Don't see how a tube could be stronger than a solid if the materials are the same. I would suspect if you have seen a difference, it was also due to a material difference. It will be lighter, of course.
But, a larger diameter tube will be stronger than a thicker wall. Imagine trying to bend a 2" fencepost tube or conduit compared to a 3/8" solid. On the subject of bent / breaking axles.... Had an axle break on me at Grattan in May during a test day. It was something that we were trying with Don Handley, using a larger axle with the ends turned down to the normal 1.25". There wasn't a good radius on the transition which created a huge stress riser. This decided to snap at the apex of the last turn going on to the straight at Grattan. Somehow I didn't hit the wall. However, the flailing axle broke both carbs, of which pieces went completely through the engine. So, the bill included: axle (of course), carb bodies, bearings, complete engine tear down, Gates drive belt ($$$), and an assload of work. Now have a continuous diameter axle. It may bend, but it shouldn't snap. In fact, the drive belt tension causes a little bit of a bow in the axle. Look down the hollow tube and see for yourself, I bet I'm not the only one with a little bit of rear toe-out! Phil -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chris Reinhardt Sent: Wednesday, January 31, 2007 5:28 PM To: [email protected] Subject: Re: [F500] Bent Axle Ain't no engineer here, but a hollow axle will resist bending better than a solid one. I believe it has to do with #1 the flexibility, #2 the surface area both inside and out... Plus the missing 3/4" bar, assuming you're using .25 wall axles, is equal to about 5.5lbs. CR Dave Phaneuf <[EMAIL PROTECTED]> wrote: John The axle ( 1.125 dia. solid ) that came with my car was slightly bent so following a recommendation from Don at Red Devil I made one up out of a steel he suggested, ETD150, it's 150ksi tensile and yield is about 125 ksi. It bent, no crash just bumps, at that point I redid the whole rear suspension and used a piece of 4340M also called 300M ....it's has held up fine. I seem to remember the certs that came with it showed a tensile of about 280ksi and a rockwell of about 52-53 on the c scale. Maybe overkill but I haven't had to mess with it since. Dave Phaneuf --------------------------------- 8:00? 8:25? 8:40? Find a flick in no time with theYahoo! Search movie showtime shortcut. ________________________________ FormulaCar Magazine - A Proud Supporter of Formula 500 The Official Publication of Junior Formula Car Racing Subscribe Today! www.formulacarmag.com or 519-624-2003 _________________________________ _______________________________________________ F500 mailing list - [email protected] To unsubscribe or change options please visit: http://f500.org/mailman/listinfo/f500 *** Please, DO NOT send unsubscribe requests to the mailing list! ***
