Bill Dearborn

Was at Watkins Glen the past two days where one of the other C5 Z drivers had 2 wheel bearing failures. On Monday the flange that holds the wheel on to the wheel bearing broke off the left front as he was entering Turn 1. Luckily, there is a large run off area there and he came to a safe stop. The brake caliper held the wheel on the car. On Tuesday the replacement bearing broke the same way as he was exiting Turn 7 (the Toe of the Boot). This time the wheel, brake rotor, brake caliper and brake line came off the car. The caliper bracket mounting eyes on the knuckle broke off so the car could not be repaired at the track. I took some pictures of the failed bearing so people could see what can happen under severe load. The bearing that failed on the first day had about 15 track days on it. The second bearing was a used spare.

The first picture shows the two pieces that used to be one and the second shows them placed together.





Bill

gonzalezfj

That corner is a stress concentration point in all wheel hubs and it behooves the racer to check them carefully EVERY TIME you change wheels. Make this a part of your wheel-changing routine. I have spotted two with incipient cracks that would have ended up the way your friend's did.

Frank Gonzalez

ghoffman

Good advise as always! What is interesting here is that it is a rear, most of these have been fronts.

davidfarmer

That is exactly the type of failure someone had at VIR last week. Fortunate, he found it before it separated completely. In his case, the joint shifted slightly, causing the rotor to scrub the caliper, which led him to investigate.

Unfortunately, you can't see that particular joint unless you take the rotors off.....not fun between sessions.

Wicked Weasel

glad no one got hurt and this is why we are all are looking for the better wheel bearings.

I replaced all of mine this year and this winter I will go with the Van Steel ones.

Bill Dearborn

He used a rear bearing as the replacement for the front bearing. He said the bearings were the same other than the provisions for the drive shaft in the rear. Although when I had my left front replaced under GMPP a couple of weeks ago the dealer couldn't do it right away as they only had a right front bearing and had to overnight a left front bearing.

Bill

LG Motorsports

I would like to know what wheels were on the car and did they have spacers without a chamfer on the bearing side.

In all the races we did with our bearings and with the high g load with wings etc, we never saw this happen. Never.

So it seems that there might be some other reason that the failure occured. Especially having 2 in one weekend. I would suspect that the reason was not the bearing but the wheel or spacer.

Do you know this info?

Thanks
lou G

sothpaw2

At least street tires limit your side load for longer bearing life. Good thread.

Janni

How sticky were the tires? Were they wider than stock? If so - that can easily contribute.

Viper guys have fixed wheel bearing issues with a higher torque for the nut - 300 ft lbs - and that solved the issues (was a change on the Comp Coupe from Dodge to address and most parts were same / close throughout the prior years). YMMV, but it's worth considering.

Also, every time car is up in the air with wheels on - try to move the bearing to check for tightness.

0Randy@DRM

Nothing better then having a rotor hat or spacer or wheel not sit flat. "Broken before the car even got on the track" 100 foot pounds X5 times can pull the hub apart like that.

Randy

Slalom4me

CRC offers a non-destructive "Crack Check Red Dye Penetrant
Inspection Method" which consists of three aerosol cans (est $10 ea)

• Cleaner #0815500 (15.1 oz.)
• Penetrant #0815503 (9.4 oz.)
• Developer #0815506 (14.2 oz.)

Apply the cleaner and give it time to evaporate. Apply the penetrant,
give it time to penetrate then remove any excess using a cloth
dampened with cleaner. Then apply the developer and examine for
signs of red dye indicating possible defects.

Very easy to use at home or at events.

.

Slalom4me

By coincidence, I came across a video yesterday that CF member
Wtknght1 posted of his non-catastrophic hub failure last year.



.

John Shiels

I am sure they can break but I have run big GY slicks and Hoosiers for4-5 years with .850" spacer front from CCW and 3/8" rear from DRM. I load them up preety good also. I have had them fail but the fllange didnot seperate.

davidfarmer

that's a good point by LG & Randy....impropper hub-centering would indeed cause more load on the flange than the hub center. And I'm with Lou, in all my my SCCA, World Challenge, HPDE, and NASA events, I've never personally had one do this.

I do know the car at VIR last week had CCW's on it. I'm fairly sure their hubcenter fit properly, but I've never run them personally.

Bill Dearborn

No spacers were used. C5 stock front calipers. I believe the wheels were CCW wheels. They had Dunlop Race Slicks that he bought from the used race tire guy in Wisconsin mounted. I believe they are the equivalent size to a 315/35/17 street type tire.

The slicks may allow him to put more stress on the hubs Vs the Hoosier/Kumho DOT R tires but I really don't know know how much more force if any they could generate. He gets around the track quickly and he is definitely several seconds faster than my 2:15/2:16 laps.

I just looked at Chris Ingle's video posted above. His description of what he felt was very similar to what this guy felt just before the hub broke. He knew something was wrong but the flanges on both bearings must have come off the hub almost immediately Vs just spinning on it like Chris's did.

This is definitely something to check before going to the track. He was lucky that his incidents happened where they did Vs going around the carousel turn where you are pulling high Gs at 85 to 90 mph for several seconds. The Armco is far away there but not that far away.

Bill

db2xpert

Been running Hoosiers for 7 yrs, never had an issue. Two failures on the same car, in this short timeframe?
Seems to point at some problem on the car.

Joel

Slalom4me

What brand were the hub bearings? If uncertain, are any
identification marks still visible.

.

Bill Dearborn

Not sure about either of them but the used spare and another unit were in Timken boxes.

Bill

ZR1 MK

My CCW wheels arent a tight hub center fit like my stock wheels. Mine are hub centered with the wheels center cap, but others are centered with the wheel. I never had a bearing failure, but should we be concerned if the tolerances arent small enough?

ryan0

was he just pounding curbs and hooking corners?

if 2 different ones break back to back, the most common answer is 'youre doing it wrong'.