I think the lowest rolling resistance tyres in 26" are the newer folding conti speed kings. Either the Racesport, or the shieldwall. Pumped up hard they are pretty damn fast rolling on tarmac and dry smooth off-road stuff, as there isn't much in the way of tread. There is some volume, for comfort, too.
Check out bicyclerollingresistance.com to see how tyres compare. The measurements are comparable if not exactly the numbers you might measure out in the wild. I have used it as a guide and my experience has given me confidence in what this chap is doing.
If you are interested in drop bar conversions that are a bit more modern gear on old frame then read on.....
If you decide to go for lots of gears and Sram flappy paddle brake shifters i can confirm the following work very well:-
10 speed Rival or Apex levers. *
*The 10 speed ratchet drum thing can be easily modded if you want 11 speeds. You just need to dremel and file a 10th indent.
Also you can mount the ratchet drum on some machined bar, with a screw to hold it in place, then put in a lathe chuck, or chuck on a pillar drill/mill bed and do some passes with a bit of tool steel ground to the right profile, to make the extra indent.
10 speed X9 medium cage or X0 short cage rear mech(exact actuation with clutch)
2x10 X9 top pull front mech(42t cage) **
** i am going to try a Sram XX 2x10 mech as these go up to a 45t . The above 42t front cage was a good fit to 52t ring but the cage is a little short for the ring combos and a 13t at the back. I think the old XX has a longer cage so that could improve things. The bigger attraction is the cable pinch bolt set up being alot better than the X9, which is cr@p. Hopefully the XX cage swing will match the cable pull, but it is cheap enough to experiment.
52/36 52/33 50/34 50/33 Sram 10 or 11 speed chainrings(the 33 is a T.A.)
As far as cassettes and chains go i have found 11 speed cassettes and chains to shift cleaner than 10 speed items, with the 10 speed levers. Just delete a sprocket. I have used Shimano cassettes as there are way more options and KMC chains as they are plentiful and cheap. The x11 is very good.
When i was using the medium cage X9 i was also using a dropout thingy to lower the mech. With that and Altus jockey wheels(much larger than the standard so the cage can take up more chain) i was able to stretch the whole setup to 52/33 front and 13-42, at the back. It all shifted just tickety-boo. Chain was pretty long but no slapping with the clutch'd mech.
It was all done for a bit of fun to see how far things can be pushed and how much nonsense there is from manufacturers about capacity.
I got all of that out of my system and am now running 50/34 and a shimano 14-28 junior cassette(deleted the 20t) and it has given alot of trouble free miles, with the X0 rear mech. I have one of the larger Altus jockeys in the bottom as you get a couple more links wrapped. I Might drop the 23-25-28 carrier and just start with 24 and then have 21 down to 13 as not using the 28 and 30mph is too far the wrong side of 100rpm with 50-14, on 26x2.2 .
Another option is a 46t chainring and 24-21-19 and down to a 12t There is also the Praxxis 48/32 sub compact setup, in 110bcd, and a 5 arm 110bcd spider just needs machining down so the chain clears the 32. Then one could go back to the 13t.....and so on and so on and ....."nurse!....more phene please".
Crank used through all of this is a cheapo XD2 110bcd double. It works but the arms are super flexy. Could be alot better and will be replaced with something stiffer. The square taper BB is stiff as you like.... it is the arms that can bend into the chainstay by 2-3mm so avoid this chainset if you have minimal clearance. The RD2 is probably better as it isnt a 'hidden bolt' crank, so at least the drive side arm is beefier, at the spider.
Campag 9 speed brifters also shift the above mechs very well on 10 speed cassettes. Just delete a cog, or set the stop screw.
I had Frogleggs cantis, when i had the campag levers, and they worked very well, with some old Aztec blocks. Sram levers are way more bendy and didn't work as well with the Fogleggs. I changed to some old shimano short arm cantis and, with swissstop BXP pads, the braking is brilliant. Really, really so. Got some old XTR on the way, as a little treat.
As with anything, your experience may be different. I am not a doctor, but my patient seems happy and has not had a breakdown.
