Author Topic: Seat posts  (Read 5727 times)

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Offline dracolytch

Seat posts
« on: June 16, 2010, 09:46:31 pm »
I've been having LOTS of problems with my seat posts. Since it's a comfort bike, it has a shock in the post itself. First, I had an issue with the fact that my seat, over time, kept going down. I replaced the post quick-tightener with a old-school clamp... That helped (readjusting weekly instead of every couple of hours).

Next, I bent the bracket that holds the seat on the post... It was a cheap steel one that came with my first post... So I replaced the seat post with one that has a much more sturdy mounting bracket.

Now, the gasket/seal/something at the top of the shock on my current seatpost is broken, and it's only a couple of months old.
 
At 225lbs I'm a big guy, but not huge... This is getting a bit crazy. Thoughts? Tips? Tricks?

Offline paddleboy17

Re: Seat posts
« Reply #1 on: June 17, 2010, 11:41:13 am »
For some mysterious reason, some bike vendors think bicyclist weigh 160 pounds or less.  I don't remember all of the details, but Mavic either made a rim or wheel set (based on their rim and hub) for riders up to 160 lbs. 

Lots of bikes are not great at holding a seat post up.

If you are looking for a new suspension post, the Cane Creek Thudbuster is a pretty solid design.

You will have to do some research to determine if your current post can be rebuilt or not.
Danno

Offline waynemyer

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Re: Seat posts
« Reply #2 on: June 18, 2010, 09:56:03 am »
+1 on the Thudbuster.  Suspension seatposts (other than the TB) have a generally bad reputation, if only for stiction.  Most, if not all, are just not made to take regular use and abuse.

I have had my share of seatpost issues.  I used to weigh 190 pounds with another 20 or 30 pounds in my saddlebag.  My seat wouldn't stay put and I finally broke the QR seat collar.  I put on a Salsa Lip-Lock seatpost collar and called it done.  My seat hasn't slipped down on my since.
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Offline whittierider

Re: Seat posts
« Reply #3 on: June 18, 2010, 10:50:48 am »

Quote
My seat wouldn't stay put and I finally broke the QR seat collar.

If it's just slipping down, what I found works is to put blue LocTite (thread locker) on the post itself before inserting it into the frame.  It is still adjustable, but doesn't slip by itself when the collar is at normal tightness.

Offline dracolytch

Re: Seat posts
« Reply #4 on: June 22, 2010, 12:16:06 pm »
Ok, since we got a couple thudbuster fans here: One bike shop guy said that the thudbuster isn't something you'd really have fore a lifetime, and because of all of the moving parts it requires some level of maint. every year or two. Fact? Crap? For now, I just replaced with a $25 basic aluminum post.

Offline CastAStone

Re: Seat posts
« Reply #5 on: June 22, 2010, 12:50:59 pm »
Any suspension seat post will require occasional care, but so does your chain and such. Ah well.

I'd be surprised if your new aluminum seat post helps much. Big guys (I'm over 300) can't keep their seats up in certain tubes, period. That's why we shouldn't ride Carbon fiber seat posts - we have to clamp them almost to the point of crushing them to keep ourselves up for a days ride, and at that point, if you turn it just a little bit more - crack.

I've always wondered if I'd be better off buying a steel seatpost and spraying it every day until it does that molten-rust thing and its stuck into place.

Offline whittierider

Re: Seat posts
« Reply #6 on: June 22, 2010, 02:51:12 pm »

Quote
That's why we shouldn't ride Carbon fiber seat posts - we have to clamp them almost to the point of crushing them to keep ourselves up for a days ride, and at that point, if you turn it just a little bit more - crack.

Carbon posts are always a problem unless you put the LocTite on the post as mentioned above.  I understand there's also some kind of carbon-specific goop to put on them.  I weigh 170 pounds and couldn't keep it in place even with the clamp ends pressing against each other, until I tried the LocTite (on the post itself, not the bolt threads).  One son has broken a seat post binder bolt and a collar trying to make it tight enough to stop the slippage, but there has never been any damage to the carbon frame or post.  That area is made to be clamped.  He weighs quite a lot less than I.

Offline paddleboy17

Re: Seat posts
« Reply #7 on: June 23, 2010, 04:54:29 pm »
Ok, since we got a couple thudbuster fans here: One bike shop guy said that the thudbuster isn't something you'd really have fore a lifetime, and because of all of the moving parts it requires some level of maint. every year or two. Fact? Crap? For now, I just replaced with a $25 basic aluminum post.

A ThudBuster is a more complicated mechanism than a basic post.  Here are the likely failure points: the pivots and the elastomers.  The pivots need lubrication, and could eventually fail, but I would not stay up late at night worrying about it.  The elastomers will weather, and need to be replaced.  But there are other things on your bike that need maintenance too.  Chains, bar tape, cables.  The added maintenance argument sounds a little lame to me.

If you want suspension, the ThudBuster is a great way to go.  Right now I am running aluminum posts, but I have spent more to get micro adjustability.  You decide what is important to you.
Danno