On Saturday, September 8, 2018 at 5:09:34 PM UTC+1, wrote:

The other option mentioned here was the Sturmey S2 kickback hub. I have one and like it a lot. You would need a 20 tooth cog with your 50 ring to get a high gear in the mid 90s. The low would be 67” which could work.. You’d need to lengthen your chain.

I'm not planning on taking up iron man racing, and am perfectly happy with the 126 gear ratios on my everyday, anyday bike, of which I use a double handful.

But this Sturmey S2 sounds like the business, and will no doubt be cheaper than the Schlumpf Drive, though it is possible the Schlumpf might be a superior solution to the OP's problem, and as a racer he might be impressed with its superior lack of avoirdupois: it doesn't weigh much.

The Schlumpf is a two-speed gearbox which replaces the bottom bracket; there are versions that require bottom bracket shell machining, and a version with its own discreet reaction arm that does not require bottom bracket shell alteration. The Schlumpf comes in a high-speed-drive version and a torque multiplying mountain-drive version, either of which might be suited in conjunction with a proper selection of chainwheel and sprocket, though the mountain-drive with it's instant 2.5 reduction (or multiplication, depending which range you will consider "normal") seems an instantly obvious choice. The Schlumpf Drive avoids the untidy problem of a chain tensioner and keeps the appearance of a fixie. It is operated by knocking a button on the crank end of the pedal with one's heel and for those with small feet there's a version which turns the whole crank into a hot button.

Many more variations and adaptations make the Schlumpf a universal gearbox:
http://www.schlumpf.ch/hp/schlumpf/f...riebe.engl.htm

Andre Jute
Mo gears is not nesarly betta gears!