“Help! My bike won’t stop!” A few words about rim brakes.

There’s some words of advice that I find myself repeating, over and over again, to new or relatively new cyclists. Even to some more experienced ones.

Recently, the advice was relating to the rim brakes provided with most road bikes. And it occurred to me that I’d be better off blogging those words for posterity. [This is a work in progress – additions are welcome and I’ll probably edit at a later date.]

There are three main reasons that people have trouble stopping, or with handling:

  1. Bike setup – components, etc. Sometimes the tools can be blamed.
  2. Bike setup – geometry. Does the bike really fit? Adjustments made to geometry can so easily have a negative effect on handling.
  3. Technique – how brakes are used. To stop is the obvious answer, but it’s sometimes not that simple.

This post primarily deals with 1. However, the other points do have an impact and cannot be immediately discounted, especially if you’re trying to help a newbie cyclist.

The advice doesn’t change that much depending on whether your bike is new or secondhand – some stock pads and brake calipers which come with new bikes are pathetic, and I’ve seen old and new cable messes.

So, here we go:

Change brake pads.

For the biggest improvement. Stock pads, even Shimano, are usually very poor, and often seem to pick up a glaze and grit from the road. I’ve always found Kool Stop Salmon more than enough, but other friends swear by Swissstop.

Don’t even think of the integrated shoes and rims – my experience of them was downright dangerous.

Check the pads are aligned properly on the rim, and also equidistant from the rim on both sides.

Much woolliness when braking is caused by one side making contact before the other. If the caliper moves too freely, tighten the bolt holding it on the frame. Some toe pads in,

Clean rims and pads.

Dirt and water can impair performance, and shorten the life of your bike parts. If I don’t have time for a full bike clean, I’ll often wipe the rims down with baby wipes and use a metal file to take any glaze or unevenness from the pads.

If I’m riding in the rain, I’ll clean my rims off every now and again with light braking. If I go over a gritty surface on a leisure ride, I sometimes stop briefly to rinse my rims with a bit of water from my bidon. A hose outside a cafe on a wet ride is a bonus.

Check both calipers are springing back freely.

Dirty brakes can stiffen up, especially if you don’t use mudguards or clean/lube them often enough. Lack of maintenance added to the passage of time can also create play in the caliper, which impacts on performance. If there is play, brakes are expensive to refurbish and it’s usually more astute to buy new calipers.

Adjust the brake cable tension.

The bite point should be equal for front and back – about a third in of the total lever movement.

If you have short fingers, you could bring it in further for better control, but be aware you may have to adjust the tension more often.

You could also insert some shims (older groupsets) or adjust the settings to bring the lever initially closer. I have shims in all of my shifters.

Check the brake cables are running freely.

The inner wire needs to be able to move freely within the outer, and if it doesn’t, braking will be poor. The ends of the outer cables need to be finished properly and not catching the inner wire. (My new bike this year had this problem.)

If your bike is secondhand, it would probably benefit from new cables. Every bike I’ve bought secondhand has had some corroded cables.

Cables are the wrong length?

Some new and secondhand bikes come with cables that are far, far too long. I’m guessing this is because it gives leeway for fitting longer stems without doing a total cable overhaul. However, sloppy cables negatively affect braking performance. If the stem has been shortened, the cables will almost certainly be too long. I’m pretty certain most bike shops won’t address this issue after doing a fitting.

Similarly, outer cables can be too short, which also impacts braking and is dangerous.

Change the calipers

As mentioned above, it’s common to have a new bike with cheaper calipers which are out of odds with the rest of the groupset. Some people have even sworn to me that they have a full Tiagra groupset when the brakes have been Tektro or unnamed.  Upgrading your calipers can be a massive boost.

New tyres?

Some tyres are renowned for poor grip, and the narrow tyres found on many budget bikes don’t have as good a contact patch as wider variants. My descending improving immeasurably when I changed to Conti GP 4000s in 25c.

If however you’ve stuck too-wide tyres on narrow rims, you’ll experience what they call the ‘light bulb effect’ on cornering, so it’s worth checking the profile of your tyres for this.

Technique?

As a last point, just a few words of advice can sometimes help a nervous braker or descender to improve their speed or safety. Foot and hand positioning, looking around corners, weight distribution, line, weather etc. Mental attitude also contributes to this – tension and fear isn’t something you can overcome overnight.

Watching a few clips of YouTube can be invaluable, or preferably, I recommend signing up to a race training or skills course.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s