Is your rudge one of these , if it is i would be interested to hear more about it please
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That's the one. Mine is blue - that may seem incidental and unimportant, but there are subtle differences depending on age of manufacture, which seems to also coincide with colour change. £65 would seem a good price - they aren't particularly rare, but some sellers price at nearly £200, claiming rarity! Usual things to watch for on a used bike ie crash damage, stuck seatpin or bar stem. In addition, check it folds! They were also available in different frame sizes, and some sellers seem to have difficulty working out how to measure them because the seat tube extends below the BB

. The Blue ones seem to be favoured ones (I just happened to be lucky, as I didn't know this prior to buying), having slightly better equipment eg the brakes, but for a bike this old, if you're into fettling, as long as the basics are good, all is well. Oh - some had 700 size wheels (c/f 26 inch) and I'd suggest the 26 are better for the type of bike. I have another (now at My Daughter's house) which is a white one. A later version than my blue, it had cheaper brakes (but still usable). A friend gave it to me from his FIL's estate (he was a collector of bikes) and it was given to me a short while after I bought (and rebuilt to my spec) the blue one. It was like brand-new, so i sold it and made a charity donation. Five years later the guy I'd sold it to gave it back to me, minus the brakes,( I replaced with Vs) rear derailleur and with a knackered rear hub. A strong rider, he clearly abuses his bikes, and due to the rear hub problem the tyre had rubbed onto the L chainstay, but fortunately not too much metal wear!
Worst of all he'd taken it to his LBS who'd 'replaced' the BB by grinding away part of the seat tube, and in the process almost rendering the BB thread as scrap. Which brings me to another tip - It is possible to fit a cartridge bb to some of these bikes. I fitted a UN55 to my blue one (the 55 is 'waisted' so with a bit of wriggling it fitted, although the label was damaged

). Other frames may not give clearance, but removing the 'distance tube' from a 72mm cartridge (ie just using the cups and bearings) and an old-school lockring on the LH cup, will give a solution, and is arguably better for the bearings. Anyway, I digress. One last thing I nearly forgot..... The black frame ones I've seen had a more 'conventional' BB shell (ie in line with the seat tube); these are to be avoided, as they don't have the same rigidity as the others with the BB behind the seat tube. To sum up -Clearly not a Brompton fold, but useful for getting in a car boot. Unlike some folders this bike is as safe as a regular bike because it can never fold whilst it's being ridden, as the 'seat tube within seat tube arrangement is bullet-proof. It rides like a regular MTB - I'd challenge anyone to know it was a folder if they rode it. Crikey, I got carried away there - any questions feel free to pm to me.