LIGHTWEIGHT 25.4mm BICYCLE ALLOY SEATPOST SADDLE STEM 300mm LONG

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Standard outer diameter dimensions were important so that derailleur clamps etc. could be made in exact matching sizes (derailleur clamp inner diameter needs to match the seat tube’s outer diameter). Higher quality frames are usually made with thinned down tube walls to reduce the weight of the frame. This meant that a wider seatpost diameter usually meant a higher quality (and lighter) frame. So high-quality frames with 1 1/8″ seat tubes usually had 27.2 mm wide seatposts. If the current seatpost is a well-fitting one, and it is 30.9 mm, I’d look for a 30.9 mm dropper seatpost. To help prevent mistakes when purchasing or changing seatposts, this article explains what kinds of seatpost diameters are most commonly used and how they are measured. Only diameter (width) is dealt with here. The length of the seatpost depends on frame geometry (design) and size – i.e. how much the saddle needs to be raised from the end of the seat tube. A separate article explains the maximum amount of seatpost extension from the frame (minimal insertion length). For seatpost height in terms of bicycle fitting, see: Setting up comfortable riding position. I’d look for an adapter that notes those very dimensions: 34.9 to 31.8, or 34.9 to 30.9 (depending on the choice).It is easiest to measure the existing seatpost outer diameter – if there is a well-fitting seatpost on the bike. In case there’s no seatpost, we would need to measure the seat-tube’s inner diameter (using calipers, and minding to measure the tube itself, not the seat-clamp’s inner diameter). Hi, My bike frame seat post is 30.9mm in diameter, what size dropper post do I need for it to seamlessly fit in the seat tube? hand market (and local bike shops) is where I’d look. With a wallet in one hand, and accurate & precise callipers in the other. 🙂 If you don't feel your bike needs to be any more comfortable, and you're not fussed about 100 grams, then aluminium seems like a smart choice. If you want to drop the weight or add some cushion, look to spend more. Only valid for active forum users. Active means at least 30 postings within the last 30 days (no spam postings).

The Thudbuster ST weighs in at 580g (31.6 version) and is built out of forged aluminum with threaded, hard anodized aluminum axles. Note that the new axles are serviceable, unlike those found in the previous version. This handy PDF from Cane Creek outlines the differences between the two versions of the Thudbuster ST. Measuring the circumference of the post and dividing by Pi is a good method. There are even circumference tape measures to do it.

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Here’s our full list of suspension seatposts. As with our other Gear Index lists, find the ones we’ve tested at the top, marked with a “T” icon. We move forward with a desire to deliver the best possible components to our customers and a determined spirit of competition." Your article is confusing, because of some obvious errors. First, “Picture 1” is not labeled, and nowhere do your explain which blue arrow is pointing at which part. If you use a carbon seatpost, make sure to fit it using a thin layer of carbon paste as this stops it slipping. Pay attention to the quoted torque at which you should tighten the bolt - overdoing it can cause it to snap. If you don't own a torque wrench already, here you can find our recommendations for the best torque wrenches for bikes.

to status. UK residents only. Sigma Sports Limited acts as a broker “Licence Number 688619” and not Don’t punch it in. If it can’t be eased in by hand, it’s probably too wide. Forcing it in makes it very, very difficult to move or take out later. It might even damage some frames. The NCX seatpost features a patented parallelogram design that Suntour claims works well for small bump compliance. The post has a total of 50mm travel and was designed with low maintenance and long term durability in mind. Having said that: going a bit too narrow can be fixed with some DIY shims from Coca-Cola cans (that’s one thing that drink is good for 🙂 ), A more modern trend, mostly on mountain bikes, where stronger seatposts are required (without too much extra weight) led to a new “oversized” standard of 27.4 mm (and wider).

Suspension Seatposts Wrap Up

How to measure the seatpost diameter? The easiest and most accurate method is to use calipers (Vernier, or digital), as shown in picture 2. Measuring seatpost diameter using calipers. Not sure I understand the setup, but, if a narrower seatpost is to be inserted, using an adapter to fit the difference between the seat tube, and the seat post – then no need to change the clamp, if it’s in good condition.