I Broke Another... racing story

[jdbubb at verizon.net (Dan Bubb)]

During my one, all too brief and all too long ago, track day one of the 
instructors mentioned this. Said the hubs were the weak point of the A1 
chassis and that the first sign you had a problem was typically a long brake 
pedal not long after apparently followed by a departing wheel.
As suggested by Mark, it should be considered a maintenance item. Replace 
every year unless you have an interesting off track or even on track 
excursion, in which case replace immediately.
Dan

From: "Ben" <vwtype53@yahoo.com>
Sent: Sunday, September 03, 2006 10:57 PM
Subject: I Broke Another... racing story


> <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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