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FZ1 Bearing Failure at 110 MPH...or there abouts

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Berto

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Replacement bearing set: $59.84. New oil seal: $6.46. Replacement disc bolts: $29.28. Not being pitched into the bleachers off turn 1 with a locked rear wheel: Priceless.

Or so it felt at the time. I had a rear wheel bearing disintegrate at the track over the weekend at the end of a 100-MPH or so straight. In 30-plus years of riding dozens of bikes, I can't remember replacing more than a bearing or two and I've never had one fail.

It didn't go all at once, but close. On one lap, I thought I heard a faint tick-tick-tick, but it wasn't loud enough to resolve and I couldn't tell where it was coming from. It wasn't steady enough to rise above the engine thrash and wind noise.

On the next lap, I guess what was left of anything resembling balls vaporized, the bike shook and wobbled a little bit and the ticking was now a loud grating sound. I got slowed up and limped around to the pits, by which time the wheel was noticeably wobbling. The grating noise was the heads of the disc bolts being ground off by the caliper bracket. (See photo.) It felt like the wheel was about to come off, but the play on the shaft was about 1/8th inch, I guess.

It's always sumpin'. I'm posting it here so you hear that vague ticking sound, bad things could happen pretty quick.
 
How many times have you have the wheel off and back on for maintenace? Torqueing the axle to the correct point also has a lot to do with keeping the bearnings in good shape. Over-torque will shorten the bearing life but in the life of a bike, a couple sets isn't out of the ordinary if you ride a lot.
 
Hellgate said:
How many miles and years were on them?
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48,000 on the bike and I assume on the bearings, too. I acquired it from another owner who didn't maintain it well. I've replaced a lot of stuff proactively, including a rebuild of the swing arm.

But the wheel bearings looked and felt okay, so I left them alone.
 
Lonerider59 said:
How many times have you have the wheel off and back on for maintenace? Torqueing the axle to the correct point also has a lot to do with keeping the bearnings in good shape. Over-torque will shorten the bearing life but in the life of a bike, a couple sets isn't out of the ordinary if you ride a lot.
Click to expand...

As with any track bike, the wheel has been off a lot for tire and chain changes. I can think of four tire changes since March, plus chains for gearing changes.

I always torque it with a wrench, never the armstrong method. Also, I've replaced a lot of routine fasteners and everything that can be safety wired, is.

A couple of other observations. I never use the rear brake on the track, but once I got into the paddock, I tried it. It didn't work, leading me to believe this had something to do with the brake or the carrier.

But the reason the brake didn't work is that the disc had assymetrically pushed the pistons back into the bores, just as you'd do when remounting the caliper. That's what I felt. A couple of pumps would have brought it back.

Thinking it through further here, the likelihood of a hard wheel lock, while possible, might have been low or at least might have occurred somewhat gracefully. The outer race of the bearing was collapsed and all but a couple of the balls were gone. What was keeping the wheel from migrating further to the right--into the brake assembly--was the wheel spacer bearing directly on the hard center race of the bearing. That piece is hardened steel and remained essentially intact.

Still, I was surprised about how fast this came on and how quickly it evolved to total failure. I would have expected the onset of symptoms to be slower. The last time I checked that bearing, it felt and looked fine.

I took it to a local shop to have the outer race extracted--it was a little welded to the bore--but the wheel itself is ok.
 
FZ1riderNY said:
Man that sucks. I'm glad for you however that it didn't end up worse. It probably ruined your day at the track though.
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It did suck. Happened three laps into the third session, so for all the hassle and expense of dragging the bike 220 miles to the track, hotel, etc.--I rode 15 laps.

And so it goes...
 
Jboat said:
+1...

My guess would be a lot. How many track days? Ever use lube on that axle after a tire change? Do you happen to live near the coast? Do you ride in the rain at all?...
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All of the above. I haven't ridden this bike in the rain, but I'm sure the previous owners did. I live on the Florida coast, where corrosion is a problem for everything. I'm sure the bike has been pressure washed, too. Doesn't help. This is a dedicated track bike, by the way. Probably eight times on the track with it.

Also, I posted the video here of a crash I had two months ago. Although not that likely, an impact can cause brinelling in bearings, a small flat spot that exceeds the material yield strength, then causes rapid progressive failure under load.

More likely, the bearing was just shot and ready for replacement.
 
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