Home Brompton Installing the Sturmey Archer X-RF8(W) 8 speed on a Brompton

Installing the Sturmey Archer X-RF8(W) 8 speed on a Brompton

by Petrelli
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Having been built up the wheels the other day, I am going to installing the wheel to the Brompton and see how it turns out.

The SA X-RF8(W) aren’t a small hub, the cog that was supplied with the hub was a 20T. Judging from the size of the hub, this is as small as it goes. With the experience that we gained during the implementation of the 3 speed external system, any sprocket’s size larger than 18T might have a problem (rubbing) with the rear triangle. Its also the same case here, the sprocket is in contact with the inside of the triangle. Before we proceed any further, we needed to make some room for the larger size sprocket.     

Based on the try outs, we needed to cut about 8mm from the rear triangle to get it fitted and that is exactly what I did. After the rear triangle had been prepared and then loading on the rear wheel onto the bike, we discover the sprocket (being so large) is in contact with the tensioner wheel at the original Brompton plastic tensioner.

We went ahead to replace the tensioner with the H&H tensioner that was designed to handler larger sprocket sizes.

Machine cutting into the tip of the rear triangle.
8 to 10mm had to removed from the rear triangle to fit the 20T sprocket.
Replacing with the H&H larger sprocket enable tensioner.
Job well done.

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