Bike Anatomy Flashcards
Types of bikes
Road Bikes
Road bikes are built to handle a variety of cycling situations like cornering, climbing and pack riding. The seat tube angle of a standard road bike is 72 to 75 degrees.
Time Trial Bikes
Time trial bikes are also known as triathlon or tri bikes. These bikes feature a steeper seat tube angle of 76 to 78 degrees.
Handcycles
Handcycles are specifically designed for individuals with lower mobility impairments. These bikes come in a variety of styles and materials and allow for various adjustments, wheel configurations and gearing variety, depending on a cyclist’s needs. Seated or “chair style” handcycles may allow for increased propulsion.
Bike Saddles
Come in a variety of styles that differ in materials, stiffness, length, pressure points and width at sit bones
Traditional saddles – hard, narrow and long.
Anatomical Fit (AF) saddles – reduce pressure on prostate and perineal nerves located between the pubic symphysis and the coccyx. Select when having problems with soft-tissue pressure and numbness. Note: does not reduce chafing.
Time Trial/Tri specific saddles - reduce pressure on the nose of the saddle. Select when most riding is in the aero position.
Select saddles that support athlete’s “sit bones”
Saddle choice is critical for comfort and it may be necessary to try different saddles until the perfect feel is achieved.
Bike Frames
- Carbon Fiber
Very lightweight and versatile
Constructed by manufacturers using proprietary designs, carbon weave and frame designs to increase stiffness keeping the frame light
Absorbs most road vibration and is very forgiving
Can range from affordable to very expensive
High resistance to corrosion - Titanium
Lighter than steel but just as strong
Responsive but forgiving, very unique feel when riding
Very durable
Very expensive
Corrosion resistant - Aluminum
Lightweight and strong
Absorbs less road vibrations than other materials
Often combined with carbon fork and seat post to increase comfort and help absorb road noise
Affordable
Very durable - Steel
More traditionally designed with fewer bends in tubing
Absorbs more road vibration than aluminum but not as much as carbon or titanium
Heavier than other options
Softer than aluminum
Tendency to rust
Durable
Brakes
- Rim Brakes
Are caliper brakes that are mechanical or hydraulic
Have calipers mounted on the fork and frame
Are dual pivot or dual symmetric pivot, depending on the brand
Easy to maintain and lightweight
Pads need to be checked for wear
Can easily replace brake pads
Carbon and aluminum pads are readily available
Performance may suffer when wet
Most common on road/time trial bikes
Simple and powerful
Important to modulate rim brakes on long fast descents to prevent overheating the rim and potentially flatting - Disc Brakes
Are mechanical or hydraulic
Have calipers mounted on the fork and frame
Are single and dual actuated
Perform in all weather conditions because:
the breaking surface is further from ground picking up less debris,
the rotor has holes in it creating a path for water and debris to get out from under the pad and
displacement of heat through the rotor doesn’t affect the rim.
Calipers attached to frame or fork squeeze pads together on a disc mounted to the hub of the wheel, creating friction and slowing the bicycle
Self-adjusting
Can accept higher maximum breaking loads
Requires less effort, more reactive to your touch
Can be heavier and less aerodynamic than rim brakes
Requires a special frame and fork fixtures for installation
Handlebars
- Drop Handlebar
Traditional handlebar on a road bicycle
Multiple hand positions provide better comfort for training and pack riding
Allows for upright riding and lower aero positions
Has various drop and reach options
Deep, shallow and ergonomic bends
Combined with newer shifters that have internal cable routing - Bullhorns
Have a curved up and forward design and get their name because they look like a bull’s horns
Allow the cyclist a more forward position, putting more weight over the front wheel and unweighing the rear wheel
Are typically used as a base bar and are paired with aero bars
Originally used by cyclists competing in the pursuit on the velodrome
Will accommodate brake levers at the end of the bar
Are usually wrapped with handlebar tape
Provide at least three different hand positions - Aerobars
Allow for a more streamlined position out of the wind
Can clip to a traditional road drop handlebar or come as an integrated piece
Aero bar systems on TT bikes are usually comprised of a bullhorn style handlebar and clip-on aero bar
There are three types of aero bar extensions:
Straight
Ski Bend
S-Bend
Shifters can be added to the aero bar extensions allowing riders to remain in aero position while shifting
Clip-on aero bars may have option to mount the extensions underneath the flat portion of the bar, providing a lower profile
Adding clip-on aero bars to a road bicycle may require additional changes to the rider’s position in order to maximize pedaling efficiency and comfort
Tires
- Clincher Tires
Clincher tires have a fiber or wire bead that interlocks with flanges in rim
Less expensive than tubular tires
Requires an inner tube
Tubeless wheels are now available but require a tubeless tire
Inner tube can be easily accessed if punctured or needs replacement and it is easy to carry extra tubes
*If you flat a tubeless tire, you can put a tube in it. The tire is very difficult to mount because of the higher rim flanges. Not recommended for someone with little hand strength or arthritis. - Tubular Tires
Tubular tires’ outer casings are attached to the rim with an adhesive.
Tires can roll off rims if not properly glued
Lighter than clincher tires
Less prone to flats and punctures
May be easier/quicker to change during race
Must carry extra tire (in case of flat)
More expensive than clincher tires
Crankset and Cassette
Transfer power generated by the rider’s pedaling to the chain
The chain then rotates the rear wheel, propelling the bike
Composed of crank arms, chain rings, pedals, chain and cassette
Cranks mount to the bicycle with the use of a bottom bracket installed in the bottom bracket shell
1. Chain Rings (Front)
Chain rings bolt to the spider on the drive side of a crankset with a specific BCD (Bolt Circle Diameter)
A crankset is made up of a drive side crank arm with a spider, a non-drive side crank arm and a spindle (affixed to the inside of the spider) that passes through the bearings of a bottom bracket mounted in the bottom bracket shell
Cranksets are usually constructed of cold-forged aluminum or carbon fiber
A standard crankset comes with two chain rings having 53 teeth on the outboard ring and 39 teeth on the inboard ring
A compact crankset usually comes with 50 teeth on the outboard ring and 34 teeth on the inboard ring; There are other variations of ring sizes for a compact crankset
Chain rings can wear out and may need to be replaced
2. Cassette (Rear)
Is found on the drive side of the rear wheel on the freehub body held on with a lock ring
Will vary from nine to eleven cogs (nine cogs for “9-speed” bicycle, ten cogs for “10-speed” bicycle and eleven cogs for an “11-speed” bicycle)
For flat terrain, choose a cassette with a small relative difference of around 7% to 10% (e.g. 11-21 or 12x23); for fine adjustment of gear ratios to suit the conditions and maintain a consistent pedaling speed
For hillier terrain, difference between gears will be greater (e.g., 12-28) due to the need for a easier gear (on the cassette, the more teeth, the easier the gear)
Some rear derailleurs can accommodate a cassette with a 28-tooth or even 32-tooth cog, (e.g 12x28 or 12x32); A 12x32 cassette would be used for an extremely hilly course
Pedals
Pedals
Typically called “clipless pedals,” referring to the absence of toe cages
SPD-style pedals are most common for new cyclists
Should be chosen based riders biomechanics and comfort of the rider when clipped in
Also require regular maintenance and inspection
Come in a variety of colors and styles and are made from various materials
Can be single-sided or have two sides to clip into
Come with cleats that bolt on to the underside of a specialized cycling shoe
Allows the cyclists to complete a full circle by facilitating an up stroke, by fixing the foot to the pedal, and a down stroke for maximum efficiency
Certain pedal systems with a larger cleat area allow the force load applied to the pedal to be spread over a wider area, increasing power transfer into the drive train and reducing pressure on connection points.
Improved control
Improved safety due to the fact that feet are prevented from slipping off pedals
Athletes who haven’t used clipless pedals might need time to become confident using them.
Help them determine their dominant foot for clipping and unclipping
Practice in a grassy area
Remind them well before stopping at traffic lights and stop signs to unclip
Wheels
Consist of hub, hub body, spokes, spoke nipples, rims, rim tape, tubes and tires
Wheel size 700c (most common) or 650c
Choice of wheel dependent on drivetrain components
Vary in weight, number of spokes; a heavier wheel (rotating mass) will take longer to accelerate up to speed and require more energy to operate
Rider weight is a factor in selecting wheels; Lightweight cyclists can use wheels with less spokes
Vary in type of materials (aluminum alloy, carbon)
Types of wheels: traditional spoke, aerodynamic and disc
Spoke holes: most rim surfaces require rim tape; the exception is tubeless wheels
1. Traditional Wheels
Pros: Lighter than aerodynamic and disc wheels. May be faster when ascending hills (average 5% grade) and technical descents.
Cons: For time trialing and triathlons, conventional spoked wheels will not be the fastest combination.
2. Aerodynamic Wheels
Aerodynamic wheels have greater rim depth, a triangular or pyramidal cross-section, a fewer number of spokes (or blades in lieu of spokes) and a greater distance between spokes.
Pros: Reduce wind resistance. Blade spokes are more aerodynamic. 30 seconds to two minutes faster than spoked wheels in flat terrain.
Cons: Heavier than standard wheel sets. Increase surface area in crosswinds.
3. Disc Wheels are solid or covered wheels and are sometimes constructed of honeycomb carbon fiber. They are designed for the rear wheel only. More current versions are spoked wheels simply covered with Mylar to improve aerodynamics.
Pros: Reduce drag and improve airflow around the rear end of the bicycle. Faster than spoked wheels on flat terrain.
Cons: Heavier than spoked wheels, which may be a factor with a less powerful cyclist or any cyclist on a climber’s course.
