|   seat tube/seat post diameter question | mtbfreak9er
Dec 10, 2002 6:06 AM | | can i run a 27.0 seatpost in a 27.2 seat tube? or am i going to have nasty creaking & slippage?
finding a shim to take a 27.0 to a 27.2 is nearly impossible....maybe i'll go the coke can route?
thanks!
rt |
| Don't really know, but the coke can's too thick. | Bikebreath
Dec 10, 2002 6:13 AM | | I'll bet you could get away with it the way it is, but please, please, let someone with real knowledge set us straight.
Bb, [ has been told he, "knows just enough to get in trouble." ] |
| i thought so too.... | mtbfreak9er
Dec 10, 2002 6:18 AM | | and besides, it would clash terribly with the new frame.
;-)
btw, i'll be in Baltimore as of rush hour on the 16th....
rt |
| Duct Tape is exactly .2" thick | Hollis
Dec 10, 2002 6:14 AM | | I'm kidding! I have no clue, I'm sure some smart Passionite will know for sure.
Hollis (Like Pa used to say, "If you cant fix it, Duct It!") |
| and i belived you for a minute there! | mtbfreak9er
Dec 10, 2002 6:19 AM | | if it can't be fixed with either duct tape or asprin (advil), it should be thrown away/shot & put out of it's misery.
;-)
rt |
| I'm leaning more towards the Al can idea... | Doc
Dec 10, 2002 6:33 AM | | Duct tape will just crush down to nothing when you tighten the clamp bolt. You don't need to wrap the seat tube in the can to get this to work- just use thin strips 3 or 4 mm wide and slide as many along the side as you can.
It might be easier if you put like 4 strips in first, bend the tops over the top of the seat tube and then put the seat post in, this will act as a "wedge" and will be easier than trying to put the strips in while the seat post is in place.
Superglue might work pretty well :P |
| I did the pop can thing.... | bones
Dec 10, 2002 6:49 AM | | It works alright, but a pain in the ass if you're changing seat height etc. It also scored the inside of the frame pretty badly.
I finally coughed up the 50 bucks and bought the appropriate sized post.
b. |
| I did the pop can thing.... | mtbfreak9er
Dec 10, 2002 7:01 AM | | i don't think i'll be doing much changing the seat height but scoring the inside of the tube is not cool.
i wonder if i'll be able to tighten down the seat clamp sufficiently to keep it in place without doing damage to the frame or having to constantly battle the post slipping....
rt |
| You and your damn seatpost dilemmas. | wm
Dec 10, 2002 7:18 AM | | Maybe I can find another 27.2 sitting around here somewhere. I can have it to you by, say...March?
wm |
| LOL! | mtbfreak9er
Dec 10, 2002 7:23 AM | | only if you promise to lose it, find it, lose it, find it again, put it in your car and drive around with it for 3 months before mailing it out. ;-)
rt |
| oh admit it. | wm
Dec 10, 2002 7:37 AM | | You loved the anticipation.
wm |
| that's me... | mtbfreak9er
Dec 10, 2002 7:52 AM | | a confirmed anticipation junkie!
rt |
| Why not just try it first? | K'Endo
Dec 10, 2002 8:35 AM | | Just run the 27-oh for a couple of fairly short rides. If it's a problem, try the next solution. Always try the easiest solution first, rather than getting stuck doing nothing while trying to anticipate every little thing that might (or might not) go awry.
I ran a post that was .2 too small on my old XC bike it wasn't a big problem. I did find it slipped when the post was greased, so I wiped all the grease off, and as much as I could from inside the seat tube and the slippage quit. I know, I know ... someone will slam me for the heinous act of running without a greasy post. Well, too bad, it worked. Besides, if the post is a bit too small it's less likely to weld itself to the inside of the seat tube in the first place!
Kn. |
| perfect! | mtbfreak9er
Dec 10, 2002 8:51 AM | | the plan was to try running the post w/o any additions. i was just wondering if there was any reason why running a post that is .2 too small is a really bad idea.
since it's an alu post in a ti frame i'm hesitant to go the no grease route. however, if it starts slipping maybe i'll just rough up the bottom of the post with a little sand paper to creat a surface with a tad more friction.
cheers ken!
r |
| I feel like... | Zaphod
Dec 10, 2002 9:17 AM | | I've seen seatpost size adapters somewhere in the back of BIKE or Dirt Rag. I would avoid the coke can plan. That's fine for a beater bike. If you do decide to go that route, for godsake, use "black label" or "Schaeffer" beer cans. Anything else would be uncivilized.
If you're putting an alum seatpost into a ti frame I'd be extra careful to grease or use anti-sieze compound. A ti frame is forever. A stuck seatpost will really be a drag. Throw down for a new post and ebay your old one.
-Zaphod |
| Lurker's $0.02.... | alibi
Dec 10, 2002 9:31 AM | | Assuming you're refering to that new $2500 frame, just pony up the $50 and get the right post. Any compromises will lead to creaking/rocking/slipping and you stand to damage the collar or seat tube from over-tightening. Eventually you'll need to drop the seat for one reason or another, and there you'll be at the trailhead, fishing for the shims that have slid down the seat tube. Nashbar has Syncros posts for ~$40; it's not like 27.2 is an uncommon size.
Just my $0.02; lurker mood back to ON. |
| the Synchros is what prompted the question.... | mtbfreak9er
Dec 10, 2002 9:37 AM | | the only size they DON'T have is a 27.2, like you said, it's not like 27.2 is an uncommon size. so i went for the 27.0. thanks for the info on rocking/creaking/slipping. i'll keep an eye out & if it feels like i have to really crank down on the bolt or any of the above are happening, i'll start looking for a different post.
cheers.
rt |
| Get the right size post <i>now!</i> | shiggy
Dec 10, 2002 11:50 AM | | Running an undersize post - even if you think it fits by cranking down the binder - will damage the frame. It may void any warranty on the frame as well. |
| Oh come on, now | K'Endo
Dec 10, 2002 3:14 PM | | We're not talking a huge disparity in post/tube sizing - just zero point two millimeters! The thickness of a thumbnail! This isn't stretching the mechanical limits of the seat tube for heaven's sake, so let's not push the panic button.
My experience has been that, if the seatpost clamp is cranked too tight, the bolt snaps before the seat tube sees any permanent damage. Snapped bolts are cheap to replace.
Kn. |
| If the frame dose not have a separate seat collar... | shiggy
Dec 10, 2002 5:12 PM | | ...the "ears" are damaged, too. Frame repair time. |
| that was my thinking as well | mtbfreak9er
Dec 11, 2002 5:48 AM | | it's not like i'm trying to clamp a 26.8 into a 31.6 with no shim. the disparity is tiny. add to that it's not like i weigh 200 lbs & am planning on doing 8' drops (which, even if i was, i'd drop the seat anyway!).
i might just try the post and if it creaks or slips, i'll remove it immediately. besides, at some point in the not so distant future, i'm planning to put in an order for a seatpost w/dean. voila! problem solved!
thanks Ken.
rt |
| the coke can comment was supposed to be a joke... | mtbfreak9er
Dec 10, 2002 9:33 AM | | guess i should have indicated that with a ";-)". my bad.
all i really wanted to know was whether there was any dire reason why i SHOULDN'T run a 27.0 seatpost in a 27.2 seat tube (without a shim).
as far as i can tell from the responses, there really is no reason why i can't do it. the only danger is possible slippage.
rt |
| Lemme get this straight.... | AK Ken
Dec 10, 2002 12:16 PM | | you've got a brand new TITANIUM (read expensive) bike frame that's never been ridden (what other parts were you waiting on yesterday?), you live in a metropolitan area with access to large bicycle shops, you have the online capability to order the correct seatpost at your fingertips, and you're gonna WHAT?
If this were the only bike you had to ride and it was the first Sunday in 3 years that it wasn't raining and all your pals were going to ride and the only way you could go would be to use the undersize post reefed down in the frame, I'd be more sympathetic to trying that for ONE ride only till you could get the proper post.
And even if you get the collar cranked down enough to hold the undersize post from sliding down, what about the rest of the post inside the seat tube that's flopping around like a dead fish? Oh,no it might not seem bad at first, but after a few months it gets more and more noticeable, and then one day your seatpost SNAPS CLEAN OFF because it's been scored where the sharp top of the seattube has been working on it with the rest of the post for leverage.
Presuming you're not skewered on your own post and laugh off the near miss to the land of enchantment, you finally give up and buy the correct diameter seatpost. But whoa, it WON'T GO into the seat tube because you've sprung the opening by reefing the clamp down on the smaller post.
But other than that, I don't see any problems.
Ken
ps: Did you notice in the 'beer can' link the guy said he was shimming an ALREADY OVALIZED seatpost?
2. If you're going to try tape, use electrical tape that can be stretched super tight for a clean, wrinkle free fit. I'm not optimistic about tape working.
3. If you use the beer can shims, I second the thought that you put long strips down the post to give the most uniform fit possible in the seat tube. |
| you've never been to the LBS's in Atlanta... | mtbfreak9er
Dec 10, 2002 12:55 PM | | for the most part they suck. however, that aside, at a certain point you (ok, me) run out of $$$ and have to make do with what you have/can afford till you can amass savings to finance your (and my) habit again. hence the 27.0 post.
yes, i did see that Zinn was talking about an already ovalized seat tube. and as far as i understood what Zinn was saying, he was suggesting creating a sleeve out of the alu. pretty much just like you would get if you bought a shim. (at least that's how i understood his description). regardless, i'm not going to do that.
i certainly see your point, and i will keep it in mind. the last thing i'd want to do is destroy a frame i waited 3+ months for. on the other hand, the money tree in my back yard has lost it's leaves for the winter & ya gotta do what ya gotta do. it's a lot easier to ride a bike with a seatpost than without.
rt |
| rt.... | Stick
Dec 10, 2002 1:25 PM | | I have an old 27.2 post at home that I'll send you free of charge. I snapped one of the round 'nuts' on it, but it's fine otherwise. I'm sure somewhere in the parts bin at one of your crappy lbs's you can find a replacement. If not, you're not out anything anyway, right? :)
Assuming all of the pieces I did have didn't get lost in either of two moves I've made since the last time I used it for anything, I'll pack it up and ship it ASAP. Lemme look for it when I get home.
Shoot me an email w/ your mailing address and it's yours...
(or, I can mail it to wm and you can wait for him to lose it, find it, lose it, etc...)
-Joe |
| thanks... | mtbfreak9er
Dec 10, 2002 1:31 PM | | but not necessary! :)
this whole thread turned into a lot more than what i bargained for! i'm going to get a 27.2 ti post from Dean eventually (in the next month or so). i was really just curious about the 27.0/27.2 thing.
yikes, i'll be more careful before my next seatpost post! ;-)
rt
ps- preferred mode of getting any seatpost to me is to lose it, find it, drive it around in your car for a few months, THEN send it to BB for him to do the same! |
| Okay, fine, I purposely | AK Ken
Dec 10, 2002 2:33 PM | | overstated the horrendous potential consequences for dramatic effect. I'm just giddy because I washed cars outside today (it's 32 degrees!)
It may all be a moot point, as I'd be a little surprised if you could get the post to stay put anyway without some sort of shimming (not to be confused with shimmying, which now that I think about it might get you the money for another post). If you try it and the post doesn't slide down the worst that will probably happen in the near future is a rocking and/or creaking that you'll find irritating.
Sorry I presumed you were made of money, being a DOCTOR feeding at the gubmint trough and all :-) Okay, don't pack up noneathem jurms and mail to me, I was just spoofin ya.
Hey, answer me this: what's the OUTSIDE diameter of the seat TUBE? Do you need a trick Silver Salsa quick release seat collar clamper? I've got two that don't fit anything we own because I KNOW what size I need, dammit, I don't have to get out the digital calipers with autormatic metric conversion that I have laying right over there and actually measure before I order! Kinda like carpentry, I cut that board twice and it's STILL too short!
Whatever you do, have fun.
Ken |
| 32F: mmmmmm....toasty! | mtbfreak9er
Dec 11, 2002 5:52 AM | | my car needs washing if you're on a roll. hehehe
thanks for the Salsa QR clamp offer. i've got a matching one in black sitting unused in my stuff that would actually probably fit the Dean. but the clamp they sent is awfully purty. ;-)
usuns gubermt paid docs don't get what we used to. so's i's be po' right now.
rt - your anthrax is in the mail. |
| very timely, indeed. | mtbfreak9er
Dec 10, 2002 11:38 AM | | thanks for the link.
rt |
| Get a Nashbar post for only ~$12; they come in all sizes.nm | Chuck D
Dec 10, 2002 2:26 PM | | |
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