Brompton seat post bung

More info

Brompton Seat post bung

The seat post bung from Brompton is a rubber bung which fits into the bottom of the steel seat pillars / posts stopping the seatpost clunking on the ground when the seat post is lowered / put down

It also helps to prevent the bike rolling when Eazy Wheels are fitted and you don't want it to! (e.g. On a train or slight incline)

It's also useful if you often park on tile / wooden floors as it will stop your seatpost chipping / scratching the floor.

The black bung is for use with steel and (no longer available) titanium seat pillars.

The kit used to contain a grey bung for use on aluminium seat pillars - this is (since 2012) no longer available and not included.

The easiest way to fit the rubber bung to the seat pillar is to have the bicycle folded, lying on its side, or inverted / upside down.

Before fitting the correct rubber bung assembly, check that the cone is just nipped up to the rubber bung but not starting to bulge the rubber. In this condition the rubber bung assembly should slide into the seat pillar up to the shoulder.

Note the rubber bung may be a tighter fit in titanium seat pillars and may require twisting to get it in up to the shoulder.

Brompton Seat Post Bung Installation

Current (2017 onwards) model seatpost bung

No tool is required - simply push the bung into the bottom of the seatpost

Pre-2017 model seatpost bung (no longer available)

To secure the rubber bung, tighten the bolt with a 5mm allen key approximately 10 turns. The objective is to achieve a good tight fit without excessive bulging that could interfere with the folding operationTo secure the rubber bung, tighten the bolt with a 5mm allen key approximately 10 turns. The objective is to achieve a good tight fit without excessive bulging that could interfere with the folding operation

This required a 5mm allen key

Brompton Q part code: QSPBUNG[2]
Brompton old Q part code: QSPBUNG
Brompton old Q part code: QEZWBUNGA
Brompton part number: 9007361
Brompton old part number: 9037117

Reviews

Grade

Patrick 24/06/2015

Brompton Eazy Wheel bung assembly complete

The bung plugs a hole, stops the seatpost from scraping on the ground and helps prevent the Brompton from rolling on a train. Great! That is exactly what I wanted it to do so can't say more than that! If you haven't fitted one yet, why not?

1 out of 1 people found this review useful.

Grade

Michael Kennedy 04/02/2015

Seat post bung

New seatpost required a seatpost bung. Never had one before. The easiest thing to fit. Very pleased to be finally free of the 'clunk' as seatpost hits concrete! Any post new or old deserves one.