Bike Seat Posts
As the primary supporter of your body weight on your bike, your seatpost is a critical component. For the most part, seatposts are utilitarian in nature. For most recreational riders, the seatpost that came with your bike will probably last the duration of the bike's life. As long as it is long enough to be adjusted to the saddle height that suits you, and stays in one place when tightened correctly, your post is doing just fine.
There are two primary seatpost types, distinguished by the way they attach to the saddle. Inexpensive department store and children's bikes often employ a "one piece" clamping mechanism in which a single bolt controls a clamp around the saddle rails, usually tightened from the side. With these seatposts, adjusting the saddle position can be difficult.
Most mid- to high-end bikes come equipped with a "micro-adjust" seatpost. These posts utilize a more effective clamp that involves one or two bolts that tighten the post above and below the saddle rails. These bolts allow the saddle angle and position to be adjusted to precisely suit the rider.
Racers and fast recreational riders may choose to upgrade their saddle in the interests of saving weight or improving ride quality. Most after-market seatposts are made of either aluminum or carbon fiber.
Carbon seatposts can smooth out the ride of an overly stiff frame—and as a bonus they tend to save a fair amount of weight over most stock seatposts. Plus, they're flashy, and they'll look great with your carbon frame.
That said, they're not for everyone. Some compact frames may require a large amount of exposed seatpost and have rather sharp seatpost angles. If your frame leaves over eight inches of seatpost exposed, we suggest sticking with an aluminum post.
Aluminum seatposts deliver many of the qualities of carbon—stiffness and light weight—at a lower price. Thomson makes some of the most reliable seatposts and stems on the market, and the Thomson Masterpiece Seatpost is actually the lightest seatpost we offer, at a mere 158 grams for a 27.2mm x 240mm post. Or, the Fizik Cyrano R3 Aluminum Seatpost is a great, inexpensive upgrade for a stock post.
Many posts feature "setback"—which means the post bends backwards a little bit, to accommodate riders who prefer to be positioned farther back on the bike. Many racers prefer setback positions, which emphasize the role of the quads and hamstrings in the pedal stroke. Many of the seatposts we sell are available in both straight and setback varieties.
Meanwhile, many time-trial riders and triathletes prefer to be positioned over or in front of their pedals, allowing them to maintain an aerodynamic position, emphasize the muscles that are most effective on flatter courses, and, in the case of triathletes, save other muscles for the run portion. Tri-oriented Profile Design makes the Profile Design Fast Forward Carbon Seatpost to help riders get this position on a regular road bike.
Is Your Seatpost Stuck/Corroded/Seized?
For some chemical reason, carbon fiber likes aluminum. When you pair an aluminum seatpost with a carbon frame, or vice versa, you run the risk of the post seizing to the frame. When left in contact for long periods of time, carbon and aluminum may bond together, making adjustment difficult if not impossible. It's not common, but it happens.
Seized seatposts are a result of improper installation. Seatposts seize when they have not been adequately greased before installation. A good smear of grease prior to installation will prevent seizing.
If your bike has been sitting for a couple of years and you find you can't adjust your seatpost, hope is not lost. You're probably going to have to pull the bottom bracket out and see if you have a hollow seat tube (Bianchi is a popular brand that often doesn't). If you do, make sure the top end of the seatpost is fully sealed—if it's not, plug up the hole. Then turn your bike upside-down, get a can of Coca-Cola, pour it down the seat tube, and let it sit overnight. Seriously: there is something in carbonated sodas that loosens up seized parts. Just be careful once you do get the seatpost to budge that you don't end up with Coke all over the place, and make sure you flush everything out thoroughly with sudsy water so you're not wondering where all those ants are coming from next summer.
Steel seatposts and frames run the risk of corrosion. Corroded steel parts are even more of a problem than seized aluminum parts. If you've got corrosion in a steel frame, take it to a mechanic. As a preventative measure, always install steel posts with a little grease.
If your post is stuck, but you don't think it's all the way seized, flushing it out thoroughly with WD-40 or Tri-Flow Superior Lubricant and letting it soak in overnight will probably get things moving again.
As with any bike maintenance procedure, be very careful. You don't want to crack a frame or get a piece of cracked seatpost lodges in your frame. Stuck and seized parts are best loosened with patience, technique, and Coca-Cola rather than with brute force.
Don't hesitate to contact us at [email protected] or 1-800-682-0570 with any questions about seatpost selection, installation, or maintenance.