Some more info on R20's...

Rear spacing is 114 mm and front is 95mm which makes fitting a modern hub a pita since those fork blades are exceptionally stiff and don't really give. I used some super slim lock nuts on my front wheel and also had to file the dropout to handle the diameter of a modern axle. Go slow and work from the front and you should be okay... I have a die grinder with a tapered cutter and this makes short work of this kind of job but if you don't have great skills with these I would not suggest it.

If you are rebuilding wheels you can use the stock front hub but note that it will be a Raleigh hub with a one sided cone adjustment, the adjustable cone goes on the non drive side and the bearing pre-load gets set when the wheel is installed.

SA cone wrenches are great to have.

The P20 has a narrower bb shell than an R20 so after re-tapping to 24 tpi and adding a few threads for greater depth (shells were 72)... R20 bb shells are wider and will need to be narrowed which makes the job a lot harder if you go this route. I have also noted that the bb shells with many lower end Raleigh bikes are not uniformly finished and they can vary between bikes so make sure you measure carefully.

They may be one of the most fun bikes ever made... elegant when original and a blank slate for many people to build on.

My next 20 project will be a folding mtb / trail bike with 24 inch wheels and disc brakes.