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H
Handlebars
These can be of the drop or upright fashion and can be in different sizes.
Hardtail
A Mountain Bike without rear suspension.
Hat
Necessary in the winter for cool rides and useful in the summer too. A small brimmed hat can keep the sun out of your eyes and reflect some of the sun’s strongest rays.
Headsets
The bearing system that attaches the fork to the frame for turning and balance.
Heart rate monitors
Often combined with speedometers to provide a single cycling computer that provides a useful training tool for cyclists. Heart rate is a simple method of gauging exertion. There are a number of ways to work out an individual’s optimal training heart rate.

Polar, Cateye, Mavic, Suunto and Garmin are established manufacturers.
Helmet
To be worn at all times whilst on a bike. All helmets should comply with the relevant regulations. The extra cost is usually to do with comfort, fit and lightness.
Hubs
The middle part of the wheel. Spokes attach to the outside of the hub and the axle runs through the middle of it. The cassette is attached to the hub on the rear wheel.
Hybrid bike
A mix between a road and a mountain bike. These are strong and robust but have thinner wheels, no suspension and lighter frames than mountain bikes.