Sunrace 8-Speed Freewheel

Product Information

This tool is a splined unit that may be mounted in a vise or turned with a wrench. The splines engage matching splines in the interior (always rotates with the wheel) part of the freewheel body. Different brands of freewheels have used different spline patterns, but there is a recent tendency to standardize on the Shimano pattern. Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s. There are a few exceptions:

An additional complication is that "road" front derailer cages are shaped to fit well with a 52-53 tooth big chainring, while most current "mountain" front cages are shaped to fit with a 42-44 tooth big ring. Long-cage (SGS) derailers have greater takeup capacity, and work with all types of cassettes. Long-cage derailers are commonly called "mountain" derailers currently, though in the past, this style of derailer was known as a "touring" derailer. (The marketeers retired the use of "touring" as a buzzword in the late '80s when mountain bikes became the hot item.) "Road" vs "Mountain" Front Derailers Shown here is an aluminum body that has suffered this sort of damage. Someone has filed down the burrs to make it re-usable after a fashion. Campagnolo/Shimano 8-speed cassettes have different spacing , so you can't generally get good indexing using a Campagnolo 8-speed wheel with a Shimano shift system or vice versa.Very early Freehubs (sometimes identifiable by the absence of the typical bulge on the right end of the hub barrel) which have non-interchangeable bodies. The Freehub body of these hubs is held on only by the axle bearings, and will slip off once the axle is removed.

The same procedure works for off-brand Freehubs that have a LH threaded fastener accessed from the LH side of the hub, too. It doesn't work with freehub bodies that screw directly into the hub shell. While rear indexing is the same for all recent shifters/derailers, Shimano fronts use a different amount of cable pull for drop-bar vs flat-bar controls. Are the shims trapped underneath the bearing balls? If so, you will have to remove the bearing balls before you can remove a shim, and replace shims before installing bearing balls. You can remove the bearing balls with a magnet, or turn the freewheel over far enough to spill out the bearing balls, while holding the outer body so it doesn't fall off. Long-cage derailers have greater takeup capacity, and work with all types of cassettes. Long-cage derailers are commonly called "mountain" derailers currently, though in the past, this style of derailer was known as a "touring" derailer. (The marketeers retired the use of "touring" as a buzzword in the late '80s when mountain bikes became the hot item.) These chainrings have the teeth slightly farther to the right than the older chainrings to work a little better with the narrower chains. There is no difference whatever in the crank spiders.Replacement bodies are not available for these early hubs, which can sometimes be identified by the narrow barrel, without the characteristic bulge on the right end. (The bulge is to accommodate the threading for the hollow bolt used on newer Shimano Freehubs) See the photos below, kindly provided by David Landsberg. Mountain" hubs will likely be slightly better sealed against dirt and mud than "road" hubs, but this is rarely an issue in practice. The wider 135 mm spacing will generally result in a slightly stronger wheel due to reduced dishing of the spokes. Old Chainrings, New ChainsThere is a lot of confusion about the compatibility of narrow 9- and 10-speed chains with older cranksets. Shimano says you should replace the inner chainring(s) with specially designated 9- or 10-speed ones, but then they're all too eager to sell you stuff, whether you need it or not. A freewheel that has been ridden for a long time, especially by a strong rider with low gears, may be quite difficult to remove because the threads are so tight. Unless you are willing to put up with friction shifting, you need to install new shifters. Indexing handlebar-end shifters, top-mount shifters or downtube shift levers let you know how to shift by feel. Brake-lever shifters return to the same position after every shift, so you don't know what gear you are using. They also tend to be expensive. Brazed-on bosses for downtube shifters on some older frames will not fit today's index shift levers or cable stops, so you will need to use a clamp-on adapter.

If you do re-space your hub, you'll also need to re-dish your wheel, because the extra space will all be added on the right side by installing the wider Freehub body. You'll need to tighten spokes on the right, possibly also loosen some on the left, to move the rim 2mm to the right so that it will once again be centered in the frame.

Freewheel or Freehub?

My 1984 Record Ace now has a triple with 26/36/46 and a 10 freehub with a 32 on the rear.Old age does not come alone! For example, Shimano doesn't make any true "corncob" (one-tooth-jump) cassettes for time-trialists or flatland riders. In 7 speed, the closest is the J (13/14/15/16/17/19/21). When discussing cassettes, the terms "Road" and "Mountain" are marketing terms, not technical ones. The right side of the outer freewheel body looks like this when all cleaned up. A bearing race is visible. All recent freewheels and threaded hubs, regardless of where made, use ISO threading. The older British and Italian standards use the same thread pitch but a very slightly different thread diameter, and are generally interchangeable. However, for strong riders and on tandems, it is best not to mix and match -- freewheels sometimes do strip the threads of aluminium hubs. A French freewheel may start to thread onto an ISO/British/Italian hub but will soon bind. An ISO/British/Italian freewheel will skim the top of the threads of a French hub and will slip forward if an attempt is made to use it. Do not force a freewheel -- you will ruin the hub.