i was rumaging through a buddies old bike stuff and came accross a pair of brand new suntour xc powerbrakes. cb-6000 it says on the box. has aluminum rollers, supposed upgrade. arms are drilled full of holes from the factory. the brakes are brand new, with original pads and it even has braze on studs with them. he worked for a shop that built BCA mtbs on contract in the 80's so i figure that's where they came from. i know they aren't wtb's but are they worth trying to talk him out of the pair and selling? or are they kind of worthless. he's got some cool stuff laying around, couple of wickeds, one with original 80's cook brothers cranks a 26/24 cannondale with a switchblade fork and some old six speed new gruppo parts, specialized threaded sealed bearing hubs, new etc, but you guys all seem to be looking for roller cams and know what they are worth, so i figured i would as the experts.
Just last weekend, I restored to riding condition an '86 High Sierra with dual rollercams that I found in the trash, for a friend who rode a High Sierra back in the day before he got fat and lazy. First time I worked on rollercams in more than a decade.
From what I recall: XC Pros had holes thru the arms, XC Sports had dimples, not holes clear thru. The early best Pros had linear springs, like many V brakes ane like Charlie's originals. All later ones had internal coil spring, worthy but more sensitive when trying to center them.
Early Suntours used flared cams like Charlies that changed travel and mechanical advantage as the lever was squeezed. That was the whole point of the brakes, lots of travel at first so they opened nice and wide, then pad travel per unit of lever squeeze reduced dramatically as the pads neared the rim, providing massive power just as the pads got to the rim. Problem with that was it required a modicum of understanding to set up the cams correctly. The idea was to have the pads meet the rim right at the curved tips of the cams, where power was maximum. Most folks even most shops had them set so the rollers never got close to the tip of the cam, out of either stupidity or fear that the cam would pull through as the pads wore. To resolve that issue, SunTour later sold its rollercams with triangular cams that had no flare at all so mechanical advantage stayed the same no matter where onthe cam the rollers were located. This cancelled out the brakes' main advantage and folks who demoed the later ones didn't see what all the fuss was about, so they faded from the scent.
If you got straight sided cams, try hard to locate the earlier flared oned.
I think XC Pros came with aluminum rollers. XC Sports and other lower versions originally had plastic/nylon ones tht tended to break. Then suntour sent out aftermarket upgrade brass rollers to resolve that issue. all later ones came with brass I'm thinking.
BCA=Willie Ehrlich, a fellow Hunkie, I used to live in Bethlehem and knew him well, great guy. I recall riding an '83 BCA with 32" wide bullmoose style handlebars. Too bad his soccer team failed.
don't know much about the fats. both have been powdercoated. no stickers on them, but he may have a kit laying around. one is an 86-90 model with six speed and a roller cam. the other is not in as good shape but i havn't seen it. it's older as well. i'll ask about them next time i see the guy.
Those are the best SunTour rollercams, and the version most true to Charlie's design. All the good features. Worth I should think would depend entirely on how badly someone wants/needs them. If I had a bike with bosses for them, I would not hesitate to use them.
Looks like you have them ID'd but here's a pic of early XC-Pros (and where the rollers should be at rest - not all the way up on the circular part of the cam)...
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