Brompton Standard Chain Tensioner
Chain tensioner for 1-speed and 3-speed Brompton folding bicycles
Also suitable for 5-speed Brompton folding bikes
This is one of two types of chain tensioners used on Brompton folding bikes
- Standard chain tensioner (no derailleur) - this one
- Derailleur chain tensioner (for Brompton bikes with two rear sprockets)
If you are not sure which one you have - check out our video below:
The Brompton chain tensioner is one of the "essential" list of spare parts for Bromptons with a single rear sprocket and performs an important role in keeping the chain taut whether the bike is being ridden or in the folded/parked position
It works using a big spring (internally) to keep the chain under tension
The chain then glides over two jockey wheels - these wheels will wear over time - they are changeable. To make the jockey wheels last longer, keep your chain clean and not over lubricated
This chain tensioner internally geared hubs where only one single rear cog / sprocket is fitted (1-speed, 3-speed or the older 5-speed).
The chain tensioner shouldn't be done up too tight (just over finger tight - approx 5NM for Sturmey Archer and approx 8NM for SRAM hubs). If it is over tightened then you will crack the plastic of the chain tensioner
Instructions for the tensioner are included - or you can see them in the downloads tab
The chain tensioner has to be removed in order to remove the rear wheel - so it is worth knowing how it is done (in case of puncture) even if you don't need a new one
Brompton 2020 Q part code: Q101506
Brompton Q part code: QCTA
Brompton part number: 9023004
Weight: approx. 128g