julio 27, 2026
New-Old-Stock Suntour XCD (4050 Series) Roller-Cam Brake Caliper Set Thank you for your interest in this item and please visit our store for other offerings. We have very reasonable shipping terms and combine orders to save money (for customers) on shipping costs. We also maintain customer friendly return/refund/exchange policies. Product Description: This offering is for a new-old-stock Suntour XCD (4050 Series) roller-cam brake caliper set. I have very little experience with these types of calipers, but will still do my best to explain how they mount and function (based on some research and conversations with others that are a lot smarter than me). First of all, I should probably mention these calipers will not mount on traditional mountain bike cantilever posts or studs (and please keep this in mind, as this will likely limit compatibility options). As I understand it, cantilever studs are positioned slightly inward (or towards the rim), while roller-cam studs are positioned slightly outward (or away from the rim). I have also been told U-brake calipers mount similar to roller-cam brake calipers, so if your particular mountain bike or hybrid will accept U-brakes, then these roller cam brake calipers should also mount fine. The mechanics of a roller-cam brake caliper are truly unique. I want to compare the mechanics to a traditional cantilever brake caliper, but there really are a number of differences. First, a cantilever brake caliper uses a transverse cable to move the arms, while the roller-cam caliper utilizes a triangular shaped cam to control the arms. Both cantilever and roller-cam brakes attach directly to the frame or fork studs (although, see discussion above for compatibility issues), but the roller-cam arms pivot on these studs with a see-saw like action. So the way this works is the triangular shaped cam is pulled upward by the brake cable (as you squeeze the brake levers) and each side (edge) of the triangle contacts rollers at the top of each caliper arm. As the cam pushes these rollers outward (as the rollers slide down the edge of the triangle), the caliper arms pivot. This action moves the upper part of the caliper arm outward and the lower part of the caliper arm inward (and towards the rim surface). This explains the see-saw action that converts cable movement to caliper movement and ultimately braking power to the rim surface. Evidently, the roller-cam design gained some traction in the late 80's when there was a desire to mount the rear caliper under the chain stays. This was more difficult to accomplish with traditional cantilever brakes, because their footprint was wider and would often bump or rub against crankarms when mounted in this position. Unfortunately, I have also been told roller-cam brakes are more difficult to setup, so this can make wheel changes, etc., more of a challenge. Lastly, there is a concern that roller-cam brake shoes contact higher and higher on a rim as the pads wear. So if pads are not checked regularly, they may eventually start to rub on the sidewall of the tire, which could result in a blow-out. Again, I am just leaning on what others have written or mentioned to me in conversations, but I still hope some of this information is helpful when considering this unique brake caliper offering. Some other observations regarding these calipers include the following items. The caliper arms are made from a forged aluminum alloy and the mounting hardware (i.e, bolts and bosses that slide over studs) are made from a hardened steel. I also see what appear to be high quality brass components built into the caliper arms. There are the brass rollers at the top of the caliper arms that we discussed earlier. Then there are the brass sleeves in the middle of the caliper arms that slide over the bosses and represent the aforementioned pivot point for these arms. Other specs include a postal scale weight of 576 grams (both front and rear calipers and all mounting hardware pictured) and a reach in the 35.5 mm to 42.5 mm range (depending on where the brake shoes are positioned within the slotted section of the caliper arms). As for condition, these roller-cam caliper sets are very nice and still retail boxed. Even the original grease applied at the pivot points, etc., appears relatively fresh. Brief discussion concerning Suntour labeling in the late 80's and early 90's... For those that are interested, the pecking order of Suntour mountain bike groupsets with indexing capable drivetrains is somewhat confusing...due primarily to the various model number/name changes over a relatively short time period (from the late 80's to the early 90's...so the final years of the original Suntour company headquartered in Japan). To the best of my knowledge, there were anywhere from four to eight indexing capable mountain bike groupsets from the late 80's and into the early 90's...and these XCD (4050 Series) components were middle of the pack (and one step below Suntour's competition-level groupsets). So good quality bicycle components, but not designed for racing or other high-duress applications. I can also confirm Suntour originally referred to these components as part of the 4050 series groupset (and one step below their competition-level 5000 series components) in the late 80's. Although, at some point from the very late 80's to 1990, these components were rebranded as the XCD groupset (which placed them just below the competition-level XC-Comp groupset). I don't know the reason behind all the re-branding, other than it appears by the early 90's, Suntour was attempting to move away from labeling that included numbers in the branding name. Terms and Conditions: You may visit our store by clicking on this "Store Home Page" link and please note the product categories on the left side of our "Store Home Page". We have also moved our "Terms and Conditions" to a separate page within our Ebay store. You may navigate to this page by clicking on the link on the left side of our "Store Home Page" (below the product categories) or you may click on one of our "Terms and Conditions" direct links herein. Note to international customers regarding shipping... We apologize to those that feel some of our international shipping charges are too high. We only charge actual shipping rates, but once an order exceeds a certain amount, we hesitate to use the least expensive US Postal Services First Class International service. We feel this way, because this service is not trackable or insurable...so more risk of loss. We prefer the US Postal Services Priority Mail International service for more expensive orders, because this service is trackable at USPS.com and insurable...so less risk of loss. Unfortunately, this service is more expensive, especially for smaller/lighter packages, relative to the First Class International service. We are sorry about these higher shipping costs, but hopefully our notes help to explain why this is the case. Note to international customers regarding customs... We also apologize to those that feel their country import taxes, duties and brokerage fees are excessive. As a small US business, we are required by customs' laws to declare each order as a retail sale. Additionally, the declared order value must be equal to total store purchases and/or winning auction bids (less any shipping costs, as these are not considered in the declared value). As a result, each customer will be responsible for paying his/her own country taxes, duties and brokerage fees, which will be collected upon delivery. Again, we apologize for these additional costs, but we cannot afford the penalties and fines that come with breaking customs' laws...so we have to strictly abide by them.