OK, I can't resist commenting on this any longer. Any axle with the stock
style taper and removable hub even if made with modern steel is still
subject to breakage including a lost wheel. I'm not familiar with the
Addco design, but have seen pictures of "uprated" axles on the Cambridge
motorsports site - those still have the taper. The problem is that under
load, the end of the axle flexes inside the hub until it eventually
breaks. It's fine on the street, but the loads in extended corners with
grippy rubber cause the flex and eventual failure. One such failure is
documented at http://www.tonydrews.com/Jack_Car_2.htm - these were uprated
axles and hubs in good modern steel but essentially stock design. They did
NOT come from Cambridge or Addco. This doesn't have anything to do with
what type of limited slip (or welded differential) as far as I know.
It takes a while to fatigue the axle enough to break it, so frequent
replacement could avoid this problem. The fix appears to be using a
different rear axle with the hub integrated. The southwick conversion uses
Ford 8" rear end axles (I believe) with triumph splines machined onto the
inner end. The stock ends of the axle tube are cut off and new ends are
welded on. There's nothing magic about having Southwick actually perform
this type of conversion except that they've got the jigs already made and
have worked the bugs out. I would think someone in Germany would be
capable of doing something similar. This type of thing is commonly done
for stock car racing in the US. I'm not sure what a good source would be
on the other side of the pond. The axles can still break (although it's
less likely - they're good for about 500 horsepower), but when it DOES
break the wheel stays on the car. It breaks inboard of the outer bearing,
and the outer bearing holds the axle remnants in place until you can bring
the car to a controlled stop. Pictures of the replacement axles and new
ends welded to the stock rear end housing are partway down the page at
http://www.tonydrews.com/Jack_Parts.htm.
This is probably not something that can be done by this weekend, but
something I would definitely have done soon.
Courses with extended "carousel" type corners seem to cause the most
harm. At one of our tracks, we are in a corner for at least 15
seconds. That's where we experienced this problem.
Are there many solid axle triumph TR's racing over there? Maybe the tires
you're using there aren't as hard on the axles as some of the ones used
here. I know of probably half a dozen TR-3's and 4's that have broken the
axle and flipped in the US.
- Tony Drews
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