I’ve updated the site’s Reprint/Reuse Policy (which is now linked in the Administrative Pages menu on the right for ease of reference) and I encourage everyone to read it. The policy is not significantly different than it has been, but I’ve reformatted it to make it easier to read and to clarify a few points.

As with all of the site’s policies, I’ve tried very hard to balance what I reasonably need to do to protect myself and my rights with an appropriate respect for common sense and the principles of fair use. If you have any questions, please feel free to contact me.

ETA (Jan. 13, 2016): I have made a further update to the policy — including reorganizing and reformatting parts of it — in the interests of clarity, avoiding inadvertent contradictions, and trying to balance a bunch of conflicting priorities. I encourage you to read the updated policy if you’re interested in excerpting an article, reusing photos, or anything like that, and to let me know if you have questions or concerns. My intent is not to be scary or unduly restrictive while covering myself and the people who are kind enough to let me use their photos and other material.

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ron

July 2, 2015 at 12:21 am

I hope you still answer suspension questions. You answered a question for me back in 2010.
You didn’t address one part of my question in 2010. With MacPherson struts being used on heavier cars and suv’s, and one Honda truck. My question was, are the diameter of the pistons any larger for struts used on heavier cars or suv’s.
Also, I’ve noticed that car & truck control arms are getting smaller and flimsier looking. Many are being made of aluminum, which in a metallurgical study I read. They stated if a vehicles wheel strikes something hard enough, the aluminum arm may actually crack. As a result of this they advised the use of more material and/or bracing, to equal the strength of steel. This obviously isn’t what’s happening, just check out the 2016 Honda Pilot’s new control arms.
Well that’s my rant. What’s your expert opinion?

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1. Ate Up With Motor
  
  July 2, 2015 at 3:53 am
  
  Ron,
  
  The reason I never answered that part of your question is that I don’t really know and didn’t feel qualified to say — I’m a historian, not a mechanic or a tuner.
  
  If I correctly glean the essence of your question, it amounts to, “Are MacPherson struts (or modern suspension components in general) fundamentally flimsier than conventional shock absorbers for a given application?” Considered as purely as a damper, a MacPherson strut is not fundamentally *different* from any other shock absorber, so I would assume that you would specify a thicker piston rod for the same reasons you would in a conventional shock absorber — for applications where you need greater bending stiffness. (It’s the diameter of the piston, not the piston rod, that actually affects damping rates.)
  
  Modern automotive engineering benefits from a high level of sophistication in load/stress modeling — you can estimate with a pretty impressive degree of precision how much stress a component is going to undergo without ever having an actual piece of metal in hand and thus avoid using more metal (and adding more weight) than you need to achieve the desired level of strength. That’s particularly important for suspension components because they directly affect the vehicle’s unsprung weight, which has a substantial impact on ride and handling. The trickier question, of course, is what the manufacturer has decided is an acceptable level of strength. Most modern SUVs and trucks, even ones with 4WD, are rarely driven off-road and there’s a lot of consumer pressure for them to ride and handle like cars, so it’s counterproductive to use massive serious-off-roader shocks except as part of some optional H-D or off-roading package.
  
  So, I would say in general (a) no, I would not assume that because suspension components look slimmer and/or are made of aluminum or other lighter materials they are necessarily going to crack or break in normal, real-world use, but (b) I wouldn’t necessarily assume that the manufacturer’s definition of normal, real-world use would encompass severe off-roading. That said, ANY component may break if it’s subjected to forces beyond what it was expected to endure (or in ways it wasn’t designed to endure — just like a nail is not really designed to resist bending), and even super-ultra-heavy-duty off-road components aren’t indestructible if you whack a boulder or a curb at high speed.
  
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