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DIY: what material to use as DIY shim seat post?

5 min read

Asked by: Hope Williams

Aluminum is easier to work with and “conforms”, making it a better shim in most case. Steel will take wear a bit better in cases where the fit is poor. Aluminum will “stick” to steel in a way, which is probably good, to keep it from sliding around when you want it to stay put.

How do you make a seatpost shim?

Quote from video: While holding the can tight against the post. Slide it in until there's about an inch exposed. Make your find adjustments while sinking the shim down to just above the clamp.

Can you use a seatpost shim with a dropper post?

Quote from video: And i haven't had issues uh you can typically do this with droppers as well it doesn't really make a difference.

How do seatpost shims work?

Once you have a new and upgraded seat post, you need a seat post shim to ensure that the new seat post will fit your bike frame. Bike seat post shims usually consist of steel, aluminum, or PVC. It allows you to increase the diameter of your seat post.

What is a seat post made of?

Seatposts can be made of steel, aluminum, titanium, carbon fiber, or aluminum wrapped in carbon fiber.

How do you measure a seatpost shim?

Quote from video: So now most people aren't going to have a seatpost gauge lying around i happen to have one but so you're going to want to use a like a digital caliper. Here in measuring millimeters.

How do you extend a bike seat post?

Quote from video: Extender is offered in three frame sizes with round tubes for 22.2 frame 25.4. And a 27.2 seat post size. On those you will need a secondary c-clamp to go with it which you need the 25.4.

Is it OK to use a seatpost shim?

Seatposts have a minimum insertion length which protects the seatpost and the frame from cracks. If the shim is as long or longer than the minimum insertion length required by the seatpost, it will work just fine.

Is seatpost adapter safe?

As far as safe to use – as long as the shim is at least as long as the minimum seat post insertion required for the frame, in theory you are stressing the frame no more than using the correct diameter seat post. Many frames do require 100mm or more, and many seat post shims are not 100mm.

How do you shorten dropper post travel?

Quote from video: The travel of your dropper. Start by setting the saddle height to about half of its fully extended height. You will not be able to adjust your post travel that's fully extended.

How do you make a seatpost fit?

Quote from video: And slimmer seat posts to someone else who actually has a bike that has a proper seat tube size for that seatpost. My word of advice. Is in a pinch yes you can use a shim.

How do you measure seatpost diameter with a ruler?

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 you get a seatpost out of a seat tube?

Quote from video: Put the bike on its side over a bucket. And then apply the boiling water around the top of the seat tube making sure that you do it on both sides. It's probably not going to free up straightaway.

How do I choose seatpost length?

Length. Make sure you have the correct length of seatpost for your needs. Seatposts are available in several lengths from 280mm to 400mm so measure the amount of post you have showing (plus the minimum amount of insertion that needs to be in the seat tube) before purchase. If in doubt, measure your old post.

How long should my dropper post be?

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.

What size seatpost clamp do I need?

Note: The seat clamp diameter needs to match the diameter of your seat tube rather than your seatpost, which is a little smaller. For example, a 27.2mm seatpost (a size commonly found on road bikes) fits inside a 28.6mm diameter seat tube, so it’s a 28.6mm clamp you need.

What is the standard seat post diameter?


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’).

Why does my seatpost keep slipping?

The main reason for a slipping seatpost is too little friction between the seatpost and seat tube. The first cause is a clamp that isn’t tightened enough. Because of the load on the seat post while cycling, it slowly slips down. This is a very common issue!

What does seatpost clamp do?

Quote from video: Похожие запросы

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 do you install a seat clamp?

Quote from video: Installing your seat post clamp on your open frame sounds like an easy thing. But they're like a couple of points that are really important. One is there is a pin in your clamp.