Part 2: Bearings — Is My Bike Good Enough to Race?
Part Two: Smooth Movin‘ — You gotta have great bearings[content_box type=”with-header” title=”StartConfident Summary” text_color=”dark” color=”default” animation=”fade-in”]
- Fit. Smooth. Durable. That’s all that counts to get you goin’.
- If you are fitted to your bike perfectly, you’re more than half way there
- Every bearing must roll or turn smooth
- Racing is hard on a bike. Durability is clutch.
The wheels on the bike go ’round n’ ’round.[/dropcap]
The first installment of our survey into a race-able bike was concerned with great fit. Assuming your frame is the right frame for you, and your saddle and bars are in the right place, we turn our attention to anything that spins or turns and bears weight.
Any part that rotates and bears a load must do so smoothly and without play:
- Bottom Bracket
- What exactly makes a good wheel?
Was Sir Isaac a cyclist?
There are many aspects of physics that come to play when we’re talking about bike racing. When it comes to evaluating your bike’s fitness for racing, one of the most important is entropy. At the risk of sounding like your 10th grade science teacher, entropy refers to the tendency of a machine or system to run down.
Simply put, when you grab a wheel and spin it, after a while, it will stop.
What we’re trying to ensure as racers (and bike evaluators) is that every rotating and spinning part on our race bikes will go for as long as possible before Newton’s laws invariably take effect.
Why this is important may not be so obvious.
Efficiency is often faster than raw strength
Bike racing, at it’s core, is an endurance enterprise. Ultimately, the riders who can dish out speed by the most efficient means possible end up winning. There are lots of ways to do that. Your job, as you look over your trusty bike, no matter it’s age or material or groupset, is to ensure that all of it’s rotating parts are spinning with as little in the way as possible.[callout icon=”hb-moon-bike”] What we’re trying to ensure as racers (and bike evaluators) is that every rotating and spinning part on our race bikes will go for as long as possible before Newton’s laws invariably take effect.[/callout]
You want nothing resisting you while you pedal. You don’t want to be fighting against your own equipment. Your goal is to have every possible watt of energy generated by your heart, lungs, and muscles to make it through the rear wheel and onto that little contact patch under the rear tire.
Enter the unsung bearing. Your leg’s best friend.
There’s a reason they’re called “bearings”
Your bike’s pedals, bottom bracket — where your crankset is attached, headset — where the handlebar and fork’s steerer tube are attached to each other, and your wheels — through their hubs, all must bear weight AND bear the strain of rotational force under your mighty, churning legs.
They bear a lot, in other words.
Every second of a race, all of these items are under stress, and lots of conflicting kinds of stress. Weight, torquing, twisting, spinning — it’s amazing, really. But these little engineering marvels enable smooth, efficient speed. Well, that is, when they’re not worn out.
As we go forward with this overview, if you discover any conditions about your bike that you can’t repair on your own, please — take it to a professional shop that is courteous and serving of beginning racers. It’s more fun to be safe and fast.
Grit and play are your efficiency-robbing enemies
Headset — Lift your bike a couple inches off the ground by grabbing the brake hoods. Now, “turn” the handlebar from side to side as if you were turning the bike. It should feel silky smooth. If it feels like there’s sand in there; a gritty, crunchy kind of feeling, you most likely need to replace your headset bearings — or your entire headset.
One other test: straddle your bike and apply the front brake. Now, try to rock the bike forward and backward, gently. Is there any play in the fork? Do you feel or see it wiggle? With a smooth headset, a little wiggle just means you need to have it properly adjusted. But a wiggle that accompanies that gritty feeling may be a headset that won’t stay adjusted, and needs new bearings, or just needs to be retired.
Pedals — Pedals, despite the sheer abuse they take, can often go for years without needing to be replaced. They often feature robust bearings and beefy steel axles to hold up to their difficult job. Test them by leaning the bike against a wall or putting it in a stand, and just gently rotating each pedal with your hand. Feel for the grit. Additionally, grasp the pedal firmly, and attempt to wiggle the pedal on it’s axle in a direction it wasn’t designed to go. You’re looking for any kind of looseness or play. There should be none. The pedal should simply rotate without any deviation. Play or “off angle rotation” can’t be repaired. If you’re sure the pedal is securely tightened (without being tighter than the manufacturers recommended torque setting, usually stamped or etched on the pedal in Newton meters, or Nm — there’s that Newton guy, again…) and there’s play, it’s time to go pedal shopping. Wiggly pedals can become incredibly unsafe, especially in a race situation.
Bottom Bracket – If your bike was made anytime after 2003 or so, it probably has an external bottom bracket: that is, the bearings are outside of the tube through which the crank’s axle runs. Prior to that, cartridge bottom brackets were installed inside that tube. After 2007, many manufacturers started using bottom brackets that were pressed in to the frame under force.
All of these designs use large bearings that must rotate smoothly in order to maximize your precious pedaling energy during a race.
Internal cartridge bearings can be disassembled, cleaned, new ball bearings cheaply inserted, and rebuilt.
External bottom bracket bearings can’t be replaced; the entire external bottom bracket must be replaced, but…thankfully, they aren’t frightfully expensive.
Ditto for the press-fit bearings. Trouble with these, though, is that they require quite special — and expensive — tools. The others can be do-it-yourself jobs.
Regardless of the kind you have, pull the chain off the chainring by hand, and gently place it on the bottom bracket shell — that’s the part of the frame the bottom bracket is either in or on, depending on the kind you have. Now, rotate the crank. Smooth as butter? Good. If it’s not, you need a replacement.
Now, stand over top of the bike, and grab the crankarms. Attempt to wiggle the crankset inside the frame. If there’s any play, but the rotation is smooth, you need to have the crank adjusted. It should rotate without play, but not have any binding.
Wheels. Without whom…
There are fewer more miraculous inventions than the bike wheel. To say that they are of the most importance next to the frame is an understatement. They are the very spirit of your bike, and no mechanical part of your bike will affect the speed and efficiency of your bike like the condition of your wheels.
But for this discussion, we’re chiefly concerned with your hub bearings.
What makes a good wheel?
Let’s start with an evaluation of your hub bearings.
Take the wheel out of the front fork, or the rear dropouts. Remove the skewers.[callout icon=”hb-moon-bike”] What we’re trying to ensure as racers (and bike evaluators) is that every rotating and spinning part on our race bikes will go for as long as possible before Newton’s laws invariably take effect.[/callout]
Now, hold the ends of the axle with the thumb and forefinger of each hand. Using your free fingers in the spokes, get the wheel spinning.
Pay attention to what you feel as you hold the rotating wheel. If you’ve read this far, you know that what you don’t want to feel is any gritty, sandy, crunchy sensations. This is a cry for new bearings. But don’t worry. Bearings wear out, and racing will mean that you’ll experience this every season, or every other season.
Cartridge or balls? Any hub made since the early 2000’s will most likely require cartridge bearings. These little steel, ceramic, or steel and ceramic (known as “hybrid”) bearings should be pushed or pulled out using a bearing tool in order to prevent damage to your hub. Whacking them out with a hammer and a drift or screwdriver isn’t recommended.
Hubs made in the late ’90’s and prior will likely use a set of traditional steel ball bearings. These can still be acquired, greased up, and repacked at home using a pair of tweezers, some bike-specific grease, and a pair of inexpensive cone wrenches. The challenge is in adjusting the hubs after you’ve installed the new bearings. Too tight and you have a hub that binds. Too loose, and you have a wheel that wiggles side to side while it spins.
Cartridge bearings can be reasonably priced for a set of steel ones. Ceramic bearings are, in my opinion, ridiculously expensive and simply don’t hold up like steel ones do. Hybrid bearings, where the outside ring (or “race”) is made of steel and the inside balls are ceramic are pricey, but not as expensive as all-ceramic bearings.
I have personally installed several sets of hybrid bearings, and enjoy the balance of durability and smoothness they provide. There are a number of bearing suppliers online that can help you determine which ones your wheels require, including VCRC Bike, and Boca Bearings.
Hub Play. Once you know you have smooth-spinning hubs thanks to smooth bearings, you need to be sure that the hubs are adjusted properly.
A check for this is to put the wheels back into their dropouts. Secure the quick release skewer. With the bike sitting on the ground, grab the wheel up near the brake calipers. Can you wiggle the wheel side to side, as if to cause it to make contact with the pads?
Some wheels have wimpy rims and equally wimpy spokes. Or, the spokes may be improperly tensioned. These conditions can contribute to wheel flex. Wheels flexing under your pedaling aren’t necessarily helping you go faster, are they.
Assuming the spokes and rim aren’t simply “soft,” you want to ensure that any side to side shifting at the hub is removed. All modern hubs have a mechanism for dialing out this play.
A great wheel is truly a symphony of factors working together: a rim that is stout, can hold up to road abuse and stay true, and has a smooth braking surface. Spokes that are properly tensioned. A hub of sufficient strength to hold up under tension to help minimize flex. Smooth, well-adjusted bearings.
Racing requires that your wheels pass muster on all of these fronts.
Notice that I didn’t mention weight.
While it’s true that you do want to minimize rotating mass, especially during hilly events, a smooth, true, well-tired rim / hub / spoke combo can be raced successfully even if it’s not the most featherweight carbon aero wing money can buy. A heavy wheel is harder to get up to speed; going from a standing start to 20+ is harder on a heavy wheel than a light one. But once you’re rolling, it’s all about smoothness, and our next topic: durability.[icon_box icon=”hb-moon-bike” icon_position=”left” align=”left”] Question: Do you regularly check for bearing wear, or just ride your steed ’til it’s crusty?[/icon_box]