Why would you even use the rear brake? It will only lock up and get you into trouble. Loosen it till it won't lock up when you pull the lever to the bar at 20 mph.
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Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1