The Stub Axle (Part Deux)

[John Coffey]

Yes, I did it again... I must have pissed off the powers above earlier this

year.

Yesterday (last June) I was at a driving school at Buttonwillow race track near

Bakersfield, CA. Got through a couple sessions and on my third, while

coming down off Magic Mountain (a little hill on the west side of the track)

I heard the now familiar BANG followed by a weird, wiggly feeling in the

back of the car.

It was a little scarier at 80+ mph, but the wheel stayed on and I found that I could apply power if I loaded the left side of the car. So, I made it back to the pits and spent the rest of the school bumming rides with the instructors.

This time I broke the stub axle on the right side of the car and, luckily, it didn't trash the brake drum.

Since the shot peened Nissan Comp stub axles aren't available anymore, I've been doing some research on Cryogenic treatment (in addition to shot peening) and found that there really isn't much REAL information specific to this application. Here's a note regarding the subject from a Professor of

Metallurgical Engineering:

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Dear Mr. Coffey,

The relationship between cryotreatment and fatigue of steel parts has not

been studied that much. While there are many who have tried cryotreament

for one reason or another, only a little scientific work has been done on

it. Many sales claims are out there with little proof. Having said that,

there are also a lot of people who have tried it and are very happy with

what it does for them. I have spoken to a number of them and they seem to

know what they are doing, so I believe that it is doing something to some

of the properties of certain materials, particularly certain kinds of

steel. Only a few people talk about it improving fatigue however, instead,

most of the claims are for improved wear resistance.

I have not seen any literature that speaks to the effect of cryotreating on

welds. That doesn't mean that it doesn't do anything for the weld, it just

means that no one I know has looked at it.

My recommendation to you is to bypass the speed shops and steel treaters

and talk directly to some of the full time cryotreaters. They will often

do a trial run for free and let you see if you like the results (some of

the steel treaters might also if you push them a little). This lowers your

financial risk (assuming of course that you don't damage your car due to an

early failure of one of the treated parts) and lets you see for yourself if

it is worth the cost. I won't recommend any specific companies to you, as

I would rather stay neutral, but you can find a large number of them

through an internet search.

----

So, I guess I'll have my next set shot peened and cryo treated to see if I

can keep the wheels on my car!

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John Coffey

johncof@veriomail.com