Rear Hinge & Service Tool
This section is dedicated to the rear hinge service parts and tool.
Brompton rear hinge, except for the P/T line, is consisted of a stainless steel spindle, held by two bushes, and secured by two screws and nylon washers at both ends.
The new P/T line has a similar rear hinge design. The dimensions of the spindle, bushings, and washers are the same. Instead of having two opposing screws tightened against the internally threaded spindle, the P/T line uses a hollow aluminum spindle, and a thru bolt secured to the drive size frame.
With use, both the bushes and the spindle will wear, and gradually developing lateral plays on the rear triangle. According to Brompton service guide, when the lateral movement of the rear triangle exceeds 5mm, it is time to service the rear hinge. Typcial service involves replacing the bushes, or the bushes together with the spindle.
After the old bushes are removed, and the new bushes pressed in, the bushes needs to be reamed to precise diameter to closely match the size of the spindle.
We have 3 reamer specifications, which we will explain below.
1. Brompton specification - this reamer is designed to be used together with Brompton factory bushes and spindle kits. By choosing this reamer, you are committed to using Bromptn bushes and spindle kits (that we don't supply).
2. 9.55mm diameter reamer - designed to be used together with bushes & spindle kits we supply. The cutting diameter is the same as Brompton spec reamer (9.55mm), but the diameter of the pilot section is different.
3. 9.50mm diamter reamer - the is the specification we initially carried. It must be used with the matchin 9.50mm spindle kit. We will continue to support the owners of this reamer with matching spindle kit in the years to come.
We have 2 spindle kits designed to match the size of the reamer. It is very important to select the spindle kit according to the reamer you have or intend to purchase. The bushes used in these kits are the same. For the Brompton spec reamer, you will need to use Brompton factory bushes or spindle kits available from Brompton dealers.
In the case of P/T line bikes, you would need the 9.55mm reamer together with the bushes. The alloy spindle, if worn, can be obtained from Brompton directly at low cost.
** Please note that due to the flexiible nature of the bush linings, the bush inside diameter after cutting will be smaller than the diameter of the reamer. For example, the bush diameter after cutting with the 9.55mm reamer will be 9.50mm. To avoid confusion, we refer the spindle kits by the corresponding reamer diameters.