Learn About Wheels

PRESTA VALVE: Presta valve-the smaller non-car looking air valve.

SCHRADER VALVE: The car tire looking valve.

SPROCKET: The guy on Saturday Night Live (in addition to the cluster of toothed rings on the back wheel.)

CASSETTE: Same damn thing as sprocket but referring to the entire unit.

TUBULAR TIRE: A tire that is physically glued to the rim. Commonly know as a sew up tire.

CLINCHER TIRE: A tire that pushes against the side of the rim and uses air pressure to stay in place.

RIM: The big metal hoop of the wheel.

HUB: The center part of the wheel that attaches to the bicycle and also where the spokes are held on one end.

FLANGE: The part of the hub where the spokes come out of.

NIPPLES: A "nut" that is made of brass or aluminum that holds and tightens one side of the spoke. The nipple is usually found protruding from the rim.

EYELET: The holes on the rims where the spokes come out of. On many rims, a brass sleeve is used to distribute the pulling load of the spoke.

DISH: The centering of the rim in conjunction with the hub.

BUTTING: Reference to the changing thickness of a spoke throughout it's length. Usually a spoke is either double butted (thinner in the middle) or straight gauge (no change).

LACING: crossing spokes over one another.

TRUING: adjusting the tension of the spokes to make the wheel straight or true.

WINDUP: the torque place on the hub when pedaling or braking.

HOP: what a bunny rabbit does, or what you do on your bike over small logs. Also refers to a part of the rim that is not round but instead has a small bump in it.

SUPPORTING A LOAD: A wheel is subject to two kinds of loads; static and dynamic. Within these loads, forces of compression, tension and torsion are all at work while riding. All of these forces would very much like to rip apart the wheel. It is up to the hub, rim and spokes to keep everything in its place. While some manufacturers opt for heavier-albeit stronger wheels, others try to redefine the wheel and the roles each part play.

SPOKES : Spokes have been an integral part of a wheel since it's inception.

MATERIALS: Metal has been a common element to use due to it's elasticity and strength. Some companies have played around with newer materials like vectran, which is stronger along it's longitudinal axis yet flexible enough to tie in a knot. Carbon fiber has been very popular as well but must be carefully used.

BUTTING: A common and cheap way to produce a spoke is to just roll a continuous piece of metal out never changing it's diameter and this is called a straight gauge spoke. The drawback to this type is the weakest point is now where the spoke bends (at the head). More likely than not, this type of spoke will break at that bend.

When a spoke is butted, the diameter changes in certain places along the length. The result is a stronger, lighter spoke. Butting a spoke makes it stronger because the load placed on the spoke gets drawn towards the center and thus reducing the stress placed on the head. A double or triple butted spoke will never break at the head in a properly built wheel.

LACING OF SPOKES: To achieve maximum strength from a rim, spoke, and hub; overlapping of the spokes is necessary. In the 32 hole, wheel design, a triple cross pattern- or crossing one spoke over three spokes going the opposing direction is a common practice.

The reasoning behind crossing spokes is to keep the wheel from winding up while under the torque of pedaling or braking. If a wheel was able to twist along it's radial axis, then we would loose efficiency and the wheel would not last as long.

We can get away with making different cross patterns and in fact, can build a front wheel with a radial pattern.

RIMS: Rims are a crucial part of your wheel: they help resist all types of loads. Most rim designs are based on increasing sidewall strength where the braking surface is, while others try to incorporate the height or profile of the rim into the overall strength. We have found the power-beams in profile 1 above, give the best strength to weight ratio of any rim.

MATERIALS:

ALUMINUM: has historically been a favorite material with major manufacturers. It comes in 6000 (softer) and 7000 series. You can anodize it and make various aerodynamic shapes. Much cheaper to make than carbon fiber and thermoplastic but it deforms easier.

CARBON FIBER: wheels have become a very popular with people wanting aerodynamics and a unique looking wheel. Due to the fibers strength along it's strand, it has extremely good properties keeping the wheel true. However, the materials and cost associated with it are also higher than a regular wheel.

BRAKIING SURFACES: Ceramic coating has been applied on many rims which only helps in wet or very cold weather because the ceramic heats the pad and rim up quicker. In hot weather, ceramic rims actually work worse than a non-coated rim.

Most quality rims on the market today have some sort of etching done to the surface to improve the surface contact between rim and pad. The problem is, this surface wears out in about a year and you are back to a regular smooth surface.

HUBS: some hubs make "clickety" noises, some have generators or internal gears, and some just sit there like a bump on a log. They all serve the purpose of allowing the wheel to go around.

HUB DESIGN: Hubs in general, are very strong and do their job very well. However, certain applications like disc brakes and front suspensions require that a hub becomes like Steve Austin in the Six Million Dollar Man. Hubs dictate how a wheel will behave and how the lacing of spokes will occur.

BEARINGS: Many companies use what are referred to as "Cartridge Bearings" which are basically replaceable bearings that come in their own enclosure. The benefit to this design is ease of service and less expensive manufacturing. The other system incorporates the hub itself as part of the surface that the bearings roll on. This type of system thought, does need to be re-greased about every 5 years so many companies have put in grease injection systems.

AXLES: The part that connects the bike to the hub is the axle- like a car. The centermost part of the hub (aside from quick release) and needs to be very strong. Most axles are steel, some are aluminum or titanium. With aluminum and titanium, the rest of the hub must be strengthened to help transfer loads.

SKEWERS: A normal sized skewer or quick release does just fine with road bike and recreational riding. However, the overzealous need the QR to be thicker and stronger. At Cycle Dynamics, we have found a strong correlation between a oversized skewer and the stiffness of a bike and wheel.