Steering Head Bearing Maintenance | How To

Shop Talk

Maintenance
Few suspension components have as dramatic an effect on your bike's performance as steering head bearings. If they're too loose, too tight, or damaged in any way, the steering, and handling qualities of your bike will take a real hit. Fortunately, steering head bearings don't need much attention, and what maintenance is required is relatively easy to perform.

Bearing types
There are four types of steering head bearings in widespread use. With some exceptions, motorcycles built prior to 1979 will generally have loose ball-type bearings, while the bikes built after that generally use caged ball, sealed ball, or tapered roller bearings. As far as maintenance goes—with the exception of the sealed types, which don't require lubrication—a discussion of one is as good as another.

Inspection
The owner's manual will list the prescribed inspection and maintenance intervals but at the minimum, I'd suggest inspecting the steering head bearing adjustment and condition at least once a year (See Tips on page 74 for a list of common problems and their symptoms) and servicing them every two to four years depending on your riding habits.

The condition of the bearings can normally be determined with a few quick external checks, which can be done in ten minutes or less.

Jack the bike up until the front wheel just clears the pavement, and then gently rotate the fork from side to side. It should turn easily and smoothly. If the forks binds, or it feels like it has detents or notches in any position, it’s a safe bet that the steering head bearings have become dented and need replacing. Because the bike spends so much time with the fork positioned straight ahead, the most noticeable dent will usually be felt there.

Occasionally the control cables or the wiring harness will cause the forks to bind as they’re swung, so if something catches your attention, make sure it's not an improperly run cable that’s creating the drag.

If all feels well, grab the fork legs slightly above the axle and gently try to pull them toward you. If the bearings are loose, you’ll feel a definite rocking movement, or even hear a clicking noise. If there’s any doubt, have a helper place a finger on the upper steering stem clamp—if he feels movement when you rock the fork, the bearings are loose.

Adjustment
Adjustment particulars vary by make and model so refer to your bike's shop manual for the details. What we want to do is remove all play from the bearing, yet only put the slightest preload on it. This takes a fine touch and some practice so don't be too surprised if it doesn't come out perfect on the first attempt. A word of warning here; over-tightening the bearings will cause greater damage and handling problems than leaving them slightly loose will, so better to err on the side of caution and go gentle on the adjustment.

Start by loosening the triple clamp pinch bolts. This will allow the forks to move slightly in the clamps as the adjusting nut, located on the steering stem, is turned. Presuming the bearings were loose enough to feel play, tighten the adjusting a nut a 1⁄4 turn and recheck them. If there’s still play, take another 1⁄4 turn, and so on until all the play is removed. Here’s where it gets a little sticky: There’s a fine line between removing the play and preloading the bearings, and in fact some slight preload is a good idea (and often specified), so how do you know when to stop?

Depending on the manufacturer's preferences, the preload, which is sometimes referred to as “fall away” can be measured in different ways. For example, Harley-Davidson recommends letting the forks swing from left to right and back again, and counting how many bounces it takes. 2 3⁄4 is about right, for a dresser. Other manufacturers recommend using a sensitive (and expensive) torque wrench to measure the turning effort.

I’m a cheap SOB, so I use a five-dollar fisherman’s scale and a length of twine to measure it, using the following method. With the forks aimed straight ahead, wrap the twine around a fork leg and tie it off to the scale. With the scale at a slight angle to the fork, apply a bit of pressure. If it takes less than two pounds to start the fork moving, the adjustment is loose. If takes more than four pounds, the adjustment is too tight.

When you’re happy with the adjustment, torque the lock nut and clamping bolts and run through the inspection process again; often a dented bearing won’t make itself felt until the proper preload is placed on it. If your freshly adjusted bearings now feel like a worn out ratchet, they’ll need replacing ASAP.

**Steering head bearing lubrication/replacement **
With the exception of the sealed type of bearing, all steering head bearings need periodic lubrication, which in most cases is about every two years or 20,000 miles. Since the replacement procedure is nearly identical, we'll consider the two jobs as one, differentiating the process where need be.

The toughest part of the job is removing the front end. Your manual will provide the details, but in broad strokes, you’ll be removing everything that’s attached to the steering head and you’ll find the work goes easier if the parts removed are kept as manageable as possible, especially if you’re working by yourself. While you may be tempted to remove the fork in one big chunk, complete with wheel and fender still attached, I’d recommend against it. It’s a whole lot easier to break down the front end one piece at a time, and don’t forget to protect anything left on the bike—particularly the fuel tank, which at very least should be covered with a heavy towel.

Once the ancillary parts have been removed, you can remove the steering stem, but before you do, rotate it from side to side. Often marginal bearings that felt fine with the fork hanging on them will feel rough and sticky once that weight’s been removed. Sometimes all it takes is a good cleaning and repacking to restore them to health, but examine them closely, for they may be due for replacement.

Keep a good grip on the steering stem as you remove the lock/adjusting nut(s). The top bearing is always a loose fit, so once the retaining nut is removed the stem is free to drop onto the floor. If it sticks, a light tap with a mallet should free it up. Although loose ball steering head bearings are rare these days, some of you may be working on bikes that use them. In that case a couple of clean rags placed under the frame should catch any that make a run for it.

With the big fun out of the way, it’s time for the grunt work. Start by removing the stale grease from the steering head and bearings. It’s a dirty job, so be prepared with plenty of clean rags, and if you like them, latex gloves.

Once the bearings and races are sparkling clean, carefully inspect them. A bearing on its way out will give clear visual indications—look for dents, flaking metal, small pits, and rust marks where the rollers or balls contact the races, and use the edge of your fingernail to find any ridges or craters. In most cases, if the bearings felt good during your routine inspections, they’ll look and feel fine when you physically check them, but you can never be too careful, and it really sucks if you have to re-do the job halfway through the summer.

If it’s a simple repack job, there’s no real reason to remove and possibly damage the lower bearing from the steering stem. You can get the thing as clean as it needs to be by lathering it up with WD-40 and scrubbing it with an old toothbrush. While the preferred method of repacking a bearing is to either use a bearing packer or to hand pack it from the open end, a credible job can be done with the bearing in place, so long as you work patiently. Bear in mind that these are not high-speed bearings and rarely rotate more than a few degrees so they’re not under the type of stress that something like a wheel encounters.

**Replacement **
If the bearings require replacement you'll have to remove the frame races, and the lower steering stem bearing/race. Start with the races, for which special tools are available. Yep, they'll make the job go smoother and faster, but they're a little pricey, especially for a one-shot deal. On the other hand, a nice long punch works just fine. Work the punch around the edge of the race to avoid cocking it, and it'll come out without any drama. Remove the upper race, carefully—if you belt the thing straight up and out with a manly blow who knows where it's going to land, but my guess is square on a formerly dent-free painted part.

Removing the lower race from the steering stem can be a little tricky; again, there are special tools available, but generally, you can clamp the stem in a vice with soft jaws, and hammer the thing off with sharp chisel. If it’s a real problem, your favorite motorcycle, machine or automotive job shop should be able to remove it without much effort.

Before starting the installation, compare the new parts to the old. There’s nothing that’ll make you feel sillier than trying to drive a 15⁄16 OD bearing onto a 1-inch steering stem, and almost succeeding.

The lower stem bearing is a press fit onto the shaft, and the part of the job that seems to give the most trouble. Burnishing the shaft with a piece of emery paper will remove any rust or burrs that might prevent the new bearing from sliding smoothly into place, but show some restraint—the idea here is to polish the shaft, not to remove a lot of metal. A little light oil or grease between the race and shaft will also help smooth the way.

Get a piece of pipe that fits the bearing’s inner race, making sure it’s long enough to seat the bearing without bottoming on the steering stem. If it’s all Jake, grease the new lower bearing and position it squarely on the shaft, and using firm blows, drive it into place.

Clean the inside of the steering tube, making sure there’s no rust, paint or burrs where the races sit, then use the appropriate tool to drive them into place, bearing in mind, (no pun intended), that the driver should only contact the lip of the race. Lather the races with grease, then pack the upper bearing, and install the stem and adjusting nut. Snug down the adjusting nut to seat the bearings (the operative word here being snug). There’s no need to get carried away with a six-foot breaker bar, just run the nut down until it bottoms and it give maybe half a turn extra to seat everything, then back it off and follow the normal adjusting procedure. From there it’s a straight reassembly job, though as with anything of this nature, I’d caution you to properly torque all the fasteners, and make sure everything goes back where it’s supposed to. Don’t forget; as straightforward as this job is, you’re still performing a fair amount of surgery, so it s easy to overlook a small detail, like properly tightening a caliper bolt or axle nut.

Lastly, it’s always a good idea to recheck all the fasteners and the bearing adjustment after the initial road test, and again at the 500-mile mark. After that, stay with the factory recommended inspection and maintenance schedule, and chances are good that the new bearings will outlast the originals.

Required tools
1. Factory shop manual or equivalent
2. 1⁄2 Torque wrench
3. Common hand tools
4. Lift or motorcycle jack
5. Good high temperature EP rated grease; disc brake rated wheel bearing grease works fine
6. Any special tools required for your bike
7. Brass or heavy steel hammer
8. Drifts to install and replace bearings and races

**Resources **

AllBallsRacing
Aftermarket steering head bearings
allballsracing.com

Motion Pro
Fork tools and more
motionpro.com

Balls to that!
Prior to 1979, the vast majority of motorcycles were equipped with loose ball steering head bearings. In the intervening years, caged ball, sealed ball, and tapered roller bearings have become the industry standard, and loose balls, so to speak, have become a thing of the past. Nowadays, whenever I run into a bike that still has them (and you'd be surprised how many older bikes still on the road do), my first inclination is to grab an accessory catalog and seek out a set of aftermarket tapered roller replacements. Without debating the technical merits of one type over another, I can tell you that as a rule, aftermarket tapered roller bearings are easier to install, have a longer lifespan and are often cheaper than the loose ball-type of bearing. As a bonus, they will generally improve the bike's handling, all of which makes them an extremely attractive and easy-to- install upgrade if you're refurbishing an older bike.

Steering head Symptoms
Tech Tip
Although this issue's How To details steering head bearing maintenance and replacement, it doesn't delve deeply into the symptoms of worn out bearings, presuming that in most cases any problems will be found during a routine inspection. This assumes the owner is keeping up with maintenance and that steering head bearings are in good shape to begin with. In retrospect, that's assuming a lot. The problem with steering head bearings is that any problems are likely to creep up so slowly that many riders don't even realize there's a problem until someone else points it out. Fortunately, there are some dead giveaways that the bearings are heading south if you know what to look for.

As the steering head bearings wear, they put tiny dents in the races, making the fork feel like it has detents in it when swung from side to side. Because the dents take some time to form, they may not be all that apparent, especially when the weight of the bike and rider is on the front wheel. A quick check is to jack the bike up, and swing the fork through its arc. If it feels like it drops into a detent in any given position, especially when the wheel is straight ahead, trouble is on the horizon.

Very loose steering head bearings will allow the fork to move back and forth in the frame. With the front brake held on, rock the bike back and forth. If you can detect any noticeable movement in the fork, the bearings have loosened up. If you’re not sure, have a helper place one hand on the frame neck and the other on the upper clamp to detect any movement between them. You may also notice some chatter when the front brake is applied, or even hear a click/clack as the bike comes to a stop.

Another loose steering head bearing symptom is a wobble or shimmy on deceleration, particularly when the bars are held loosely. Other things can cause that same problem, especially an out of balance front wheel, so be sure to investigate all possibilities. But more often than not, all it takes to subdue one of those shimmies is to give the steering head adjusting nut a 1⁄4 turn or so.

Tight steering head bearings are less common, and are always the result of improper maintenance. Most bikes come from the factories with less than adequate steering head lubrication, and neglecting the things only makes it worse. I’ve taken apart more than one new bike that didn’t have enough grease in there to lubricate a sneeze, and I’ve seen overzealous clean freaks cook the grease right out of the steering head with a pressure washer. Many manufacturers also use inexpensive lithium-based greases which evaporate over time, so there’s a few good reasons to repack the bearings according to the manufacturer’s recommendations. I’ve also seen plenty of ham-fisted mechanics over tighten the bearings simply because they lacked knowledge or finesse.

Tight steering head bearings make a bike very difficult to steer, especially at low and moderate speeds, and particularly in a straight line. The bike will require constant steering inputs and tend to fall from side to side as you overcorrect, and won’t be much better at speed or through turns. A tight bearing will also dent the races and destroy itself in short order. Which brings us back to the How To on page 66.