|   USE Alien carbon- to shim or not to shim? | Spotty Dog
Oct 28, 2002 3:39 PM | | I have been using a 27.2 carbon Alien shimmed to 31.8 for 9 months with no problems (despite my intial reservations). As a 15Olb rider I can feel the post flexing occasionally, but after 15 races it is in still in perfect condition. Now I have changed frames and my new Litespeed has a 27.2 seat tube, SO do I buy a 25.0 mm post and shim to to 27.2 or do I use my trusty post without a shim. I know USE say I must use the smaller post with a shim, but the seat tube has a neat alloy insert with a chamfered top which is machined to high tolerances,with no sharp edges. Does anyone have any experience of running USE Carbon posts without shims, either good or bad? |
| i'm doing the same thing..................... | bogart
Oct 28, 2002 4:40 PM | | and i'm 200lbs but i don't have much seatpost showing and i don't really feel the flex. i also don't have much riding time on my setup.
so basically, i don't really know the long term of it. i would think that an FS bike might be easier on it as opposed to a hardtail. also, do you like to "dead @ss" around much or are you off the seat alot.
A buddy cracked his old style USE (which was thinner than the current ones) on his road bike by overtightening the clamp. |
| i'm doing the same thing..................... | Spotty Dog
Oct 29, 2002 12:23 PM | | I ride my bike in Vets XC only, apart from the fun days out, so I ride hard,I don't jump or do hard landings, yeah I ride out of the saddle a fair amount. I am going to a Ti hardtail from a FS bike, but then again the tolerances on the Giant seatube were just terrible and the fit of the post in the new Litespeed is like a hydraulic piston in cylinder, I cannot see any stress raisers in this setup and for sure I will not have to tighten the clamp down as hard. I figure I will take a chance,if I was buying new from scratch it would not be an issue, I would just feel agreived buying a new post exactly the same design as the one I already have if I can use the old one. |
| i'm doing the same thing..................... | bogart
Oct 29, 2002 3:03 PM | | my last hardtail required me to run a really long seatpost. i remember how much it flexed and of course that's at the top of the seat tube. it would be very easy to gouge a carbon post. i think in a circumstance like that a shim would be necessary. |
| re: USE Alien carbon- to shim or not to shim? | Patrik Westerlund
Oct 29, 2002 5:14 AM | | I asked USE that question and they said that the warranty would be voided, so I chose 25.0 and a 27.2 shim. They said that you're not supposed to use any of the diameters without shim. It's about the same weight so it's no big deal. I'd hate to break one knowing it's my wallet that takes the heat..... |
| re: USE Alien carbon- to shim or not to shim? | Earthworm Jim
Oct 29, 2002 12:24 PM | | I have spoken to many bike shops about this post before I bought one for my road bike as I was concerned that at 250lbs I would crush a 25.0mm post.
The post has been great for cyclocross with no suspension or rear fat tyre.
I think the reason they are recommending a shim is the fact that the coating on their posts is very thin, (they are trying to achieve the lightest post), and you can almost feel the weave as you hold it. All of the other seatpost I have seen come with a thick gloss coating that probably protects it from slight knicks in the fibres. This coating probably adds more grams to the post than the plastic shim anyway. |
| No but... | Samu Ilonen
Oct 29, 2002 10:19 PM | | I have riden a year without shim in OCLV road bike and I weight +80kg but in Ti-frames I would look very carefully sharp edges that may cut post. |
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