# The dreaded single-bolt seat post



## Skins45 (Jul 31, 2015)

Hi all,

I just bought a Breezer Repack and along with it came enough "points" to basically pay for a KS eTen, needless to say, I got that too!

But I am a bit worried about the single-bolt system since I could never get the saddle from wandering when I had the stock clamp on my old bike. I quickly switched to a double-bolt QR and all is well. Anyway, I'm trying to be proactive with this one and want to make sure it doesn't flinch from the start.

I know the general excepted method is to put carbon paste in the contact point but I feel like that won't even do the trick. My thought is a low-grade epoxy (one with a melting point ~200F) in the contact point (where the teeth are) and around the outside. That way I can just hit it with a heat gun and take it apart easily when I want to switch seats or ADJUST. Obviously I'm wary about doing this since there are plastic parts nearby (at least i think there are? I haven't taken possession yet). Thoughts?

FWIW, I'm a bigger guy at 210 and as noted previously, have absolutely ruined a single-bolt seat in the past.


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## watts888 (Oct 2, 2012)

All my bikes are single bolt, and I'm in about 235lbs, probably over 250 lbs ride weight. I've had a couple seat's slide on the rails, but this has only happened 3-4 times in the last couple years, and usually because I set it up wrong with too much layback. I just make sure the top and bottom saddle rail plates are lined up and that the angle adjust are in the groves. Other than that, check the bolt tension every now and them and make sure the seat rail clamps are lined up.


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## J.B. Weld (Aug 13, 2012)

Be sure to grease the threads and the shoulder of the bolt (where it contacts the seatpost) and then torque it correctly (a lot). It really makes a difference IME, and if done correctly from the start you will have no problems.


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## One Pivot (Nov 20, 2009)

Dont ruin a good part before you even give it a try.

I had one single bolt post that wouldnt last 5 minutes without drastically slipping, no matter how tight. I had another few that never slipped for the years I had them.


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## faceplant72 (Oct 25, 2009)

My avatar is the result of the bolt breaking on a single bolt clamp, but most work fine unless they get stripped. I like the setback on most single bolts. The idea of epoxeing the teeth together sounds like a good way to weaken the system since it will prevent full engagement of the teeth.

Sent from my SM-G900P using Tapatalk


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## Skins45 (Jul 31, 2015)

Thanks for the responses. So what I'm taking away from this is to just try it and see if it starts to slip before modding anything. I'm going to just hope that the post that broke before was cheap/weak.


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## 127.0.0.1 (Nov 19, 2013)

you want something to worry get a Giant XTC

single bolt hidden wedge. 
carbon paste and correct torque, nothing moves


so I suggest TACX carbon assembly compound and big smear and crank that post down it won't go anywhere



epoxy and heat gun ? lol will ruin the bike


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## watts888 (Oct 2, 2012)

J.B. Weld said:


> and then torque it correctly (a lot).


Exactly. Never tried grease on the plate/nut interface, but will have to give it a shot. My posts are cheaper ones ($15 type, so a litle bit better than the $10 ebay ones), and the nut rotates on the plate at a slight angle when tightened down. As of yet, no problems, but can't help but think that keeping the correct alignment will be even better.

I don't have carbon paste, but do you think regular axle grease will work fine? Never dealt with carbon parts before, so don't know much about carbon paste.


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## Skins45 (Jul 31, 2015)

127.0.0.1 said:


> epoxy and heat gun ? lol will ruin the bike


Please elaborate as to how a low grade (low melting point) epoxy and a heat gun will ruin a bike? Remember, we're just working with the top of the seat post here lol. And nobody said you can't remove the seat post while doing it....


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## Skins45 (Jul 31, 2015)

watts888 said:


> I don't have carbon paste, but do you think regular axle grease will work fine? Never dealt with carbon parts before, so don't know much about carbon paste.


The carbon paste is specifically designed to create friction. I'll probably just end up getting a 1oz tube and using it from the start. Epoxy will be my last ditch effort but I will not let this dumb little seat post win.


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## J.B. Weld (Aug 13, 2012)

Skins45 said:


> The carbon paste is specifically designed to create friction. I'll probably just end up getting a 1oz tube and using it from the start. Epoxy will be my last ditch effort but I will not let this dumb little seat post win.


Do you have carbon rails on your saddle? I've never used carbon paste on anything but carbon fiber. Except for the fact that it would make readjusting seat angle difficult to impossible I doubt that epoxy would actually hurt anything, just completely unnecessary IME.


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## Skins45 (Jul 31, 2015)

My intent would have been to adjust the seat angle, mark line on both top and bottom of the clamp, then epoxy to adhere. There would be no need to adjust later. And, if I want to switch seats or even adjust, then heat the epoxy to remove and start over!

Carbon paste can be used on alloys too. At least that's what I've seen on the tubes and from other users.


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## 127.0.0.1 (Nov 19, 2013)

Skins45 said:


> Please elaborate as to how a low grade (low melting point) epoxy and a heat gun will ruin a bike? Remember, we're just working with the top of the seat post here lol. And nobody said you can't remove the seat post while doing it....


I don't need to prove a negative here. useless endeavor. just check 100% the bike shops no one does this half-arsed epoxy stuff, for reasons.

it's your bike do whatcha want.


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## Skins45 (Jul 31, 2015)

No problem. I asked for thoughts and you provided. I don't, however, subscribe to the mindset of; "well if the industry isn't doing it then it must never be done". I don't want to beat a dead horse - I do enjoy debating, so thanks for this - but I think I can safely assume 100% of bike shops do not use Milspec gun lube to lube chains, but there are very well documented cases of people doing exactly that with exceptional results.

I'm not sure your opinion is wrong in the end. Epoxy might be overkill. I just like making darn sure something is going to do exactly what I want, or not do exactly what I don't. Nothing was more frustrating than a wandering seat every 10 minutes through a five hour ride.


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## 127.0.0.1 (Nov 19, 2013)

carbon assembly paste is used on carbon/carbon or carbon/metal interfaces for best results and no need to overtorque. used on metal/metal won't do any harm


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## Legbacon (Jan 20, 2004)

I haven't used a single bolt post for years but when I did they worked well enough. A few friends on single bolts including the same post you have don't have issues. The only reason I would sell it and buy a 2 bolt is to get rid of the offset. If you like the position, torque it and ride.


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## phlegm (Jul 13, 2006)

watts888 said:


> ...
> 
> I don't have carbon paste, but do you think regular axle grease will work fine? Never dealt with carbon parts before, so don't know much about carbon paste.


Just to close this out, carbon paste a.k.a. assembly paste consists of suspended "grit" in a gel. It helps prevents slippage, and most importantly allows carbon parts to be tightened sufficiently without over-torquing. Regular grease would not fit the bill here.

Re the grease bit, I suspect Mr. Weld was referring to the bolt threads. The idea being that you get a more accurate torque reading when a given bolt can rotate smoothly in the nut.


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## J.B. Weld (Aug 13, 2012)

phlegm said:


> Re the grease bit, I suspect Mr. Weld was referring to the bolt threads. The idea being that you get a more accurate torque reading when a given bolt can rotate smoothly in the nut.


Yep, it was fairly common for people to bring their bike in the shop complaining that their seat would never stay put no matter how hard they tightened the bolt. A couple minutes cleaning/greasing and then torquing the bolt and we wouldn't see them again for that problem, many of these people were long term regular customers so I know the fix was good.

Cheap one bolt posts with a stamped steel top rail piece? Bin it.


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## Paulsmith55 (Jan 16, 2015)

10 years working in bike shops and I've only seen seat post clamp issues on quick release seat post clamps and department store bikes. Maybe you had a problem with too much grease on the seat tube in the past?


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## Skins45 (Jul 31, 2015)

Paulsmith55 said:


> 10 years working in bike shops and I've only seen seat post clamp issues on quick release seat post clamps and department store bikes. Maybe you had a problem with too much grease on the seat tube in the past?


My post was in regards to the single bolt clamp for the seat. Not the post qr or other clamp.


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## Paulsmith55 (Jan 16, 2015)

Skins45 said:


> My post was in regards to the single bolt clamp for the seat. Not the post qr or other clamp.


Yep, never seen that problem before with a single bolt seat post clamp. I have a Scott Spark 910 and I beat the hell out of it, no issues. The issue would be from too much grease on your seat post.


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## J.B. Weld (Aug 13, 2012)

Paulsmith55 said:


> The issue would be from too much grease on your seat post.


Not the issue op's talking about.


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## Harold (Dec 23, 2003)

Paulsmith55 said:


> Yep, never seen that problem before with a single bolt seat post clamp. I have a Scott Spark 910 and I beat the hell out of it, no issues. The issue would be from too much grease on your seat post.


guess you've never seen the knurled surface of the angle adjust portion of a cheap single bolt post wear out and refuse to hold an adjustment, eh?

I've seen plenty of those. has happened to me, too.

Sometimes, it happens in a wreck where the seat is grabbed and the forces involved just shear the knurled surface clean. No fault of the user. Sometimes it happens because the rider tightened the clamp when the knurls weren't mated together well between the clamp and the post. User error. Sometimes it has to do with the bolt not being tightened enough and the movement wearing the interface. Another user error. Either way, there are sources for failure.

There are other clamp designs that don't have this problem. I like the two bolt infinite adjust type like Thomson uses. It's never done me wrong. Easton uses it, too, on some fairly inexpensive posts. I have both.

Oh, and assembly paste is good stuff. I've taken to using it on metal/metal interfaces, too. Not just when carbon is involved. For that matter, Thomson strongly recommends it on their dropper. Go figure.


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## SwampyC (Oct 7, 2015)

I have a Giant dropper that wanted to move whenever I put my weight back and came down hard on the seat if I didn't unweight the rear. Grease and torqued to spec, would move at least once a ride, usually more. After cleaning and applying carbon paste, never again. It's been months and I'm around 270 with gear.


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## Skins45 (Jul 31, 2015)

Suppose I should update since receiving the eten. I've been on 6 rides with a good mix of xc and drops. Zero movement from the start. Clamped the single bolt with carbon paste in the clam and its great. I now have zero worries.


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