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Questions and answers about sports

Getting the right seat post

5 min read

Asked by: Gerald Craft

How do I know what size seatpost to get?

To find out the diameter of your seatpost, you must remove the seatpost from the bicycle frame and look for the size, which is stamped just below the “Minimum Insert” line toward the bottom. The number will be a three-digit number (such as 26.8 or 27.2 or 31.6).

How do I choose a seatpost?

The dimensions of the seat tube can vary from bicycle to bicycle, so when choosing a seatpost, it’s important to get the correct diameter. The most common diameter is probably 27.2mm, but other sizes between 21.15 and 35mm are often found as well. Seatposts also vary in length.

How do I know what dropper post to get?

To choose the correct travel dropper post, measure from the seatpost collar to the seat rail (in your climbing, or highest setting) on your current bike. Subtract 50mm from this measurement and the resulting number is the maximum travel length dropper post you can comfortably run.

Are all seat posts the same size?

Seatpost diameters generally range from 22 mm to 35 mm in 0.2 mm increments. The most common size is 27.2 mm (1.07 in) for most bikes, especially for the higher-quality models.

Can I get a longer seat post on my bike?

Pretty much all you can do though is put a longer stem, possibly raise and lower it, use wider handlebars and adjust the saddle angle+ position a bit further back (which may be easier with a different seat post). The biggest things you have to do are get the effective top tube right.

How do I choose a seatpost setback?

Straight and Setback Seatposts

The amount of setback or offset is best determined through a basic bike fit at a participating bike shop. They will look at the relationship between your knee and pedal axle, as well as your hip angle/mobility and will determine how far you should sit behind your crankset.

Does seatpost offset matter?

The zero offset helps to put those folks over the pedal easier. Zero offset posts also work well if the top tube (real or virtual) is longer then ideal. Moving the seat forward reduces the distance between the stem and the saddle.

How do you measure sit bone width at home?

Quote from video: And it looks like he's a height 100 millimeters. So that's going to be the distance. Between daniel's sit bone so you found the distance between your sit bones.

Where should sit bones be on saddle?

The optimal saddle width guarantees that the sit bones lie completely flat on the saddle. This is the only way in which pressure is relieved on the sensitive area in men and on the pubic arch in women and ensures more efficiency.

Can I fit a dropper post on any bike?

A dropper post can be a great upgrade for any mountain bike, but it’s important to find one that’s compatible with your bike. Here’s a few things you’ll need to consider: Seat post width – you will need to identify the width of your existing seat post as this is the size you will need when choosing a dropper.

How do I know if my bike is dropper post ready?

To find this measurement:

  1. Set your seat height at the highest, comfortable pedalling position.
  2. Grab a tape measure.
  3. Measure from the top of your seat tube to the saddle rails.
  4. Compare this to the size chart for the post you’re considering to confirm availability.

Can you adjust seat height with dropper post?

Quote from video: You can adjust the height.

Will a 31.6 seatpost fit a 30.9 frame?

You can fit a narrower post into a wider frame using a shim (a thin sleeve of aluminium or plastic), for example a 30.9 mm dropper post into a 31.6 mm frame. However, there is no way to fit a wider post in a narrower frame, for example a 31.6 mm post into a 30.9 mm frame.

What seatpost has the most setback?

These two-bolt seat posts have a generous 30mm of setback, among the longest ever. This is very important for those who ride leather saddles that often have little fore-and-aft adjustment due to the short rails.

What is the standard bicycle seat post size?


While there are any number of post diameters out there, most modern road and MTB bike frames accept a seatpost of either 27.2mm in diameter (‘standard’), 30.9 or 31.6mm (‘oversize’).

How do you measure bike seat height?

The saddle height is always measured with the crank arm pointed down and in line with the seat tube. The distance from the center of the pedal axle to the top of your saddle is your seat height.

Heel method

  1. To start with, raise your saddle roughly to your hip. …
  2. Sit down on the saddle and touch the pedal with your heel.

How is seat tube length measured?

Seat tube length is the straight line distance between the centre of the bottom bracket and the top of the seat tube.

What size seat clamp do I need for a 34.9 seatpost?

Clamp diameter: 34.9mm. Seat Post Fit: 31.6mm. Weight: 25g.

What size seat clamp do I need for a 25.4 seatpost?


28.6mm seat post clamp applies to 25.4mm seat post.

How does a bike seat clamp work?

The seat post clamp goes around the top of the tube. When the clamp bolt is tightened, the frame material flexes slightly (the slot allows this flex to occur) and tightens against the seat post. This, of course, is what holds your post in place.