Those steep straight downhills can be a bit scarifying. There's one just east of & into Percé on the Gaspé, somewhere betw 17 & 20%. I bailed out on that, & decided to take the truck route, the bypass which takes heavy vehicles and uncertain cyclists around the main street of the picturesque wee village. Happily, the bypass meets the highway again just before an A-grade bistro and art gallery, created from a repurposed creamery.
Nearly 15 years ago, riding eastwards through the midlands of Kwa-Zulu Natal, we came to a steep downhill leading into Mooi River (Andre may know it). It was late afternoon on a brilliant December (early summer there) day, all green and gold with the sun behind us, we were alone on the hillside and we touched 60 km/h -- only to find a roundabout a hundred metres after a gentle bend. Aaahhh, Jaysus, Mary an' Joseph!! -- we scrubbed off just enough speed (we had unladen bikes, this was a family-supported tour, thank god) to get through the roundabout, which for some reason had no traffic in it when we arrived.
On another, shorter-but-steeper downhill the next day, I feathered my brakes.
On our Aussie's big SF hill -- I was surprised that his front wheel wasn't lifting off the tarmac: long Nomad wheelbase, perhaps?