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I am the new owner of a Trek Madone 5.9 SL and for the most part am very happy with this bike. I got hit by a car that ran a Red light on December 9th while riding my Merlin Extralight that had around 40K miles. Fortunately I was not seriously hurt and the Merlin is not that beat up. So the insurance company paid for a new bike and the Trek seemed the way to go. I wanted Compact Drive but was not sold on the Bontrager cranks so I bought a FSA K Force CD crankset and installed it after about 150 miles. I weighed the bike (60cm) before and after the installation and it was the exact same weight....16.64 lbs.
The Merlin is a more comfortable bike but theTrek does come close, surprisingly these bikes handle very similarly. The big difference that is noticeable is when you get out of the saddle....the Trek feels much more efficient! I am using the saddle off of my Merlin (a WTB which I also have on my MTB) and in order to get my optimum saddle height I am above the Max setting on the Bontrager carbon post. So now I am looking at needing to get a new post. What is curious to me is that in the Trek catalog and in other race photos it seems that the Discovery riders all using Shimano posts and I am curious why they are not using the Bontrager Carbon? Overall I am happy with the new bike, I just wish I had it when I was still a racer!
 

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Carbon posts need to be installed very carefully. A bit below the specified clamp torque, they might slip down into the seat tube. Much above the specified clamp torque, they might break. In a pro race environment, a carbon seat post might have to get installed or tightened hurriedly - out on the road, without the needed time or tools to do the job right.

Aluminum seat posts don't come with such baggage. You can hose down on a lot them without breaking them, and when you're done tightening, you can be sure that they aren't going to slip down. Within the pro race environment, it makes sense sometimes to use the least complicated component if given a choice.

As far as weight is concerned, the difference is slight: A 250 mm long Bontrager Race XXX Lite carbon post weighs 175 gram. A 270 mm long Shimano Dura-Ace aluminum seat post (the post on most Discovery bikes) weighs 195 gram. With the Dura-Ace post then, you get a 20mm longer post that doesn't slip, can be tightened down hard without a torque wrench, and can be clamped if need be. Good choice for a measly 20 gram more, in my opinion.
 
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