With a 526% range you can see the attraction. Its not the cheapest option, but you will have gearing for any hill or mountain climb. Using this brilliant hub you can also fit disc brakes to your Brompton.
To start, you need a Vostok or Kinetics rear triangle.
So the Stock BWR with 50t has a gear range of 302%, ratio of 1.99-6.03 with MPH per
90 RPM (cadence) at 8.9-26.9mph.
Using a 54t chainring the following ratio / speed is found;
13t would give 1.16-6.09 / 5.17-27.2mph - this would be the most common choice.
14t would give 1.08-5.66 / 4.8-25.3mph - for someone looking to climb mountains with a loaded bike
15t would give 1.00-5.28 / 4.48-23.6mph16t would give 0.942-4.95 / 4.20-22.1mph
17t would give 0.88-4.66 / 3.96-20.8mph
Notes about the build;
Using a Rohloff with the 13t sprocket / wide carrier the chain line is quite far out and you have two options. Either leave the chain ring where it is and run a slightly sub optimal chain line or use a 122mm bottom bracket and potentially affect the fault.
When building with Kinetics I tend to leave the bottom bracket, however with Vostok, because you need to generally use their fork hook as well to fit the shape of the rear triangle, I go for the wider bottom bracket.
When it comes to the wheel build, Rohloff are happy as long as the one cross lacing pattern is used and the rim does not obstruct nipple movement to spoke angle. The build are use is a one cross pattern with the spoke heads facing out; this offers the best nipple spoke angle of entry to the rim.
For the axle nuts, I use the standard Rohloff M10 nuts on non drive side however underneath the tensioner I use a M10x5x15 nut. This nut ensures the wheel is held securely, that the tensioner is held separately with the outer nut and just takes away any
concern that the wheel isn’t secure as it should be. On the outside of the tensioner I use an M10x17x5mm nut to secure, with the tensioner modified this fits perfectly flush to the edge of the axle.
When it comes to shifters I tend to favour the stock Rohloff twist shifter, they always build up with really smooth shifting and it’s super easy to blast through a whole number gears in one movement. There are aftermarket shifters and some of them are better than others but in classic Brompton style, I want the bike to be as functional as possible and if it takes a knock the Rohloff shifter probably isn’t going to come off too badly.
The S type handlebar works very well as there is no real bend to it however the M type/H type handlebar has quite a short grip section. Two options for this are using a very short 60 mm grip - Sram do one that fits nicely or using an alternative handlebar such as the Joseph Kuosac mid rise. These are 600m wide, normally need 20/30mm cutting off to allow perfect fold less you’re using large easy wheels and or rear rack, so allow a lot more room for a full-length grip and shifter
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