Brake pad replacement
Depending on the type of brake you have the type of bike you ride, the gradient and type of terrain you ride and the amount of distance you cover you’ll have to replace your brake pads on a regular basis.
The type of pad you should buy depends entirely on the above factors as well as the age of the bicycle. The best way to check brake pad replacement is to physically look at the amount of ‘meat’ left on the pad. For most rim brake style pads (excluding some carbon specific pads). You should check for grooves running down the middle of the pad. These improve braking performance by allowing water to run of the pad during braking water reduces the effectiveness of the brake so once this pad tread disappears you should look at replacing them.
Disc brake pads are slightly more subjective but from personal experience I never let my pads go under 2mm. The more your pads wear the further forward your pistons will have to move to contact with the rotor. Giving more leverage for wear to your pistons/brake and a bigger chance of damaging your caliper.
You may notice that we noted the age of your bicycle in the above factors. This wasn’t a generalization to the type of bicycle you ride or the type of brake that might be fitted to it. It was a nod towards any possible warranties you may have with your brake manufacturer. During this warranty period we recommend that you always use original manufacturer replacement pads and parts. Once this warranty is expired many riders opt to use aftermarket pads, which are usually much cheaper than original manufacturer parts and you won’t risk invalidating any warranty.