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Fragile - must be Italian
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2,308 Posts
Discussion Starter · #1 ·
I have a 2003 NRS with a 27.2 seatpost and the shim. The problem is that I can't get the damn seatpost to stop slipping, no matter what I do. My post is a carbon 27.2, so I originally didn't torque the bolt down really tight in fear of cracking the post. Well, after the post kept slipping I kept tightening the bolt down more...and more...and more...to the point that it's as tight as I can get it! And the damn post STILL wants to slip.

My buddy had a Specialized that had a shim and he had the exact same problem with a 27.2 Thomson. He ended up ditching both the shim and the 27.2 and put a 30.9 on his Specialized and the slippage problems went away.

Can I run a 30.9 seatpost on the NRS? If so, is there a minimum insertion amount that is required to keep the seat tube from cracking?

Somebody in the past also mentioned a beer can trick - cut a small sliver of beer can, wrap it around the shim (between the seat tube and shim), and then retighten the bolt. I guess that sometimes corrects seatpost slippage problems with shims. But to be honest I *really* hate that stupid shim and would like to get rid of it once and for all if at all possible.

Thx...Doug
 

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[paste title here]
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515 Posts
Yeah run the 30.9 seatpost. I ditched the shim months ago and its been one of the biggest improvments on my bike. Im running a 30.9 Thomson seatpost and it fits nicely in the seat tube. I think Duckman was saying that giant reccommended running a 410mm seatpost as it will not void the warranty. Do a search and there should be lots of dicsussions on that. I would reccommend the thomson b/c it felt a lot more solid than the titec seatpost i had on before. Very noticable difference.
 

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Niner EMD
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100 Posts
Giant requires a minimum of 150mm of insertion length. This is about down to the top of the rocker arm in the 18.5 inch NRS. I use a 360mm thomson 30.9 post. I have had no creaking and no problems. (I am 145 pounds) Giant requires the 410 length to ensure that however much you let out the post it will meet the required insertion length. However, you know how much post you need. So, make sure to have 150mm in the seat tube and you are good to go! For me the 410 was absurd. It was 3/4 of the way down the seat tube. I cut it a month ago and haven't looked back.
As for the tube size the 30.9 fits snugly. I would guess that the 30.8 slides a bit easier in the seat tube. I dont change my post height often so for me its not a big deal. I would say that if you are removing your post often, changing the height multiple times per ride etc. then go for the 30.8. If you grease it and leave it the 30.8 or 30.9 will work well.
 

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Fragile - must be Italian
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2,308 Posts
Discussion Starter · #4 ·
Anybody try a 30.9 carbon post?

I found a Syncros 30.9 carbon post for a good price -- it's 350mm, which should be fine if all I need is 150mm inserted into the seat tube. Has anybody tried running a 30.9 carbon post in their NRS? Will this work ok?

Thx...Doug
 
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