Here's my green R20 from probably 1971, according to the Sturmey AW that came on the bike. What's left which is original are the frame, fork, mudguards, and bottom bracket. This bike came to me already a bit of a project, so I really went for it.
Next thing to go will be the chrome mudguards. I like them, but for riding, I really want a set of newer, lighter ones, so I'll be adding a set of Blumels sometime this week. Need to find some P-clamps to attach the stays to the fork.
The Redshift stem is a great addition to the bike and really helps with fatigue. I had a 3 speed on this prior and have taken a few 20 mile rides, and didn't experience the harsh vibration that the other R20 we have gives.
The Sturmey RXL-RD5 is a finicky beast. I've found that it's quite sensitive to chain tension, and likes to be ever so slightly looser than how I'm used to setting up an AW. If it's just a smidge too tight, it will automatically shift from 3 to 5 or 4 to 5. This happened the other night when on a test ride and I was not putting much force into the pedals, so I think I'm still good to go. Today's ride of a few miles gave me no bad noises, no auto-shifting, it was great. I set it up with a 20 tooth cog paired with my 46 tooth Williams ring and crankset, it will give a good spread of gears for my commute. I have a ~3 mile climb from the Schuylkill River up to my work in Germantown, Philly.
The bike is already heavy but I'm thinking of adding an Abus cafe lock so I could fold it up, wrap it around a pole, and secure it with the heavy chain compatible with the Abus. We'll see if I'm really up for that when I get the new mudguards on.
Both of the Twentys we have are fantastic bikes and ride so well, that I just want more excuses to use them.
Happy riding all, stay cool and hydrated.