as the kids chest hit the top of the post, it nearly punctured his lung, and bruised his heart. He ended up in the hospital a few days later, not realizing his rib was broken.

    I have expereinced broken bolts on single bolt posts and that is scary, that is why my bike now have thomsons and a really old syncros (1989) on them. i'll never trust a single bolt design again.

  21. #21
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    Quote Originally Posted by stan4bikes
    Even if it's for display only...you may forget and hop on for a ride..if it then breaks we would have to change your name from "pinguwin" to "paingoinin"
    Or... PainGroin

  22. #22

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    Late nineties Syncros posts are prone to problems.

    Quote Originally Posted by donk
    They must have had a run of bad tubing and machining, I have seen at least a dozen that broke in a similar fashion. The majority of the ones I saw usually "peeled" away from the bonded head at the rear or front. i bet if you check closely, you'll find other cracks near the bolts.

    Worst injury I've seen from a failed seatpost (not syncros) is a broken rib. It broke in 2 places as the kids chest hit the top of the post, it nearly punctured his lung, and bruised his heart. He ended up in the hospital a few days later, not realizing his rib was broken.

    I have expereinced broken bolts on single bolt posts and that is scary, that is why my bike now have thomsons and a really old syncros (1989) on them. i'll never trust a single bolt design again.
    I have two early Syncros posts. These have the machined heads. You can see the lines on the aluminum from the tool as it shaped the aluminum heads. I bought a broken Syncros post recently for a project. The head had separated from the post. Apparently a common complaint with later posts. Looking at the head, there are no machining marks. In fact, the surface irregularities suggest that the head had been cast rather than machined. Even the section that inserts into the tube was cast, integrally with the rest of the head. I measured the diameter of the insert section, and found it to be very uneven and out of round. It is little wonder that it came loose. An interference press fit requires that the mating parts be precisely turned to achieve a 1/1000th of an inch diference in diameter. I brought the head to a machinist, who turned it on a lathe. I had the head inserted into a cromoly tube, and I now have a very nice cromoly seatpost with a Syncros head that does not work itself loose. I am planning to transfer it to a titanium tube which I purchased on eBay.

    You could shorten the seatpost to below the crack, and then do what I did. I would not do it if it is expensive. Just buy a new one. Buti f you know somebody with a lathe, you can salvage the post as I described, using the original tube.

  23. #23

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    Pinguwin: sorry for the late reply. Marshall here at Syncros. Two things: First, don't fix the old post. Second, email me and (depending upon the diameter) we may be able to replace the post. Cheers.

  24. #24
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    Quote Originally Posted by MCSquared
    Pinguwin: sorry for the late reply. Marshall here at Syncros. Two things: First, don't fix the old post. Second, email me and (depending upon the diameter) we may be able to replace the post. Cheers.
    Awesome Customer Service!
    Needed: 26.8mm XTR seatpost, blue GT/Grundig Jersey.

  25. #25
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    Quote Originally Posted by gm1230126
    Awesome Customer Service!
    Absolutely.

  26. #26
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    i'll see your cracked seat post..... and raise you a cracked stem.... and cracked bb.......and a cracked fork.........im all in......

    ud
    MID 90'S YETI F.R.O.16" NEED'S SOME TLC......INTERESTED??.......SEND PM.

  27. #27
    He be a moose too.
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    A happy ending there is. The other day a manager at Syncros noticed my post about a post and contacted me, asking for my address. Today the morning mail held a pleasantly-shaped package. So I have a new 27.2*425 seatpost. FWIW, the new post appears to have a reinforcement at the top.

    The cracked post was an original Synrcos post made 15 years ago. Since then they've been bought out a couple of times and as such, never thought about a warranty. Whodathunkit? Looks like they stand behind their goodies pretty well. I'm pretty tickled about that.

    Pen-Goo-Eee-Nee
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  28. #28
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    Awsome. What's with the hole at the bottom of the post?

  29. #29
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    Quote Originally Posted by muddybuddy
    Awsome. What's with the hole at the bottom of the post?
    syncros always had this hole there. it's part of the charm.
    WTB: Bomber Z2 1 1/8 steerer, in good to excellent shape OR bomber rebuild kit.

  30. #30
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    Post Holin

    Quote Originally Posted by muddybuddy
    Awsome. What's with the hole at the bottom of the post?
    I've always been told that the hole is there so you can lock up your post, if'n you have a quick release seat binder. Never actually seen anybody pull the post and run it through a U-lock, but it's there.

    Plum
    This post is in 3B, three beers and it looks good eh!

  31. #31
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    Just tried it with a U-lock. My Kryptonite Krypto-Lock doesn't fit. The metal itself fits in but with the plastic coating, nope. Though I have heard the U-lock thing mentioned before.

    Pen-Goo-Eee-Nee

  32. #32
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    Wow, great costumer support. I wonder if the would replace mine too...

  33. #33

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    drullse: sorry for the late reply but we have been at the annual bike industry torture session known as Interbike Las Vegas. Email me and we'll see what we can do. We don't make all the original seatpost sizes but if we do we'll replace it.
    Marshall

  34. #34
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    Hi McSquared, You got a PM since I didn't have You Mail-Adress.

  35. #35

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    drullse: could you please try again....email didn't make it through to me. You can also get me from the Syncros site www.syncros.com in the make contact section. Thanks.

  36. #36
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    Jep, I did. Hope it's coming through to You!

  37. #37
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    Good customer service... i'm impressed. I had thought Syncros had totally gone down the tubes since the Canadian operation got bought out.

    Cool!

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