The Brompton S-Type folding bike comes outfitted with a low, narrow, mountain-type flat bar for better aerodynamics and lighter weight than their other models. It’s a popular configuration, but people frequently complain about the minimalist, 105mm-wide, factory-supplied handgrips. After riding my Brompton for a couple of months, I too have found the stock grips to be uncomfortably narrow and lacking in support. Normally I’d just replace the stock grips with a pair of my favorite 130mm-wide Ergon GP-1 grips, but on the S-Type there’s not enough room on the narrow bar for a full-width handgrip, shift lever, and brake lever.
One possible solution was to keep the stock bar and cut down a pair of standard 130mm grips to the Brompton 105mm width. I tried this with a pair of size-L Ergon GP-1s, but found it to be an unsatisfactory solution. The Ergons did provide more lateral support, but my hands were still cramped and confined along the width of the bar.
Ultimately, resolving the issue required replacing the stock handlebar with a Race Face Air Alloy mountain bike flat bar (any standard 25.4mm mountain bike flat bar would work equally well). Installation was simply a matter of replacing the bar and trimming with a tubing cutter to the minimum width required to accommodate the full-width Ergon grips, brake levers, and shifter; this ended up being approximately 515mm (35mm wider than the stock Brompton bar).
The new bar/grip combo is a dramatic improvement over the minimalist stock set-up. The full-width Ergon grips provide substantially more shock absorption and support, and the brake lever and shifter are in a more ergonomically correct position in relation to the grips. The overall width is only slightly wider than stock and doesn’t affect the fold at all. Brompton would be doing their customers a big favor by supplying a wider bar and better grips as standard equipment in the future.