Thursday, September 13, 2012

PRO Vibe-7s seatpost - tested

How excited can one get about a seatpost?

Well, if you're a regular reader; you already have a certain expectation about just how overboard I can go in my excitement about little things...  Additionally, as a certified bike fitter; I have my hands on a lot of seatposts - and honestly; they can be a bit of a frustration point for me - some are easy to use and adjust while others are an absolute pain.

You see; like many components on your bike, the seatpost is more than just that necessary part that connects your saddle to your bike. And while we forget about it quite often, the function and ease of operation of your seatpost has a great deal of influence over the comfort and ride characteristics of your bicycle. So; let me discuss how the Vibe 7s performs in these categories.

So, if you've read any of my reviews on a lot of the components I choose for my own bike you know that there is a little bit of a superficial element to my selection: yeah, it has to look good first. (Hey, at least I'm honest about it.) After that - it's all about function: how easy is it to set up and can I leave it alone once everything is set to go.

The Vibe 7s certainly fits into that category: set it and forget it.
It features a one-bolt clamping mechanism; and that is one big reason I was interested in it. For ease of adjustment I prefer the one bolt mechanisms. After years of fussing with the two-bolt system on my Ritchey WCS post I was ready for something more simple to use. I had always liked the Bontrager and Specialized one bolt systems - but since I'm not working with Trek any longer and I have a certain aversion to bike-brand parts on other-brand frames; I chose the PRO (another part of why I chose my entire PRO Vibe 7s support kit).

Installing a saddle on a seatpost is often an exercise in patience, will power, and in certain situations brute force and intestinal fortitude. The one-bolt system certainly makes it a little less daunting; unless you have to re-assemble the mechanism after mistakenly removing the bolt. The PRO system also appears to be friendly to carbon fiber saddle rails: like the ones found on many top tier Fizik, Specialized, and Selle Italia saddles, since it applies it's clamping forces on the top and bottom of the rail and not around the circumference or from the sides.

To put it simply: loosen the bolt, arrange the saddle rails in the clamp, and tighten to torque accordingly.

Bonus Tip: This is where it's important to make a note about torque values. The PRO seatpost has a maximum torque value of 11 nm. However, it would be wise to check the torque specifications for your saddle rails as well - especially if they are carbon fiber. I know the carbon-railed Specialized saddles carry a maximum torque value of 9 nm. In this instance where we may have two items with differing torque values: error in favor of the lowest torque value.

Here is where the good one-bolt posts really shine. A poor post doesn't provide enough latent friction to allow you to adjust one axis of the saddle position without working to support the other. I.e.: the post won't maintain the tilt adjustment while you move the saddle forward or backward along the rails or vice-versa. I've found the PRO post to work well here.

Usually it is the tilt adjustment that requires your attention while trying to adjust the fore and aft position of the saddle. An experienced mechanic or fitter has usually developed a method of dealing with this - but it sure is a pleasure to come across a seatpost that does not get all loosey-goosey (which is a technical term...) in every direction once the bolt is backed out far enough to make adjustments. It would be possible to create this scenario if you back the bolt out too far - but it is possible to adjust the saddle in the clamp with enough tension remaining in the system to create the latent friction necessary to hold both adjustments. Nice.

I mentioned in the intro that the seatpost can influence the comfort and ride characteristics of the bike - but what I'm referring to is probably not what you were thinking. As it pertains to ease of adjustment: an improperly adjusted saddle - or one that will not hold those adjustments once they're set - will create a situation where your bicycle does not fit properly or comfortably. An improper and uncomfortable position on the bike will often not only disrupt the weight distribution on the bike but may also inhibit your ability to control the bicycle easily and effectively. Therefore; the comfort and handling characteristics are impacted by the seatpost.

I selected the aluminum post; but there is a carbon fiber model in the Vibe series and it looks very nice.  I've decided that the budget of this married father-of-three doesn't have room for carbon fiber components any longer and I prefer the less-worrisome durability of the alloys versus the composites if for nothing else than peace of mind. My steel frame certainly supplies a smooth-enough ride to not require a carbon fiber seatpost anyhow (although the jury is honestly still out about whether they provide any noticeable vibration damping anyhow - at least as far as I'm concerned)  

Finally; the circumference seems accurate and it slides nicely into the 27.2 mm seat tube of my Waterford R-33. You should expect such perfection from the component arm of Shimano though... It's also available in a 31.6 mm diameter and both sizes are available in two lengths - so most road frames; whether traditional, compact or sloping geometry, will be well served.

The bead-blasted finish of the black aluminum post has never budged a millimeter in my frame - a quality that is important if you're particular about your riding position and is commonly hard to find on carbon fiber posts.

I suppose a glowing, raving recommendation to run out and immediately buy one would certainly feel over-the-top and insincere here; but if you're considering this post or have had one recommended to you by a fitter or mechanic; you will not be disappointed.

Leave a comment if you have questions or your own experiences...

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