MEASUREMENT & SELECTION
| Vuelta USA makes a chainring for almost every bicycle and
almost every need, from recreational riding to the most demanding
competition. The following information and guide will be able
to help you select the right Vuelta USA chainring for your cycling
application. |
WHAT TYPE CHAINRING DO YOU NEED?
Vuelta USA makes the five most popular chainring types currently
in use for road and mountain bikes. They are:
| ROAD |
- Standard 130 BCD five-bolt pattern in
Flat and SE Plus for most road double and triple applications.
- Campagnolo-Compatible 135 BCD five-bolt
pattern in Flat only for standard Campagnolo road double cranks.
|
| MOUNTAIN |
- Compact 58/94 BCD five-bolt pattern in
Flat and SE Plus for MTB triple and 29er applications.
- LX/XT/XTR M960-Compatible 64/104 BCD
four-bolt pattern in Flat and SE Plus for Shimano-compatible
MTB triple cranks.
- Standard 74/110 BCD five-bolt pattern
in Flat and SE Plus for road and MTB triple and 29er applications.
|
WHAT IS BCD?
BCD stands for Bolt Circle Diameter, the distance between bolt
holes measured in millimeters by an imaginary circle that passes
through the center of each hole in a chainring. Virtually every
modern crank and chainring is manufactured according to this method,
which makes it possible to select a wide variety of gearing to meet
specific applications or needs.
Based upon the above descriptions, you should be able to easily
determine the Vuelta USA chainring (or chainrings) that you need
for your particular type of riding.
To measure the BCD of the chainring you need to replace, measure
the center-to-center distance between any two adjacent chainring
bolt holes with a ruler or calipers calibrated in millimeters.
If You
Measure |
Chainring
BCD Is |
Chainring Bolt Pattern
and Crank Type Is |
| 34.3 mm |
58 |
5 MTB Compact Triple |
| 45.3 mm |
64 |
4 LX/XT/XTR M960 |
| 43.5 mm |
74 |
5 MTB Std./Road Triple |
| 55.4 mm |
94 |
5 MTB Compact Triple |
| 73.6 mm |
104 |
4 LX/XT/XTR M960 |
| 64.7 mm |
110 |
5 MTB Standard |
| 76.4 mm |
130 |
5 Road Standard |
| 79.5 mm |
135 |
5 Campy Road Standard |
CHAINRING ANATOMY
A chainring is more than a piece of metal; it’s a precision designed
and manufactured component that’s the heart of your bicycle’s drivetrain.
When it comes to a chainring that has to work perfectly every time,
it’s the details that go in to that make the difference. The following
terms describe the different parts of chainring anatomy.
- 6061 and 7075: Two grades of aerospace
aluminum alloy used to manufacture Vuelta USA chainrings.
6061-T6 aluminum is used for middle and outer chainrings and
has a tensile strength of 42,000 psi. 7075-T6 aluminum has
a tensile strength of 74,000 to 78,000 psi, which makes it
perfect for making our SE Plus chainrings and small inner
chainrings – aka granny gears – so they can handle high loads
under tough riding conditions.
- Anodizing: A finishing process applied
to aluminum that protects the material and maintains its appearance.
- Bevel: Machined area of chainring or
chainring tooth that provides clearance for other moving parts,
such as cranks, chains and front derailleur guides. A chainring
tooth may have at least two bevels to allow proper chain clearance
and shifting.
- Chainring Bolt Hole: Attaches the chainring
to the crankarm. A Vuelta USA chainring can have four or five
chainring bolt holes, depending on its model and tooth size.
- Clocking Mark: Part of an SE Plus chainring
that lines up with crank arm at the 3 o’clock position to
indicate correct installation.
- CNC: Computer Numerically-Controlled
machining. This is the only way Vuelta USA chainrings are
made.
- Countersink: Machining in the Chainring
Bolt Hole that lets the chainring bolt fit flush with the
surface of the chainring.
- Cutout: Area of a chainring that is machined
out to remove excess weight and also add to its appearance.
- Non-Pressure Side: Trailing side of chainring
tooth that does not bear load from chain.
- Pressure Side: Front side of chainring
tooth that bears load from chain.
- Relief: Area of chainring that is machined
to provide clearance or remove weight. Is also area machined
into chainring tooth to assist shifting on an SE Plus chainring.
- Shift Pin: Steel rivet that assists shifting
and guides chain on backside of an SE Plus chainring.
- Shift Ramp: Machined areas located on
backside of an SE Plus chainring that assist shifting and
maintain proper chain location.
- Valley: Machined-out areas between chainring
teeth.
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