Hello Joe,
>From our previous conversations I think you are on the right path. Due to the
>history of failures in this area and the "extreme" consequences I think that
>your efforts are valid.
>From the inspection on my failed stub axles and hubs I think that your failure
>point is accurate. Does the nut loosen and the create a wear point which leads
>to a stress fracture, or does the hub create a bending moment which causes the
>thin end of the axle to work harden into the very brittle Marstenic condition
>which then leads to failure? I am not sure, but am working on this. However it
>would seem that both solutions lie in the hub / stub axle connection. The
>Datsun solution takes this into account. Like you I am not keen on the mix of
>parts, nor the resulting inertial mass, nor the difficulty in balancing the
>parts. So we continue to look for a better solution.
How do you propose making the hub / stub axle connection?
Good to hear from you.
Bill B
Ps: that new article on the Ro-Spit rear suspension is due to come out shortly.
-----Original Message-----
From: Joe Curry [mailto:spitlist@gte.net]
Sent: Sunday, December 29, 2002 4:13 PM
To: Friends of Triumph
Subject: Rotoflex rear Hubs
Here I am again trying to reinvent the wheel (or maybe just what it connects
to).
The application is the Hub, outer axle and vertical link (upright) on a GT6
rotoflex application.
The trouble with the original design as I have been informed is that the forces
being applied to the hub causes the threads holding the hub onto the
shaft stretch, loosen and start wearing on the hub. Ultimately it ruins either
the shaft, hub or both.
After Receiving the two assemblies from Team Triumph (thanks Scott) I have been
thinking a lot about how best to approach a solution. Here are my
thoughts exposed to the list for critical review. Go ahead and take your best
shot. In the end, I am hoping that I will achieve something that will
cure the problems and do so at a very affordable price.
1. One solution that is already in use is to use a Datsun hub that has the
securing bolt on the inside of the upright. This appears to be a good
solution but I am afraid that availability of parts is going to be reduced in
the future. Also, it involves a lot more parts than what I think are
necessary.
2. My vision involves the use of Clive Averill's CV-Joint conversion with a
different twist. I have already had Moser make a pair of inner axle
shafts to connect from the GT6 flanges to the VW Diesel Rabbit CV-Joint, so I
am looking to replace the outside axle and hub with a different bearing
configuration.
3. By having a shaft manufactured with the hub integrated onto the end, and
having the retaining hardware on the inside of the upright, I am thinking
that the forces will be better contained and less likely to cause the normal
problems. By using the CV-Joint rather that the rubber donut, the tripod
end of the shaft can be changed over to a splined end and allow the shaft to be
threaded further up to accept a pair of jamb nuts to keep the shaft
properly aligned with the bearings. I am thinking that aircraft type nuts with
safety wire holes will keep them from separating.
4. In examining the upright, I see that there is a lot of room to position the
bearings further apart. I am thinking that the further apart they are,
the better able they will be resist wobbling within the bearings and contain
the forces that try to tear up the bearings and hub. I am also thinking
that by replacing both bearings with straight rollers instead of the tapered
variety, it would further control these forces.
5. With all the above taken into consideration, It remains to find bearings
that are the correct size and strength for the job and have a pair of
axles machined with the hubs permanently attached, threaded for retainer nuts
and splined for the CV-Joint and grooved for the retaining circlip.
If I can have these shafts made for around $200 each, it would make the project
very affordable. This seems to be well within reason since I had both
the inner axles with splines on both ends made for $227.
So, There you have it. I appreciate any input, especially anything that would
shoot holes in my theory. I'd rather find out before investing a great
deal of money.
Regards,
Joe (C)
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