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M Sleeve | Premium Seatpost Sleeve for Brompton (ACPT Line)

M Sleeve | Premium Seatpost Sleeve for Brompton (ACPT Line)

Annoyed that your seatpost keep slipping when you ride?

Need a more durable and grippy seatpost sleeve?

Look no further than the M Sleeve!

We've improved on the stock Brompton sleeve with our own groove patterns to make it grip well inside and out, and topped it with a taper roof to prevent dust/water from getting into the seatpost frame hole.

✔ durable material

✔ grips inside and outside

✔ No glue required

✔ prevents dust/water from entering seatpost frame hole


Get yours today and enjoy a better ride on your Brompton!



Now selling version 2 that comes with additional features to better resist twist  and turns. We are the best sleeve in the market!



Normal: for seatpost 31.8mm diameter

Thicker: for seatpost 31.6mm diameter

For carbon and titanium seatpost.

(For reference, the brompton standard seatpost is 31.8mm diameter)


M Sleeve has been tested up to 90kg weight. It 

Please remove your current seatpost sleeve before installing.

To fit the M Sleeve, you will need to untighten the seatpost bolt to widen the size of the frame hole to fit both the M Sleeve and your carbon or titanium seatpost, before tightening it back.

 Ensure that the M sleeve knob aligns perfectly with the knob indentation inside the frame. While holding down the sleeve in position at its top rim, while slowly pulling your seatpost through it in a slow spiral twisting motion.

Do not pull the seatpost vertically through for the first time as it might cause misalignment of the sleeve to the knob.

The sleeve may feel tight to slide up and down initially, this is normal as it is brand new. Leave the M sleeve clamped in the seatpost for 30 minutes to an hour and it will slide more easily. Over time with use, it will get smoother and smoother.

Regular price $38.00 USD
Regular price Sale price $38.00 USD
Sale Sold out
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Customer Reviews
5.0 Based on 7 Reviews
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Filter Reviews:
Sean T.
Hong Kong Hong Kong

No more slipping seat post

I like my carbon Darimo seat post very much but previously it always slip, no matter using the stock sleeve or the T brand sleeve, now using this one and I no longer suffer from slipping, it just works.

Vladimir S.
Germany Germany


After 10 years it was the time to change the original Brompton sleeve. The Makericks was the choice: no reaming and no glue required. Installed with ti parts workshop titanium telescopic seatpost. Works as expected.

Chee M.
Singapore Singapore

M Sleeve for T line

I have tested the sleeve it work so well on my t line schmolke seat post 31.6 mm after 50km ride it does not slip at all. Highly recommend! /Users/chancheemeng/Desktop/IMG_4900.JPG

Makericks3D M Sleeve for Brompton (A, C, P, T Line) | Premium Seatpost Sleeve Review
United Kingdom United Kingdom

Smooth saddle height adjustment with the M sleeve

It just works. A much better part than the original. I hope it lasts as long. Smooth action.



A better one to one replacement of the stock Brompton T Line sleeve. It grips much better and best of all, I love the shade of red it comes in. Zero regrets! If your stock T Line seat post keeps slipping, you should consider replacing it with this.

Makericks3D M Sleeve for Brompton (A, C, P, T Line) | Premium Seatpost Sleeve Review