Chuck,
I feel myself being drawn inexorably into the ranks of the Blind Men's Elephant Club. I think this thread has about run its course, though.
I'm not saying the tire isn't hugely important. I'm not suggesting we could ride around without tires. I am saying that in comparing one wheel against another, the tire is a factor that needs to be neutralized so it does not confuse the issue of which is the better wheel. I'm saying that assuming the tires are properly sized and properly aired up, the wheel with the stouter rim section is going to be stronger and more durable. This isn't anything radical or brilliant. The rim makers traditionally offered "strada" and "corsa" rims. The corsa rims were lighter because they were intended for the smoother, track environment. Strada rims were heavier to stand up to the rigors of the streets and roads.
John Hurley
Austin, Texas, USA
From: Pacific Coast Cycles [mailto:paccoastcycles@sbcglobal.net] Sent: Thursday, August 27, 2009 12:38 AM To: classicrendezvous@bikelist.org; John Hurley Subject: Re: [CR] Strong, Longlived Wheels
I agree with John Hurley that much of what we understand is more alike than the way we end up putting it into words.
There is some vaguely worded stuff in there for sure, but something that isn't in any way vague is off base by enough that I feel it needs to be addressed. John says that when it comes to handling potholes the main factor would be rim cross section. Not even close. It is easy to understand that a tire is the first thing that meets the edge of any obstacle. If we overcome the tire's cushion, which is to say, we bottom it out and the rim is thereby taking the blow, the cross section of the rim won't make much difference.
Most rims for the last 25 years have been very "hooked bead" in design. They normally respond to edge overload by dinging the hook area. It is soft enough, admittedly because of its cross section that in mild cases, it will save the overall section of the rim from deforming. Still, it will cause uneven braking. A thicker bead catching section, typically used on single wall rims will usually deform the whole rim even in a mild impact.
One way to illustrate the point that it is tire cross section and not rim cross section that has great effect on impact resistance is the mountain bike tire/wheel combo. If you haven't ridden both, you can't be expected to understand this example, but just put a real skinny tire on your skinny mountain bike wheel and do your regular ride intensity and you will have a graphic example of what the tire does.
Chuck Hoefer
Vista, California USA
From: John Hurley
I mean, shouldn't the question should be which wheel performs better given the same tire? When it comes to handling potholes, I would think the main factor would be rim cross-section.
With all these variables in play, it is no wonder that theories abound, some of which border on superstition.
John Hurley
Austin, Texas, USA
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