"Good job Modifying" is a relative term. There is Mild to Wild. Mild might be to simple change out the steel wheels to aluminum (which is one of the first things that should be done for safety reasons), or a bottom bracket conversion which could be a Retap of the threads or a Phil Woods/UN 72 set up (or a couple of other clever tricks). This Forum is jam packed with info on R-20 conversion info to use and even edit to think of other creative work arounds.
I guess you kinda want prices.
Mild (wheel swap)= Price of wheels (but you will have to grind the drop outs to fit any axle larger than original)
Wild = Your marriage, Garage space and Folding bike forum research time
Serioulsy, you'd have to look at the price of the upgrades that you want to put on it (Brooks Saddle, Campy equip, Bars, Internal hubs, Dyno's. You name it, it has been done or can be
Lil Pix is working on a 24" wheeled one at the present. His isnt the first and wont be the last, (but will probably be the coolest
) I also should state that some of the fun for R-20's is to mod it on the cheap. (if you have spare parts layin' around it can be a cheap mod)
check the link to see aome R-20 variations.
Someone on the forum said that the R-20 modding is about putting your personal stamp on a classic bike.
"Many see it as a bare canvas on which to paint their masterpiece"
Quick list of R-20 Quirks:
Bottom Bracket threading TPI 26
Wheel drop outs narrow
Plastic bearing on head tub
Brake reach issues
My wife wants it out of the house
Tall head tub (issue if you want to switch stem,forks)
Steel Wheels (no stopping!)
451 or 406 sized wheels (both called 20" )
I might have forgotten something so correct me if I did
: If it were easy, everyone would have one...
- Ride em' till the wheels fall off, or your jewels go numb...
(sorry this post kinda rambles, its late)
-Two Classics Below- (Lil Pix: Fixie, Sheldon the Great:R-20 Hot Rod)