Bicycle Mechanics - Suntour accushift 7-speed bar-con friction questions
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Background: I just picked up a pair of used ones to go on a C & V roadbike in friction-only mode. They were black and I decided to buff them bright, so stripped off the anodizing with easy off (painted on the shifter levers with a chip brush, not dipped or anything). As many here know, those shifters do not come apart fully like the older Suntour bar-cons.
I neutralized and rinsed out the lye solution and used WD-40 for water displacement, and Breakfree CLP for lubrication.
I reassembled the right hand shifter and found that it does not give the micro-ratchet action I've read about - it either has 7 speed indexing, or a smooth friction feel, but with lots of slop- say 1/8 inch at the upper end.
Is this shifter worn out? Did I hose the mechanism with my anodizing stripping foolishness?
The non-switcheable left hand one for the chainrings has no real slop, and a slight ratchet feel on up-shifting.
08-03-12, 12:36 AM
the 'power ratchet' is reserved for the non-indexed levers, meaniing the left one only. The right lever operates in either index mode, or basic (lame) friction mode.
with that in mind, the most enjoyable useage of suntour levers, is with the right side indexed....
have modified cassete spacing on one of my bikes to do this; ratcheting front, with indexed rear, feels superiour to the modern shimano bar end shifters....
Key point; accushift 6 will have the right amount of cable pull to operate a 7spd shimano derailer&cassette
Nicer suntour levers that are convertible between acushift 6/7 mode ( ex: suntour GPX, my favorite), when left in 6 mode, can be hyperextended to get the 7th shimano gear
lesser suntour levers that are 6spd only, need dremeling to access the 7th gear
I suspected as much, but the right hand one will make a ratcheting motion and click sometimes when the lever is pushed to the side and the bolt is not tightened down fully.
Still, should the lever have that much slop in friction mode? It literally is about 1/8 inch or 4mm at each end of the arc.
(Way back in the early 80s I ran a set of the older Suntour micro ratchet barcons, and they were really great.)
These are intended to go on an early 80s Bianchi that has a nicely functioning Campy NR rear derailleur; it's not getting converted to index!
08-04-12, 01:05 AM
pretty sure i've got the same barcons (6spd ver) around here
Oh, you mean the way the right lever can be jiggled a little bit even when fully tightened down and the cable tension is holding?
Thats normal for accushift. you know how shimano rear derailers have built in side-to-side play on the upper pully wheel to assist with shifting?
Suntour accushift derailers dont do that; instead their method is to have the play in the shift lever itself. The extra slop causes a built-in overshift to make gear changes faster, which then falls back a tiny bit when your hand is off it.
Okay, that would explain it. I guess I'll see if they work well with the Campy NR rear in friction mode; if not, I'll be selling a set of beautifully bright-polished 7 speed accushift bar-cons soon. Thanks so much for the help!
08-04-12, 07:23 PM
If you're exclusively friction mode for both front and rear; there's always these:
since they're friction-only, they have ratchets for both sides
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