[Fot] TR4 axle shafts

[John Styduhar]

My club in the USA (Vintage Racer Group) understands the weakness of
vintage factory parts and has the following safety allowance in its rules:


*4.5. CLUTCH, TRANSMISSION, AND FINAL DRIVE*

*4.5.1. General:  *The clutch, transmission, and final drive systems must
be the type and design as originally fitted by the vehicle manufacturer.
Within the confines of the original housings, internal components are free.

*4.5.2. Transmission:  *The gearbox must have the same number of forward
speeds as supplied by the manufacturer, or homologated as an option for
that model.  Ratios are free.  Reverse must work (driver actuated lockout
is permitted).  The system of gear synchronization must be as originally
fitted by the manufacturer.

*4.5.3. Final drive:*  Ratios are free.  Limited-slip differentials may be
fitted, if originally available from the vehicle manufacturer or as a
period aftermarket device. The original casing must be retained.  Modern
aftermarket axles and wheel bearings may be used.



On Mon, Jan 20, 2014 at 11:52 AM, Tony Drews <tony at tonydrews.com> wrote:

> That makes more sense.  By the way, in the US there is a similar rule
> about rear axles - but it wasn't strictly enforced.  Anyway, all of the US
> sanctioning bodies accept the modification I describe as a safety
> improvement that does NOT violate the rules.  It might be interesting to
> ask your governing body for an exemption - this is not a performance
> improvement, just a safety improvement.
>
> Also, tracks with long sweeping corners (like the "carousel" at Road
> America) are particularly hard on the stock design.
>
> What you are describing, if properly engineered, sounds like a good
> solution.
>
> Cheers, Tony Drews
>
>
> At 01:44 AM 1/20/2014, MadMarx wrote:
>
>> Scott and all the others responded,
>>
>>
>>
>> I never intended to find an alternative to the Southwick conversion. The
>> reason is a different one.
>>
>>
>>
>> Our rules say: Strengthened axle shafts are allowed but no word about
>> doing
>> any changes to the axle housing.
>>
>> As I understand the rules the stock housing has to remain stock.
>>
>>
>>
>> I had on my wish list:
>>
>>
>>
>> 1.    Make it safe
>>
>> 2.    Keep it within the rules
>>
>> 3.    Keep it interchangeable with the stock system
>>
>>
>>
>> I own a Porsche 911 and this car has a TR2 like axle spline on which the
>> hub
>> is pushed on.
>>
>> No woodruff key, not press needed to remove. Quite simple thing.
>>
>> The TR2 has the same idea but not well engineered. So I thought I could
>> use
>> the TR2 shaft as a basic pattern and remove all the wrong stuff to make it
>> last as good as the Porsche shaft does.
>>
>>
>>
>> The good thing would be if I hit a concrete wall and bend the shaft, I can
>> part out any TR4 road car for a spare axle on the track parking lot to
>> make
>> the car going again.
>>
>>
>>
>> Racing in Europe is quite strict with rules and also competitors might
>> protest you out of competition if the car is not bullet proof according to
>> the rules.
>>
>>
>>
>> Sorry to rise concerns.
>>
>>
>>
>> Cheers
>>
>> Chris
>>
>>
>>
>>
>>
>> Von: Scott Janzen [mailto:sjanzen at me.com]
>> Gesendet: Montag, 20. Januar 2014 03:28
>> An: Tony Drews
>> Cc: MadMarx; fot at autox.team.net
>> Betreff: Re: [Fot] TR4 axle shafts
>>
>>
>>
>> I know of at least one TR racer that has just gotten the modified axles
>> from
>> Southwick, and had a local machine shop do the axle housing modifications.
>> This would avoid the need to ship the whole axle assembly.  Not sure what
>> sort of jig is needed to get the housing ends in the correct position for
>> welding - perhaps the axles themselves?
>>
>> The axles are available from a number of circle-track aftermarket
>> suppliers
>> - quite possible they could be modified locally as well, and a quick
>> search
>> indicates they are about $300/pair. If they have to be bought from the US
>> anyway you might as well have Southwick do it and send them to you.  They
>> might be able to supply the axle housing ends as well.
>>
>>
>>
>> Southwick Machine
>>
>> Coal Valley, Illinois
>>
>> Robert Southwick
>>
>> robsouthwick at gmail.com
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>>
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>>
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