I Broke Another... racing story

[vwtype53 at yahoo.com (Ben)]

<long...well, for me at least!>


Well, this weekend was not so nice to my mk1...

As most of you know, I road race my '80 Scirocco.  Amazingly enough, I am still using many stock
components, like A1 hubs, wheel bearings, ball joints, axles, 020 trans, etc.  There is no
question that I am pushing my luck with some of these components.  I am pushing quite a few more
horses through the drivetrain than the little 1.6 did back in 1980.  I am also generating a lot
more grip with my 205-width race tires... oh, and I'm braking, and generating a LOT more heat,
than the VW engineers ever imagined that mk1 chassis could.  Needless to say, things are being
stressed and have a tendancy to break now and then.  Now and then was today.

For the second time in 3 years I have succeeded in breaking a hub!  Yep, the hub sheared at the
point where the neck enters the wheel bearing.  So basically my wheel was being held in place only
by the axle and axle nut!  I consider myself lucky that my wheel stayed in place (for the most
part) as I came to a stop.  I was exiting a turn and applied throttle only to have the engine rev
freely to redline.  I thought at first my clutch had just exploded or possibly the trans pinion
shaft sheared all it's teeth... I ended up coasting down the straight and pulled into the grass to
wait for the session to end...they hooked me up and towed me back to the pit area where I pulled
things apart... I hate getting towed back into a sea of Porsche's... not that they don't break too
(more than one Porsche was towed this weekend), but it doesn't help for them to see the vw being
towed back.  It's happened more than once to me over the years.
Then again, I try to make up for it when I keep up with most of them on the track...   :)

I think that the hub failure was due to a combination of the heat cycles from braking and the load
cycles from each and every turn I make on the track.  The heat generated from my brakes while
slowing from 120mph down to around 70mph (in about 2 seconds or less) is intense.  Then add in all
the smaller turns throughout the track and you have some serious heat building... not only in the
rotor and pad, but surrounding knuckle and hub assembly.  And doing this for 25 minutes straight,
3 times a day for a 2-day weekend, and several times a year... yeah, it's a lot of heat cycling.

Obviously, the biggest factor here is that I am racing on sticky tires and generating a lot of
grip... which puts a lot more load on the hub/bearing assembly.  One trick that the A1 race guys
use that I've read is to over-torque the axle nut.  The axle nut sandwiches the hub against the CV
and will help reduce some of this stress.  I read of guys using massive breaker bars to get the
torque on that nut to over 300 ft-lbs!  Anyone heard about this?

Well, just wanted to share my experience.  A friend helped me get my car home, so no worries
there... I'll be repacing the hub and bearing soon.

At this point, I think my only option for upgrading would be using the A2 knuckle and bearing. 
But then I would need to use the A2 strut/shock housing and ball joints I suspect.  Not sure if
the A1 tie rod end would work on the A2 knuckle... has anyone upgraded a rocco to A2/A3 front
suspension components?

Tighten that axle nut!!  ;)



Ben Harder
1980 Scirocco
1997 Jetta GLX

http://www.geocities.com/vwtype53/

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