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Old 05-12-12, 08:56 AM   #1
landdnl
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New seatpost very snug

I just got a Pro Stealth EVO Monocoque Carbon Seatpost - White (27.2mm x 350mm). I took out my FSA K-Force Light Carbon Seat Post to put in my old bike. I cleaned the inside of the seat tube to get the carbon paste out. When I tried to put it in to make sure it would fit it was very snug. I figured if I just used carbon paste at the clamp area and installed it, there would be no way to get the seatpost out in the future not to mention straining the carbon fibers. I measured the O.D. with digital caliper and the top 2/3's of seatpost was right at 27.2mm all the way around. But the bottom 1/3 measures 27.5mm in places. The seatpost wasn't cut down and has no burs. I know there is a lot of debate greasing an aluminum seat tube with carbon seatposts, but i'm thinking about putting some Phil Wood waterproof grease inside the seat tube below the clamping area and carbon paste around the clamping area. The O.D. might be because they used a little too much clear coat during the manufacturing process. I don't really want to sand the post upsetting the fibers. Anyone have any better ideas? By the way, I did try an alloy post I had on hand and it inserted easily. It is an almost new frame with no damages.
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Old 05-12-12, 09:59 AM   #2
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0.3 mm oversize is kind of a lot, since seatposts typically come in 0.2mm increments. I'd consider returning it as defective before you go and do something which would render it unreturnable. You should not have to modify a new piece of hardware to fit where a properly-sized one does. If, as you suspect, they used too much clearcoat that should be the manufacturer's problem, not yours.
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Old 05-12-12, 10:09 AM   #3
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Quote:
Originally Posted by dsbrantjr View Post
0.3 mm oversize is kind of a lot, since seatposts typically come in 0.2mm increments. I'd consider returning it as defective before you go and do something which would render it unreturnable. You should not have to modify a new piece of hardware to fit where a properly-sized one does. If, as you suspect, they used too much clearcoat that should be the manufacturer's problem, not yours.
Unfortunately I bought it online from Wiggle in the U.K. It would be a hassle to return it overseas.
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Old 05-12-12, 10:09 AM   #4
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Yeah, that sounds defective. I'd say take it back to the lbs for a refund/exchange.


Edit: didn't see your reply. That sucks.
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Old 05-12-12, 01:29 PM   #5
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If the seatpost is made of carbon just sand the clear coat a little bit. Probably they put too much clear and went off specs. If you bought the white version, same situation, just sand it a tiny bit and put grease in the seastpost.
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Old 05-12-12, 02:04 PM   #6
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"It would be a hassle to return it overseas." It would be a bigger hassle to f___ up your new frame and Wiggle won't help you if you do. The part is clearly defective and Wiggle should make it right, which includes writing off the bad post or making arrangements to return it on their dime. You should not be on the hook for return freight on a defective item. You have an alloy post which fits, use that while you get the return sorted out. At least you will be on the road, which you won't be if you damage your frame.

If you won't return the post (which in my opinion is a mistake) you will need to figure out how to use it. If, as you think, the OD is too large due to excess clearcoat then you should be able to remove it without affecting the carbon fibers. You don't have to remove it all, just enough to be able to insert the post without force. If the sanded area is well below the top of the seat tube then the force on it should be minimal anyhow. It's your choice of course, I just wouldn't do it, myself.
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Old 05-12-12, 05:18 PM   #7
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I think I will try my luck at sanding the lower 1/3 of the seatpost with some 240 grit at first and if all goes well finish with some 320 grit. That way if it doesn't work it shouldn't leave obvious sanding marks in case I need to return it. I'll keep the strokes horizontal so as not to potentially disrupt the fiber. On a side note: Since I'm using a carbon post in an alloy frame, wouldn't the benefits outweigh the perceived risks of using grease in the seat tube below the clamping area to reduce the potential bonding problem. Every couple of months I still need to verify the seatpost is not trying to bond anyway, which IMHO would be more potentially damaging than not using any grease and putting more stress on the fibers moving the seatpost around. I do not ride this bike in bad weather. I think some of the reason the manufacturers stress no grease is they're afraid they'll have to cough up free seatposts when people have slippage and overtorque their seatpost that is lubricated in the clamping area. Thus they crack. I'm not saying the manufactures are wrong but there a lot of reputable people that do grease their carbon beauties. Wish me luck!
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Old 05-12-12, 07:05 PM   #8
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Success!!! It took a half hour but now it fits perfectly and can barely tell where I sanded. Thanks for all the input!
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Old 05-12-12, 08:23 PM   #9
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Yeah, no big deal, IMO. 0.15mm isn't a whole lot of paint.

I used to make carbon yacht components, which admittedly are on a much larger scale, but my feeling is you could sand right down to the carbon and even slightly into it without affecting strength much at all.

The outside layer of many carbon assemblies is usually mostly for cosmetics and abrasion resistance. Under the woven ply, there's usually much less pretty and abrasion-resistant unidirectional plies.
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