Originally Posted by
tcpasley
FYI - Here is a trove of Helicomatic cogs, spacers, and freewheel bodies available in my neck of the woods:
Helicomatic gear cogs and free hubs made by Maillard - $50 (N. Raleigh) =>
https://raleigh.craigslist.org/bop/d...868973629.html
Not sure if the seller would ship, but the deal looks good.
Originally Posted by
jlaw
you're going to need the freewheel tool shown below or an improvised tool if you want to remove the Helicomatic freewheel.
If you don't have this already you might find one on ebay or perhaps your local bike shop. Maybe someone on this site will let you borrow it.
I would not bother ****ing around with the Helicomatic. There's literally dozens, if not hundreds, if not thousands of other hubs out there that don't have the propensity for breaking spokes or blowing up the tiny bearings or having soft races like the lower level Maillard Helicomatics irrefutably have.
Originally Posted by
jlaw
Duo Pars can handle a fairly large cog (32T +) and were evolutionary in their day, but they are known to be a bit fragile.
I would also not **** around with the Duopar. Again, there are literally dozens, if not hundreds, if not thousands of other derailleurs that don't present the issues that these have. If you want to stay period correct, or vaguely period correct, there are many excellent, top quality long cage derailleurs available that have the same range as the Duopar- with none of the dual parallelogram, triple pivot issues.
Yes, the Duopar was revolutionary- it was the outrageously expensive gold standard of the time- it could handle a 38T cog. There are many people that have used them for decades without issue. It could shift unbelievably smoothly. It was also made from stamped steel and plastic with cheap pulleys. IMO/IME a Suntour XC triple pulley RD has the same capabilities and none of the inherent issues or cheapness that a Duopar Eco have. Step up to a Shimano M730 or M735 XT derailleur or a Suntour XC Pro or XC Comp and you have an incredibly "better" derailleur.
Originally Posted by
jlaw
Also, re: new brake pads - Kool Stop pads will work with the brakes you have. If you buy the Eagle 2 model (internal backbone) you may have to trim the length for the front to get them to not hit the forks. They will probably work on the rear as is. Some on this site have used one of the Kool Stop road-style pads that have a 'holder' with replaceable pads - and they didn't hit the front fork because the entire mechanism is shorter than the Eagle 2's. Investigate before you buy.
I put the non-threadedKool Stops Eagle 2's (black and salmon) on my Trek 620 and they stop well - I get a little squealing if I ride them hard for a distance,but nothing major.
I personally think if you have a bike as nice as an 85 620, with XT brakes- spend the extra bank on the Kool Stop Cross Pads, with the fancy shoes, so they don't look like cut off MTB pads.
Kool Stop Cross Pads by
Dave The Golden Boy, on Flickr
XT XTR1 by
Dave The Golden Boy, on Flickr